John..

I used to take my CIS injectors from my 79 Scirocco to the Bug Shop in Milford, NH where they had a little hand operated injector cleaner setup. Sounded like a little chirpy bird every time the injector opened up.

I am still amazed that Porsche kept the CIS so long on the 911 turbos. Someone told me changing to a stand alone with the same amount of boost on a 930 yielded 100 HP. Not sure I buy that, but I agree electronic is better. Now, lets talk about fitting that MAF conversion setup to the CIS...just kidding.

Nonetheless this is all good information. I have some people inquiring about the turbo setup for the CIS cars. I was planning on avoiding that whole system which is why 928 International got my entire Euro induction (minus those big heads and cams of course) in trade for a US L-Jet top side. Hindsight is always 20-20 and I now wish I had a CIS setup to play with. Too many lines going in too many directions...I'm so confused!

Randy V

Thanks for your assistance Carl - here's my problem:

At engine revs over 5,000 (while driving), when it returns to idle the engine lugs like it is missing on one or more cylinders. The engine seems to run fine at above idle speeds. By turning the engine off for approx. 5 seconds and restarting, the engine idles smoothly again.

In the not-too-distant past I've replaced all electrical components during a routine freshening (coil, wires, plugs, cap, rotor) and and last year had replaced a balky fuel distributor with a rebuilt one to cure a 2000-rpm miss.

Vacuum lines have almost all been replaced.

I've had suggestions that it may be vacuum-related, but have had no conclusive issue to address.

Any ideas?

Carl Fausett

I actually had that happen to me on my race car.

It was the "Vacuum Limiter" mounted on the side of the throttle body.
Item 18 in the photo attached. Although the vacuum line to it was OK, the rubber damper in side had perforated and was passing air.

It's function (as I understand it) is to prevent the engine from killing if you are up there in the RPM's and suddenly drop off to idle. The throttle plate closes, the engine stubmles and stalls. This lets her down a little easier.

Frankly, on my race car I have it completely disconnected with no problems.

My next guess would be to look at your "Auxillary Air regulator" too.

Start there.

Jim bailey - 928 International

Carl the vacuum limiter I believe was more for emissions part of the exhaust gas recirculation / control circuit .

GlenL

EGR? Do any of these cars have it?

Looking at the cylinder head people often wonder about that square hole in the middle of the head. Could that be a unused access point for the EGR?

Randy V

Thanks, Carl.

I had suspected that decel valve but have not yet removed it. On my car, the small vac hose from the decel valve goes to some other sort of round disc valve - I blocked off the lines from the decel valve to that other thingamabobber but it made no difference. Last time I had my car smogged, they actually saw that and made me reconnect everything for the test - one reason why I haven't completely deleted the decel valve - that and it's a pain to get to the thing.

Chuck Schreiber

Randy,

My 79 does the same thing. In addition, it lopes (like a big cam) and misses when it is really hot out. Looks like it wants to idle at about 250 Rpm's. When it's cold out the car starts great and runs like crazy! If you figger it out, let me know.

Carl,

I was the guy getting the big brakes done on the old bugger in Wichita. Sorry I did not get a chance to talk to you in depth about the supercharger kit. I did get a chance to talk to your sons. (great kids!) I meant to come over and got caught up BSing and admiring all the cars at the OC convention.
Really wanted to take a look at the gold car more in depth and go for a ride to check it out with my Assometer!! I think the SC kit is in the future but I need to finish all the have to's before I get there.
I'll probably give you a shout with questions as I get closer.
The SilverBulit needs some guts to back up its name!!!!!!!!!

Rich9928p

It may not be a cure all, but it can't hurt. I replaced all the injectors and grommets in my '79 track car and it made a world of difference. Odds are that even if your injectors have been cleaned (most shops clean them improperly anyway) in a car this old they're not flowing well. OB CIS injectors aren't as expensive as electronic injectors, so the hole in the wallet isn't quite so bad.

Carl Fausett

Thanks Chuck - my kids told me you were interested, but you and I never hooked up at the 928 OCIC. We will! I'm ready for you.

Rich - You are right - if you are serious about your CIS performance a new set of injectors can do wonders.

I am still exploring the dusty nether-regions (sp?) of CIS top end... how far can it go?

I recently made a completely new set of injector lines from the fuel distributor to the injectors with results that could be claerly felt in the drivers seat... but now that I have opened them up I am finding I may be short of volume during WOT right from the tank, so I am addresing that.

I must mention "these are not problems anybody wioth our 6 psi or 9 psi kits would encounter" - I'm playing on the race car and trying to see how far the CIS system will go.


Here are some pics...

Chuck Schreiber

Rich,

I remember talking to you about replacing the inj. at cocktail hr. in Wichita. It may be the first thing I do. 25yr old injectors-definately could not hurt to replace.

Carl, looking forward to talking to you.

jpitman2

These are both marked the same Bosch part no? What are we looking at here - the delivery end with the valve removed?
jp 83 Euro S AT 48k, 4 original, 4 new injectors.....

BC

NIce. DO tell. Thinking about new injectors anyway, and....

Carl Fausett

The center photo is a closeup of the end of the injector lines themselves - right where they attach to the injectors. The bottom photo is the banjo bolt at the top of the fuel distributor. We figure we increased the fuel available to the injector by aboyt 200%