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-   -   three times every start (http://forums.pelicanparts.com/porsche-911-technical-forum/439921-three-times-every-start.html)

calling911 11-07-2008 08:29 AM

three times every start
 
Could someone verify for me I am thinking correctly. I have a 76 that takes exactly three turns of the starter when its cold. In other words.. I turn the key and it starts.. it runs for about 2 seconds and dies. I turn the starter again and it starts and dies after 4 seconds.. I turn it a third and it starts and after 6 seconds it almost dies but keeps running.

Other than that it runs perfectly... doesnt have to cool off all that much and I need to do this again.

cold start injector not working?? Thats what I was thinking and I thought Id test it which I guess means removing it which looks to be a ton of work cuz its hard to get to.. so I wanted some advice before I put in the time to do this.

thanks

calling911 11-07-2008 08:34 AM

Sorry, I did another search and I need to check control pressure first.. out to the garage now..

911Etarga 11-07-2008 09:04 AM

I have the same problem with my '71 (w carbs though). Let me know what you find.

psalt 11-07-2008 09:23 AM

Hello JP,

This usually means the mixture is too lean, the idle speed too low, or if you have a vacuum retard distributor, the timing is too retarded

The thing to remember about the cold start valve, is that it is out of the equation when you release the key from the start position. It has nothing to do with cold running. On later SC models, it is almost always the retard kicking in and causing the stumble. One of the faults with CIS is it was calibrated for a new engine and as the engine wears, there is less vacuum and more vacuum leaks, which result in less air plate deflection and a weaker mixture at idle. I would check the timing, check for vacuum leaks at the injectors with propane (wiggle them), then try a richer mixture.

calling911 11-07-2008 10:18 AM

Quote:

Originally Posted by psalt (Post 4288678)
Hello JP,

This usually means the mixture is too lean, the idle speed too low, or if you have a vacuum retard distributor, the timing is too retarded

The thing to remember about the cold start valve, is that it is out of the equation when you release the key from the start position. It has nothing to do with cold running. On later SC models, it is almost always the retard kicking in and causing the stumble. One of the faults with CIS is it was calibrated for a new engine and as the engine wears, there is less vacuum and more vacuum leaks, which result in less air plate deflection and a weaker mixture at idle. I would check the timing, check for vacuum leaks at the injectors with propane (wiggle them), then try a richer mixture.

Thanks. I'm guessing you are right.. I am too lean. Thanks for pointing out that the cold start injector only fires during starter rotation.. I didnt know that. So thats is certainly not it.

I think between control pressure and mixture I'll get it. Last year I adjusted my WUR without guages.. took a lot of time but my gauges were in a moving truck at the time.. so Im gonna check that and make sure I got it right.. I just dont want to do anything that will change the driveability of the car which is absolutely perfect right now.. I mean it idles, and accelerates perfectly and is smooth as silk huming down any road in any gear.. I crap I just jinxed myself.

calling911 11-07-2008 10:19 AM

Quote:

Originally Posted by 911Etarga (Post 4288639)
I have the same problem with my '71 (w carbs though). Let me know what you find.

I could be wrong.. but I dont think what I find would have any bearing on your car. Maybe someone else can chime in but non CIS is like night and day if you ask me.

So here is my guess on your problem... something with the floats???

Just a stab.

calling911 11-07-2008 10:49 AM

You know, I just need to follow MY OWN advice. :)

http://forums.pelicanparts.com/showthread.php?t=387704&highlight=cis+mixture+adju stment+allen+wrench

Paulporsche 11-07-2008 11:51 AM

[QUOTE=calling911;4288877]You know, I just need to follow MY OWN advice. :)

True, although now that you have your pressure gauge, you can measure what works, have it as a benchmark, and post it to get it on the record.

For example, I've recently "discovered" that apparently my engine needs a CP spec that is lower than stock.


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