EFI fuel pump relay smokes and burns up fuel pump? Safety concerns.

[casadejohnson]

Going to work today my Bronco had a quick stutter and then I got a puff of smoke from the glove box ( Where my ECM and relays are located ). I shut it down and checked the relay. It was pretty warm so I swapped it out and started it up and it ran fine. Next I swapped back to the original relay and it still ran fine with no more smoke or electrical burning aroma. Fast forward to the end of the day and I drive home without issue. When I pulled it into the garage, I see that I have a fuel leak. Further inspection reveals that the insulator on the positive fuel pump connection is melted and is the location of the leak. So my theory is that a power surge from the smoked relay to the insulator caused the melting and leak. What I don't know is if the problem is just a bad relay or is there another problem that fried the relay which in turn fried the pump? I want to go wheeling this weekend but I'm a little scared of it now. I don't want to put my kids in the back if its just a fire waiting to happen. Anyone Seen this before? The ground is good and the fuel pump is not very old.

 

[Broncobowsher]

Other way around. The short in the fuel pump burned up the relay.

 

[73azbronco]

This^^^^^^^^. Relay did it's job.

 

[casadejohnson]

So, If I replace the pump I should be OK? I did hit a pretty serious dip in the road before this all happened. I was surprised that the original relay still worked after the smoke and that a new pump fried so soon. ( Less than 500 Miles )

 

[Steve83]

If you want to try to milk the last life out of that toasted relay, keep a spare in the truck.

What brand was that new pump, and where did it come from?

 

[73azbronco]

I would also check to be sure the wiring to the pump is proper, proper size, proper ground. Bad on either of those two items and you can burn pumps up by not giving them proper voltage.

 

[casadejohnson]

If you want to try to milk the last life out of that toasted relay, keep a spare in the truck.

What brand was that new pump, and where did it come from?

The relay hit the trash. I always have a couple spares in the console. I just assumed it would not work after it smoked. The Pump was a Carter ( Made in USA ) and it came from Oreilley's. I'm going to see if I can get them to replace it so I have a spare pump again. I replaced it with a spare that I picked up used at a Bronco swap meet. I'm almost glad this happened, the replacement pump is MUCH quieter than the Carter and it seems to hold line pressure better. My other pump use to bleed off fuel pressure after 20 minutes or so. This one has been holding about 40PSI for about an hour now.

 

[casadejohnson]

I would also check to be sure the wiring to the pump is proper, proper size, proper ground. Bad on either of those two items and you can burn pumps up by not giving them proper voltage.

I rerouted my fuel system last year and replaced all the wiring at that time. I did do an inspection and it all appeared to be good.

 

[73azbronco]

Inspection as in using a voltmeter at the pump to be sure it see's 12V while running?

 

[casadejohnson]

Inspection as in using a voltmeter at the pump to be sure it see's 12V while running?

First a visual and then, yes, out came the meter.

 

[ransil]

The relay should be fused.