george44

Difficult to start when hot after sitting for more than 10 minutes. Only way it does start is to press the accelerator pedal to the floor, keep it there, and then crank. It starts immediatelly. Car normally starts without any problem. It's a '79 Euro (no O2 sensor and no smog pump). Thanks guys!

George

Jeff Curtis

Next time it does this...get out of the car and pop the engine lid.

Pull off your airbox cover and filter, gently push up on the air sensor arm to feel if there's any resistance, meaning fuel pressure behind it.

My SC used to do this and I would find that the plunger in the Fuel Distributor would be stuck all the way UP! There would be NO resistance behind the air meter.

This continued to baffle me as it seemed like a "vapor lock" type situation, but as you've discovered...if you play with it long enough...it'll start. <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />

ronb

My 79sc no smog pump has similar issue, ie warm starts. Have you checked that the thermotime and warm up regulator are working? As a temporary patch you can jump out the thermotime so it always thinks it's starting cold; it will dump a bit of fuel in which will be a slightly chokey start, but it will be a consistent (slightly strangled as the fuel works through the system) warm start until you can get to the wu regulator.

george44

Thanks Jeff, I'll try that and see what happens. I believe everything else OK, like the warm-up regulator and thermo-time switch. When cold the car starts virtually instantly, idles above 1,000 RPM (say at 1,500/1,600) and then gradually decreases and drops to 750 RPM. Exactly what it should do. Warm start, I drove it today, several warm starts, it went on without any problem. As I've said it does not do it all the time which makes it difficult to diagnose. Thanks!

George

Jeff Curtis

George, I forgot to mention that I relieved my SC a long time ago of the thermo time switch that controlls the "cold start" or 7th injector...as a matter of fact the 7th injector was just there to plug a hole!

SO, my experiences with coming out of 7-11 and the car not starting may have been related to different issues...as I had all kinds of 12V wires re-routed, etc.

My previous suggestions, were just that...out of curiosity, as I KNOW my FD plunger would default to the furthest upper position at times.

leonardo911sc

Good day to All

Is this thread still active?

I have some very specific questions to CIS experts and i would appreciate your kind assistance

theiceman

i would look to pelican , the very best CIS people are there. Most have left this site

vetter59

I used to own a 78 SC coupe many years ago with a similar problem, started right up when cold , but once you drove it for awhile , and then let it sit for more than 15-20min after shutting off engine., I would have to crank a few times to get it to run again. Bosch CIS injection has a accumulator and a check valve designed to hold fuel press for a period of time when shut down until it fully cools off, if I remember about 30 psi, so when hot it starts easily. I replaced both check valve and press accumulator and it took care of the hot start problem. If you have a CIS fuel test gauge, you can verify your fuel pressure is with in limits after it's shut off and the allowable time it's supposed to stay there. The check valve is fwd, behind the fuel tank is cheap.

systemsc

Yes, very likely the cause.

leonardo911sc

Dear Lou S
Good day

Exactly same problem.
Will fire up at when cold but when hot after 1 hour will need about 10 sec of cranking

1. New fuel pump with check valve
2. New accumulator genuine
3. Rebuild WUR 089
4. Cold pressure 1.7 Bar @ 18C, warm pressure 2.8 bar and 3.5 bar with engine running. System pressure 5.2 bar
5. Residual pressure 1.5 bar after 30 min
6. Tested TTS. Working
7. Ordered new FD fuel relief valve. I dont think this will solve the problem though since residual pressure is within spec.

Any ideas?

Soft_Click

According to my ‘84 Carrera manual, this is expected behavior

theiceman

A Carrera is not CIS , it is motronic , completely different systems ..

Soft_Click

Sorry, my mistake. Interesting to learn about those continuous injection systems!

theiceman

George i have CIS gauges if you want to do a fuel pressure leak down test let me know. Ill drop them off next time im in Burlington if you are interested .

theiceman

you learn a whole lot once you have an issue with one lol... i love them but some hate them .