1988 f150
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1988 f150
what would cause the engine rpm to change when i remove the wire that connects to the starter solenoid from the ignition switch. I have been going through map sensors so i think its a short or something but i cannot find the problem ,any ideas
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I agree with you it shouldnt affect the way it runs but it does and thats why it is driving me crazy. I have checked the grounds,actually took them off and cleaned the metal then it ran okay for 3000 miles, I guess I will start pulling the wires and see what I can find Thanx for your thoughts
Lead Driver
Joined: Jul 2007
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From: Rhode Island
The only thing I can think of is you're disturbing wires - try wiggling wires in the area and see if you can duplicate the issue. The only other possible thing is some sort of back feed through the neutral switch, to the computer. The computer looks to see if the transmission is in neutral or drive. There are wiring schematics around here, I believe subford is the wiring guy.
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I was on the same track as you, I went ahead and ordered a new safety switch since it is fairly cheap and easy and I will go ahead and start wiggling and checking the wires. Thanx for your help and I will keep you updated so if somebody else has this issue thanx again Leadhead
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Hello Should that why that goes to the solenoid starter switch have volts to it ,it has 7 volts, I thought it was only hot when you turn the key to the start position, and where does 7 volts come from oh the nuetral safety switch changes nothing except my wallet
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The little wire that activates the solenoid that comes on when you twist the key to the start position has a constant 7 volts to it, I thought the little wire only had juice when you twist the key to start position not all the time,. I think I will shoot the truck it has had a good life . Just kidding what will I spend my extra time on. I will have to trace the wires to the switch and see what happens thanx for your time and advice
Fleet Owner
Joined: Oct 2005
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From: Kentucky
The Red/Light Blue wire also goes to the Ignition Control Module (ICM). This changes the dwell setting, spark "On Time", when starting the engine. That 7 volts is leakage from the transistors in the ICM. Perfectly normal.
Start Circuit diagram:
Start Circuit diagram:
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thank you rla2005 ,but why would the rpm fluctuate when I remove the wire from the solenoid it drops a couple hundred then steadies to norm then when I replace it fluctuates a little too, is that also normal