S14 SR20DET missing bad, intermittently

[x91s13shawnx]

it has been a week and still no luck. It runs good on cold starts every time. i can drive around the block a few times before it starts messing up. it tries to die out so i give it gas and most of the time that doesnt help, let me know if this has happened to you before or if you have any ideas, thank you.

[x91s13shawnx]

please help

[vocationalzero]

Bleed clutch? Leaky master/slave cylinder? Sounds like its definitely loosing fluid pressure somewhere. Possibly air bubble...

[x91s13shawnx]

clutch is ok now, car is still doesnt run very well at all. it stalls out and breaks up most of the time when i give it gas, i switched mafs and that didnt do anything.

[CRyan]

Breaks up?

[x91s13shawnx]

yeah i rev it and it seems like it isnt firing right.

[x91s13shawnx]

i can also smell gas

[PyR0NiAk]

Sounds like at least 1 cylinder isn't firing. Check plugs..

[x91s13shawnx]

yeah i am tomorrow. i think it could be my cas

[PyR0NiAk]

CAS usually won't let car run at all..

[x91s13shawnx]

well my spark plugs are all good, any other ideas?

[PyR0NiAk]

So you checked and made sure all 4 were getting good spark? If so, your injectors are next..

[x91s13shawnx]

yeah, i let the car sit for a day and i started it up and it was running good. i drove it around the block a few times and it was pulling hard and running strong and right when i was pulling in my driveway it started doing it again.

[PyR0NiAk]

So would you say it runs good when cold? Or was that the first time it's ran well while cold? Also, have you checked for codes?

[x91s13shawnx]

yeah runs good when cold. i looked and i have a knock sensor code.

[x91s13shawnx]

would that cause my problem?

[PyR0NiAk]

Bad knock sensor retards timing.. A bad coolant sensor will definitely cause it to run bad when warm though, and MAYBE it's throwing your knock sensor code..

[x91s13shawnx]

yeah i already tried the coolant sensor and it didnt help

[PyR0NiAk]

Got a friend with a good MAF you can borrow?

[x91s13shawnx]

yeah i did that and it didnt help either

[PyR0NiAk]

Maybe it's the knock sensor then.. I've just never read anything about them only causing issues when warm. I recommend you do a little research.

[x91s13shawnx]

i did research and that wouldnt cause my problem

[PyR0NiAk]

What are your AFRs?

[x91s13shawnx]

thats what i am thinking it is. i am going to order gauges. i just drove it for 30 min and it only stalled out once

[PyR0NiAk]

What type of modifications are done and with what tune?

[x91s13shawnx]

its just an s14 sr20det in my s13. Its all stock i have an exhaust, hks intake, fmic, walbro 255 and z32 fuel filter

[CRyan]

At first this sounded like a normal coolant sensor problem.

But you say thats been replaced. . .hm.

I still vote something dealing with it. . .I mean, theres no other real valid reason as to why it runs great on cold start and craps out as it warms up.

Do you keep your eye on temp as you drive it to see about when it happens? I would suspect MAYBE injector is sticking, but again. If its pulling hard at cold start, and bogging out as it warms. . .That is obsolete.

AFR would help only to know exactly when it starts to run rich. I would say maybe check amperage at the MAF. Who knows, maybe you aren't sending something right to the ECU. . .

[zachattack_5491]

Did you change the correct coolant sensor? One goes to the gauge, and one goes to the ECU.

Also, there's a 99.9% chance that my s13 is the only one in history to have this problem... but on a hot day, something messes up the voltage to my fuel pump and it cuts out randomly or turns off. Who knows, maybe we have twins.

[PyR0NiAk]

I thought of the fuel pump earlier. Is it hardwired? The knock sensor code is most likely a result of a lean condition and the 'bogging' would be from it retarding the timing.

[x91s13shawnx]

yeah i changed both sensors, the fuel pump is wired using the stock wiring setup