Stalling when in drive auto? Any ideas

[Louis]

Hi folks.
I’m out in car all is good. I park for 40 miniutes afyer a 20 minute drive.
I start the car and all is good.
It revs freely in P and in an.
I put it into drive and start to drive off and it starts to stall.
I won’t go over 2k revs and stutters and stalks when I try and drive.
If I try and hold four steady AR 2k to progress it does kind of lunges, surges.
I’m going to park up and grab a coffee and come back to it.
Any ideas or experience of this appreciated, cheers Louis

[Louis]

When in drive it cuts out at about 1200rpm when I try to drive off, same in reverse. In neutral and park it revs as normal!.

[Amonlym]

heat soak issue? does it get better after a minute of idle or so?
any warning lights or different sounds?
is it the same in tiptronic and drive?
check oil level in box also

[peter thomson]

Fuel pump failure. Similar to issue I had or filter blocked

[glyn]

this was the first issue I had with a failing autobox, but at the sametime I had issues with a wheel sensor, the abs was just applying the brakes to one wheel randomly, I ended up pulling the abs fuse, your issue maybe tcl related if its not a fuelling issue, you can get rid of the tcl by plugging up the two vacuum lines at go to the grey canister from the throttle body, and also pull the abs fuse, and see if it still does it, you could do with a battery disconnect, ive also had a similar issue with the clip coming offthe throttle body, not all of these things bring up warning lights, if you do have a failing fuel pump or blocked filter theres a easy way to find out, just pull a spark plug and look at the colour/state of it, its reallt obvious when a car is running lean, ive had all sorts of issues over the years and they have all had similar symptoms, sorry if ths isn't clear!

[Louis]

HI Guys, Thanks for the suggestions.

It revs freely with no problems in park.
It revs freely with no problems in Neutral.
I put it in Drive, or Reverse and as I push the accelerator pedal it gets to 1000rpm and sort of cuts, the rev counter needle drops down and it starts to stall.
If I feather the pedal I can keep it at 1000 rpm and move, but it cuts as soon as I try and drive normally.

It does not get better with idling.
If I switch off and leave it 15 minutes and try again, all is normal.
No warning lights until the revs drop and it starts to stall.
When it doesn't happen everything is fine, no issues!.

Could be a heat issue?, but it doesn't happen all the time.
happened a couple of weeks ago, then fine for 5 days, then it happened last week and was fine and it happened again today, and is now fine.
I have a walbro 225 lph pump, in there for a few years but never any issues.


Please see video attached below (youtube link) (too big to load here).

https://youtu.be/gc_DZ3AeiR8


cheers Louis

[glyn]

just watched the vid, it looks like youre gonna have to remove tcl from the equation, there are two vac lines headed from the throttle body to the tcl canister, pull them off and put a bolt in each hole and then see what it does, are there any random quiet grinding noises when youre pulling up to a stop ?

[Amonlym]

Im sure i read a post recently about the loom above gearbox/transfer box getting pinched by movement due to worn out mounts, causing all kinds of bad behaviour. worth a look?
will it rev up more than shown in video? 5-6K?
how does it respond to hard steering inputs, AC on full, high electrical load and being revved?

[Louis]

just watched the vid, it looks like youre gonna have to remove tcl from the equation, there are two vac lines headed from the throttle body to the tcl canister, pull them off and put a bolt in each hole and then see what it does, are there any random quiet grinding noises when youre pulling up to a stop ?

I will try bypassing the tcl to see, but I may need to wait until it happens again as it is fine most of the time!.
No Grinding noises, all else working fine.

[Louis]

Im sure i read a post recently about the loom above gearbox/transfer box getting pinched by movement due to worn out mounts, causing all kinds of bad behaviour. worth a look?
will it rev up more than shown in video? 5-6K?
how does it respond to hard steering inputs, AC on full, high electrical load and being revved?


I will check for pinched loom.

Engine mounts are polybush, so they are solid.
It will rev as normal right up
Hard steering no problem.
AC on full no issues.
electric load etc all good.
I have a 680A 75AH battery and a 120amp alternator.

[Atik]

Fuel pump failure. Similar to issue I had or filter blocked

I'd look at this one.

[Louis]

Re fuel pump:
It revs fine. In neutral, ticks over normal in neutral.
It’s only when I put it in drive or reverse the the revs drop, idle becomes uneven and it stalls when I try to pull away.
Put it back in park or neutral it ticks over fine and will rev freely to red line, no issues.
Would putting it in drive or reverse put the fuel pump under more strain and cause a fault???.
Thanks for input.

[Amonlym]

Hi Louis,

Yeh, drive / reverse apply a fair amount more load to the engine. This is what i was trying to check with the steering and ac and electrical loads - these would also increase engine load. And all of these should adjust the idle to compensate for that load - but in different ways which might have helped identify a different issue too.

The alternator load is entirely ECU controlled, it measures the voltage and changes the excitation in response. I believe the normal idle control loop of the ECU is used here to adjust the idle back to normal rpms.
The PS has a pressure operated vacuum switch which then bumps up the engine speed to high loads, if it doesn't work properly the car will tend to stumble when the steering is moved at idle
The AC has an ecu controlled ISC adjustment that is stepped in based on the AC loading.

Maybe you have an air metering issue? Have you tried unplugging the MAF to force the car to the tables, see if that helps? Listening for the sound of the fuel pump is also worth doing as mentioned by the others, pull up the rear bench. you should hear it fairly clearly thru the access panel. Get a volunteer to cycle key a few times and you should hear it cycle on/off.

[Louis]

Hi Jake,
Yes, I know where you are going with the electrics, but all electrics are in good shape, no dimming lights or voltage drop when accessories are switched on etc.

I am going to check all my small vacuum lines as I am guessing there may be something there!.

I will try unplugging mac, it won't run without it, but will let it stumble and then disconnect battery and try it again.

cheers :)

[Nick Mann]

The fuel pump has to flow a LOT more when under load. As such, based on some tables in the ECU (throttle position, load?) the fuel pump relay shoves 12v in rather than the 7v used at idle. Maybe the fuel pump is ropey, maybe the relay is ropey? Good luck finding it - intermittent faults are fecking annoying!

[Louis]

Hi,
still waiting for it to do it again (I agree about intermittent faults being a PITA)
I have the relay jumped so the pump gets full voltage all the time.

I will have to wait until it does it again so I can check a few things

[elnevio]

Stock fuel pump Louis, or after market?

[Davezj]

It sounds like something heat soaked in the engine bay, do you have a spare IFS (Ignition Fail Sensor) to swap out, the one on the top of the front rocker cover. it will take 5 mins to swap out worth a try.
i have a spare i can send you to try but i am not sure the post office wil stillbe running a few days time so it might not be possible to send.

[rajvr497]

Had an issue like this in the pass, it was the air flow sensor at fault, also do a boost leak test.

[Davezj]

you can check the for a MAF issue by just unplugging the MAF and going for a drive the ECU will just use some basic fueling tables to keep things safe. but if it drive you will know you have a MAF issue.

[glyn]

just as an update, I have just had a similar issue and mines manual now, no lights or anything and I swapped my fuel pump out for a walboro prolyl 2 months ago,i chages this issue down to a vacuum leak, it was intermittent I literally pulled over on the way to work and searched roadside for it while it was doing it, the vacuum leak was the tcl solenoid, it works fine and tests fine until it gets hot then it holds open, so maybe have a look at the tcl solenoid or the next time its doing it just plug the hole on the vent for the tcl solenoid, not sure if this will help you but I thought it might be worth noting.

[Louis]

Thanks Glyn, It hasn't happened again yet, but I have a list to things to check when (if) it does, cheers Louis

[Braddy40]

Hi folks.
I’m out in car all is good. I park for 40 miniutes afyer a 20 minute drive.
I start the car and all is good.
It revs freely in P and in an.
I put it into drive and start to drive off and it starts to stall.
I won’t go over 2k revs and stutters and stalks when I try and drive.
If I try and hold four steady AR 2k to progress it does kind of lunges, surges.
I’m going to park up and grab a coffee and come back to it.
Any ideas or experience of this appreciated, cheers Louis

My Legnum suffered with exactly the same symptoms two days ago except mine was from a cold start and after standing in my garage for a week.
Revs great in park , but pulling away with even the slightest pedal in drive or rev felt like it was starving the fuel and stall..
If I did manage to get it moving it was fine under constant acceleration at speed ( I guess less strain under motion) but problem returned when having to stop and pulling away again .
Good plugs, battery, connections ,wiring, air filter clear. Fuel pump may be the issue but no past signs of issues going up steep hills.
It fortunately cleared after persistently trying to drive for half an hour in a car park . Symptom suddenly cleared as if there was crap in the fuel system and problem hasn't returned (yet)
Just ordered a new fuel filter and will be adding redex or cataclean to the fuel. Typically wont know if this will fix the problem unless the problem returns in the near future.
Has your problem returned since?

[Louis]

Hi Simon,
I never got to a full conclusion, what I did do was go through my small vacuum hoses and replaced a few of them that were loose on the pipes. I also changed for a new ifs ignition fail sensor as they are known to give up and cause problems.
I also found a crack in the plastic pipe that comes off the rear of the front rocker cover ( beside the ifs).
It hasn’t done it since, so it could have been any of those things.
I did suspect a coil pack but haven’t changed them and it hasn’t happened again.
Other poss causes in thus thread are worth checking as others have had similar problems and found these other causes to be the case.
:)

[Braddy40]

Hi Simon,
I never got to a full conclusion, what I did do was go through my small vacuum hoses and replaced a few of them that were loose on the pipes. I also changed for a new ifs ignition fail sensor as they are known to give up and cause problems.
I also found a crack in the plastic pipe that comes off the rear of the front rocker cover ( beside the ifs).
It hasn’t done it since, so it could have been any of those things.
I did suspect a coil pack but haven’t changed them and it hasn’t happened again.
Other poss causes in thus thread are worth checking as others have had similar problems and found these other causes to be the case.
:)

Thanks for the reply and help Louis. Good to hear your problem hasn't returned. Cheers.

[Braddy40]

Unfortunately a new fuel filter and cataclean additive didn't fix the problem as the stalling while pulling away in Drive issue suddenly returned last night after a month . As before after half an hour of trying to pull away and reverse suddenly cleared the problem to get me safely home.
Am going to try the TCL solenoid option next. Would anyone be able to help point out exactly what hoses are worth cleaning out or blocking off for testing as some go to the vacuum solenoid and others to the grey barrel. Sorry for my lack of knowledge on this, I don't want to block off the wrong ones when testing or disconnect and clean too many pipes.
I also noticed that Viamoto is selling MD165142 Emission control solenoids, is this the same as a TCL vacuum solenoid ?
Many thanks in advance

[Braddy40]

you can check the for a MAF issue by just unplugging the MAF and going for a drive the ECU will just use some basic fueling tables to keep things safe. but if it drive you will know you have a MAF issue.

Intermittent issue reared its ugly head again last night. Was hoping that the new fuel pump fitted by Dave at the last garage day over a month ago fixed the problem.
Also recently replaced Fuel filter, spark plugs and new injector seals.
Decided to test the MAF sensor today and unplugged it with the engine running and went for drive. Was expecting it to cut out but only ran a little richer.
Should it be able to do this as looking at online videos show the engine immediately cutting out when disconnecting on other cars highlighting a failed MAF sensor?

[Confused]

With the MAF unplugged, it falls back to a very basic Throttle Position Sensor based airflow table, which allows it to continue running, even without a valid MAF signal.

This is very useful, as it gives us a common troubleshooting technique for these cars - if it improves without the MAF, then the measured airflow isn't matching what the engine is seeing. Quite often this is an air leak (loose pipe, damaged intercooler etc), but sometimes it can be the MAF itself has failed.

[Braddy40]

With the MAF unplugged, it falls back to a very basic Throttle Position Sensor based airflow table, which allows it to continue running, even without a valid MAF signal.

This is very useful, as it gives us a common troubleshooting technique for these cars - if it improves without the MAF, then the measured airflow isn't matching what the engine is seeing. Quite often this is an air leak (loose pipe, damaged intercooler etc), but sometimes it can be the MAF itself has failed.

Hi, thanks for the quick reply and help. I wouldn't say it improved but definitely wasn't worse.
Being an intermittent problem I am always having to trying to fix a problem while the car is running ok as the stalling and stuttering last night lasted around 30 min or so and clears as quickly as it appeared. It could return in a week or a month after driving most days.
I did take a look at the sensor and it looked quite clean but didn't have the appropriate cleaner to do the job properly and instead put it back together and took it for a drive.
Have been noticing recently that if I rev the car in park and quickly take my foot of the pedal it idles very low and sometimes stalls. Could be connected.
Probably worth me giving it a clean or hopefully get a replacement.

[Braddy40]

Could anyone suggest a preferred good mass air flow sensor cleaner.
Saw a couple on ebay 'Liqui Moly Air Flow Sensor Cleaner' and 'CRC Air Sensor Clean' among others but not sure if is safe for our cars.
Many thanks.

[Braddy40]

Cleaned the MAF sensor today with 'Liqui Moly Air Flow Sensor Cleaner' hoping to eliminate problem but issue remained.
I only disconnected the battery for a couple of minutes after cleaning it so disconnected again for 15 minutes and now it is running ok. ( for now)
Does it usually need a 15 min disconnect to set things right with a MAF clean?

[hbkuk1]

This is going to be your stepper motor (idle control valve) for sure
Get a new one and install it it may still stall a few times until it learns it’s new idle

[Braddy40]

This is going to be your stepper motor (idle control valve) for sure
Get a new one and install it it may still stall a few times until it learns it’s new idle

Thanks for the advice Rich. Good to hear as that was my next step. Bought one recently from Viamoto but wanted to try and isolate the fault rather than trying too many fixes at once. Cheers.

[Braddy40]

Gutted, problem returned! Cant believe it! Very close to giving up!
Staggered, Stalled and broke down again this morning after a couple of weeks of perfect performance thinking that cleaning the MAF and replacing stepper motor fixed the problem. Problem always happens from cold and always seems to fix itself when the engine naturally gets to its hotter temp .65-95. There seems like a slight sudden change in tone as it improves.
Was stuck on the road side for an hour and now its running perfect again, and probably will for a couple of weeks until I least expect it .
I have now replaced old for new Fuel filter, Fuel pump, spark plugs, injector seals, boost and vacuum solenoids, stepper motor and had Dave's Boost leak check,. Even removed the Blitz BOV and replaced the lower recirculation valve to improve the idling. And every time thinking there was a slight improvement!
I am still thinking it might be the MAF sensor as I only cleaned rather than replaced and while I was on the roadside disconnected the MAF and it did run better to limp me home.
Please, please , PLEASE, does anyone have a spare MAF sensor for sale?
Even if it was a a loan, long enough to find out if the problem returns.
Any help would be greatly appreciated as I don't know where to turn and what else to replace!

[Confused]

I'm going to throw temperature sensor in as a potential fault.

There's two - a two-pin one drives the dash, a single-pin one drives the ECU.

If you can get some logging set up with EvoScan (HOWTO: Log from your ECU for less than £30 (https://www.clubvr4.com/forum/showthread.php?76811-HOWTO-Log-from-your-ECU-for-less-than-%A330)), and monitor the coolant temp - I wonder if this is maybe incorrectly reporting sometimes, either due to a bad sensor, or dodgy wiring...

A new sensor is available from Viamoto (https://www.viamoto.co.uk/proddetail.php?prod=Engine+Coolant+Temperature+Sen der+-+Mitsubishi+Legnum%2FGalant+VR4) pretty cheap!

[Braddy40]

I'm going to throw temperature sensor in as a potential fault.

There's two - a two-pin one drives the dash, a single-pin one drives the ECU.

If you can get some logging set up with EvoScan (HOWTO: Log from your ECU for less than £30 (https://www.clubvr4.com/forum/showthread.php?76811-HOWTO-Log-from-your-ECU-for-less-than-%A330)), and monitor the coolant temp - I wonder if this is maybe incorrectly reporting sometimes, either due to a bad sensor, or dodgy wiring...

A new sensor is available from Viamoto (https://www.viamoto.co.uk/proddetail.php?prod=Engine+Coolant+Temperature+Sen der+-+Mitsubishi+Legnum%2FGalant+VR4) pretty cheap!
Hi Garry , many thanks for the suggestion. I will definitely try this out and contact Mike/Viamoto regarding the part. I didn't try this option out as I thought this would only effect the car when hot but being such a cheap part its silly not to at this stage, and then move on to trying to get an accurate diagnostic . Was even considering phoning around Mitsubishi dealerships to see if their mechanics still owned or had access to MUT II. Thanks again and fingers crossed.

[Confused]

Finding someone with a MUT II won't do any more than a paperclip and flashy dash, or EvoScan for data logging - other than cost you a substantial amount more money! No Mitsubishi dealer has anyone working there any more who worked there when these cars were new, that's if they even knew what they were in the first place, anyway!

[Braddy40]

Finding someone with a MUT II won't do any more than a paperclip and flashy dash, or EvoScan for data logging - other than cost you a substantial amount more money! No Mitsubishi dealer has anyone working there any more who worked there when these cars were new, that's if they even knew what they were in the first place, anyway!

Hi. Contacted the south Wales Swansea Mitsubishi branch earlier today and they asked me to contact them in the new year to see if they could get the MUT II up and running and that they also had a Mechanic there that had been working for them for 40 years! Probably meant they had someone working there that was over 40 years old :))
You just saved me £85 and managed to do the 'flashy dash'. Discovered all had lights had constant short flashes which I guess means no faults found. Probably need to try it again when the actual stalling fault returns. Will have a paperclip on the ready.
Have also ordered the two temp sensors from Mike. ( something to keep me busy over xmas :) Cheers.

[Davezj]

I'm going to throw temperature sensor in as a potential fault.

There's two - a two-pin one drives the dash, a single-pin one drives the ECU.

If you can get some logging set up with EvoScan (HOWTO: Log from your ECU for less than £30 (https://www.clubvr4.com/forum/showthread.php?76811-HOWTO-Log-from-your-ECU-for-less-than-%A330)), and monitor the coolant temp - I wonder if this is maybe incorrectly reporting sometimes, either due to a bad sensor, or dodgy wiring...

A new sensor is available from Viamoto (https://www.viamoto.co.uk/proddetail.php?prod=Engine+Coolant+Temperature+Sen der+-+Mitsubishi+Legnum%2FGalant+VR4) pretty cheap!

garry isn't it the other way round the single pin sensor drives the dash and the 2 pin sensor drives the ecu input.

it doesn't really matter about the the dash sensor, you could disconnect that one and it would only effect the the gauge on the dash, but the ecu temp sensor failing can mess up the fueling, depending on if it fails short or open.
i can remember off hand which way round it will be but one method of fail will signal the ecu that coolant temp is permanently hot or it will signal the ecu that the coolant is permanently cold.

fail showing hot will cause issues as the car warns up as it will cause lean fueling i think.
fail showing cold will cause issue once the actual coolant temp is hot as it will continually over fuel the car as the ecu thinks the engine is not warm and need the extra fuel that is initially fed to the engine to make cold starts smoother.

but as you have an intermitant failt it is probably the wiring going to temp sensor rather than the sensor itself.

[Confused]

You might be right, Dave, in that it's the 2 pin rather than 1 pin.

The one I linked is correct for the ECU.

[Tony_T]

If it turns out to be the MAF, cleaning won't do anything. Please read this post I made on the OZ VR4 forum from when I traced and repaired the fault on one of mine, it's really a quite simple repair so here's a copy and paste:

The hardest part of the repair is getting the top lid off without breaking any of the four little plastic tabs which hold it on. In my case it seemed that there could have been a bit of silicone sealant also keeping the lid on which made it harder so I ended up breaking two of the tabs and having to improvise some clips to take their place. So, remove the MAF from the car and if you like, dismantle it from the plastic airway parts to make it easier to handle. Then remove the lid. Under the lid you'll see a metal shield which is held in place by springy tabs. Just ease the shield out, try not to bend it so it will fit back nicely later.

NOTE: the purpose of the shield is to prevent any radio frequency signals nearby from affecting the operation of the MAF. Test at idle with it removed but DO NOT take the car onto the road without it in place: I do not accept responsibility for any crashes caused by sudden changes to the car's operation while driving due to some nearby radio emission e.g. your cellphone!!!!!

Our MAF works by the incoming air, which has had turbulence caused by the special inlet and shaping, passing over two heated wires causing their temperature to vary. As with most metals the electrical resistance of these wires is temperature dependent so we have a variation of resistance in response to the airflow. To allow this resistance change to be measured accurately the current which flows through the wires to heat them must be carefully regulated. This is accomplished by having a precision resistor in series with each wire, the voltage which appears across this resistor is compared with a reference voltage in some simple electronics and the resulting error signal is used as feedback to the current control transistors. This means that when the car is switched on these resistors also heat slightly due to the current flowing through them, and when the car is switched off again they cool. As with most things they expand and contract slightly with this heating and cooling. They are soldered to copper tracks on a fibreglass based circuit board which has a different amount of thermal variation and this causes stress to be applied to the solder joints at each end of these resistors, eventually causing the solder to crystallize and become an intermittent connection which is very susceptible to vibration. In my case the car would often idle but when any throttle was applied the vibration caused the contact to make and break rapidly giving extra pulses from the MAF to the ECU. The ECU saw this as heaps more airflow and ramped up the fuel to the point where the mixture would not ignite stopping the engine and producing rather a lot of black smoke occasionally.

The repair:

I'm assuming you or someone you'll get to do this for you is confident with soldering of electronic components:

Locate the two larger resistors which are flat rectangular items on the circuit board towards the top right of the board if the socket which connects to the car loom is on your left. Mine had the value 6R2 written on them, I expect all MAF's will have the same value resistors, it could be written 6E2 by some manufacturers. Using a small soldering iron somewhere around 30 to 50 watts power and preferably temperature controlled carefully melt the solder on both ends of one of these resistors and lift it away from the PC board. A pair of fine tweezers may be helpful but don't damage the resistor. You may have to keep heating the ends alternately a few times to get it off (don't force it) unless you have one of the special soldering tools which heats both ends at once.

Don't do both resistors at once as all resistors have some production spread of actual resistance and this has been accurately compensated for at the factory (you'll see some tubular resistors on stand-off legs which have been chosen for exact calibration) so you don't want to mix them up.

Once it is removed, use the iron and some fresh electronics grade resin cored solder (preferably 60/40 leaded not lead-free as it cracks too easily) to reflow and clean the lands on the PCB where the resistor attaches. Then do likewise with the terminations on the actual resistor. When fully satisfied that all is clean and good to go, solder one end of the resistor back onto the PCB, leaving the resistor sticking up at a small angle so the other end is clear of its land on the board (if you're not too familiar with these things, they're not directional so can face either way). Now take a piece of scrap automotive electrical wire and strip it down to get some fairly thin single strands of copper and cut a strand about 5 or 6 mm long. Solder one end of this flat to the free land on the PCB and then curve the other end around to meet the resistor end flat-on. Now solder it. This provides a bit of 'give' by movement of the wire for the expansion and contraction so should help to prevent the problem from happening again. (I didn't do this when I fixed mine, I just soldered them back as they had been on the board and thought of this idea later so I will do it sometime).

Repeat for the second resistor.

Don't be tempted to just reflow the solder on the resistors in place: you won't get to the solder under them and it will be a very short term fix if it fixes it at all.

When you're happy that everything is connected correctly (it's possibly worth gently pulling on the curved wires to be sure they're really soldered properly) then refit the MAF to the car and test with the car stationary and tapping on the circuit board (not too hard that you break something though) with something insulating like a plastic pen to see that there's no change in engine operation at higher revs due to some other problem. All going well, fit the shield in place and go for a test drive (it won't pop out if you got it out without bending the metal fingers). If it passes the drive test then refit the plastic cover, putting some silicone sealant on if you wish (that may also hold it OK if you broke some tabs!) but use neutral cure silicone not RTV as RTV has an acid solvent which will corrode electronics.

Hope this helps you or someone else sometime. Several of the Aussies have done this and reported it fixed their fault successfully.

[Braddy40]

garry isn't it the other way round the single pin sensor drives the dash and the 2 pin sensor drives the ecu input.

it doesn't really matter about the the dash sensor, you could disconnect that one and it would only effect the the gauge on the dash, but the ecu temp sensor failing can mess up the fueling, depending on if it fails short or open.
i can remember off hand which way round it will be but one method of fail will signal the ecu that coolant temp is permanently hot or it will signal the ecu that the coolant is permanently cold.

fail showing hot will cause issues as the car warns up as it will cause lean fueling i think.
fail showing cold will cause issue once the actual coolant temp is hot as it will continually over fuel the car as the ecu thinks the engine is not warm and need the extra fuel that is initially fed to the engine to make cold starts smoother.

but as you have an intermitant failt it is probably the wiring going to temp sensor rather than the sensor itself.

Many thanks for the input Dave.
As I have already ordered both sensors as they were so cheap from Viamoto I will probably go ahead and fit them to at least cancel out yet another possible cause. I will definitely give the wires a good check while changing them.
Not sure if this makes sense but am hoping that the sensor is maybe reading hot or just giving a mixed message to the ECU from a cold start causing an incorrect fuel mix.

[CHESHIRECAT]

Hi Tony, I had a potential MAF fault recently and came across this thread I've had a a look at the circuit board as you suggested. I'm not really sure what to look for when you say crystalised solder. I've taken some pictures there does seem to be some brown stuff as you can see. Notably a couple of the tabs on the cover were broken so it looks as if someone may have been in before. I've taken some pictures maybe you can suggest if these solders need redoing. Thanks Steve.

8329183294832908329383292

[Tony_T]

Please read my description fully.
It's ONLY the two resistors with 6R2 written on them which can be seen clearly in your pictures. They're the only ones which get hot and thus thermally stress the joints. The solder may not look bad but once they are removed it will be seen. Please follow the instructions carefully and exactly or have someone with soldering skills do it for you. I can see that yours have not yet been resoldered even if someone has been in there before for some reason.

[Braddy40]

Hi Tony, Thanks for adding the post for repairing the MAF and mentioning that cleaning the sensor wont fix the problem. The simple repair looks a bit scary to me as I have no confidence in my soldering or electrical skills. Wish you lived a bit closer to fix mine!
Definitely worth fixing as a new one costs around£750. I just worry about making mine worse than it is, not being 100% its at fault anyway.
Hope Steve manages his fix , would be good to hear how it went.

[Tony_T]

LOL yes if you were here I'd surely do it for you. It really isn't as scary as you think, don't you know anyone near you who dabbles in electronics and would do it for you for the price of some of their favourite beverage?

[Confused]

Braddy40 if you're willing to post your MAF to me, and cover the cost of returning it to you, I'm happy to do the soldering aspect of it for you, as per the instructions posted above.

Will mean your car is off the road for a few days whilst it's in transit to and from me.

Garry

[Braddy40]

Braddy40 if you're willing to post your MAF to me, and cover the cost of returning it to you, I'm happy to do the soldering aspect of it for you, as per the instructions posted above.

Will mean your car is off the road for a few days whilst it's in transit to and from me.

Garry

That would be amazing Garry! Many many thanks. Might use the time its off the road to sort out a couple more jobs, weather permitting.
I will PM details etc. And of course also include costs for your time as well as postage costs. Thanks again!

[Tony_T]

Confused that's a great offer you've made to Braddy40 and a good solution for him, thank you. Once confirmed the fault is fixed, would you consider offering the same service to other members who are sufficiently close to you to make it practical? Perhaps for CHESHIRECAT as he was the one who asked first and doesn't seem confident either?
I'd have done the same but it would seem a bit ridiculous to post something all the way from UK to NZ just to resolder four joints. Freight internationally is horrendous both in price and in time delay now due to COVID-19 having stopped almost all flights.

[Confused]

I definitely would be willing to - it looks like CHESHIRECAT has done half the hard work already by removing the cover!

Feel free to PM me if you'd like me to attempt the fix as described.

[CHESHIRECAT]

I definitely would be willing to - it looks like CHESHIRECAT has done half the hard work already by removing the cover!

Feel free to PM me if you'd like me to attempt the fix as described.

Thanks for the offer Garry much appreciated. I spoke to Mike at viamoto recently and he mentioned the diode was faulty on his brothers legnum. I've done a diode test with a multimeter and I think the diode itself maybe faulty. The test guide instructed to remove one side of the diode for the circuit before performing the test which I was unable to do however, so I am not 100% sure if that is the issue. There are some PCB repair shops near me so I will try and get it looked at once they open again.

Thanks also to Tony for your help.

[Braddy40]

Thanks for the offer Garry much appreciated. I spoke to Mike at viamoto recently and he mentioned the diode was faulty on his brothers legnum. I've done a diode test with a multimeter and I think the diode itself maybe faulty. The test guide instructed to remove one side of the diode for the circuit before performing the test which I was unable to do however, so I am not 100% sure if that is the issue. There are some PCB repair shops near me so I will try and get it looked at once they open again.

Thanks also to Tony for your help.

Hi Steve, I also heard that the diode can be at fault and replaced. Was hoping that the soldering fix might be linked to the diode . Found this test in a manual that I haven't managed myself but hopefully will be of some use to you.83328

[CHESHIRECAT]

Ah thats awesome, the manual i have i think only had a test requiring a test loom.

[CHESHIRECAT]

Well I've run the test as instructed. The resistance value at 20c was good and it changed as i heated it, although i'm not to confident on how accurate my probe thermometer is measuring air temp. It seemed slow to react. So the upper reading wasn't bang on. So maybe my diode is ok. Bit strange, i might take it to be looked at anyway.

[Braddy40]

Well I've run the test as instructed. The resistance value at 20c was good and it changed as i heated it, although i'm not to confident on how accurate my probe thermometer is measuring air temp. It seemed slow to react. So the upper reading wasn't bang on. So maybe my diode is ok. Bit strange, i might take it to be looked at anyway.

Well done for running test. Maybe the diode is on its way out if that is possible . Not sure if your cars issues are intermittent as whatever we are testing could be working ok at the time of the test. Getting the suggested soldering sorted is a good move as we are at least canceling out another possible cause.
Would be interested in finding out what the results are if you get it looked at. Cheers.

[CHESHIRECAT]

Well done for running test. Maybe the diode is on its way out if that is possible . Not sure if your cars issues are intermittent as whatever we are testing could be working ok at the time of the test. Getting the suggested soldering sorted is a good move as we are at least canceling out another possible cause.
Would be interested in finding out what the results are if you get it looked at. Cheers.

yes its possible. I had an issue the same as OP that that happened once, but the car has been off the road for the last month. I also seem to have an issue where the revs are not raising as I would expect on cold mornings, which made think it was a MAF issue. I also had a strange experience when changing the idle speed stepper motor, the instructions said to turn the speed adjuster screw all the way in and hold the rpms at 2000 until the engine was warm. then back it out the 650rpm. However when in screwed it in the revs dropped instead of rose, so i backed it out instead but the revs only rose to a max of 1000rpm. I did replace the oring on the screw has its was square and hard but I have not run the car since. So, there is something odd going on I'm just not sure what. I may try measuring and adjusting the stepper motor position manually. I have also checked the ecu temp sensor and that passed ok. I did a flashy dash when the car had the stalling issue and got error codes for MAF and ECU.

If anyone has any insight or ideas I am open to them. Thanks Steve

[Braddy40]

Hi Steve, Focusing on the MAF is probably the way to go for now as we may have similar symptoms with our cars. You may have read further back on the thread that I have replaced most possibilities .
Sounds like you bought the stepper motor from Mike/ Viamoto as he also included a similar guide with mine. I was lucky with fitting mine, keeping the battery disconnected doing the job and when reconnected didn't need to make idle screw adjustment.
BUT I have carefully turned my idle screw half a turn to the left rather to the right to slightly increase my idle as it was quite low also making an accurate start point marker.
Not 100% if this is correct and someone please correct me if I am wrong but It does sound like the FTO, GTO and Evos react better to idle screw adjustments where as our cars don't like it as much.

[Confused]

If you've mucked about with the idle screw, without correctly locking the idle valve using a MUT or EvoScan, then you'll really struggle to get it to idle properly, as you would have always been fighting the ECU adjusting the stepper.

[Davezj]

do you have a link to the thread you did about full idle setup using evoscan to lock the stepper motor and set the idle with the BIST (Base Idle Set ???) screw.

https://www.clubvr4.com/forum/showthread.php?78733-Idle-issues&highlight=BIST+screw

post 10 gives a good description of what to do to set the idle correctly if you have adjusted the BIST screw randomly.

[CHESHIRECAT]

do you have a link to the thread you did about full idle setup using evoscan to lock the stepper motor and set the idle with the BIST (Base Idle Set ???) screw.

https://www.clubvr4.com/forum/showthread.php?78733-Idle-issues&highlight=BIST+screw

post 10 gives a good description of what to do to set the idle correctly if you have adjusted the BIST screw randomly.


Thanks guys, thats bad news. I followed the instructions that were included with the stepper motor. I will look into getting a cable and evoscan. It never ends...

[Tony_T]

Good luck getting any response from the Evoscan guy, the website hasn't been updated in ages, the links for images and diagrams are mostly broken and on many Mitsubishi forums I've read folks are complaining that they sent their payment and got no response. Unfortunately I believe the software needs a serial number from him to activate unless someone has made a crack for it. It may also be tied to certain cables; maybe others here can chime in with their knowledge.

As a last resort, can the stepper motor be manually turned to a roughly midway position and refitted without plugging it in? If so you could adjust the screw for an idle speed which doesn't stall, let the engine warm up fully then adjust it again for a suitable idle, then plug the stepper back in. Would that work?

[Confused]

I have used my serial number on multiple machines over the years, and with different cables, so I don't think it's locked to a specific cable, or requires internet access to activate.


If getting hold of a new copy of EvoScan and a cable proves troublesome, then there are a few of us around who have the cable & software, off the top of my head there's myself in Nottinghamshire, Davezj in Manchester, foxdie and Nick Mann in Birmingham - if any of us are nearby enough to meet up, we'd be happy to assist in getting your idle screw re-adjusted to the factory pre-set position to allow the stepper to work correctly.

[CHESHIRECAT]

Good luck getting any response from the Evoscan guy, the website hasn't been updated in ages, the links for images and diagrams are mostly broken and on many Mitsubishi forums I've read folks are complaining that they sent their payment and got no response. Unfortunately I believe the software needs a serial number from him to activate unless someone has made a crack for it. It may also be tied to certain cables; maybe others here can chime in with their knowledge.

As a last resort, can the stepper motor be manually turned to a roughly midway position and refitted without plugging it in? If so you could adjust the screw for an idle speed which doesn't stall, let the engine warm up fully then adjust it again for a suitable idle, then plug the stepper back in. Would that work?

Hi Tony, yes the motor can be adjusted manually, thanks for the tip. Maybe I can warm it up, then adjust the stepper motor manually, then with it unplugged adjust the idle screw. Hopefully it works better now I have replaced the o-ring. I'm also going to a local community repair group on Saturday to have my MAF PCB repaired, how great is that!

P.S. do you know what it is that the stepper motor is moving?

[CHESHIRECAT]

I have used my serial number on multiple machines over the years, and with different cables, so I don't think it's locked to a specific cable, or requires internet access to activate.


If getting hold of a new copy of EvoScan and a cable proves troublesome, then there are a few of us around who have the cable & software, off the top of my head there's myself in Nottinghamshire, Davezj in Manchester, foxdie and Nick Mann in Birmingham - if any of us are nearby enough to meet up, we'd be happy to assist in getting your idle screw re-adjusted to the factory pre-set position to allow the stepper to work correctly.

Thanks for the offer Garry. That's too kind. It will be a few weeks at least before I'm able to travel with the car unfortunately. I'm balls deep in few jobs on it at the moment, and once those are done I need some welding for the MOT.

[Tony_T]

CHESHIRECAT Doesn't the stepper just move a plunger which blocks or progressively opens an air duct? I haven't seen one from our cars but I remember the one on my 4G63T worked like that. Let us know how the MAF turns out.
Confused I would sometime like to try a copy of Evoscan, I have a cable I bought on Aliexpress for use on Carole's BMW so I that could use BMWscanner 1.40 which could do a couple of things more easily than INPA and the related software could. It worked fine and judging from the driver filename it looks to be a FTDI chipset so it might work with Evoscan if the software can be tricked by using a common activation code. However I've yet to find a copy anywhere to download as all links seem to have broken.
Since Carole has now replaced the BMW (YAY!) with a 2009 Mitsubishi Outlander I do need to get some better Mitsi software going. I found a copy of one year's MUTIII software which I must try sometime with that cable, I also downloaded MMcodingwriter 2.3 since there are so many options which can be changed in the ETACS programming, hopefully that will work too.

[Confused]

Yes, the stepper motor does move in/out to move a plunger, just as you describe. Whether you can manually move it to roughly the right position and adjust... it might get you closer, but I'd still try to do it properly!

[Braddy40]

Hi Tony, yes the motor can be adjusted manually, thanks for the tip. Maybe I can warm it up, then adjust the stepper motor manually, then with it unplugged adjust the idle screw. Hopefully it works better now I have replaced the o-ring. I'm also going to a local community repair group on Saturday to have my MAF PCB repaired, how great is that!

P.S. do you know what it is that the stepper motor is moving?

Hi Steve,
You could possibly give the old stepper a good spray with carb cleaner or wd40 to remove any sooty build up and put back on as it may have needed a clean rather than replace.
I have included some images of my idle screw position (10-12 mm depth) which I realise is a wild stab in the dark but a rough position to work from and might be worth a try if the idling is awful at the moment anyway.
Just thinking that trying both things together might at least get you close to what it was as your original fault might be in the MAF.
Hope it helps and sorry if this isnt such great advice.83338833398333883340

[CHESHIRECAT]

Yes, the stepper motor does move in/out to move a plunger, just as you describe. Whether you can manually move it to roughly the right position and adjust... it might get you closer, but I'd still try to do it properly!

It looks like there is a drive on the end of the stepper motor so I'm wondering if whatever that the stepper motor moves may be stuck. Does the plunger just move in and out or does it rotate?

[Tony_T]

Commenting from a lack of actual knowledge here, but it is likely a worm drive kind of arrangement converting the rotary movement of the motor to linear movement of the plunger, it may not be movable by hand, Confused will likely either confirm or correct that assumption. I wonder if it can be dismantled and cleaned out in case it is full of gunge from the EGR?

[Confused]

There is no EGR on a VR-4, so the inlet actually stays pretty clean! It's only the crankcase breather that gets pulled back into the inlet pre-turbo.

I've given my spare throttle body & stepper motor to foxdie only the other day, but maybe he can have a quick look at what happens to it when he has it on on the bench.

[Tony_T]

Oops, sorry!