Intermittent FP/INJ fuse problem

[MeanBuicks]

Last week, about 20 miles into my morning commute, my FP/INJ fuse blew. Replaced it and the car made it home fine. Drove it about 10 miles this weekend without incident.

This morning, just a few miles from where the fuse blew last week, it did it again. Replaced the fuse and the car made it the last 25 miles to work.

Both times, the fuse blew while rolling along a smooth 4-lane with the cruise control on. The pump wiring is completely original with no hot-wire mod. The fuel pump is a ten-year old, 150,000-mile, Bowling Green Customs job and the injectors are Ford blue tops with about 100,000 miles on them. There is also a 3-year old Quad Air volt booster on the car.

Could the fuel pump be on its way out causing momentary current spikes? I looked briefly at the fuel injector harness for signs of chafing/shorting but saw nothing. The fact that the fuse went twice on smooth blacktop rather than over RR tracks or bumps has me doubting that it's a wire shorting on something.

Since the fuel pump is probably about used up at this point anyway, I'll probably replace it. Any other suggestions?

 

[salvageV6]

Fuel injector harness could be intermittantly shorted. I'd start with a close inspection there.

 

[John Larkin]

Remove the volt booster and see if it does it again.

 

[MeanBuicks]

Do you think that could cause the problem? The fuse hasn't failed while the VB was functioning (as indicated by brighter headlights). Can the volt booster do strange things while inactive? I haven't noticed any other electrical maladies at this point.

 

[MSDGN]

Did you replace the stock oil pressure sender with aftermarket one for a guage...if so where is the connector for the stock sender...it can short out against the block...front cover..etc and will cause that fuse to blow...just a thought...

 

[MeanBuicks]

Now we're talking!

I still have the stock oil pressure switch down there but the connector is another story. It's a disolved, scammer mess that won't stay in place any more. I'll take a closer look at that to see if it's possibly the culprit.

Are there replacement connectors available for that?

 

[MSDGN]

Yep...#12085529 from your GM dealer...not cheap though around $20($16 from discount dealer) but it's the same stock molded connector...it comes with 3 white wires molded in that you have to splice into the original wires...other option is a standard 3 prong headlight connector but it isn't sealed plus I didn't like the way it fit...not real tight

 

[Red Regal T]

Good possibility that scammer mess is the cause of your problem.

 

[MeanBuicks]

Update

Yesterday afternoon, in the company parking lot, I used some electrical tape to cover up the exposed wire ends on the oil pressure switch connector, or what was left of it. The drive home was event free.

I broke out the service manual at home, cleaned up the wires and reconnected them individually to their respective terminals on the pressure switch. They are on there pretty good and tight. This morning's commute back in to work was uneventful too.

That just may have been the problem. Thanks to everyone for their help!

 

[TurboJim]

I've seen the switch itself cause this twice. If it happens again, pop a new switch in there and see.

 

[NC87GN]

I've seen the FP/Inj fuse blow consistently like you were experiencing.. Be sure to check the injector harness wires that are tied to the fuel rail. Check the wires as some may have rubbed through the insulation. Also if there is any short in the coil pack module it will blow a FP/inj fuse also.. HTH..

Mike Banas
87GN