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nick-f1
10-04-2004, 12:36 PM
Hi, I have read several threads regarding unleaded fuel and the ecu, can anyone tell categorically that the ecu will degrade performance on a standard vr4 engine? I ask this because my Legnum had been run on unleaded before I had it and putting 98 ron fuel in now makes no appreciable difference. If I reset the ecu by disconecting the battery for a minute on 98ron fuel will this make any noticable difference to the performance? Bearing in mind its totally standard. Please excuse my ignorance on this but, there is a lot of conflicting info on this forum regarding this topic.

Thanks
Nick :undecided

ileonc
10-04-2004, 07:24 PM
Hi, I have read several threads regarding unleaded fuel and the ecu, can anyone tell categorically that the ecu will degrade performance on a standard vr4 engine? I ask this because my Legnum had been run on unleaded before I had it and putting 98 ron fuel in now makes no appreciable difference. If I reset the ecu by disconecting the battery for a minute on 98ron fuel will this make any noticable difference to the performance? Bearing in mind its totally standard. Please excuse my ignorance on this but, there is a lot of conflicting info on this forum regarding this topic.

Thanks

Nick :undecided


Basically the higher the Octane rating, the more 'resistant' to detonation under compression a fuel is. A litre of Unleaded 95 and a litre of 98 have the same 'energy', its just the resistance to detonation thats different (or different cleaning chemicals in optimax etc etc)

If you run a higher octane rating on a reset ECU the boost can be higher (since the fuel / air mix won't detonate and do damage to engine bits), if you run normal unleaded the ECU will retard the boost so the fuel / air mix won't detonate since its resistance to detonation is low.

In a nutshell, fill up with Optimax, go through a tank(if you have normal unleaded in there too) and then reset the ECU on the next one, you should have full boost!

Brind
10-04-2004, 07:36 PM
What it feels like:

The accelerator should be very sensitive and the slightest touch should send the car off like a bat out of hell.

If the ECU has shut down you'll find it isn't quite so irratic and you need to push the pedal down about an inch to really get it moving, not very fast but just moving normally.

Run the old stuff out and fill with a super unleaded fuel (Optimax is best IMO) then remove the power from the car for at least 30 seconds to a minute and it will be back to its bat out of hell self.

nick-f1
10-04-2004, 08:29 PM
Thanks Ileonc and Brind for yr replies, this makes things much clearer. I wasn't sure if this boost cut by ecu only happened if boost had been increased by tuning goodies. I will do as you advise and see what happens, the car feels pretty rapid anyway but not faster than my old rover turbo (205hp). So hopefully will see some improvement in a week or so. Got to go to Newquay next friday so look out the Devon exprssway!

Thanks again
Nick :-D :-b

wirdy
10-04-2004, 10:22 PM
then remove the power from the car for at least 30 seconds to a minute and it will be back to its bat out of hell self.

Just to add, when I do this my car runs like a bag of $hit for 10-15 minutes (especially if you are in town, but not so noticeable on the open road), erratic idle, anti-stall cutting in all the time. Take it easy after ECU reset, let it re-learn at a steady rate & after 10-15 mins you should notice the difference when you boot it :)

SGHOM
10-04-2004, 10:50 PM
Take it easy after ECU reset, let it re-learn at a steady rate & after 10-15 mins you should notice the difference when you boot it :)
now I am confused ???
I thought that after resetting the ECU, [ disconnecting battery ] you were supposed to go out & thrash the nuts off the car, so that It "learns" you driving style, & adapts the gearchange/throttle response etc ??
someone clarify ??

Brind
10-04-2004, 11:00 PM
Just to add, when I do this my car runs like a bag of $hit for 10-15 minutes (especially if you are in town, but not so noticeable on the open road), erratic idle, anti-stall cutting in all the time. Take it easy after ECU reset, let it re-learn at a steady rate & after 10-15 mins you should notice the difference when you boot it :)


Mine never does this at all.

Revs the same, idles the same, sounds the same, put your foot down and it is completely different! it's almost a different car.
The ECU cut back really makes alot of difference, at least on mine anyway.
In fact when mine was first reset I almost stacked it into a roundabout! as the power caught me completely unawares! :$ :$

Bare in mind I only have a filter and backbox which isn't standard.

Spirit
10-04-2004, 11:01 PM
Got to go to Newquay next friday so look out the Devon exprssway!

Oh don't worry Nick, it's quite used to the perils of a VR4 - as I live in Plymouth ;)

If you get to experience it, one of my favourite bits is going up Haldon Hill towards Exeter - great if not too much traffic and you can floor it at 80+ up it :-D :-D :-D

Spirit
10-04-2004, 11:04 PM
Just to add, when I do this my car runs like a bag of $hit for 10-15 minutes (especially if you are in town, but not so noticeable on the open road), erratic idle, anti-stall cutting in all the time. Take it easy after ECU reset, let it re-learn at a steady rate & after 10-15 mins you should notice the difference when you boot it :)

Have to agree with Brind, I have reset my ECU on numerous occassions and never had any issues at all - works fine immediately. And thats with induction, de-cat, Super Drager and boost controller fitted ;)

Brind
10-04-2004, 11:06 PM
now I am confused ???
I thought that after resetting the ECU, [ disconnecting battery ] you were supposed to go out & thrash the nuts off the car, so that It "learns" you driving style, & adapts the gearchange/throttle response etc ??
someone clarify ??

Why would you want to do that?

It learns your driving style for sure, unless you blat the car everywhere it will learn your average driving style.
The engine ECU will learn regardless.

I've never had any issues, pull the plug connect it again and then drive off and notice the instant power you now have.

wirdy
10-04-2004, 11:47 PM
It learns your driving style for sure, unless you blat the car everywhere it will learn your average driving style.
The engine ECU will learn regardless.

Crikey, perhaps I've got the wrong end of a huge stick here then.

I thought it was just the tiptronic that learnt driving styles :$ .
When I said 'take it easy' I was really just saying don't wrag the ar$e off your car because that may cause knock and make your ECU to back off again.

Maybe someone with a better knowledge of the Mitsi ECU could put us all right on this...I thought the ECU reset just speeded up the process of resetting the ignition timing to 'normal' (when it sensed no knocking) and that if you left it alone it would do this on its own anyway, but it would take alot longer? This being the reason for the 'feel' of better performance, rather than a slow increase again which not be so noticeable?

Spirit
10-04-2004, 11:53 PM
No you are right mate, it is just the gearbox ECU that learns your driving style (the Invecs II) and the engine ECU is as you described - well, from my understanding too

Brind
10-04-2004, 11:56 PM
I was answering Derek.

The engines ECU is different to your Tiptronic's ECU.
The engines ECU will learn regardless, blatting it won't make any difference.
If you blatt it, your Tiptronic's ECU will learn that style.

Cross purposes I think...

wirdy
11-04-2004, 12:05 AM
Cross purposes I think...

Noted ;)

nick-f1
11-04-2004, 11:24 AM
Great info guys - thanks very much. Just one question more at this stage- is it possible to reset ecu other than by disconnecting the battery? Reason being is that I don't have the bumpf for the pioneer cd system and don't know if it will need a code or not. Its a face-off so it shouldn't in theory?
As to driving will take it easy after reset- just in case- and mines a manual shift so no probs there. And Pete- Haldon Hill is great especially coming back home-- that long sweeping bend at speed............ brilliant.......as long as theres no prat in his bl**dy volvo in the way! Thats the only enjoyment I get going to the wifes family....... is the trip there and back! :cool1: :-b

Cheers
Nick

Spirit
11-04-2004, 11:32 AM
No other way to reset the ECU that I know of Nick, sorry.

If you do need a code for your stereo (and as you said with a face off I doubt it) then there should be a local specialist who can get it for you - Turnbulls Radio in Plymouth can, and I know a couple of local dealers who actually use a mobile guy who has never failed to crack a code yet :-D

If you are coming past Plymouth on the way down or back and fancy a coffee then give me a shout - my home is always open to CVR4 members ;)

nick-f1
11-04-2004, 11:50 AM
Thanks Pete for the invite, I might just take you up on that- we go thru Plymouth both ways so will see how much time we have. I will have the kids as well tho'-Family wedding , so depends how early I can get away sunday. Also I'll start writing out my list of questions now -Ha ha.

cheers
Nick

Spirit
11-04-2004, 11:55 AM
Dont worry about the kids mate, I have an 8 year old too ;)

Sunday would be better for me as working on Friday. If you think you may, then PM me and I will send you my mobile number. Do you know where the Plympton turn off is? We are litterally 2 minutes from there so not much of a detour from your route

Pete

nick-f1
11-04-2004, 12:56 PM
Yep fine know it well- a mate of mine used to live in plympton. I don't know how early I'll be leaving friday anyway yet- car goes in for cambelt thursday, so if there are any problems ie: waterpump or idler/tensioner I might not get it back 'till friday sometime- if then. Will know more during the week so will pm u then with my mobile no or do u have it? can't remem.ber if i put it on the form or not

Nick

Nick VR4
11-04-2004, 06:57 PM
Off topic I know
I use to drive to Plympton every few weeks a few years back
Had a company doing work for me there use to stay at Kitley Hall or Boringdon Hall
Plympton nice place as is Plymouth :-D

Brind
11-04-2004, 08:52 PM
On topic again.. :)

You could try whipping out likely fuses, eventually you will get it.

This way you can be sure of leaving in the fuse to your radio and even the alarm (ELITE 3) which needs to be disabled before taking away its power aswell.

nick-f1
11-04-2004, 09:31 PM
Had actually thought of that but a bit trial and error. My alarm is cobra but thats the same isn't it? By disabling do you mean disarm Brind? I will have to check yr instructions ( thanks for that posting by the way I haven't got those either) in members area.

Nick

Brind
11-04-2004, 09:46 PM
Yeah it is the Cobra alarm, just had a funny five minutes and posted them up, quite a few people have been asking about this alarm.

You have to put it into Valet mode, just disarming it won't work and it WILL sound if you remove the power!! trust me it did when I first removed the power and having your head stuck under the bonnet as it starts sounding is NOT very amusing! :rolleyes5

zedy1
11-04-2004, 11:00 PM
trust me it did when I first removed the power and having your head stuck under the bonnet as it starts sounding is NOT very amusing! :



i ave to do that everyday :D