2G Rough idle when cruising and backfires when accelerating

[Sjd6795]

So bit of a problem, I dont have a way to data log so I'm just going off educated guesses. I took my turbo off the other day to check it after a rebuild and it has no play, spins perfect, no damage, and doesnt leak. During the reinstall I fixed a manifold stud, replaced gaskets and seals and any exhaust leaks that previously was there. Got fresh oil put back in the car and went to drive it and it drove great pulled super hard not like before when i had the exhaust manifold leaks. The next day it started acting up I would get into boost in 2nd and it would feel almost like a clutch slipping but the rpm and speed would match up I know it's not that. The next day after that when getting into boost the car would just stumble and backfire super loud.

I have replaced spark plugs with bpr7es, and wires with ngk me77. I'm out of guesses on what it could be at this point. I'm thinking maybe fuel pump next? I do have a walbro 190 I can toss in so that's free. I'm certain I dont have any exhaust leaks or boost leaks. But I will make a boost leak tester this weekend and test.

 

[Sjd6795]

Car cold starts just fine and it's not everytime it stutters and backfires sometimes I can boost to 5k rpm

 

[ThunderChild]

Sounds like fuel delivery or timing issue. What's the CAS/CKP situation? Which car is this?
Does it seem to do it only once warmed up? How about coolant temp sensor?

 

[Sjd6795]

Sounds like fuel delivery or timing issue. What's the CAS/CKP situation? Which car is this?
Does it seem to do it only once warmed up? How about coolant temp sensor?

97 gsx, timing was fine before hand and right after the reinstall I do not think it jumped. Cold or warm or does it. Coolant temp is fine car doesnt overheat or anything

 

[pauleyman]

Check the timing. Better to know for sure than to guess.

 

[Sjd6795]

Check the timing. Better to know for sure than to guess.

I will but timing was fine before almost certain it's still good. Taking any other suggestions as well. Does it seem like a fuel pump problem?

 

[pauleyman]

I see the words
Do not think and
Almost certain.
The thing is if the car run better, stronger maybe that was enough to make it skip if it was marginal. The only way to be sure is go look.
If it's fine at least you ruled that out.
If you touched anything else during this job go look there first.

 

[Sjd6795]

I see the words
Do not think and
Almost certain.
The thing is if the car run better, stronger maybe that was enough to make it skip if it was marginal. The only way to be

I see the words
Do not think and
Almost certain.
The thing is if the car run better, stronger maybe that was enough to make it skip if it was marginal. The only way to be sure is go look.
If it's fine at least you ruled that out.
If you touched anything else during this job go look there first.

Only touched exhaust manifold, turbo, intake, j pipe, downpipe. Everything had fresh gaskets, seals, and even used copper sealant to be extra sure.

Tomorrow I'll check over timing if it's off hopefully I can adjust it easy enough. Not really in the mood to be doing a full timing job.

 

[Sjd6795]

So I found part of my issues apparently the turbo got hungry and tried to eat my honey comb sideways. Luckily it did not damage the maf any, I got it straightened out the best I could and put back in. The car idles great now and now hesitation and stuttering when driving.

However I notice that I am at a loss of power the car does not pull hard prior to the issues. I went over my spark plug wires and noticed according to a 97+ chart they was not in the same order but the car still ran fine in this order. Before I found the honey comb issue in the maf I put them according to how the chart shows and the car like I said above started fine and idled fine. When getting on the car to do a pull boost comes on and stays at my set 15 psi but it doesn't have that "pull" that it should and I also noticed during shifts it would backfire "in a good way" but I guess that means I am rich and I am wondering if changing my spark plug wires to the "correct order" would cause loss of power and the backfire.

Note: my car has a black box ecu would that change the firing order any?

 

[Sjd6795]

Idle seems fine, no strange noises.

Here comes the spooky part. After I fixed the honey comb and put it all back together apparently I forgot to plug the maf connector back in. But the car drove for the most part fine during the test drive??? I only realized it was unplugged when I had removed my battery to fix a tie down mount and the car would start then die immediately. Due to the FP intake the maf connector is so close to the fuse box on the passenger side fender there is no way it can fall off on its on. I have to pull the intake to the side just to get it on and off, it also snaps and locks in. Could the ECU remember the maf from when it was plugged in and when I unplugged the battery the ECU forgot anything that it had learned?? I don't see how the car drove with it unplugged and had no idle problems.

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[miguelmcv]

The ECU can run the car without the maf with no problem at all, it is not able to run it on high boost but will be drivable,.

If it died after connecting the maf, then your maf is most likely dead.
Just replace it and you should be good.

 

[Sjd6795]

The ECU can run the car without the maf with no problem at all, it is not able to run it on high boost but will be drivable,.

If it died after connecting the maf, then your maf is most likely dead.
Just replace it and you should be good.

It ran with no maf connected. I reset the battery and it would just die. That's when I found the maf unhooked. Hooked it back up and it's doing good now. I need new honey comb though