1980 sc starting problem warm-up regulator?
09-10-2006, 10:04 PM
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1980 sc starting problem warm-up regulator?
I have a 1980 sc that is having problems starting. Engine will turn over start for a quick second and then die. I believe that it may be the Warm-Up Regulator. Any ideas? and if so any good place to purchase one?
09-10-2006, 10:44 PM
#2
What are your fuel pressures: primary pressure, cold control pressure, and warm control pressure? You need to start with the answer to this question before you go further with your warm-up regulator. I suppose since the car doesn't stay running, you won't be able to get the warm control pressure, but for cold starting, the cold control pressure is key.
Brett
Brett
09-11-2006, 09:37 AM
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Hello Mike,
If your symptom is it fires then dies, but fires and keeps running properly after the second or third try, it probably isn't the WUR. On a cold start, the CSV supplies the initial enrichment and it sounds like yours is working. Once the key is in the run position, the CSV is out of the picture. The problem usually is a lean condition from age and vacuum leaks. The engine fires on the CSV fuel, but the vacuum is too low to lift the sensor plate enough to supply a rich enough mixture for a cold engine. The second or third cranking supplies extra fuel from the CSV which is often enough to get through the initial lean stumble, then everything evens out. This problem is a bit tricky to diagnose because you only get one try a day to replicate the problem. The final version of CIS is calibrated lean on cold starts and it does not have active idle control, so you often have to find the best compromise settings for your conditions. Your car also has a vacuum retard to help pass the curb idle emission test, but Porsche did not use any thermal switches like other OEM's. Sometimes the engine will fire fine cold, but once the vacuum retard kicks in, the mixture is too lean to keep the cold engine running with the additional friction. The first thing I would do is check your ignition timing and mixture with a dwell meter at the Lambda test port. If they check out OK, I would leave the vacuum retard line disconnected and plugged and reset the idle speed to 950 rpm. If the car starts cold and runs fine the next day, your problem is probably just old age, not the WUR. There is a Lambda temperature switch to add enrichment below 59F on your engine, but if your car is garaged it may never come into play. It is on the right side timing cover and it should be grounded below 59F. Stoddard sells a replacement switch that grounds at a higher temperature if this is your problem. You also need to check for vacuum leaks around the injectors and sleeves. Use an unlit propane torch and listen for changes in the idle speed. If the O rings on the injector holders are original, they are probably leaking. Unlike the later EFI engines, the Lambda CIS engines need some adjustment as they age and you probably can find a good compromise by eliminating the vacuum retard and making minor timing and mixture adjustments.
Paul
If your symptom is it fires then dies, but fires and keeps running properly after the second or third try, it probably isn't the WUR. On a cold start, the CSV supplies the initial enrichment and it sounds like yours is working. Once the key is in the run position, the CSV is out of the picture. The problem usually is a lean condition from age and vacuum leaks. The engine fires on the CSV fuel, but the vacuum is too low to lift the sensor plate enough to supply a rich enough mixture for a cold engine. The second or third cranking supplies extra fuel from the CSV which is often enough to get through the initial lean stumble, then everything evens out. This problem is a bit tricky to diagnose because you only get one try a day to replicate the problem. The final version of CIS is calibrated lean on cold starts and it does not have active idle control, so you often have to find the best compromise settings for your conditions. Your car also has a vacuum retard to help pass the curb idle emission test, but Porsche did not use any thermal switches like other OEM's. Sometimes the engine will fire fine cold, but once the vacuum retard kicks in, the mixture is too lean to keep the cold engine running with the additional friction. The first thing I would do is check your ignition timing and mixture with a dwell meter at the Lambda test port. If they check out OK, I would leave the vacuum retard line disconnected and plugged and reset the idle speed to 950 rpm. If the car starts cold and runs fine the next day, your problem is probably just old age, not the WUR. There is a Lambda temperature switch to add enrichment below 59F on your engine, but if your car is garaged it may never come into play. It is on the right side timing cover and it should be grounded below 59F. Stoddard sells a replacement switch that grounds at a higher temperature if this is your problem. You also need to check for vacuum leaks around the injectors and sleeves. Use an unlit propane torch and listen for changes in the idle speed. If the O rings on the injector holders are original, they are probably leaking. Unlike the later EFI engines, the Lambda CIS engines need some adjustment as they age and you probably can find a good compromise by eliminating the vacuum retard and making minor timing and mixture adjustments.
Paul
09-12-2006, 02:25 PM
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UPDATE: Played around with the car last night. It started on the 3rd attempt. Idle was a bit high so I turned the idle screw down all the way. After 5-10 min the idle speed needed to be increased, again by hand. I tried to cover the intake hole completely... the car still ran and I could hear air leaking in somewhere? I turned the car off and tried to start it again, it started right back up. I then stopped it and about 15 min latter tried to start it again, with no luck!
Any more ideas?
Any more ideas?
09-13-2006, 09:27 AM
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Hello Mike,
I suggest you get a manual and learn how the CIS system functions. The Auxiliary Air Regulator is designed to bypass the throttle when cold, raising the idle speed until the heated element closes the window. You should not be making any idle adjustments until the engine is fully warm. The AAR closes when warm and the CSV terminates after repeated cranking, so little can be learned from your experiment. Set the idle screw back where it was, let it cool down and try it again. Once the engine is warm, set the idle to 950 rpm, check the timing with a light and look for vacuum leaks with carb cleaner or propane, not by choking down the engine. What is the history of this engine ? If you can't get it to idle with the bypass closed, you may have a damaged airbox.
Paul
I suggest you get a manual and learn how the CIS system functions. The Auxiliary Air Regulator is designed to bypass the throttle when cold, raising the idle speed until the heated element closes the window. You should not be making any idle adjustments until the engine is fully warm. The AAR closes when warm and the CSV terminates after repeated cranking, so little can be learned from your experiment. Set the idle screw back where it was, let it cool down and try it again. Once the engine is warm, set the idle to 950 rpm, check the timing with a light and look for vacuum leaks with carb cleaner or propane, not by choking down the engine. What is the history of this engine ? If you can't get it to idle with the bypass closed, you may have a damaged airbox.
Paul
