S14 SR Sputters at High RPMs....Intermittent...

[SWAT Team S14]

ok, heres the problem:i have a s14 zenki sr20det in my 95 240....at low rpms the car is fine....cruising around town, the car works great (except occasional stalling when stopping, but i know thats because of my bov).....but when i rev the car past 3500 rpms or so, it starts to sputter & cut out....it backfires & won't accelerate. now this doesn't happen all the time, but it has been getting worse (i.e. happening more frequently).

now, heres what i've done:i retraced & double checked all the wiring (i didn't do the wiring b/c i'm lazy), but found nothing. the car has a z32 mafs & an apex'i s-afc ii, but i have tested both & found nothing.....i've tried 2 crank angle sensors, but it didn't make a difference. i've also tried a different igniter, but still the same. the only thing i haven't swapped out is the mafs, but i don't know anybody that has an extra one & i don't wanna throw away 150-300 dollars if thats not it.....plus, as i've said before, i have tested the sensor (numerous times) & it checks out fine.

so, i would like to know if anybody has experienced this problem, or has any idea as to what may be causing this. i'm a gm & ase certified master tech, so don't treat me like a punk kid or think you'll talk over my head......and please give me thorough answers.......thanks in advance for any info you can provide me with.

[spec-u-later]

Could be a boost leak. I had the same problem and it was a bad coupler.

[IanS]

First off, a little more info about your setup will help us troublshoot, things like what turbo you have, and how much boost, also, who tuned your SAFC, and what your base electrical timing is set too. first off, do the easy stuff, get yourself a can of electrical parts cleaner and spray it on the mafs, it doesnt take much to cause them to read iradically. Also, checking for boost leaks is always a good idea, especially since it runs fine until you start to get into boost. If that doesnt nail down the problem, try pulling out your spark plugs, what kind of plugs are they, and what are they gapped to, what condition are they in and how many miles have you had them in. Do you have an wideband A/F reader? If so what do the readings look like when the problem occurs.

Hopefully some of this helps, Ill keep an eye on this thread.

-Ian

[SWAT Team S14]

it still has the stock turbo on it....i plan on upgrading it soon, thats why i have a z32 mafs. i set up the s-afc ii myself, & a friend who has installed a number of these rechecked my install, but everything was fine. the idea of the boost leak has crossed my mind before, i'll have to look into that.....o, i set base timing & gapped the spark plugs (ngk platinum) by the fsm....sorry, i'm at work & off hand i dont know what those specs are. i'm gonna try a few things later today & i will get back to you.......thanks a lot

[fast_s13]

sounds like a boost leak to me

[92SR20S13]

did you use a rom tune with the z32 maf?..same thing happend with my car and i changed my plugs and got a new chip and everything works great now

[SWAT Team S14]

yup, it was a boost leak.....the 90 degree silicone elbow between the hot pipe to the intercooler had ruptured.......replaced it & runs fine again!!!

[silk240]

what do you mean by ruptured??