Fuel supply 1982

Jan,
I'm only familiar with my '79 KJET CIS system. Is your '82 this system too? Somewhere it went to LJET, but I'm not sure when.
If it is KJET, then it is all pressure controlled.
I think that your '82 is a KJET CIS (continuous flow) like mine. Anyway, here are some specs for '82's from the Workshop Manual.
The easiest spec to check is the fuel delivery flow rate. This specs assumes that the fuel filter is good and no that there are no flow obstructions.
The fuel filter is, of course, another potential problem source.


Don't know what brand pump you got, but I went with Bosch when I refurbished my system.

Here's another reference that you might find useful.

drive.google.com/file/d/1uuj9bm0UfVWtrbxPVGRfaoASQRbQftl3/view

BTW, if you don't have a copy of the 928 Workshop Manuel (WSM), I got my copy from Roger at 928sRus. It is indispensable!
As you have found, keeping these classics running is both challenging and rewarding!

there are so many things that can be causing this problem. First of all disconnect the fuel line, squirt some gas into the intake manifold and hit the starter.
when the engine starts take note if gas is flowing from the line at that time and if it keeps flowing when the engine shuts down. If gas is constantly flowing then the pump is functioning properly. If gas is constantly there then the next step would be to make sure your new check valve is not stuck in the closed position.

Hi and thanks for answers.
New fuel pump, original, installed and same problem. The car starts right up and dies. Fuel pump is running a second after it dies to build up pressure. So fuel supply to engine is good.
Then today we started up several times. I opened to one of the injectors to see if any fuel was actually coming that far, and it was. I read about the k jetronic system and found out the reason for starting up is the extra fuel valve that gives extra fuel into the air-filter and the mix comes in that way when the engine is cold. That means it dies not use the injectors to start up when cold.
Started several times and the engine started to run rough for a few seconds. Then we did this a few times and found the engine is running the 10-15 seconds and that must be via injectors. It is like it needs some exersize as it has been sitting for a while empty of gas. I also looked at the filter in the warm up valve and it is nice and clean. I guess next step is to find out what pressure there is on the warm up valve. I am learning about this, but again have to leave the project some days for work.
If you have any suggestions now I am this far it would be appreciated.
Cant get the pictures uploaded

OK . I am now assuming your check valve is not stuck in the closed position so you not have to check if your damper is working.
Better yet for quick results just replace it and see what happens. You might be pleasantly surprised.

Jan,
That’s good news that it’s showing signs of life!

I found the fuel system to be the most difficult aspect of my car to understand.
It’s beautiful in concept, but hell if it gets out of wack.

I reread all of your posts and have some questions, just so we are all on the same page.
Your car is a K Jetronic system, correct? It is a “simple” CIS system, right?

You said that it stopped running 6 months ago.
Was it running well? It it just abruptly quit?

While you are on a work break, I think that you are probably right that you are probably headed to measuring the system and control pressures, so you might order a CIS fuel pressure test set with lots of adapters. You will not know what’s happening with the system without Knowing the pressures.

Another thing that you could do is to run some sort of cleaner through the system, particularly because it’s been idle for some time. I use Techron, but many other swear by other products. You can circulate the fuel and cleaner by jumping the fuel pump relay.

Here are a few more references that you may find useful.

forums.pelicanparts.com/porsche-911-tech...hooting-dummies.html

forums.pelicanparts.com/porsche-911-tech...jetronic-issues.html

rennlist.com/forums/928-forum/807102-cis...nal-reflections.html

Hopefully, you will not need these, but here are some places to check the injectors, WUR, and fuel distribution, if needed. CIS injectors can not be rebuilt. Roger At 928sRUs can get You Bosch or Mercedes, should you need them.

WUR and fuel distributor testing and rebuild:
www.cisflowtech.com/

Injector testing:
www.witchhunter.com/

Good luck!

HI again and Thanks for answer.
The car drove up from Fl to New England without any problems after a big service in Florida before the trip. Previous owner then emptied it
for gas, ran it empty as it was going to sit for the winter in the cold. Then in the summer here he sold it to me or rather we did some swopping. I came there with a new battery and some fresh fuel and we expected the car to run. So it did run fine earlier.
The fuel system is a CIS k jetronic system as on older 78-79 928's. It is from Europe and has a /11 engine in it = 300 hp but same fuel system as all older ones. I have earlier used Tectron with good results.
I got a original fuel pump from Roger 928srus which did not change anything. But it was worth a try. So I have a fuel pump for sale...
The car starts up and limps and dies after a little while, but it comes more and more. Now it is sitting for a while as i am out on an assignment.
I will get to it when home again. I have been researching a lot on the internet and a Belgium webpage har a lot of good info, in french, which is not a problem for me, but i have not come to try it yet. We will get there. If not i guess i have to go to a garage who can fix it, but that is too easy (and expensive) Sometimes it pays to be stubborn.