# Most basic cis system



## vwgolfcr (Jul 7, 2003)

Hey guys!

maybe you can share some knowledge with me!

i vas wondering if i can run a CIS basic without the ECU?

Pump, fuel dist, and injectors! no WUR and no ECU

FIRE AWAY!!

Thank you!


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## prjkt84 (Jan 9, 2009)

Wow , do you hate yourself today?


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## vwgolfcr (Jul 7, 2003)

c'mon guys! aren't you going to flame me? 

I DARE YOU!

I DOUBLE DARE YOU!!

well now seriously! gimme some clues about the most basic CIS system usable please!!


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## WaterWheels (Aug 14, 2005)

vwgolfcr said:


> . . . i vas wondering if i can run a CIS basic without the ECU?
> Pump, fuel dist, and injectors! no WUR and no ECU
> FIRE AWAY!! . . . c'mon guys! aren't you going to flame me?


Any and all tricks a side, CIS as we refer to it here in a Volkswagen forum is going to "require" some of the items you listed. I say tricks because CIS is an acronym and it is possible to build an injection system that might keep a motor running and still fall under the three letters of the acronym.

The most basic version is referred to as just that "basic CIS" or "CIS basic". Basic CIS has no ECU of any kind, not for fuel, not for ignition or emissions or anything.

You ask if you can "run" it without any of the items you listed. That is kind of a loaded question as the word "run" could mean that the motor starts and stays in motion or it could mean that you intend to operate the engine on say a public street in traffic? I have to go with the idea that this is going to be used on a street as a "normal" vehicle. If not then I guess you’re just playing games.
*Pump *- If you can somehow produce gasoline to flow under pressure without using some type of pump then yes, you could delete the pump from the complete system. If you have no other or better way then I guess that answers that one.
*Fuel distributor* - This is like the pump, as all really are, if you have a better way to get the fuel in the correct amount to each cylinder then by all means use it (but it will then be referred to as a "fuel distributor just as fuel rails are). And then there is the engine speed and load conditions to deal with. You need to be able to adjust the fuel delivery as these things change too. 
*Injectors* – These would be hard to delete but “could” be dropped if you didn’t use the motor for driving. You do not have to have the fuel on a CIS system delivered through injectors. Only problem is that if the fuel were to be delivered to the individual cylinders through other means the engine would not run very well. The injectors atomize the fuel and if it were just “poured” in, as a stream or droplets, the motor would not run real great. The injectors also hold some fuel under pressure when the motor is shut off which aids in hot starts, so you would lose that benefit too.
*WUR* – This item could be deleted if you really had to for some weird reason. The acronym WUR is really not used much anymore as it was sort of incorrect and it is now called a control pressure regulator as that is what it really does. If it were deleted there would be no adjustments made to the top of the fuel distributor plunger, which would not matter if you had a way to remove that item, and the mixture would suffer. Cold enrichment and warm operation would have to be set to a “middle ground” setting and this would make driving a real hassle at times. To be honest, I have a feeling that the control pressure regulator was a kind of afterthought and the original development systems did not have one. But that is just my belief, nothing more.

Cold start injector could be removed but it would make cold starts hard, idle air by-pass valves or auxiliary air valves could be removed but they too would cause driving issues. But really I just have to ask; What is the bottom line here with this question?


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## vwgolfcr (Jul 7, 2003)

I want to run an aircooled engine with CIS injection, the thing is that ill be using the vehicle for off road and having a lot of extra stuff on or around the engine is not what i want!

i believe that the CIS injection is a great option! 

ok
obiously the pump airflow meter, distributor lines and injectors are MANDATORY.

as you say, CPR is also needed. 

if I set the idle with the adjustment screw in the TB are the idle air by-pass valves or auxiliary air valves necesary? i think people get tired of funny idle and delete them!

you seem knowledgeable, does an aluminum fuel dist. work fine with the FPR(grey box on the right side) disconnected? or is it better to get the iron fuel dist??

thank you very much for your input! i hope you can help me some more!


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## WaterWheels (Aug 14, 2005)

I'm going to have yo look into this a little as for some reason I remember CIS being used on air cooled Beetles at some point, maybe it was a conversion?

For the time being I'll say this.
The aluminum fuel distributors, VWMS units a side, are all some form of electronically trimmed CIS systems. I really don't think this is the way you want to go. To be honest I really don't think CIS is your best route either. Have you thought of using something like Digijet?

Correct, if you use the screw on the throttle body to set the idle then the by-pass valve and even the AAV can be deleted. Might cause a little warm-up issue like using a carburetor without a choke and the idle may wander a little, but you can do without them.


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## Glegor (Mar 31, 2008)

WaterWheels said:


> I'm going to have yo look into this a little as for some reason I remember CIS being used on air cooled Beetles at some point, maybe it was a conversion?
> 
> For the time being I'll say this.
> The aluminum fuel distributors, VWMS units a side, are all some form of electronically trimmed CIS systems. I really don't think this is the way you want to go. To be honest I really don't think CIS is your best route either. Have you thought of using something like Digijet?
> ...


first VW cars to receive CIS were super beetles in the 70s...


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## didget69 (Jan 5, 2010)

*Incorrect info*

VW Aircooled Beetles/Vans NEVER had CIS injection from factory - they only had electronic injection, like D-Jet or L-jet.

A guy by the name of Gary Miller made kits/components to adapt CIS to aircooled VW engines - 

didget


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