# Stupid question cis order



## MKIGTITDI (Aug 25, 2007)

Is the order of the distributer on the fuel injection block the same as the firing order at the distributor?


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## ds1919 (Oct 13, 2004)

well, I kinda wonder if you're joking, but if you're not, I;ll explain.....

CIS stands for Constant Injection System. Meaning, fuel is sprayed thru the injectors all the time, and "all at the same time". The rate may change, but its always flowin' as long as the motor is runnin'.

if you have an issue with your car, go ahead and elaborate on that so we can try to determine your next step in solving the problem....


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## WaterWheels (Aug 14, 2005)

Think that was no, it does not matter which port the injector lines attach to. It is only important they reach from the injector to the fuel distributor without causing any problems, i.e. getting caught in the v-belt or rubbing on something (stainless steel braided lines can saw their way through things like aluminum manifolds).


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## MKIGTITDI (Aug 25, 2007)

Well its been running great since ive started running straight either 110 leaded or 100 leaded race gas but in a pinch i had to run a tank of ethenol laced 92 in her and now shes just not running right. Its not starting after its been ran and then sits per say to run into a store then when i come out i have to crank the motor for about 30 second to get it to fire again. It also is missing really bad under load above 4500. So im looking into all options. Ive had so many problems with the cis in every mk1 ive had so im getting ready to go to carbs but wanted to hit up one more autocross before i do the swap.


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## WaterWheels (Aug 14, 2005)

Whether you use 87, 91, 100 or 110 octane gasoline will make little or no difference on the engines running. Yeah, if it were a race engine with high compression and race tuned ignition then using a higher octane level might be of some use or even required, but for almost any street engine, 95 is about the highest anyone should need. Using leaded fuel is also not a good idea as everything that required the use of lead has long been changed and more harm than good could come from its use, CAT damage and deposits.

I know none of the above helps with your problems though. The first thing you state, _"Its not starting after its been ran and then sits per say to run into a store then when i come out i have to crank the motor for about 30 second to get it to fire again."_, sounds a lot if not exactly like heat soak. Some would call it vapor lock, where the fuel in the lines gets too hot and begins to vaporize causing a blockage that the fuel has a hard time pushing through (air compresses). The second issue _"It also is missing really bad under load above 4500"_, could be a few things but in this case I would guess a fuel delivery problem. I would think both are related or closely related. First thing I would do is run a complete fuel pressure test to discover if there is infact any fueling issues, which I'd bet there are.


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## MKIGTITDI (Aug 25, 2007)

Thank you very much for the input im going to have a buddy of mine thats a vdub mechanic test the fuel delivery and pressure. With the octane the reason why im running the higher octane as well as leaded is im at 12:1 compression and i dont have a cat or any O2 sensors to make mad either.


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## WaterWheels (Aug 14, 2005)

Don't know or see what you've done to raise things up to 12:1 or why, but leaded is still a bad thing. The lead was there to lubericate things like old exhaust valve seats. That is no longer a problem as they make all the parts out of harder material now and the lead is just an envionmental issue now. I've built some race engines years ago with around 14:1 static compression and raced them on pump fuel. It is easy to say I need 100 octane fuel or whatever, but 95% of the time it is just a matter of setting the engine up correctly. Is this a street driven car? If so then it needs to function throughout the entire engine speed range, not just flat out (WOT). Aside form any issues I or others might find with leaded fuel, if you take a trip be prepared to have to tank up with un-leaded as leaded is getting rare.


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## MKIGTITDI (Aug 25, 2007)

Yeah and expensive i only use the car for racing here any more at local auto-x races. So i usually take a 5 gallon can with me to go to races. My plans are to soon go to bike carbs then in a couple of years im going to build up a racing TDI motor for it so its cleaner and a hell of alot more fun.


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## Glegor (Mar 31, 2008)

hows the check valve? will the system hold pressure after you shut the car off? my GTI does the same thing. have to prime the fuel pump usually after its been running. and if you park on a hill, you gotta prime the pump 4-5 times to get fuel flowing again..


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## MKIGTITDI (Aug 25, 2007)

It shouldnt be that i just installed a new one. I had no issues there for a while (running leaded 100 or 110) until I ran a tank of corn laced 92 and now theres a **** ton of problems.


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## dkfackler (Feb 8, 2010)

WaterWheels said:


> Think that was no, it does not matter which port the injector lines attach to. It is only important they reach from the injector to the fuel distributor without causing any problems, i.e. getting caught in the v-belt or rubbing on something (stainless steel braided lines can saw their way through things like aluminum manifolds).


He's right. Those ports are 'hydraulically identical'-- there is no 'firing order' on the fuel distributor.


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## dkfackler (Feb 8, 2010)

WaterWheels said:


> Don't know or see what you've done to raise things up to 12:1 or why, but leaded is still a bad thing. The lead was there to lubericate things like old exhaust valve seats. That is no longer a problem as they make all the parts out of harder material now and the lead is just an envionmental issue now.


Lead can clog the CIS injectors and give you a hot-start problem. They clog in a way that let's 'em leak. This happened to my '77 Scirocco. A long road trip on unleaded cleared the trouble.


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