No Bs I Will Pay The Person Who Finally Diagnoses This Problem Correctly

[rabenne]

I have a 2g with a 6 bolt. I have t3 t4 50 trim with turbonetics manifold, victory performance o2, megan racing downpipe, 550 cc injectors, walbro 255 fuel pump, aermotive fpr, fmic, dejon tool intake pipe, new ngk wires, and new ngk plugs bpr-7es with .028 gap. Im only running 12 psi right now, and under light throttle the car is running AWESOME. Once i break about the 60% throttle mark, after boost builds to 12 (3500 RPM), around 4200-5000 rpm the car loses its power, and jerks around, and misses hard... its killing me trying to figure it out. I just did a boost leak test and it held pressure to 20 psi no problem, and after i removed the air source, it continued to hold pressure for 25 seconds. I have a Zeitronix zt2 with pocketlogger zt (SICK SHIT 59 samples/second) and according to that I am running a nice solid 11.5-12.2 AFR. This doesnt really change when car misses... .the problem is I let off the gas when it happens so its hard to tell whats goin on. Im really lost on this one, and so is everyone else Ive spoke with. I am running 43 psi fuel pressure at idle with vac line off, and it goes to around 38 psi with it on.

My guesses,

1. bov is opening early and dumping all the volume of the boost, but still maintaining enough to read 12 psi at the autometer c/f boost pressure gauge. It feels like a boost leak kinda, but I have tested it two times, nothings leaking.

2. FUEL CUT? it doesnt feel like i hit a brick wall at all... more like the crank missed some power strokes, then got itselt together agian, then misses again.


I am willing to pay $50 via paypal to anyone who can give me a no bullshit answer, that actually proves to fix my problem.

THANKS
William Powell

 

[hellotbone]

Tell me something if you take it out and just stand on it with minimal warmup does it still do it? Or does it only do it once its warmed up? Mine did the same exact thing when the coils were bad. I was also rich. When I changed the coils out and leaned my car out a touch I was good to go. Mine would buck and pop and backfire in the mid like crazy same thing you are describing. Worth a shot also both my coils when COLD would read perfect doing an ohms test. When they were hot they were way out of wack. Read my profile you and I are quite similairly outfitted.

 

[rabenne]

Alright, I will keep that in mind, my first step is determining if this transistor is blown or not... I am trying to find somewhere to repair it near chicago, but im having no luck. I need my car to get to school, so I dont want to be without it for more than a couple of days.
IF it is not the Maf reset output transistor I will try a new coil pack. Which coil pack is best with a 6 bolt 2g??? But it does it at any operating temperature right now. I know that does not rule it out, but Dave Mertz has me convinced that its the transistor. He said it is common when the sensor ground is blown, to also damage that pin, as it is directly next to it. Hopefully this will be fixable... If anyone knows, please let me know. thanks


William Powell

 

[hellotbone]

Alright, I will keep that in mind, my first step is determining if this transistor is blown or not... I am trying to find somewhere to repair it near chicago, but im having no luck. I need my car to get to school, so I dont want to be without it for more than a couple of days.
IF it is not the Maf reset output transistor I will try a new coil pack. Which coil pack is best with a 6 bolt 2g??? But it does it at any operating temperature right now. I know that does not rule it out, but Dave Mertz has me convinced that its the transistor. He said it is common when the sensor ground is blown, to also damage that pin, as it is directly next to it. Hopefully this will be fixable... If anyone knows, please let me know. thanks


William Powell

Someone who hasn't tried this will probably tell you they don't work but I have run everything on my 6bolt a 97 coil a 95 coil and currently a 90 coil. I got my working 90 coil from the junk yard for 30 bucks. New the dealer wanted something like 400 if I remember right.

 

[rabenne]

Hey thanks, if I rule out ECU and its still doing it I will buy a used coil pack to test your theory. THANKS AGAIN

Will

 

[1995gsxtreme]

Did you ever find a result on the compression test?

 

[hisandherturbo]

So, do you know what your problem ended up being? casue I am having the exact same issue of bucking as soon as I hit boost.............. NO LEAKS, good coils, wires, plugs. I can never even get close to WOT so I haven't ruled out the 02. I am also running very rich (DSMLINK trims pegged at 12.5 and AEM WB also showing it.

THX
JOE

 

[VaB90gsx]

12.5 : 1 AFR is not rich... 12.5 is equal to parts of air per part of fuel. If you take more fuel out the first number will go up. You're running lean and probably hitting fuel cut.
since you've leaned it out even more it's probably running worse.

 

[hisandherturbo]

I wasn't saying 12.5:1 is rich....... I was saying my fuel trim settings on DSMLink are pegged out at 12.5% if you are unfamiliar with DSMLink........ that just means it's adding 12.5% more fuel. My WB is showing in the 10's at only part throttle.

JOE

 

[jfruauff]

Check your spark plug boots were thye go into head for any cuts. I had the same problem in a honda we put a turbo swap in a few weeks ago and we thought it was a fuel problem then we caught the little cut. It only has to be very small cut..

 

[hisandherturbo]

Just curious, did it idle fine? Could you drive it up to any RPM??? Could you drive to any speed with no problem???

THX
JOE

 

[jfruauff]

Check your spark plug boots were thye go into head for any cuts. I had the same problem in a honda we put a turbo swap in a few weeks ago and we thought it was a fuel problem then we caught the little cut. It only has to be very small cut..

I say it definetly the igniton system. Check the wire like above. Also are you using the right heat range plug and correct gap.. To big of a gap will do that...

 

[olmytsi]

I wasn't saying 12.5:1 is rich....... I was saying my fuel trim settings on DSMLink are pegged out at 12.5% if you are unfamiliar with DSMLink........ that just means it's adding 12.5% more fuel. My WB is showing in the 10's at only part throttle.

JOE

If your fuel trims are pegged at 12.5%, than you are running LEAN. The ecu is correcting this issue by ADDING fuel

 

[jfruauff]

12.5 isnt lean. Its not rich but not lean. I usually tune turbo car between 12.0 to 12.5. I am not saying it not a little hight 12 I think it the best for performance and safety but 12.5 is bad. I have ran higher with water injection.. I really think its a spark issue. If you really think it fuel the easiest way to tell is to get on a straight quiet road go WOT threw 3rd or 4th and when you get to redline turn the car off and let it coast to a stop. Then get out and pull a plug the tip will get real white.. I really think its spark..

 

[olmytsi]

We are NOT talking about air fuel ratios....we are talking about FUEL TRIMS!!!!!!!!!!!!!!!!!!!

 

[hisandherturbo]

We are NOT talking about air fuel ratios....we are talking about FUEL TRIMS!!!!!!!!!!!!!!!!!!!

TY OLMYTSI!!!!!!!!! I AM GLAD SOMEONE SEES THIS!!!!!!!!!!! seeing as how I can never get into WOT!!!!!!!!!! It appears the car is staying in "closed loop" staying in closed loop 1 reason would be BAD FRONT O2. Seeing as how my readings stay pretty much 0'd out. And I also just dis-connected my front O2 drove the car around, and wouldn't you know it................ drove the exact same way it has been. So the way I figure it, if you dis-connect something and nothing changes....... that must be the thing????????? let's hope

JOE

 

[olmytsi]

Failure to switch between open and closed loop is often one of the 02 sensors. Just log them both to see which one isn't cycling/behaving properly.

 

[hisandherturbo]

Well seeing as how I only have a front one casue the rear one is my WB........ I am going to go and pick it up now....................

 

[hisandherturbo]

Well............... My O2 was bad........... BUT it didn't fix my problem. NOW WHAT????????????????

 

[mrpeanut120]

Did you check this out?

It's Magnus Motorsports info on a 1g in a 2g swap.

It says:

On a 95-96 car with stock 2G head
Swap Plugs 1 and 4 with 2 and 3 (order is not important)

 

[olmytsi]

Yeah but the car won't stay running unless you change the order so it's not his problem.

 

[MMM]

defianantly play with spark plug gap. I had the same problem with my RB25DET. Its called spark blowout.

 

[95WTSI]

I had a problem with my coil packs and I don't think that is what you have. My RPM's dropped to like 150 and the car shook like crazy, even when I shut it off and restarted it. not cool!!!

 

[AWDDSMCRAZY]

my afc read 1286 Hz of airflow when this happened.... this seems way too high... is this off or just me?

Far as I know fuel cut is at like 1606 or there abouts right? I had a problem similar to what you are saying, but mine spiked up over 1606hz. Mine was a boost leak and why I didnt get an aggresive fuel cut was because I had the fuel cut thing activated on my MAFT.