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breathe, pause, think.
 
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Join Date: Nov 2001
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930 CIS, WUR, etc.-any books available?

Are there any books that explain the CIS, WUR, tuning, etc. FOR THE 930 MOTORS SPECIFICALLY?

I have a limited understanding of the fuel delivery system for my 77 930. And every time I read these types of posts, I'm convinced I could tune my motor for optimum efficiency and power if I had a better understanding of the information. I've read alot of tidbits about CIS, WUR's and fuel pressures from posts on this BBS, but I'm just not getting the big picture.

The extent of my "tuning" has been limited to adjusting the AAR and setting the CO%. Then for the next month or 2, I have to adjust the idle to compensate for a high idle at low oil temps (through warm up) and a low idle at high oil temps/traffic situations.
I'm convinced that my WUR has a problem.

I'm thinking of purchasing an LM-1 system so I can get the basic information I need from my motor (under real driving conditions)to do this correctly.

I have the factory manuals, am I missing something?
Any tips?

thanks,
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Old 02-28-2007, 08:58 AM
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I'd suggest tracking down some of the annual supplements that Porsche produced for each model year. There's some good information in those.

Your problem is a little different. Sooner or later, when trying to sort out a problem like this, I suggest starting with the basics. Too often, we tend to look at specific components that we think could cause a particular problem. In the end, I think it would be quicker to just start with checking for vacuum leaks, fuel pressures and so on. Don't forget that the ignition system needs to be considered as well. Make sure that the advance/retard is free and functioning correctly.

JR
Old 02-28-2007, 05:12 PM
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Crotchety Old Bastard
 
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"Solving Bosch Continuous Injection System (CIS) Problems" by James Weber is a good start.
Also go to Rennlist and find Jim Williams tech articles on the subject.
Pelican has good info in their tech section as well.

The idle does not normally fluctuate due to WUR issues. Many things (unfortunately) contribute to idle quality. There are various thermal and time switches and valves that regulate idle during the warm up cycle. What you are describing sounds like the initial cold start idle is set too high and then comes down too low when warm. Is that right? Have you bench tested your AAR? Vacuum leaks on the hoses connecting the cold activated CIS components?
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 02-28-2007, 05:57 PM
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breathe, pause, think.
 
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Quote:
Originally posted by RarlyL8
"Solving Bosch Continuous Injection System (CIS) Problems" by James Weber is a good start.
Also go to Rennlist and find Jim Williams tech articles on the subject.
Pelican has good info in their tech section as well.

The idle does not normally fluctuate due to WUR issues. Many things (unfortunately) contribute to idle quality. There are various thermal and time switches and valves that regulate idle during the warm up cycle. What you are describing sounds like the initial cold start idle is set too high and then comes down too low when warm. Is that right? Have you bench tested your AAR? Vacuum leaks on the hoses connecting the cold activated CIS components?
Hi brian,
Yes, the cold idle is at ~1500 and after driving it for a while (oil temp to ~190) it will eventually drop to ~1000. If I park it and restart it ~1 hour later it will idle at ~400-500 RPM.

Thanks for the tips guys, I'll start reading up on testing procedures in the factory manuals and maybe I can find that book from James Weber.

I think I'm too rich under boost...it stumbles to get to 0.8 bar and my gas gauge is dropping faster than normal these days. I haven't checked for vacuum leaks for a while, I can start there.

Thanks,
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Old 03-01-2007, 06:31 AM
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Crotchety Old Bastard
 
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If you are running that rich the cold pressure may be too low.
Do you have CIS tools to check your fuel pressure and CO?
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 03-01-2007, 09:37 AM
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breathe, pause, think.
 
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I can get the fuel hoses and guages from my friend, but I'll likely be purchasing the LM-1 package to check CO% and AFR's. I'll look up the cold pressures from the factory manuals and go from there?
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Old 03-01-2007, 10:17 AM
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There's a CIS trouble shooting book that explains how it works pretty well. I don't who the author is though.
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Old 03-01-2007, 10:36 AM
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I was told this was good and just ordered it from Amazon..

Bosch Fuel Injection and Engine Management (Bosch)
http://www.amazon.com/Bosch-Fuel-Injection-Engine-Management/dp/0837603005

This looks good also..
http://www.amazon.com/gp/product/0879385707/ref=sip_pdp_dp_0/002-5823941-5068045
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Last edited by GaryR; 03-01-2007 at 11:06 AM..
Old 03-01-2007, 11:04 AM
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'how to modify and tune Bosch CIS fuel injection'.

Is this a good book also...I was going to buy it this weekend...

Thanks

Bob Snyder
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Old 03-01-2007, 11:16 AM
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http://www.amazon.com/gp/product/08...5823941-5068045
http://www.amazon.com/Bosch-Fuel-In...t/dp/0837603005
For $16.46 + $19.77 with free shipping just get both of the darn things!
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Old 03-01-2007, 11:23 AM
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Looks like I'm hittin' up Amazon this weekend!

Thanks for the info folks!
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Old 03-01-2007, 02:00 PM
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