Cut out during acceleration

[suprastroker88]

So I have this 1990 7m. During any acceleration more than about 1/4 throttle, it cuts out and jerks all over the place. It almost feels as though its not getting spark or fuel. I've changed spark plugs, wires, coil packs, ecu, afm, cps, injectors, and fuel pump. no luck. Any recommendations before i get rid of this damn thing?

 

[Quin]

Sounds like fuel cut to me. What turbo, AFM, injectors, etc? Need more info. How's your AFM wiring look?

 

[RBD 305]

I had this happen to me..turned out to be a bad tank of gas. I was at 1/4 tank and decided to fill up on 93 at some Exxon before a road trip..and about 1mile into the drive I started noticing those exact symptoms. Hopefully this helps!

 

[shipkiller]

does the CEL goes on?

 

[stevenr816]

Check all of your intercooler piping, big vacuum leaks, etc

 

[suprastroker88]

I checked the intercooler piping, i just put in a lexus afm to see if that would help, i sprayed brake cleaner over the engine while it was running to check for air leaks and didnt have any. All my wiring looks great, i even had 3 shops check it out to make sure. I'm running a Turbo Concepts TC70mm turbo. I think it's running like 14psi, but i never boost that much because the car cuts out before I even hit positive boost. I think the most I've ever got to boost was about 6psi. Im running the stock injectors for the moment, Ive replaced them twice now with known-perfecting operating injectors. I've filled up with 91 chevron gas like 6 times, and i even went as far as to mix 5 gallons of 100 octane gas AND a fuel system cleaner. Still no results. I put in a walbro fuel pump and aeromotive afpr yesterday. I re-did the timing again.

There's no check engine light on.

 

[Dani87x]

Did it start giving you problems before or after you installed the LexAFM?

 

[shipkiller]

have you reset the ECU after installing a new MAF. I've seen it on a 7m with a bad maf, the owner put the new maf and the car would act the same (as if it was in failsafe), after pulling the efi fuse, he got rid of the 34 with the new maf only

 

[mkiiichip]

There's no check engine light on.

That does not mean there are not any codes set. Pull codes.

 

[suprastroker88]

i pulled codes 12 and 24. i changed the afm for the 4th time and reset the ecu. it drives fine now but if i go wot, it will NOT rev passed 4200 rpm's. if im in neutral, it will rev to redline no problem. if im not boosting it will rev it fine. but once i get any kidna of boost, it cuts out at 4200. i have my spark plugs gapped to .28. is this a sign of spark blow out or fuel starvation?

 

[suprastroker88]

Did it start giving you problems before or after you installed the LexAFM?

before. the lexus was an attempt to fix the issue

 

[mkiiichip]

Wait a min, stock injectors and lex AFM? You are running lean, you need to stop driving it that way,

EDIT are you running just the electronics or the entire lex housing?

 

[suprastroker88]

i just put it in last night. i was told to run it with a lexus because of the turbo being so big and needing more flow

 

[mk3_7m]

Well it's logical to free up restriction within the intake but if you don't balance the ratio between Air and Fuel then you're gonna run into some problems. Remember Leaner the meaner.

Which is why the 550s is a must when changing to Lexus.

 

[suprastroker88]

so is it possible that with such a big turbo, im not getting enough fuel to the motor and thats why its cutting out?

 

[Poodles]

It's not fuel cut or you'd have a stored 34.

Code 24 sounds like a wiring issue to the AFM, and code 12 could be issues with the CPS (likely wiring).

 

[mk3_7m]

Oh no I was stating that you shouldn't use the Lexus afm without putting 550s on it.

 

[suprastroker88]

Well........... I feel like an idiot. I found the issue. The coupler for the intercooler piping on the tip of the I turbo was split on the backside. I couldnt see it though until I took it all out of the car.