Weird Idle When Cold

[RobertK]

I've been battling this ever since I've had this car.

When I first start it up in the morning or whenever the engine is cold the first time it will die unless I give it gas. If I let it die and restart the car then it idles but it will slowly drop to about 500RPM and right when it sounds like it's going to die it revs back up to 700-800RPM for a min then repeats until it's warmed up.

I've checked all over for vaccum leaks. Every gasket is practically brand new and so are the hoses. The only thing I can think of is when I messed with the idle scew on the AFM that might have caused this. No CEL is being thrown when this happens. For further reference the TPS is practically brand new and the ICV is good.

[MrK]

(Shakes hand)

We have the EXACT same problem! While cold the car will die if I don't constantly give it a little gas, and it starts creeping up the rev-range as it warms up. Annoying as hell.

What I was thinking is that maybe the spark plugs in our cars are a step too cold? I'm going to install plugs that are one step hotter and come back to you with answers :)

[b*saint]

cold start bypass valve thing it sounds like. Does it buzz when you first start it up cold? If it buzzes that means its working.

[MrK]

Mine buzzes just fine....

[RobertK]

I was under the impression that the M20B25 does not have a cold start valve. I thought that was a feature only on the eta engines.

I do have a bad valve seat on cylinder #3. It leaves burnt oil deposits all over the spark plug after a month or 2 of use but even after I replace the plugs it's all the same.

I do have 19lb injectors if that makes a difference.

[MrK]

LOL I guess it's the fuel pump I'm hearing then... Good call Ritalin Kid :)

And by the way, I have 19lbs injectors as well!

[RobertK]

LOL I guess it's the fuel pump I'm hearing then... Good call Ritalin Kid :)

Actually it's usually the ICV that buzzes when you first start to turn it over.. mine is anyway.

And by the way, I have 19lbs injectors as well!

Hmm... I wonder if a MarkD chip would solve my problem. Is it possible having the 19lb injectors without the proper modifications to the DME might cause it to run extra rich when cold.. sorta flooding it out?

[MrK]

Well I have a piggyback unit, which I used to try and lower fueling at idle, and see if altering ignition advance at idle would help, and I have an AFPR, so I played around with that a little too.

No luck on all counts :(