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I was hoping someone could help me with a problem my car has developed
recently. My '86 5000CSTQ has been difficult to start for several weeks.
The following was observed:
1. When engine was cold, starting times could take up to a minute.
2. When engine finally started, it would run rough for a few seconds,
and then if it was revved a few times it would clear up.
3. However, even until the engine was fully warm, the car would
hesitate and buck slightly.
4. Where I live it hasn't got too cold yet (50ish) but the cold start
valve received no current at any time during cold starts. According to my
Bentley, it should receive a pulse, whose time length is temperature
dependent, at any temperature under approximately 70 (or is it 80) degrees.
5. Checked for leaks in air intake and vacuum system. None were found.
6. After several weeks of unsuccesful diagnosis, took the car to a
local shop. They claimed the warm-up regulator was bad. This was
concluded by them using a pressure test.
7. My own checks of the warm-up regulator revealed a resistance of 11
ohms across the terminals (I believe the manual says 14-22 is OK). I do not
have a gauge to check the fuel pressure myself (anyone know where I can
get one?). The warm-up regulator was receiving current on start-ups.
8. Gas was found in the intake air hose leading from the intercooler to
the throttle plate. My only guess was that the cold start valve was
leaking. Replacement of the cold start valve greatly improved cold
starts. The cold start valve is still not working but at least it is not
pouring gas into the engine anymore and fouling the plugs.
9. Now the engine cranks in an acceptable time period, but still takes
5-10 seconds of revs to clear it up. The car still hesitates slightly until
warm. Compression and ignition system is fine.
Does anyone know how to check the warm-up regulator?
The cold start valve is still not working. Does the thermo-time switch
located on the underside of the thermostat housing control the cold start
valve? Doesn't this control the temp. gauge as well? My temp gauge works.
Any ideas would be appreciated.
4-wheeled Fleet: 2-wheeled Fleet
'86 5000 CSTQ '84 Schwinn 10-speed
'73 Porsche 914 -modified - red with black seat