92' Not Starting - Fuel/Spark?
Thread Starter
Heel & Toe
Joined: Mar 2008
Posts: 19
Likes: 0
From: Olathe Kansas
92' Not Starting - Fuel/Spark?
I have a 92 M6 with about 138k on it. The car will not start.
I pulled the sparkplugs and smelled fuel on them, and when I cranked the engine, they sparked red.
When I tested the fuel pressure, the pump came on it spiked to 42 and instantly sets back to 36 or 37.
Does the fuel pressure seem right? How low can it be and still run/start?
Can the spark be too weak to fire? Can I test the ICM and Coils with a volt meter? If I can, what should I expect to get?
Thanks
-Brandon
I pulled the sparkplugs and smelled fuel on them, and when I cranked the engine, they sparked red.
When I tested the fuel pressure, the pump came on it spiked to 42 and instantly sets back to 36 or 37.
Does the fuel pressure seem right? How low can it be and still run/start?
Can the spark be too weak to fire? Can I test the ICM and Coils with a volt meter? If I can, what should I expect to get?
Thanks
-Brandon
Melting Slicks
Joined: Feb 2005
Posts: 2,135
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From: Sebastian Florida
St. Jude Donor '06
what do you mean the plugs sparked red?
You should have seen a electrical arc when you grounded the plug.
Did you check for codes?
If you have spark and fuel, it is either bad injectors or air or timing.
Was the car running good the last time it ran?
You should have seen a electrical arc when you grounded the plug.
Did you check for codes?
If you have spark and fuel, it is either bad injectors or air or timing.
Was the car running good the last time it ran?
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Engines need spark and spark at the right time, fuel and air and in the correct ratio, and compression in order to start and run. Use a timing light to determine if you have spark at the right time. The spark from a plug wire should easily jump 1/2 inch. Use a noid light (available at parts store) or make one with an LED (light emitting diode) and a 680 ohm resistor, both available from Radio Shack and connect this across an unplugged injector socket to see if it pulses during cranking. The home made light needs to be connected with the correct polarity across the injector socket, try it both ways. See how long fuel pressure holds with the ign off, it should hold up for a long time, if it drops rapidly you likely have leaky injector/s. If you have spark, timing, inj pulses, fuel pressure that holds, then measure compression. Also, you might try spraying starter fluid during cranking to see if the engine will start showing a lack of fuel.
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