bad fuel pressures

[GMR911]

Hi, have some CIS problems. Car has been starting hard when hot. It also has developed a hunting idle when cold and drops RPM's quicker when let off gas almost to a stall. I checked the fuel pressures and their way off. System pressure is 65.5 lbs- too low, control pressure tops off at 58 lbs- too high, and residual pressure drops immediately from 65.5 lbs to 21 lbs and to 0 lbs after 9 mins, way bad. The idle never runs up when cold, even here in the NE where the temp can get down in the fall. Car seems to run fine when warm. Any ideas, Thanks Jerry

[Scott R]

I would speculate that it's the check valve or the accumulator. You appear to be losing system pressure from behind the WUR.

[Paulporsche]

Search those items mentioned above. They are quite common problem areas for CIS cars. You can adjust your WUR, and even make it easily and infinitely adjustable if you want. Once you get the control pressures correct, your running/ stalling problems will probably go away. As mentioned, the check valve and accumulator are likely candidates for the poor starting. There are other possibilities, such as vacuum leaks and the AAR.

[Joe Bob]

Most likely the check valve in the neck of the fuel pump. Cheap fix, last time I checked, 18 bucks.

[GMR911]

Hi, Thanks for the responses. I should start with the check valve, then if that don't do it replace the accumulator to solve the residual pressure. I also want to add 2 shims in the pressure regulator in the fuel distributor. 2 shims had been taken out by a mechanic at one time which probably contributes to the somewhat low primary pressure. Does anyone have any guidelines, insights on this. I have the shims. Also, how is the wur adjustible? I have read some have adjusted theirs. but I don't see where. Thanks, Jerry

[vash]

dude, lots of ques.

my car bled off press too. it was my warm up regulator.

are you doing the CIS test in order?

cold first, WUR unplugged, car cold, not running but jumped fuel pump, valve open
system press, same thing valve closed.
warm control next, plug back the WUR, start car, note max pressure. about 20 minutes gets you there.
then at rest press, let is sit, something like 20 mins.
if the press drops, start car let the press build back up, then shut if off, shut the guage valve, if the press stays put, it is the WUR. if not you have to go about pinching off lines to determine if it is the check valve or something else.

i dont have my book with me, so i cant remember if the numbers above are that far off.

oh, you adjust the WUR, affect cold press only, by moving that brass pin up or down. you hit it with a punch, and you move it up, by taking it apart and tapping it the other way. if the cold press is too high, you knock it down, and vice versa. the brass pin is on top of the WUR. also check resistance at the WUR, you need (i think) 18 to 22 ohms.

good luck

[GMR911]

One other question- I tried to unplug the elec. connection on the wur, but it would not come off, is there a clip on the connector to release it or does it pull right off, jerry

[vash]

there is a clip. most get broken.

[GMR911]

Thanks, I thought so