911 Starting Problems.......

[DMX]

1975 2.7l CIS 911.... When the car is cold it fires up right away

no problem..... Just a little ruff with the idleing for about 5-8

seconds or so until the gas starts flowing..... When I drive

around and shut the car off I can turn it on right away again

with no problem... BUT when I drive the car around and shut it off

and return to the car at a minimum of 15 minutes or longer it

will not start for a long time..... It always starts but I got to sit

there and wait at leat 5-10 minutes trying to start the thing....

Anyone ever encounter this problem?



THANKS!

[Gunter]

Could be loss of fuel pressure due to leaking back through pump-check-valve or fuel accumulator.

[Tim Walsh]

I think the Dr. is right. From what I hear it's quite common in CIS cars. just my speculation.

[targa80]

This is a problem that shows up on the board every couple of weeks do a search on hard start or fuel pump check valve. It is a very common failure but ther are other sources for the cause. The threads will provide you with a lot of troubleshooting info.

[ruf-porsche]

Could be leaky injectors also. When it do starts up is there a lot of black smoke? If not that could rule out leaky injectors.

[Sunroof]

I just went through the same thing.
I orderd a fuel pump for my 1973.5 (uses 1974 - 1977 pump) and noticed that the check valve is internal. I already replaced the accumulator so we shall see justh ow much improvement this renders.

Regards
Bob

[DMX]

I am going to change my fuel pump... I have a feeling

it may be the problem... My injectors are burning perfect....

Hopefully changing the fuel pump will work... I have to fix this.. it

is driving me nuts....

[azasadny]

DMX,
Is your problem fixed? What was the "final verdict"?

[azasadny]

Sunroof,

Did the new fuel pump fix your problem?

[azasadny]

Many of you have followed my intermittent "cold starting" problem that eventually became a constant starting problem that caused my to have to crank my car 20-30 times, with several loud backfires, prior to the car starting. Once the car started, it ran great but the starting problem was driving me nuts. Needless to say, I replaced alot of components (fuel filter and accumulator, cold start valve and thermotime switch, throttle microswitch, plugs, CD unit, rotor, coil, Pertronix unit, WUR, etc...


Each replaced item improved the situation temporarily, but the problem still persisted. The cold and warm pressures were within acceptable limits and I had good spark at plug #1, but the car just cranked and refused to start. To make a long story short, this is what the mechanic found:

- The plugs were improperly gapped (too wide) even though I followed the instructions on the PermaTune CD unit for spark plug gapping specs.

- The plug wires and their "boots" are bad and I will replace them

- The "new" throttle microswitch that Jordi Riera sent to me worked perfectly and the old one was bad

- One of the wires coming off the Pertronix unit had rubbed until the insulation was off and bare wire was showing.

My mechanic "fixed" these things and the car starts on the first crank, idles at 950rpm and runs great. I REALLY appreciate all of the assistance so many of you have provided. I have learned alot from you kind folks. I'll post this update on the other posts that I have been on so that anyone with a similar problem may be helped. I had checked the spark at plug #1 and had a nice spark, but my mechanic showed me that others were weak. I hope this helps others out there....