I am soliciting ideas on the best way to isolate an intermittent short in the power lead going to the fuel pump in my sons 1986 GT convertible that is his daily driver.
The factory fusible link burned up recently. The ford dealer that replaced it said there were no shorts and the wire had just parished because it was AL before the fusible link and in close proximity to the battery. Seemed like BS at the time, still seems like BS now - don't get me started again on this dealer....
When I redid their shoddy repair on the side of the road at 12 because it had left my son sit again I cut out the bad link and replaced it with a blow-glow style fuse holder and a 30 amp fuse. I soldered and shrink tubed everything I did. I put in a new Walbro fuel pump around this time because the stock pump was not sounding healthy and I thought maybe there was a short developing inside the pump itself.
<edit - dealer was wrong - this circuit blowing is the EEC and ignition switch lead. Fuel pump had a self resetting breaker before the link>
The car ran great for about a month with no problems after doing this stuff. Until Friday night, now it's popping fuses every 3 feet to three miles.
This car obviously has a wiring problem somewhere in the harness now. It generally had been running/working just fine since we bought it last year and now out of the blue it has started leaving him sit due to no power to the fuel pump and a blown circuit - pretty randomly. Basically you hit a bump somewhere and at random it apparently shorts out and pops the fuse.
I have not come across any places where there is evidence of a previous repair. Hard to say - I've had to redo 95% of everything the previous owner touched. He needs to stop working cars! Lol.
I am thinking based upon wire routing there has to be some common areas that are among the first places to look. I am thinking I'd have random no start conditions due to a popped fuse overnight or a dead battery if the area grounding out is before the relay..... maybe....
Anyone with clear pics of the fuel pump power wire routing - this would be hugely appreciated!!
<edit - fuel circuit is fully inspected and repaired, other problems persist>
i am currently thinking of temporarily replacing the wire relay to pump with a new wire to try to see if the short is before or after the relay. Maybe rinse/repeat battery to relay.
ultimately I need to isolate this before other wires get messed up. I don't want to be the guy that does some crappy appearing wiring repair to an otherwise prestine condition car. But it needs to reliably run and not leave him sitting!!
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