1987 f350 electrical problem
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1987 f350 electrical problem
I recently c/o my tired 351w carb engine with a 351 EFI from an 89 bronco. I changed all wiring in engine and cab. My problem is my gauge cluster is doing the following: rpm with engine @idle is around 600 I don't think this is true as engine sounds great, when I push gas peddle down rpms go to zero on gauge, engine sounds good!,also when I put blower fan on my temp and oil pres gauges both go up and when I put blinkers on all gauge needles move back and forth (not much) but they do.
Question: are the gauge clusters from the 87 f350 and the 89 bronco the same? The cluster that is in is from the 87 f350, I do have the one from the Bronco.This sounds to me like a bad ground in cab, but where could/should I start to look? Any help/advice will be appreciated
Question: are the gauge clusters from the 87 f350 and the 89 bronco the same? The cluster that is in is from the 87 f350, I do have the one from the Bronco.This sounds to me like a bad ground in cab, but where could/should I start to look? Any help/advice will be appreciated
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From: Virginia
It does sound like a bad ground. Look for a ground strap from the firewall to the engine block back at the bellhousing. Also, if you get tired of looking for the ground, you can just add another if you like. Just go from the engine block or the battery neg, to the sheetmetal that needs grounding.
If that doesn't fix it, I would then suspect a ground problem going to the cluster itself.
If that doesn't fix it, I would then suspect a ground problem going to the cluster itself.
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Changed cluster now I have dif. problems!!!
OK,
I replaced the 87 f350 gauge cluster with the 89 cluster. All gauges work great until I turn headlights on! When headlights are on Tach gauge goes to zero and battery charge indicator goes to zero, also left turn signal indicator lights and engine light turns on. Then I shut off headlights and all is good again. I'm thinking that the engine light comes on because of the alt gauge going to 0. I don't have the rear lights on the truck connected yet, wires are all capped, that should'nt cause any problems i hope. Good Idea about burnishing contacts!
Also, when Headlights are on and I dim inside lights problem goes away!!
I replaced the 87 f350 gauge cluster with the 89 cluster. All gauges work great until I turn headlights on! When headlights are on Tach gauge goes to zero and battery charge indicator goes to zero, also left turn signal indicator lights and engine light turns on. Then I shut off headlights and all is good again. I'm thinking that the engine light comes on because of the alt gauge going to 0. I don't have the rear lights on the truck connected yet, wires are all capped, that should'nt cause any problems i hope. Good Idea about burnishing contacts!
Also, when Headlights are on and I dim inside lights problem goes away!!
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From: Virginia
It sounds like you still have a problem with the cluster grounding. The tach and various other loads in the cluster are trying to find a good ground. It sounds like they are finding it through the cluster lights. Everything sort of works ok with their ground running backwards through the cluster circuit, till you turn the headlights on. That sends voltage to the cluster lights, which blocks the ground the tach was using, and it goes out.
Crazy things happen when grounds are missing. See if you can study the old cluster, and find out which terminal was ground. I think it's a black wire.
You said something about not having the rear lights connected yet. This is a hint to me that this is a big resto project or something, which usually means a re-paint, which usually means grounds are mistakenly painted over and they have a poor connection to the metal.
Crazy things happen when grounds are missing. See if you can study the old cluster, and find out which terminal was ground. I think it's a black wire.
You said something about not having the rear lights connected yet. This is a hint to me that this is a big resto project or something, which usually means a re-paint, which usually means grounds are mistakenly painted over and they have a poor connection to the metal.
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Franklin2 great call on burnishing the contacts!! Worked on the truck the other night took the cluster out and cleaned all contacts, all problems went away great call!
Yes, it's basically a full restore I'm looking for a dually bed/utility bed right now. I'm in NY.
Thanks again
Yes, it's basically a full restore I'm looking for a dually bed/utility bed right now. I'm in NY.
Thanks again
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