Re-read my CIS book last night, and I have more questions.

lendaddy · 08-05-2003, 05:51 AM

The Bosch book on CIS is very informative, but I thought I saw a section on troubleshooting last time I read it, but alas, no.

Anyway I have an intermittant problem of my idle floating between 950rpms and 1100 rpms. It does not do it all the time, which is weird to me. It does it warm and hot, but again not all the time(maybe 1/3 of the time). And another CIS issue I have which may be related is really poor cold running. When I start her cold she idles rough and stumbles on load. This only lasts for maybe 45 seconds of driving then totally disappears. Could this be related? I am thinking cold start injector. Could be dripping occasionally and causing my random idle flux and not giving sufficient fuel for cold starts? Any thoughts? Thanks.

I have had the injectors cleaned, flow tested, vloume tested into jars, and checked my system pressure and pump volume. All were good.

1fastredsc · 08-05-2003, 05:53 AM

Actually it sounds too rich. I think lean mixtures cause back fire and popping. Rich ones cause idle hunt.

lendaddy · 08-05-2003, 06:04 AM

Yea, I thought that too and it still could be but I put a A/F meter on her and I was right at 13.5/1 at idle and reving W/O load. I have not caught her on the meter while hunting but I doubt that would tell me anything as I aam sure the guage would be all over the place while hunting. I would not be able to determine if the hunting was causing the mixture to fluctuate or the mixture fluctuating was causing the idle to hunt. Did that make sense? Plus if I were rich I would expect it to be all the time.

Thomas Owen · 08-05-2003, 06:20 AM

Which book are you refering to? I have 2 books on CIS - one is 'Solving Bosch CIS Problems' by James Weber and the second is 'Bosch Fuel Injection and Engine Management ' by Charles Probst. They helped me troubleshoot problems I had with the 3 CIS 911's I have owned, but now I have the Motronic system.
You are welcome to borrow either one, or both.
Regards,

lendaddy · 08-05-2003, 06:38 AM

Thomas,

That is a very generous offer. If you are willing I will forward you my address. Thanks again!!

1fastredsc · 08-05-2003, 06:49 AM

Timing? When was the last time you did a carbon clean up in your motor? GL with your troubleshooting.

lendaddy · 08-05-2003, 06:54 AM

Timing was dead on last I set it. Dizzy is new so I doubt any issues there. I will double check though. Could be carbon buildup I guess, maybe time for some Techron huh?

Thomas Owen · 08-05-2003, 06:56 AM

Send me a mailing address and the books will go out today.
Regards,
Tom

lendaddy · 08-05-2003, 07:02 AM

Thomas, you have a PM. Thanks again. This board is fantastic!

Bones · Bones's Garage

Techron? ...we don't have that in the UK what is it a carbon deposit remover?...Did anyone come up with the correct place to spray in water on the CIS engines and if not can any Pel's from the UK recommend a carbon depoit remover?