I need some advice.. Fast.. I'm about to lose it

[MikesS13_1989]

It is a 1989 240sx SE with the original KA24E motor

So I have been having this problem for about a month now, my car will not start normally when it is gets cold.. I have replaced the plugs, wires, dist. rotor, fuel filter and pump, it passed a compression test with flying colors, it has spark and is getting fuel.. it just wont stay started.

When I start it normally, it goes to 1500rpm, then automatically dies.. when i start it and force the gas a little bit, it will go up to 5000rpm, then when i let off it dies. If i am lucky enough to get it to stay alive, it pops (sort of like a misfire pop) and it only happens when I idle or when I let it set.

Is there something I am missing here? The distributor was running completely advanced when I got it, I have since returned it to normal and it still doesnt run.

[AZhitman]

Definitely seems to be a timing issue.

Recheck timing:

http://www.nicoclub.com/articles.php?id ... ?id=160218

[MikesS13_1989]

Thank you for your help, after spending the better half of my paycheck on parts, i replaced the coolant temp. sensor this morning and the car runs cherry

[mrbizness1]

Thank you for your help, after spending the better half of my paycheck on parts, i replaced the coolant temp. sensor this morning and the car runs cherry

I am surprised you didn't get a SES light for that, I got it for my maximas temp sensor

[MikesS13_1989]

Now the car runs ok when it is warm, but on start up, i have to rev it up to 5k to get it to stay alive, it still makes some popping when it is warming up like that.. when it runs, it runs good, no check engine light, no stalling, no weird idle.. only on cold start, any suggestions?

[AZhitman]

Sounds like an issue related to open loop / closed loop operation.

ASSUMING timing is correct and there's no ignition issues...

Start by checking AFR's with a wideband (local tuner shop can help with this) at cold start and after it's warmed up.

Also, a bad FPR can do this (ECU can compensate for improper fuel amount when warm).

Lastly, check MAFS voltage when cold and at operating temp. Could be a bad MAFS.

[c72c]

i could be wrong but i always thought hittin 5k rpm cold is not good...

i've heard crank position sensor bad/going bad can cause this.is your eng stock? no a/m fuel acc? i agree with azhitman, check out your afr.

[MikesS13_1989]

Oh yeah, i know revving that high is no good for the motor, but.. gotta get to work somehow. Its even harder to do in a little apartment complex and having some obnoxious exhaust system on it.

I'm sending it to a shop on Thursday, I'll definatly have them check the AFR, when I get paid, i will just replace the FPR, what about the Exhaust Gas Temp Sensor? The factory service manual suggests it when the engine stalls on cold start.

If it was something like the Crank Position Sensor and any other major sensor, wouldnt I get a check engine light when it is driving? the only time it is on is when the key is in ACC, when it is driving and warm it runs ok and only pops a little bit