What is CIS?

[Brian993]

I am new, and trying to learn as much as I can about the mechanics of my car, its much different than american! What is a cis, any info would help as well as pics without airbox. I cant work on mine as its to cold and snowy. Before I even touch it I guess I should know what it is.

Thanks for your help!

[wckrause]

CIS = Continuous Injection System

This is the name of the Bosch fuel injection system that was used on Porsches from 1973.5 to 1983. It was also used on many other high end European cars.
It is an electro/mechanical system that uses a moving sensor plate to measure the amount of air being drawn into the car. The movement of this sensor plate causes the fuel distributor to inject the proper amount of fuel into each intake runner so as to reach the correct fuel/air mixture. The basic operation of the system is rather simple, but it gets more complicated as devices are added to improve cold starting, prevent vapor lock, and decrease emissions.

A good source for more information can be found in a book by Probst on Bosch fuel injection.

[Doug Zielke]

C.I.S.= Confounded Injection System

(Sorry, Bill )

[Kurt B]

Isn't cis either k, d, or l bosch injection? Why do they call it CIS?
Which one is it?

[stormcrow]

Continuous injection system means the fuel is being delivered to the engine all the time. Newer systems have puls injection which is controlled by a onboard computer to controll the amount of time that the fuel injectors are open.

Older systems used mechanical engine driven pumps timed with the engine to deliver measured quantities of fuel to each cylinder.

Steve

[Saffs]

CIS is K-Jetronic. For the Euro people among us, of a certain age, we probably grew up with it, and learned to fiddle on it well. Mostly, it's less than "high end" cars actually have it, really. High end - apart from the Porsche - would be L-Jetronic - thinking of BMW et al. in the mid to late '70s.
K-Jet in Europe was seen in smaller BMWs, VWs, some Euro Fords, Volvos and Saabs, too, I think, but am not sure. (I wonder who had it first? As well as the 911 '73.5 having it, only in the US, the BMW 520i circa '74 had it after it stopped using Kugelfischer MFI).
It's known as being superbly reliable, too. It was kind of a reassurance to know you car was K-jet - albeit scary and insurance premium enhancing - as opposed to a carb, or worse, Lucas....
All the cars I've had with K-jet, I've have never had a problem with it, really. Likewise with the Porsche....
A great system, in a kind of everyday way, if you ask me, and one that I've traveled many thousands of miles with....

[beepbeep]

It's the thing we 930 users are trying to get rid of :-)

Pretty reliable tough...

[wckrause]

Along with Porsche, various versions of K-Jetronic CIS (K, KE5, KE3, with Lambda) were used on Audi, BMW, Ferrari, Lotus, Mercedes, Rolls-Royce, Saab, Volvo, Peugot, and VW.

KE5-Jetronic was used by Mercedes on the 300SL and 500SL well into the 90's.

So high end, and near high end.

[Brian993]

Does my 74 911 targa have this(dah)? I really dont know!!!

[Saffs]

Bill, in the US you didn't get the dubious pleasures of an '80s "pocket rockets" as the term was coined for "hot hatches", small but fast, neat handling hatchbacks. There was many in Europe - although the Golf GTI got to the US, of course, and a few others. Among these was the Ford XR3i, Peugeot 1.6 and 1.9 GTI (a great car, actually), Vauxhall GTE, (these were also Opels), VW Golf GTI Mk 1 et al.
The Ford XR3i was a boy racer legend in England. They were often tarted up in a "ricer" fashion. But they were great in a way. And now as an '80s icon.
Anyhow, all these cars were all K-jet in some stage of their life. And this was like the normal car persons exposure to K-Jet and fixing it. These cars are no where near high end, at all, although were sporty models. K-Jet was really across the whole range of car status.
Incidentally, what Rolls had K-Jet? Didn't know they used it. I thought the high end, large BMWs all were L-Jet too, post '77 or something and D-Jet before. Only the E21 320i (US), 323i and early E12 520i was K-Jet, to my memory. The E30 3 series was L-Jet.
Fascinating thread

[Saffs]

Originally posted by BigBpainta
Does my 74 911 targa have this(dah)? I really dont know!!!

It would of come with CIS when new, BigBpainta. No 911 CIS engine pics to hand for you to reference, sorry.

[pwd72s]

CIS? Doesn't it really translate to "buy a pop off valve"?

[Brian993]

I have a pop off installed! No worrys there. Car starts right up runs great. Just wanted to know what I am dealing with. Getting an education, instead of messing with it and messing it up. Come spring at least I wont be scratching my head. Whats this whats that(dah)!

[Wrecked944]

Here is a link to a website that explains the CIS system as it applies to Porsches...

http://members.rennlist.com/jimwms/CIShome.html

[wckrause]

The first chapter of the Probst book has a chart showing usage of Bosch FI systems in Euro cars. It says that all Rolls-Royce's had K-jetronic with Lambda, but doesn't provide any more info. Somebody on this board owns a Rolls, he would know.

You're right about the BMW's only the 320i had K-jet (but it was one of their best sellers).

[Saffs]

Originally posted by pwd72s
CIS? Doesn't it really translate to "buy a pop off valve"?

Oh, God, don't remind me, I haven't got one....!

Bill, in the UK we got the 320i for a year in '76 - '77 and then got the 323i, which was a great car - with K-Jet. I used to have a '77 320i in the UK and it was quite a rare car when I owned it in 1989 or something. I came to the US and they're everywhere, and the only E21 to make it in as an official model, right?
My proudly owned, "rare" E21 was not a conversation stopper no more....

[roGERK]

Late 1970s and early 1980s Rolls Royce Silver Shadows had K-Jetronic (CIS) fuel injection.

Its a VERY reliable system, but unfortunately doesn't allow for much valve over-lap. Hence its more of a high reliability nice smooth drive system rather than a true high performance one...

- roGER

[Saffs]

Not seen you for a while, roGERK.
Thanks for the info on Rolls and K-Jet, amazing, I never knew that....

[epbrown]

A-hem! Sure, it was added for the 2nd series of the Silver Shadow, from 1977-1980, and that, along with the climate control system, is one of the main reasons for going with a SS II. I miss the cold start reliability in my early car, though I'll concede that the dual SU carbs haven't let me down yet.

I am surprised to hear that the K-Jet wasn't just for high-end cars - since Rolls-Royces and Porsches were the chief two cars I've heard of it in.

Emanuel

[Saffs]

Originally posted by epbrown
A-hem! Sure, it was added for the 2nd series of the Silver Shadow, from 1977-1980, and that, along with the climate control system, is one of the main reasons for going with a SS II. I miss the cold start reliability in my early car, though I'll concede that the dual SU carbs haven't let me down yet.

Emanuel

I still, can't believe I didn't know RRs had CIS....
Emanuel, next to CIS the system I know best is SUs. A bit of a bugger to balance them when there's two, or three a la E Type and XJ6, but great carbs nonetheless. You kind of learn them in school in the '70s in the UK.