A fun SR related query

[Supafly]

so tonight i pull out of my friend's shop, lay into the throttle a bit and as soon as i hit about 7-8psi it feels as though i'm hitting boost cut. i drive a little further, car still runs fine below 7-8psi, but as soon as i reach that boost level the car cuts.the car ran fine the entire day today and just now began to do this. i'm going to check for possibly vacuum leaks after the AFM on the intake tube, but does anyone have any other things to look for on this?

like i said the car still runs fine until you hit that boost level.

[Hijacker]

i can almost bet that's timing. mine does it when i top out at 13 PSI. feels like the car's shuddering a bit. If it's not timing, it could be the plugs, but since you're running stock boost, I'm more inclinced to say timing.

[[s3]]

2nd on the timing, with a boost leak (depending on size) you won't be making top boost.

Also wouldn't hurt to run the ECU check.

[Hijacker]

another problem could be fouled plugs, but i doubt that since you're running stock boost. Just throwing something out there for ya.

[Supafly]

well, the saga continues....... today i started the car and it's running on 3 cylinders at idle. when i rev it it seems that all 4 eventually fire but as the revs stabilize it seems to drop back out again. last night it idled fine when i pulled in to my driveway and left it on the turbo timer.

i pulled the plugs and cylinder 3 looked kind of wet, but i couldn't tell if it was fuel or water. oil is clean. plugs overall were pretty clean, the top of the piston is what looked wet where the other 3 were dry with normal carbon buildup. did a compression test and got the same reading on all 4 cylinders. ran the car with the radiator cap off and no bubbles coming out of water when i rev the car. i kind of thought it could be a headgasket because the coolant was oddly low when i first looked. that's what i'm leaning toward at the moment, but i need to get my hands on a leakdown tester to tell for sure.

talk about ****ty timing, i was about to throw on the PFC, 550's and Z32 maf and go hit the dyno for tuning

[[s3]]

Broken headgasket = smoky car (white puffy smoke)

I doubt its your headgasket, compression is ok...I would think that you're car is running rich and fuel is being dumped on the plugs.

Need to tune it right and stop the dumpage of fuel.

Do you have a SAFC? or some sorta fuel management device?

[Supafly]

right now it's all stock electronics/fuel/afm. i haven't changed any of that yet and it's been running like a champ on those parts for months and months now.

compression test= 150 150 150 150 (psi). FSM says 156 is standard and 128 is minimum so compression is great.

[navysnail]

a leaking fuel injector will do that, change all plugs and wires, maby dist. cap, and run some injector cleaner through the tank.

[Supafly]

a leaking fuel injector will do that, change all plugs and wires, maby dist. cap, and run some injector cleaner through the tank.

good to see you read the thread

my car has no plug wires/dist cap:)

[navysnail]

sorry, forgot about the no wires thing with the sr, but the injector is still a posibility, my injectors were leaking and i just had to replace them, was like 400 dollars. the wet plug leads me to belive a leaky injector or weak spark not igniting the fuel in that cylinder.

[Supafly]

well, played with it a little more last night. injectors all test 10-11 ohms and coils all test 1 ohm between the #1 and #2 pins, all within factory specs. the car is definitely not on 3 cylinders all the time, when the cold start idle is working it intermittantly bounces on and off on the bad cylinder, and when i rev the car it clears for a moment then goes back to crap again. i did the old screwdriver stethoscope trick and all injectors were firing as far as i could hear, unless i was just hearing valvetrain noise (but they all sounded the same).

i may just toss in the pfc and injectors and see what happens.

[[s3]]

Might wanna check the PTU as well

[navysnail]

even if all the injectors are firing, they may have some build up or the tip may not seal, so it is running rich and wont run. when you rev it, the extra fuel leaking is mixed with the air and is then burned. use a bottle of injector cleaner and i assume you have checked the ecu for codes, if not then now would be a good time.

[Supafly]

how would i go about checking a redtop (#62) ECU for codes? can i put a jumper in some diagnostic port and have it flash the CEL?

[navysnail]

is it obd II

[Hijacker]

S13 redtop/blacktop == OBD IS14 and S15 Blacktops == ODB II

if you want some cheap replacement injectors, Heavy Throttle has them for like 30 a piece.

[Supafly]

i have a power FC/550's/Z32 maf ready to go on the car... i'll just try pulling/cleaning the injectors or installing the new stuff

[thundachiken]

I think a leak down test is your best bet. I had identical symtoms on my escort with a turbo BPT engine. Turned out to be a cracked cylinder head. Easy cheap fix? Run a bottle of Cargo seal or block seal in your radiator.