'76 CIS Problems

vance · 02-04-2007, 10:17 PM

I'm looking for some opinions from those of you have had the same experience.

I've all but given up on my stock CIS. It's never been right and now the car will hardly run. I've chased it with money and with little improvment.

Webers are are an obvious solution and since I live in an area that doesn't require emissions testing I don't need to jump that hurtle.

Recently I've discovered a CIS to EFI conversion kit from Bitz Racing. The reviews from those who have installed the kit are very enthusiastic.

Thanks for your input.

RoninLB · 02-04-2007, 10:52 PM

i would think test gauges and an air leak detector would diagnose most headaches. I spent the $75 for the CIS psi tester but never had a chance to use it as the system is so reliable. The leak detector is great to have for all systems.

stlrj · 02-05-2007, 12:06 AM

Before you give up on your CIS, you might take another look into your ignition since even the experts agree that 99% of CIS problems are ignition.

JohnKo · 02-05-2007, 07:12 AM

Vance, a little input (since you asked). None of this is directed at you with any particular malice.

People seem to forget that these cars ran pretty well when they were new -- there's nothing inherently flawed about CIS/K-Jetronic -- and many, many cars used these systems. Like many other things, it's very important to address the fundamentals first, like fuel pressures (and vacuum leaks), as mentioned above. Too many people end up running in expensive circles by avoiding this step and trying to cure fundamental problems by replacing peripherals. It may take money, but it definitely requires understanding how things are supposed to work, and thoughtful troubleshooting.

In terms of driveabilty and efficiency, carbs are a step backward. EFI is newer technology, probably offering increased driveability and efficiency with O2 feedback, but a conversion's not going to be cheaper than proper repair of the CIS.

One guy's opinion. Good luck...

vance · 02-05-2007, 07:36 AM

JohnKo:

Exactly the input I'm looking for. No concern about malice.

Thanks,

vash · vash's Garage

have you posted your problems before? if not, what is going on? have you run the system thru the paces with a set of gauges?

vance · 02-05-2007, 08:33 AM

vash:

have you posted your problems before? if not, what is going on? have you run the system thru the paces with a set of gauges?

I haven't posted these prolems before. I have pretty much left the care of the CIS up to my mechanic, but that doesn't seem to be working. Hard start, doesn't idle and sort of hunts under normal running. I don't have the necessary test equipment.

Thanks,

vash · vash's Garage

damn, that sounds like a mixture issue. at least that is where i would start.

azasadny · azasadny's Garage

Tab Tanner from Autobahn Garage in Findlay, OH replaced my CIS with Webers and I'm glad to be rid of the CIS. My CIS was cobbled together and never did work properly and I spent alot of time and $ chasing down several problems. One problem was an old burglar alarm that was still interfering with the ignition and fuel pump circuits. Once that problem was found and fixed, the fuel distributor had problems as well as the replacement fuel distributor I had as a spare. Instead of spending the $ to replace/rebuild the fuel distributor, I went along with Tab's suggestion to switch to Webers and I'm glad that I did.

The engine compartment is much cleaner and easier to work in and the high pressure fuel lines are gone. The Webers provide much better throttle response and I love the sounds they make. I don't recommend switching from CIS to Webers just for the hell of it, but if you're having problems with the CIS and the parts prices seem too much for you, you might want to consider the Webers! Good luck with the troubleshooting!

vance · 02-05-2007, 01:40 PM

Art Z:

“but if you're having problems with the CIS and the parts prices seem too much for you”“

You've pretty much nailed it on the head. The new parts are exensive and the results have never been very good.

Thanks,

Hladun · 02-05-2007, 03:11 PM

Owners with CIS problems are usually the problem.

76carrera3.0 · 02-05-2007, 07:01 PM

I bought my 76 1 1/2 years ago. When I first bought it it ran like crap. I knew nothing about CIS when I started. Don't dump a bunch of money into it until you have diagnosed the problem. Get yourself a gauge and arm yourself with the correct literature and specs for you engine. Study the literature and ask questions here. Do the checks in a orderly manner, stop, think and read/search, ask more questions then continue on with a new path forward. If you hope to get it all sorted out in a day its probably not going to work out well. If you take it slowly over the course of a few weeks or even a month spending the research time in between you will solve it I'm sure it work for me it just took awhile, the car now runs like a champ. I agree it sounds like a mixture problem if its hunting. You need a exhaust gas analyzer, and a set of gauges to start with. DON'T DO what I did and through a WUR on it or anything else for parts till you know. Mine turned out to be nothing more then a poorly adjusted mixture and decel valve. Thanks to a previous owner. I also agree with the ignition problem theory. If the dizzy is worn it will do some weird stuff at idle as well. Found this out as well by working thru the problems, but I never dumped the money to it till it was diagnosed. Work at it and the answers will come they always do.

vance · 02-06-2007, 07:20 AM

A couple people here have suggested ignition problems as a possible solution to my rough running engine rather than the CIS. Anyone have experience replacing points with the Ignitor Electronic Ignition sold here on Pelican?

Thanks

RoninLB · 02-06-2007, 07:34 AM

get it running properly before compounding the problem.

buy the CIS psi gauge set and come back here.

$75-100 is cheap for Independence.

calling911 · 09:56 AM

Quote:

Originally Posted by RoninLB

get it running properly before compounding the problem.

buy the CIS psi gauge set and come back here.

$75-100 is cheap for Independence.

I really like the independence line..

Its been awhile, did you figure out your problem or give up?

I have a 76' thats been out huntin'. wabbits. . I just grabbed a injector and wiggled it and it mysteriously went away.. gee a 45 cent O ring is gonna solve my problem.. I could have thrown some parts at it but if you go thru the procedures CIS is a breeze to fix.. and when its working correctly it will give you very good driveability.. anybody considering giving up on their CIS should think twice and three times. If you are going to remove it to install carbs, why not remove it, replace all the rubber and reinstall? Seems like it would be a bit cheaper and more gratifying to me. Its usually RUBBER that fails in these things.. SOMEWHERE... just find it.. A) read the Bosch manual so you understand the concept B) remove ALL of it and determine what is physically bad C) Do some bench testing and D) reinstall/adjust.. I bet A-D fixed 90% of all CIS problems for another 20 yrs of driving glee.

Sorry to bring this back but was curious what happened here.

MURF · 01-07-2008, 09:05 AM

i did t bitz on 83 with cam timing kicked up to euro carrera 3.0 specs and was delighted with response idle and overall performance was very happy for 2 years.sold car for 930

T77911S · 01-07-2008, 09:50 AM

dont forget, if you put carbs on you have a whole new set of problems. you basically have 6 carbs to adjust and adjust the same. yes better performance, they sound awesome and look even better, but i love the 20+ mpg i get from CIS. CIS is a VERY reliable system and only ONE mixture screw.
the hunting is due to running too rich. put an allen on the adjustment screw, note its position, turn it CCW about a half turn, then CW until it is an 1/8 turn less that original setting. keep doing this until it does not hunt. or, you can turn it CCW until it starts to run bad and CW until it runs starts to run bad and the set it in the middle. i would do the first. the only way to set it properly is with an exhaust gas analyzer, but this will get you running better.
(if i had the $$ i would put on carbs, even though my CIS is in very good condition)

calling911 · 01-07-2008, 09:55 AM

Quote:

Originally Posted by T77911S

dont forget, if you put carbs on you have a whole new set of problems. you basically have 6 carbs to adjust and adjust the same. yes better performance, they sound awesome and look even better, but i love the 20+ mpg i get from CIS. CIS is a VERY reliable system and only ONE mixture screw.
the hunting is due to running too rich. put an allen on the adjustment screw, note its position, turn it CCW about a half turn, then CW until it is an 1/8 turn less that original setting. keep doing this until it does not hunt. or, you can turn it CCW until it starts to run bad and CW until it runs starts to run bad and the set it in the middle. i would do the first. the only way to set it properly is with an exhaust gas analyzer, but this will get you running better.
(if i had the $$ i would put on carbs, even though my CIS is in very good condition)

You don't think that there is a reason for being out of adjustment? You think the mixture magically changed? I don't. I would guess he has a problem that caused the car to run rich.

ljowdy · 01-07-2008, 10:07 AM

This is such a volatile topic. It's been my experience that less than experienced mechanics that don't know much about CIS recommend Carburetors as "the" solution where as experienced mechanics recommend repairing the CIS.

calling911 · 01-07-2008, 10:46 AM

Quote:

Originally Posted by ljowdy

This is such a volatile topic. It's been my experience that less than experienced mechanics that don't know much about CIS recommend Carburetors as "the" solution where as experienced mechanics recommend repairing the CIS.

Are you sure you can use the word "experienced"? My guess is there is a little of what you grew up with involved.. I just missed the carb days.. barely.. Im 42but didnt get into cars till my late 20's.

All I can say is progress is a beautiful thing!