1990 ford electrical probs

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Apr 16, 2007 | 08:38 PM

Harris1

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1990 ford electrical probs

I changed my solenoid and starter today. After i put my old solenoid back on cause with new one my truck kept turning over but not starting. With the old solenoid on my truck now starts but runs rough. It seems like it is not getting enough power. Any ideas? Cause i'm stumped. Thanks.

Apr 16, 2007 | 09:55 PM

subford

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From: Easton,Ks

Sounds like you have power on the start wire (red/light blue stripe) at all times. This would take your timing back to base timing while running but not sure how you are starting it with the old solenoid and not having the starter engaging while running.
Are you jumping the solenoid to start it with the old solenoid?

Apr 16, 2007 | 10:12 PM

Harris1

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No it started fine with the old solenoid. With the new one my truck kept turning over. Even with the keys out of the ignition. My voltage gauge on the dash only reads 8 volts at all times. I disconected the battery while it was running and it continued to run. This would rule out my alternator..No?

Apr 17, 2007 | 06:40 AM

subford

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From: Easton,Ks

Quote:

Originally Posted by Harris1

If you disconnected the battery while it was running who knows what all is bad now. This is one of the worst things you can do.

Apr 17, 2007 | 11:01 AM

t4kne

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From: Massachusetts

So, it sounds like your truck was just turning over with the keys out. Not running with the starter engaged. Then, changing back to the old solenoid fixed this problem. Is this right?

Take a voltage measurement across the battery while the engine is running. If it's low, then it is pointing at the alternator/regulator.

subford: I did not know that disconnecting the battery while running is bad. What happens that makes this bad?

Apr 17, 2007 | 01:01 PM

subford

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From: Easton,Ks

Quote:

Originally Posted by t4kne

subford: I did not know that disconnecting the battery while running is bad. What happens that makes this bad?

To hear it from the sites Electrical Moderator, look at the last post in this thread:
https://www.ford-trucks.com/forums/6...-problems.html

Apr 18, 2007 | 01:58 PM

t4kne

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From: Massachusetts

Thanks. Good information. Since I never heard of it before, I looked it up. I found automative power application information that talks about this. It referes to this as "load dump". The article reads; "When the cable breaks connection, the field collapse in the alternator can cause a positive spike as high as 60V which takes several hundred milliseconds to decay."

Reference Linear Technology