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boyt911sc boyt911sc is online now
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Join Date: Mar 2002
Location: Philadelphia, PA
Posts: 12,680
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CIS troubleshooting.........

Quote:
Originally Posted by Markymike View Post
My 82 SC has severe cold start problems. I need to lift the air plate for a few seconds to get gas to it. Then it's rough till it warms up. When the engine warms up, it runs great.

I did an air leak test. I found a cracked air box and replaced it. I found leaks around the injectors and replaced the rubber donuts.

I just did the pressure test. These are the results:

I seem calm but this is driving me nuts

1. Year of engine: 1982
2. US or RoW (Rest of World): US
3. WUR model number: don't know
4. Ambient temperature at time of test (in degrees C): 76F / 25C
5. WUR Resistance (in Ohms): 9.1
6. System Pressure (in bars): 5 bar / 72 psig
7. Cold Control Pressure (in bars): 2.3 bar / 34 psig
8. Warm Control Pressure (in bars): 3.4 bar / 49 psig
9. Time delta for Cold -> Warm Control Pressure (in minutes & seconds): 50 seconds
10. Residual Pressure @ 5 min (in bars): 1.8 bar / 26 psig
11. Residual Pressure @ 15 min (in bars): 1.6 bar / 23.5 psig
12. Residual Pressure @ 30 min (in bars): 1.5 bar / 22 psig
13. Residual Pressure @ 60 min (in bars): 1.45 bar / 21 psig

Mark,

Item #5: With a 9.1 ohms reading when cold, your WUR is most likely a -090 (correct WUR). Unfortunately, it is out of spec and would need some work. This was exactly what Tim had when he sent his WUR for test (free).

Your cold control pressure is high and WCP on the low side. But it should not prevent you from starting the engine with the above conditions. If I were in your shoes, I would check and test:
1). CSV operation during cranking. I doubt it is the culprit but better to test it.
2). Test and confirm the absence of a significant source of vacuum leak. This is the most critical test but overlooked by many troubleshooters. Use the low pressure test method. Much better and efficient than the conventional carb cleaner or propane method.

Keep us posted.

Tony

Last edited by boyt911sc; 05-13-2015 at 09:00 PM..
Old 03-06-2015, 05:10 PM
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