Popping un acceleration

[Davezj]

posted in the wrong thread.

[nos monkeys]

that was like what it was when i first brought it.

I have hooked all the waste gate lines back to the stock boost solenoid and also hooked the fuel pressure regulator back up but it still seems to fuel cut at 7psi after a little bit of driving. Could this temperamental fuel cut be a worn fuel pressure regulator? if so how do i check it that? is there any other cause which is why its fuel cutting sometimes at 7psi?

Or could it be a worn boost solenoid making it boost spike which is causing it to fuel cut. should i just by pass the boost solenoid completely ( im not sure how to check if the boost solenoid is working correctly) and just put the waste gate lines directly to a vacuum port so it only runs purely on the wastegate pressure?

[Davezj]

if you bypass the boost solenoid and connect boost directly to the wastegates, you should get a 4-5psi boost and you should not get fuel cut at this boost level
you need to have a working boost gauge and maybe a manual boost controller to play with the boost and check what is happening, boost gauge will be about £15 and MBC for about £20.

[nos monkeys]

i might try it on wastegate pressure and see if it happens, i have a boost controller which came with the car but i need to buy a boost gauge that works which is on my to do list

I have been reading lots of posts on here about fuel cut and it defiantly sounds like that, i also read this comment here "If it was fuel starvation, you'd generally expect a "soft" cut, not the slam of fuel cut. You'll either get timing pulled due to det (not good) or you'll get insufficient fuel for proper combustion...and effectively a misfire."

This is what mine is like, somedays it gets worse than others which is why i thought it was miss firing thinking it was spark related but half the time it is just a soft fuel cut with a little kick.

I'm trying to search up on how to check my fuel pressure regulator and fuel pressure solenoid because maybe one of those is causing this problem, Also i will check my fuel filter and filter on my fuel pump to make sure they are not blocked and dirty. what would happen if i connect the fuel pressure regulator straight upto a vacumm port without going through the solenoid?

I can't seem to find anything on how to check my fuel solenoid or fuel pressure regulator

Also do you know how to check if my coolant temp sensor isnt faulty? because i read that it may be that giving my ecu false readings. is there a way to check it with my multi meter? I haven't got money to buy the cable for evoscan yet so probably cant buy that for a few months. . .

[Davezj]

testing sensors is all in the workshop manual, and for common thing that are on the other 8G family of cars just go through the English manual and double check the value against the Jap workshop manual.

it will not harm to connect the fuel pressure regulator directly to the vac/boost from the inlet manifold/plenum chamber.
but it just means if something goes wrong with the fuelling and the ECU needs to increase/reduce flow it can not change the fuel pressure. this would only be an issue at the extremes of operation of the fuel system.
e.g. cold starts where loads of extra fuel is thrown into the engine to aid start and idle when cold.

[nos monkeys]

sweet thanks, i had a quick look through the manual today but couldnt find how to test them but ill have another look. i just thought if i took it for a drive when it starts fuel cutting then hook the regulator directly up to check if the solenoid is faulty and see if it still fuel cuts. just thought that would be an easy way to check if its the solenoid.

That english manual is much easier to find things lol i found what i need and also found it on the japan version too, will test all the things i can tomorrow. but seems i need to buy a fuel pressure gauge. ill test the things i can without that and before i buy a fuel pressure gauge it seems to be cheaper to buy a kit that has an adjustable fuel pressure regulator with a gauge and all that so might just get one of them anyway.

[Davezj]

i would be very warey of getting one of the really cheap fuel pressure regulator as i now a couple of people that have had them and they have been faulty from the box. either gauge was broken or the regulator did not regulate, it just made the fuel pressure as high as it could and there was no vac/boost control over the pressure, which made the car massively obver fuel and cause issues. but it is better to over fuel than run mega lean.

there are also lots of fake fuel pressure regulators out there in ebay land, SARD and aeromotive. If the say they are new and they look far to cheap they are probably fakes.

[nos monkeys]

iv just checked:

air intake temp sensor
coolant temp sensor
injectors
half checked fuel pressure. This is what i done

"Racing the engine repeatedly, hold the fuel return hose
lightly with fingers to feel that fuel pressure is present
in the return hose.
NOTE
If the fuel flow rate is low, there will be no fuel pressure
in the return hose."

I also tested with the fuel regulator vacuum line off to check if pressure changes and it does. I do really need a pressure gauge to check properly but i might go ask the mitsi shop how much that would be. I also did hold the fuel in line when i reved it and the pressure increased in there so it is increasing in pressure when reved.

So far everything checks out fine but still fuel cuts. and i dont want to drive it when it keeps fuel cutting because my engine is probably running lean and i dont want to melt any pistons

[Davezj]

just try dropping the boost by bypassing the the boost solenoid, i would imagine it is very hot over in NZ at present, so fuel cut will occur at lower boost levels than when the air is cold and dense during winter.

If you drop the boost and fuel cut goes away then you know what to do to get rid of the fuel cut, either run with lower boost in hot weather or get someone to raise the fuel cut level in the ecu. It is not diffuclt to do if you have the right software and cable to do it, it is just one table in the rom

[nos monkeys]

am about to hook the wastegates straight upto a vacuum port so it will run 4-5psi. but it still did fuel cut the other when i first posted it was like 3am freezing cold and raining and still only on 7psi and kept cutting. but will take it out soon and see if it makes a difference

if i get the fuel cut raise wouldnt that be bad if my car is already leaning out? because it would just keep running lean or something

Edit: Connected the wastegate lines directly up and it still does it grrrrrrrrrrrrrrrrrr iv checked almost anything and have no idea what its problem is. do you think if i leave it on wastegate pressure and continue to drive it the engine will be fine or should i try get it looked at again i really want it running 100% though have a dam baby due in july and need this wagon ready so my gf can drive it and shes not a good driver so i need it 100% then i know its not going to break.

[Davezj]

if you are still getting the issue on waste gate pressure, i would very much doubt if it is fuel cut.
can you do a video of the the issue, then diagnosis can be much easier.
what you have to remember is we do't know what you know about the issue, we know what you tell us and if you miss of some key info we will probably give you bad diagnosis.
can you have a think and do a post that covers evrything you have checked and what the issue is and under what situation it occurs, as i would imagine you understand the issue much more now than you did when you started this thread.

have you gone through the thread that was created to cover the basic test to do wen issues occur.
i will see if i have a link to it.

is does not go through misfire but has a lot of good prcedures.
http://www.clubvr4.com/forum/showthr...oost+leak+test

[nos monkeys]

Cheers, and ill try get a video of it once i can spare some money for petrol. some days it feels like a different type of hesitation than others. so it could be more than 1 thing wrong who knows but ill get a video up hopefully soon ill continue to check stuff though

[Davezj]

excellent.

[nos monkeys]

I really need it to rain as well, the 1 day it rained it sort of was worse but im not sure if that was the rain or the 5 hour drive i did. but it sounded like it was missing and arching out. but when its fine and does it during the day it just has a dead spot at 4k rpm then starts to rev again after half a second but when it picks up again it seems as there is lack of power and just revs. but either way ill try get decent video of it happeneing. I'll duct tape my camera under my bonnet somewhere as well to see if the engine makes a noticable sound it shouldnt when it does it