Wtf Is It!!!!!!!!!

[GUY]

hey, well after a few months of of tyrin to do this i am now out of ideas. Heres the problem, I have a 90 AWD talon. The SOB acts like its getting bad fuel cut all the time but everything on the car is stock. i cant get the car to go past 4000 RPM without a bad fuel cut feel. those of you who had bad fuel cut knows what it feels like. I have heard people say its a boost leak but how can a boost leak hit that hard and not make me get past 4000? So i have not given it a boost leak test yet. I know it has a bad fuel sending unit & a bad knock sensor but that should'nt be it? This is what i have replaced, new ECU, new plugs, plug wires, coil pack(used), all new fuel injectors, fuel pump, & i replaced the whole engine harness. i think that is it. if you guys have any ideas let me know asap! thanks, steve.

 

[ndm1]

Try checking the throttle position sensor. A friend of mine had the same problem and after a lot of frustration we finally found it to be the problem.
Hope it is for you too.
Nate

 

[xveganxcowboyx]

I had signiffigant boost leaks and had a really hard time getting it to rev past 3K. I assume it was dumping WAY too much fuel and bogging the engine. Pretty hard to rev when you're unbelievably rich.

 

[oldman]

how can a boost leak hit that hard and not make me get past 4000?

Because it's the ecu cutting off the firing of the injectors that "hit that hard", how is fuel cut triggered you ask? Fuel cut happens when ecu sees a drastic increase in air flow surpassing the pre-programed safety value, it immediately cuts fuel to protect the engine against infinite boost due to a malfunction wastegate. Boost leaks on the other hand have the same effect as run away boost because you're losing metered air very quickly, causing ecu to think you have run away boost.

 

[Ultimatedsm]

Oldman, I can't believe you didn't say it!

BOOST LEAK TEST . Push 20 psi in the intake tract and if it holds around 30 seconds your good to go. If it doesn't, get some soapy water and start spraying your pipes. It has to be a boost leak. If it isn't a boost leak, its a bad MAF.

 

[oldman]

Oh yea. Boost leak test.

 

[eldiabloz13]

what would be the best PSI for a 420 engine.

 

[Defiant]

Spark plugs and wires. Throw away those non-NGK plugs.

 

[GUY]

already replaced those, they are NGKs and MSD wires.

 

[96GSEclipse]

I drive a 96 GS eclipse and from what it sounds like, I have this same problem.. But mine happens at 5000 rpms. It'll happen every now and then at maybe 3500, or 4000... But it always happens at 5000.. I had NGK spark plugs, but I bought a different kind (don't remember) and replaced them, but it didn't do anything. Still does the same damn thing. What's wrong with it?

 

[GUY]

Anyways, mostly everyone who replied told me that it was a bad boost leak & another said it might be a bad MAF. Well the other day I was working on my car and while I was doing it I accidently knocked the + cable off the battery. It was disconnected for more than 15 minutes. So the ECU was reset, I plug it back up start the car and that horrible fuel cut feeling sensation...isn't there? Now I'm pretty sure if there is a hole in one of my intercooler pipes, reseting the ECU won't patch up that hole. So is this a bad MAF? If it isn't what the hell could it be? I have replaced damn near everything that can cause this except...new intercooler and piping which is on it's way or MAF? I have a 3" GM MAF in my closet I could use that but i still need that translator. So yeah LMK what you guys think of this. Thanks in advance.

-Steve

 

[clipse_GST]

hey buddy, your problem sounds alomost exactly like mine. except mine won't let me go past 1500rpms and mine only starts doing that after the car has been running for a while. if you fix the problem before i do PLEASE let me know what you did. and i will let you know if i fix it first. thanks

 

[xcz504d]

Drive your car for 50 miles, see if it comes back. Somtimes resetting the ECU can clear out a problem, resetting the ECU clears out your fuel maps and your octane rating along with many other things. You could have a fualty ECU.

I dont think it's your MAF, because that wouldnt be affected by taking the battery terminal off like that. It would just run like complete crap, very rich or very lean, probably making it undriveable depending on how bad the MAF was acting. But it wouldn't be reset. Drive your car for a week normally like you usually would, it takes a few days for your car to build up it's fuel trims. If it comes back, disconnect the battery again, see if it resets, if it does, see if you can find someone local that might let you swap ECU's for a week, or get a datalogger to see what it's really doing with your fuel trims. You can find ECU's on this site for relativley cheap...

Let us know how it turns out.

 

[GUY]

The car has a brand new EPROM ECU in it. It did it with the old ECU and this one as well but not as bad. I haver drove the car for a while it has been doing fine, but on my way back from work today, i felt two small fuel cuts as i was turning.

 

[xcz504d]

Is you MAF stock or hacked? Does it only occur during boost? You need to find a common factor that affects it. Is it dependant upon your RPM? How much boost are you running?

 

[96GSEclipse]

Nobody replied to my last comment... But a couple of days ago, I had turned my heater on and my car didn't do this anymore.. Went all the way to redline, made me feel real good. Haven't felt that in months. It did it a couple times still, but not nearly as bad as before.. Wtf is wrong with it? Turned the ac off, and it worked a lot better... Anyone know?

 

[ddavisaf]

Fill out your vehicle profile so I can help

 

[PaulN]

I had NGK spark plugs, but I bought a different kind (don't remember) and replaced them, but it didn't do anything.

Spark plugs and wires. Throw away those non-NGK plugs.

 

[96GSEclipse]

Yeah but I had ngk plugs and it was messing up, then i changed them and it didn't do anything different. obviously not the spark plugs...

updated info.. didn't change much, my car is stock except for exhaust.. 96 GS..

 

[ddavisaf]

When your car starts acting up does your neck hurt for two or three days afterwards? Or does it just stumble and die out?

 

[96GSEclipse]

When your car starts acting up does your neck hurt for two or three days afterwards? Or does it just stumble and die out?

I don't notice if my neck hurts.. My body always hurts, I work a lot...

The car doesn't die. It'll keep driving, it's like hitting the rev limiter, except a lot worse.

 

[ddavisaf]

You're taking my comments to literally.
Does it feel like the car is attached to a chain and the chain just ran out? Or like it's bogging down and stumbling really bad?

 

[clipse_GST]

check your coolant temp sensor. that is what turned out to be my problem.