main fuel line pressure

[antonio8ac]

i have a 911 t 1974 and i want to know waht is the pressure for tthe main fuel line
with cis

thank in advance
antonio

[kodioneill]

the control pressure changes. the operating pressure can be as high as 5 bar as low as 2.5 bar

use the search function hundreds of posts on cis pressure.

[boyt911sc]

Originally Posted by antonio8ac

i have a 911 t 1974 and i want to know waht is the pressure for tthe main fuel line
with cis

thank in advance
antonio

Antonio,

A single Bosch CIS fuel pump for 911 does not deliver more than 100 psi. Do not use fuel line/s that are not intended for fuel injection. The regular fuel hose used in carburators have low bursting pressure. HTH.

Tony

[antonio8ac]

what is de pressure coming in to the fuel injection pump and how to adjust

thanks in advance
antonio

[antonio8ac]

how to adjust the CO and were is located


thank to advance

[boyt911sc]

Originally Posted by antonio8ac

what is de pressure coming in to the fuel injection pump and how to adjust

thanks in advance
antonio

Antonio,

Could you offer us some background to your problem/s so people could give you better and appropriate suggestions. The questions you have posted clearly showed that you have little knowledge about CIS troubleshooting. Please pardon me if I offended you by my last statement. That's not my intention but to make you aware that the above question does not make sense at all.

Were you refering to the fuel distributor as fuel injection pump? Keep us posted and will figure out what to do. Thanks.

Tony

[Kemo]

antionio,

I saw your other thread on how to adjust the CO. It looks like you are having some CIS issues similar to alot of other folks on the board.

I have a 78, which is probably the same as your 74.

you have a fuel pump under the gas tank...im not sure if you have an internal check valve or external with your year.

The system pressure is controlled by a few things but the most known device is the Warm Up Regulator. Its a small square box on the left side of the engine just to the left of the middle intake runner. Generally, you dont have the option to control or change the pressure from here. it is what it is. Most people replace the WUR but others have modified theirs to be adjustable.

the Air Fuel mixture, which directly affects the CO percentage, is controlled by a set screw that you access from the top of the Airbox, just to the left of the Fuel Distributor with a 3mm hex allen wrench.

It sounds to me like you are stuck in a situation where you have no mechanics around to assist you. Unfortunately, it also seems that this is the first time you have had to deal with CIS too...

My gut reaction is to tell you to search for a mechanic that can help you out. People who work on Volkswagens generally understand Porsches too and can probably help you out. Also, VOLVOs used CIS over the years I think, so anyone who would work on those cars could probably help you out as well. In this case, I would wager that it would be cheaper to pay someone to fix this rather than blindly replacing parts.

If you have no other option but to do it yourself, buy Wayne's book called "101 Projects for your Porsche 911". This will get you some good reading and off on the right foot. I dont know if there is a good book directly aimed at the Porsche CIS system, but I would buy it if there was. Keep researching.

Is there anything else we need to know about your car? There are so many better answers that will come your way if you could just be a bit more specific. jCIS is a fairly complicated system.

Like:
is the car running now?
has it setup for a while?
what have you done so far to troubleshoot?
what tools do you have, like a timing light?
can you take some pictures?