Fuel supply 1982

Jan, thanks for the added details! I have been thinking about what you are facing. It seems like there is good reason to hold out hope that whatever is happening is minor to correct. It’s possible that in the 6 months of sitting around that some of those small passages in the fuel distributor have gotten clogged or a few of the injectors are stuck or not spraying well. One thing to try, while your are waiting for CIS fuel gages, is while running the pump, press the air flow plate down by hand. That will allow some fuel to flow through the fuel distributor and the injectors, hopefully helping to free them up. Alternatively, I believe that some people advocate pulling the injectors out and forcing something like WD40 through them. I haven’t tried that myself.

I admire your stubbornness! I’m the same way. I think that’s how we really get to understand these fascinating machines.

Jan, I found this link in my bookmarks for a Baseline Fuel Tuning Procedure. You may need to adjust your air-fuel mixture.
928classics.com/bosch-kjetronic-cis-fuel/

joejabq wrote: Jan, I found this link in my bookmarks for a Baseline Fuel Tuning Procedure. You may need to adjust your air-fuel mixture.
928classics.com/bosch-kjetronic-cis-fuel/

Jan, I think that I might have just experienced what you have. My '79 was running well after having the fuel distributor rebuilt at CISFlowtech. I stopped driving the car and started working on the interior. After not driving the car for ~5 months, it wouldn't start without adjusting the air fuel mixture each time and in fact, it barely ran, finally dying in my driveway. I used the 928classics fuel tuning procedure to try to diagnose the issues. I found that the system pressure was at an inconsistent 60 psi ( it was 75 psi after the fuel distributor was reinstalled and it should be between 65- 75 psi). I pulled the System Pressure value and found that plunger O-ring and the outer sealing O-ring were both broken, In fact, the plunger O-ring was missing pieces. I talked to CISFlowtech, and they suspect that ethanol gasoline combined with sitting, caused the O-ring to first swell and then fall apart. They sent me new O-rings. I installed them and the car is back up running. I'm going to try to swear off using gasoline with ethanol to see if I can keep this from happening again. Luckily, there are a few gas stations not too far from my house that sells ethanol free gas.
I just wanted to pass this along if you haven't found your issues. I'm just wondering if ethanol (combined with sitting idle) could be the root cause culprit for your fuel pump dying and the no start?

HI again and thanks for info
Been at work...Now starting to think about this project again.
I found that if it gets going a bit it wants to start and we are looking into the fuel distributer now next. Found a mechanic who used to work on these systems, and he will come down to my garage with some knowledge and rusty memory, but we have before got impossible things up and running. He also suspect something in the direction of what you are saying. He thinks the fuel plunger is stuck due to a drop of water when the car was run empty and a bit of moisture came into the system from the bottom of the tank. I will let everyone know what we find, but have patience as work is calling this time of year.

So here we are month later.
The car is now up at a Porsche repair place and they have found that the fuel system is "just" gummed up from sitting with gas in it and now it is varnish..
They are not jumping at taking it apart and cleaning all the components.
I was thinking of running some injector cleaner in the whole system and work it a bit so it slowly will dissolve the bad gas in there. Is that a good or a bad idea ??
I have fuel up to a few injectors now so there is flow in general.
What would you use to dissolve the old gas ??

jan wrote: So here we are month later.
The car is now up at a Porsche repair place and they have found that the fuel system is "just" gummed up from sitting with gas in it and now it is varnish..
They are not jumping at taking it apart and cleaning all the components.
I was thinking of running some injector cleaner in the whole system and work it a bit so it slowly will dissolve the bad gas in there. Is that a good or a bad idea ??
I have fuel up to a few injectors now so there is flow in general.
What would you use to dissolve the old gas ??

Is it running now?
This reference from 928 Classics is by Jim Doerr, generally regarded is one of the experts for the early 928's, in particular.
drive.google.com/file/d/1uuj9bm0UfVWtrbxPVGRfaoASQRbQftl3/view
I used his procedure to get my '79 running. He recommends using Berryman's B12 Chemtool to clean the system. I didn't because I started with rebuilt components, but I know many people use B12.