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cold? start


LarryK 87

When first started (when cold) the motor fires immediatly, and for the first second or so, has a correct idle, it then starts to stumble ( like it is very rich), this clears after a few seconds ( applying throttle will clear it), then idles correctly again. and i have noticed black smoke from the exhaust when this happens.

Fuel pressure is 40 psi key on / engine off, and drops off 10 psi over 5 - 10 minutes.


Hi Larry and welcome to the CAC. :)

I'm posting here, so that we bring this topic back up top and hopefully someone will chime in with some advice. To me, it could be a myraid of things. Let's try to narrow it down. Does it smoke all the time or just on start-up? Have you had a tune-up lately? Any mods done or just stock? I think the fuel pressure is supposed to be around 46psi give or take a few, but if someone knows the exact spec, please enlighten me. Hope we can get you going in the right direction Larry.


LarryK 87

well a little more digging this week end reveled:
In the cold start circuit with coolant temp < 95F, cold start circuit should be enabled.
Test: remove fuses for Inj 1 & 2, Connect Fuel pressure gauge, Crank engine at least 2 sec. Pressure should drop off > 3lbs if cold start is working,( engine attempted to start during this time), This Passed. Run engine until coolant temp > 95F, ( does not take long here in Fla) Remove fuses for Inj. 1 & 2 and repeat test above, there should be no Pressure drop. This also passed. This tells me my cold start circuit is operating as expected. During the time i was warming the engine, there was noticable smoke from the exhaust pipes ( black, like it is running very rich).and BTW ECM is reporting a Lean condition error 44, SES comes on occasionally, but will go out after a few minutes)

Also ran Pressure tests to assure proper regulator operation,
Static pressure ( Ign on/Eng Off) Fail point is 40.5, i measured 42.
Passed, but just barely.

With engine running pressure drop off should be down around 36lbs. if regulator is ok. This also passed. But again just barely

All readings i attained seem to be on the marginal lower end, Having only had the car for less then 1 month i have yet to replace the Fuel filter, Tune up was done a 2 weeks ago. and cleared codes 22, 36, 44, 46.
I have also found that if i apply a little throttle as soon as the engine starts, the problem seems to be minimized ( no stutter etc). This all takes place with-in the first 5 - 10 seconds of startup.

I am strongly begining to suspect a vacuum leak some where, Just picked up a Vacuum gauge lastnight, but have yet tried it. I believe i have also found a disconnected vacuum line that i believe connects to the Vapor purge selenoid ( only one line connected now ) , so i have plugged that on off, it connects back up to a Tee, which feeds to the C.Cont, diaphram.

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