fbarnhill

Hi,
I know this question has probably been asked before but I have searched the archives and not come up with much.

Is there a document that gives the steps to go through to troubleshoot the CIS system? The WSM does a good job for the L-jet folks but mine doesn't say much about the CIS. My 79 Euro just doesn't want to find its 'BWAAAH'. I'v got it running pretty smoothe, and it will at least take off without stalling but it just builds the revs slowly. It will get to redline but it gets there in its own sweet time. It seems to be either not getting enough fuel or the mixture is wrong or the timming is off. I have the timming at 31BTDC at 3000 and have even experimented with bumping it a little. It just doesn't have much effect.
Any suggestions would be greatly appreciated

macreel

fbarnhill... see if this will help:
"How to Tune & Modify BOSCH Fuel Injection",
Ben Watson; MBI Publishing, 1992.

Also, 'tho it's VW, much of the CIS words apply:
"Compleat Idiot's Guide" for VW Rabbits, John Muir Press.


G'luck.

Dennis Wilson

Frank,

Haynes has a good book titled fuel injection manual which covers how to test the CIS system. You will need a CIS pressure test gauge (JCW for about $60). Before jumping into the fuel system, try checking the vacuum advance on the ignition distributor. Will it hold a vacuum? When vacuum is applied does it advance the plate in the distributor? Are the correct vacuum lines connected to the advance and retard ports on the distributor? BTW the timing at idle with the vacuum lines removed and plugged should be approximately TDC (0).

Dennis

fbarnhill

Dennis and macreel, Thanks for your suggestions. I will look up the books tonight. I know it has to be something simple. Dennis, I suppose it is possible that the two vacuum lines to the distributor are crossed. I will check it out first. I can't wait to get this thing running right. Two things I know. 1) my US 79 5 speed was much faster and more powerfull so this Euro version should have around 20 more HP if I read the lit correctly. So, I know it is capable of doing better. I have an appointment in Charlotte in August with a 928 CIS specialist but I would love to figure it out on my own!

Thanks again,

Dennis Wilson

Frank,

The early (78 and 79) US and euro versions were nearly identical. The HP difference was due to the air pumps and cats on the US versions.

Dennis

fbarnhill

Dennis, how does your 78 accelerate? Will it bark the tires on a flat out start?

Dennis Wilson

Frank,

My 78 US 5 speed will break the tires loose but my 78 Euro AT won't. Well, the Euro did once before I realized the front brake calipers were stuck.

Dennis

macreel

Frank... check your cam timing; i.e., timing belt
and timing marks all set true. Sounds like ignition
timing ~ok.

G'luck.

fbarnhill

Macreel,

That is just what Jim Bailey at 928 International said today. I just replaced the timming belt and made the 1k adjustment. The marks were spot on... It was very hard to spot the marks on the back of the sprokets but I did find and mark them. When I line up TDC, both cam towers are right on the money. I could be wrong though. It sure is a lot of work to re-check it but I think I will. I re-did the intake thinking that was the problem. Well, for now, it is running better than it has since I got it. It has a little pep but just enough for me to feel the potential....

hupp

Dennis,

Should'nt the 79 have a vacuum retard only. Reason for my question: My '79 US 5-spd has one line attached to the distributor, when this line is removed the idle speeds up. I've also notice some other discussion regarding timing and have read where some folks have a single line and some folks have two vacuum lines routed to the distributor. Just wondering what the correct set-up for a '79 US 5-spd is.

fbarnhill

Hi Scott,
My 79 Euro has two lines to the distributor. It has one on top and one underneath where you might not see it.
Guys, I switched the two lines and it made a huge difference. The idle went immediately to 1500. I adjusted the idle, put the timming back to 31 and adjusted the co. The car runs much better. It's not perfect yet but it at least has some power. It has a slight miss but other than that it runs great. Is it possible these were switched? What would be the effect of having them switched?

Thanks,

Rich9928p

My '79 Euro had clogged injectors and the fuel distributor also had some cloggs that I couldn't clean out. I replaced all the fuel injectors (less expensive than their electronic brothers), the rubber grommets (can crack and leak vacuum) and had a fuel distributor rebuild. That made the difference for sure. As a minimum, I'd suggest that OLD BOY owners replace the fuel injectors.

There are also little screens at the top where the fuel lines bolt onto the fuel distributor, I just removed them since there is no list of a part number. These screens can be clogged along with the injectors (that have screens inside).

Dennis Wilson

Scott,

If you have a single line then it will be for vacuum advance rather than retard. The increase in idle is probably due to a vacuum leak rather than a timing change. Try checking the vacuum at the line at idle and wot. If very little vacuum at idle and more vacuum at wot, that is the advance line and should be connected to the outside port on the distributor. THE WSM only shows the dual advance retard schematics for the US version but that doesn't mean there aren't other versions out there. Sort of like the fuel pump placement on early cars.

Dennis

Dennis Wilson

Frank,

Switching the advance/retard lines would cause the ignition to be too advanced at idle and only have centrifugal advance at wot. Think you have fixed the timing problem. Now you need to find the reason for the miss. As Rich mentioned, try checking the injectors and lines to make sure they are clear. After a CIS car has sat for long perionds, shellac can form and migrate throughout the fuel system when restarted. Also, check for oil fouling or fuel fouling of the plugs. A crack or dirt in the distributor cap could also cause the miss. And don't forget to check the plug wire for cracks/leakage.

Dennis

fbarnhill

Dennis,
Thanks for the help. I have replaced all the plugs, wires, dist cap, rotor and just about everything else but the injectors and fuel distributor. I pulled the tank , replaced the lines and cleaned it out. It was already pretty clean. I am going to just drive it for a while and take it to the specialist in August. I have already put 4k miles on the car in 6 months. It is really a nice car and I think it's worth getting right

Thanks,
Frank Barnhill