2G WTF! Misfire Cyl 3!

[InfiniteGSX]

This is starting to piss me off! The car was running fine, I launched it just playing around in a empty parking lot testing out some things on the Tephra Rom. Tune is clean and gets good gas mileage so far. But after the launch, the car started spitting. I was low on gas when I did it and after went and filled up. Now its soo bad it mis fires even on normal driving, can hardly get maybe 2psi before the car breaks up hard.

I replaced the spark plugs and coil pack. Same Problem. I pulled all my intercooler pipes, cleaned them and the couplers and re sealed them. I recently just pulled my IAC/FIAV and replaced it with a blockoff plate because my IAC was completely bad. And I read up that it could back up into the ECU and damage it. That is NOT ok by any means in my book. So I'll enjoy shitty cold starts and bad idle until I can get a new IAC. But even with the blockoff plate nothing was wrong till after that launch.

I don't know what to do. I'm going to check Timing to make sure its still TDC and didn't jump. I've already taken a semi long drive with it out of town and back and besides the no power because no boost, the car ran great. Got good gas mileage so far around 250 to the tank. But I'm tired of it already. Tired of the embarassment of attempting to get on it a little and hearing it just PLAAAHHHTTTHHH (yes that was a sound ).

Someone help, Throw me some idea's!

1997 Eclipse GSX
6bolt Block
2g Head
2g CAS
1g tb
2g intake
Evo8 ECU
Tephra V7
Evo 560cc injectors
Innovative Digital WB
HRC 20g Turbo
100% 3" turbo back
VSRF Short Route FMIC

Uhm...... I believe thats all.

 

[mrfister11]

are you sure its on number 3? if so switch wires and see if it moves to a different cylinder since you dont have other wires.. easy thing to do to eliminate wires.. could just be a coincidence. but that shouldnt let it go over 40.. injectors are fired just like a coil.. they are grounded out.. you can get a test light and hook it to the wire thats ground on injector connectors but im not sure if you can actually see the firing of the injectors with a test light. might be too fast.. i use ecuflash as well.. maybe you have a leak before your turbo and your maf scalings arent matching up

 

[delta448]

Have you done a compression or leak down test yet? I have a mild suspicion that you might have dropped an exhaust valve in that cylinder.

 

[InfiniteGSX]

are you sure its on number 3? if so switch wires and see if it moves to a different cylinder since you dont have other wires.. easy thing to do to eliminate wires.. could just be a coincidence. but that shouldnt let it go over 40.. injectors are fired just like a coil.. they are grounded out.. you can get a test light and hook it to the wire thats ground on injector connectors but im not sure if you can actually see the firing of the injectors with a test light. might be too fast.. i use ecuflash as well.. maybe you have a leak before your turbo and your maf scalings arent matching up

Actually it isn't persistant to this. Its all over. The other day I checked the codes again and it was Cyl 1. I tested the wires on the injectors the best I could. I even tried a different resistor pack as well as different injectors. The problem remained. I have no leaks. All hoses are good and have been checked, double checked and tripped checked. It does seem like a boost leak half the time. Boost hits a specific level and blows by. But doesn't make up for its low rpm problem.

Have you done a compression or leak down test yet? I have a mild suspicion that you might have dropped an exhaust valve in that cylinder.

As I stated above, yes and the results were the exact same they were before the problem started. Hell in fact my most recent results match the same results this engine gave me almost two years ago.

On top of that, dropped a valve... As in dropped into the cylinder? Wouldn't that negate the "running good with no visible sign of a problem"? I've never "dropped a valve", but like I said earlier, the car runs great. Does NOT knock, doesn't sound like a big hung of metal is destroying my engine. It runs pretty good. I'm getting almost 300 miles to the tank on my stock Evo8 Tune. Its just when I'm in load +3700rpm.

Another note, Today the car felt better. Would hold boost up to around 4000-4200 before spitting. And when It did start, it didn't fall flat on its face like before. It still accelerated but not heavy. I drove the car around the city in "OMFG I'm Sweating" outdoor temps.

Someone made a suggestion, to shorten the gap of the plugs. My old Plugs and new plugs which turn out to be fine are all at .28mm Gap. Someone was telling me about their car doing similar and they had to drop the gap down to like .21.

Which if that was the case, would only mask the real problem.... Which seems like a loss of voltage on the spark. And again I have replaced the plugs, coil pack and PTU with known working.

Things that have been checked/replaced:

Spark Plugs
Coil Pack
Power Transistor (PTU)
Compression/Leakdown
Injector Resistor Pack
Couplers
Hoses
Engine Timing
2g CAS
2g CKS
Ignition Timing
​

 

[delta448]

On top of that, dropped a valve... As in dropped into the cylinder? Wouldn't that negate the "running good with no visible sign of a problem"? I've never "dropped a valve", but like I said earlier, the car runs great. Does NOT knock, doesn't sound like a big hung of metal is destroying my engine. It runs pretty good. I'm getting almost 300 miles to the tank on my stock Evo8 Tune. Its just when I'm in load +3700rpm.

My terminology might be off there, to me dropped = burnt, disfigured, bent, broken, or any combination.
Did you disable lean spool?

My old Plugs and new plugs which turn out to be fine are all at .28mm Gap. Someone was telling me about their car doing similar and they had to drop the gap down to like .21.

That's a typo right? You really meant 0.028"-0.021" didn't you?

 

[BogusSVO]

Have you checked fuel pressure?

You did the noid test, with the noid test light? and it didnt blink and just stayed on?
That means that the injector would be spraying fuel all the time, and you would run rich.

The noid test is to check to make sure the ECU is telling the injectors to spray. So at If they are hung open at idle they will be at 4+k

 

[Geier]

This sounds like a case of bad spark plug wires. A boost leak is probably likely as well. Try an ohm test on the wires.

 

[InfiniteGSX]

I'm going to attempt to order me a set of nice wires and a new ECU. If its not the ECU, I can just revert it back to stock and sell it easily.