bigfish1744

Car ran for about 20 seconds and then I noticed fuel dripping on the floor at the passenger rear. Shut it down and started to investigate. The rubber fuel line that connects to the accumulator is leaking fuel. I have a message in with Roger to get a replacement line and to see if there is any other ones that I haven't already done. Engine bay and one other have already been replaced.

elgy

Did you get a pressure gauge? I have been going through my CIS system and have documented it here.
https://rennlist.com/forums/928-foru...is-system.html

Where are you in Canada? If you were in the Montreal area I could lend you my gauge.

bigfish1744

Thanks for the offer but I have a set of gauges. I have bookmarked your the thread and will you use as a reference.

I am in Sask. Not too many 928s here. I have seen 1 black 928 in the wild but that was a couple years ago.

bigfish1744

Long time, unfortunately, no significant progress. Got married. House full of kiddos will do that.

Doing my fuel pressure tests. Following the fuel tuning procedure from 928classics. The results I got so far are the following:

70psi
10min - 34psi
20min - 31psi
30min - 30psi

CCP 34psi Temp at WUR 71f.

So if I am reading the chart correctly the CCP is a bit too high.

Cymadesign

Yes, CCP is high so too lean at cold start. Did you continue following the procedure to measure the Warm Control Pressure?

bigfish1744

I haven't yet. Wanted to ask if I should adjust to get the ccp in range before proceeding to wcp or to do both, then make adjustments.

Cymadesign

I found that adjusting the Warm control pressure changed the cold control a small amount. I would go ahead and measure the WCP. Then you’ll know if you need to take the WUR apart or if you can make changes from the outside. You can adjust CCP down and/or WCP up without taking the WUR apart.

bigfish1744

Following the instructions, it is showing a WCP of 40psi.

Cymadesign

Assuming the 40 psi was with no vacuum applied, then I would leave it as is until you can road test the car. I think the spec for your car is 41-46 so you are just on the rich side. Your car should start and run with the warm and cold settings as is.

When cold starting, if it fires but then immediately dies, then it is only running on the cold start injector. You could try installing your gauges and tapping the pin down a tiny amount to lower the cold control pressure.

bigfish1744

Previously when cold starting, it would fire then immediately die. I set up the gauges and tapped the pin down, but the pressure did not change.

Cymadesign

Ok, quick recap. Car hasn’t run for a long time. It will fire briefly and then die. Replaced fuel dist, fuel filter, green wire. System pressure 70psi, cold control press high at 34, warm control pressure is low at about 40psi. Check valve appears to be holding. Tapping the pin in did not change the cold control pressure. Is this correct?

How long ago was the fuel dist replaced?

Is the fuel fresh?

Have you checked the fuel flow rate. I think for your car it should greater than 1100 ml/30 sec when checked at the fuel return on the passenger fender or at the tank return fitting at the top of the gas tank

Have you set the air/fuel ratio as described here? https://928classics.com/bosch-kjetronic-cis-fuel/

Can you hear the injectors squeal when they open

i will watch for your next update
Tony

bigfish1744

Hi Tony,

Yes your first paragraph is correct. Adjusting the pin at the wur made no difference in the fuel pressure. I replaced fuel distributer last year. Fuel tank was drained less than a year ago. New fuel added and has fuel injector cleaner mixed into it.

The fuel flow rate is way too slow. It took over 4 minutes to get 1100ml. Is that a pump issue or something up front? Both pumps were replaced by previous owner but that was over 10 years ago.

I did not proceed to the air/fuel ratio adjustment as those instructions mentioned to adjust the wur to get fuel pressure into the correct range.

Petza914

Loosen the gas cap and check the fuel flow rate again. If your vent hose is clogged, not only will it compromise the flow rate, but will also implode the tank until it cracks from the suction.

Cymadesign

OK, now you have a good starting place. So if venting is not an issue, then the fuel flow problem could be: bad pump(s), plugged suction strainer, or could be insufficient current to the pumps. You could run a jumper wire with fuse from the battery directly to the pump to rule out electrical problems. Do you know if the battery is good?

bigfish1744

Loosened the gas cap and flow rate was still super slow. No improvement.

Tried with two different batteries connected directly to pump and no improvement.