another cold start problem
 

My na944(on a cold start after sitting overnight)chugs and blows a little black smoke out of the exhaust. I can bring it up to about 2000 rpm's and it clears out in about 15-20 seconds. After that initial morning start it can sit in the parking lot at work all day and doesn't do it in the evening when I go home. Anybody had this problem before. thanks

Just a shot in the dark, but could be a leaky cold start valve...

Is it an ealy or late 944? The early cars don't use a cold start injector, not sure about the later ones. It sounds like a leaking injector. If it sits at work it only has 8 hours to leak, and probably not enough to cause the problem. When it sits overnight, it has about 16 hours to leak and cause the problem. If you have an injector pressure gauge, check it right after you shut it off, then check it first thing in the morning, and compare the readings.

Thanks both of you. It is an '86 na 944. I will check both things. I think the haynes manual tells how to check the injector pressure and I can borrow a gauge I think. Do either of you know how to check for a leaky cold start valve?

Thanks

If it has one, just remove it. I think it is held in by one, or two allen bolts ( on a 924 anyway) and place it in a GLASS jar still hooked up to the fuel line of course. and see what, if anything has leaked into the jar by morning.

Does anyone know if an 86 na 944 has a cold start valve and if so where it is located?

My -83 944 NA don't have a cold start valve (I can't see one and I have never heard of it), and I don't think any other 944 has one. I have only seen it on cars with older kinds of injection systems, like -77 audi 100, -80 porsche 924.

/Magnus

the cold start valve on early 944 n/a is located underneath the airflow meter box. if you remove the airflow meter you will see it on the block. should not be difficult to locate

Sorry, I was thinking of a cold start injector (injecting extra fuel if engine is cold) but I wrote cold start valve.. http://www.pelicanparts.com/ultimate/redface.gif Yes, the car has a cold start valve.

/Magnus

Do you know how to test the cold start valve on the 944? sounds like it may be different than on a 924 engine?

The 944 does not have a cold start injector. You probably have a leaking injector(s).

David
84 944 NA

Sounds like a leaking injector. What do your plugs tell you? Pull them and inspect. If it's a injector the plugs mite tell you which one or ones. My 86 n/a has what is called a idle stabalizer valve. It replaced the earlier cold start valves. You have to remove the intake manifold to get it out. Pretty lame place. Hey, does anyone know if this can be relocated? Seems like it can.

CH

Sounds like it needs a total tune up.
Plug wires,plugs,cap&rotor

Seems like everybody is headed in the same direction. I think everybody is just calling the idle stabiliser different things, cold start valve, etc. Don't know of but one failure on this, trash in it and wouldn't idle cold. Then it would be the same symptoms after work or all night with richness. A potential failure is a bad coil in it and the valve staying open all the time. I think this would act like a vacuum leak and idle real high when warmed up. Best bet would probably to check the plugs and look for one with excessive darkness and that may be a leaky injector.

drew1

Thanks everyone for your input, sixbanger I have new bosch +4's new wires and new cap and rotor. I think I need to pull the plugs and find that leaking injector as that sounds like the problem. Thanks for all the good input from all of you. As soon as it gets above freezing I will do that. I don't know much about injectors but the colder it is the more black smoke at start up and then it clears out and runs great.

I've been thinking about it and it doesn't seam like my injectors would have just started leakin all of a sudden but they do have 195,000 miles on them. I have priced new ones and the cheapest I can find are about $50 apiece for remanufactured ones. Anyone know where I can get a better price or rebuild kits? What about good used ones?

OK now, the car starts great and no flooding on start up, hits and starts right up fine. Then in a couple seconds it gets really rich and chugs and puffs black smoke for about 20-30 seconds and clears up and runs fine. I Thought a leaking injector but pulled my plugs after startup and they were all 4 totally black. The colder it is the worse it is. I have checked and an '86 doesn't have a cold start injector. Would the engine temp sensor be causing this? Help, has anyone else had this problem?