Hazard lights and fuel pump

[JoshT]

So I'm sitting here on the side of the road where my truck stalled and won't restart. Pretty sure it's due to a bad Duraspark ignition module, but don't have the stuff on hand to change it. So I'm sitting here in the dark with my emergency flashers on waiting for my tow to arrive when I decide to try starting it again. You know how those Duraspark modules are, sometimes if you let them cool off and they act like nothing ever happened. Well this isn't one of those times. Not giving a spark when cranking.

This isn't about Duraspark modules though. When I switched my ignition on to try starting again, the Sniper EFI electric fuel pump primed as usual. Once primed it started running in rythm with the emergency flashers. I get this is a good indication of a wire short or something of that sort, but the sniper and fuel pump wiring should be pretty much isolated from the chassis wiring. Sniper is connected direct to battery as specified in install manual, power for fuel pump comes from Sniper harness, and I have both wired direct back to battery for ground. Only place sniper is connected to chassis harness is for the on signal wire and for tach wire.

Somehow power from 4 way flashers is getting to the fuel pump, and I know no wires are shorted going to the pump.

[Ranchero50]

A weakening battery will do that, crazy as it seems.

I assume you pulled the coil wire and held it to the block to verify no spark?

[JoshT]

I'd agree with the weakening battery, if the fuel pump were cutting off when the lights flash on. Instead the fuel pump is turning on when the lights are flash on, and off when the lights flash off. I could see a weakening battery causing the pump to cut off with the lights on, but can't see how it would make the pump turn on when the lights turn on. I'll have to dig into that one.

Yep, tried that. It sparks once when key turned from off to run, no sparking while cranking, and sparks once again when turn key back to run. Let it sit for a while to cool off and still nothing.

Have a couple of spare modules from a previous vehicle to try out and/or keep in the truck just in case. Unfortunately I've got to fix a previous wire repair before I can use them. Some point in the past the ground wire (IIRC) was broken on the truck side of the harness at the 4 pin connector, to fix it the connector was bypassed and wires spliced together. Need to replace the connector so everything is plug and play again, fortunately I happen to have one of those connectors available as well.