Problem Dying

nbates55 · Sep 27, 2015

NO DICE!
The inertia switch has 3 wires. Which ones to jumper? 2 larger wires and a smaller one.
It has gotten so hot that the plug has melted a little, and the insulation on the wires as well. But not enough to keep it from functioning.
Battery was about dead, but should have been hot enough to make the fuel pump buzz. Didnt hear anything. Jumpered the 2 biggest wires at the switch. Nothing.
Turned the key on and depressed the schrader valve on top of the engine. No gas. Possibly the battery was so dead that it wouldnt run it, dont know. Battery is on a charger now.
Any ideas?

My truck has had a problem lately with dying and/or not wanting to start. Fuel pump is pretty new. I suspect the inertia switch because it wouldnt start tonight and after cranking a while (it would sometimes hit and almost run, mostly not) I felt of the wires going to the inertia switch and they were pretty hot.
Is there a way to hotwire the switch for long enough to help figure out if thats the problem? Thanks

Spott · Sep 27, 2015

Quite simple, really; you unplug the inertia switch and connect the two wires together using a suitable jumper of somr sort. If the truck doesn't run any better at that point, then your problem lies elsewhere.

nbates55 · Sep 27, 2015

Ill try that!

Similar to what I had in mind, except I was thinking just cut the wires (leave a pig tail) and just tie them together. Either way should work and I dont see any harm, except it defeats the safety feature. Which is kinda defeated by default right now anyway since it wont run.
I cranked on it a while. About ran the battery down. I checked the switch and found that the wires going to it were pretty hot. That just didnt seem right. Shouldnt be drawing that kind of power for a duel pump. Its a new pump, not much over a year old, probably not over 15k miles on it.
Thanks much!

nbates55 · Sep 27, 2015

Engine Code

I should add, that about a week ago I had the parts place read the codes on it, all it showed was PO 232 Fuel Pump Secondary Circuit High. Which upon googling that, found that among several vague options, that inertia switch can be a culprit.

adsm08 · Sep 27, 2015

Paper clip.

Spott · Sep 27, 2015

Don't cut it. There's a very high likelihood that it's not the inertia switch, and it's a good thing to have in the circuit.

The fact that the wires are hot doesn't necessarily mean that there's a problem with the inertia switch; it's likely that all the wires in that circuit got hot and you only felt them near the inertia switch.

Even if the inertia switch is proven bad, you should still keep the connector intact and replace the switch.

nbates55 · Sep 28, 2015

Cutting Wires

I plan to try a jumper. Of course, it wouldnt be a big deal to cut them and splice them back together if needed.
I agree, the safety switch is a good thing to have.
Ill check the fuel pump in the morning, see if I can hear it running. Its not very old, but from O'reillys, and if they arent any better than their starters (been thru 3 this year already), then it could be the pump...

nbates55 · Sep 28, 2015

No luck with anything I try. See edited original post. Thanks

Spott · Sep 28, 2015

Sounds like it's not the inertia switch, but it also appears that you're getting power from the fuel pump relay.

You might next try testing the fuel pump (run temporary wires straight from the battery to the tank connector) and inspecting the wires and connectors from the fuel pump relay all the way through to the pump itself.

Also, inspect the wires closely at the inertia switch connector, make sure they're not frayed or melted or otherwise damaged.

nbates55 · Sep 28, 2015

Update

The pump is a little older than I thought. Put it on new 19 months ago.
The plug and wires are a l;il melted at the inertia switch, but not enough to keep it from working. Switched relays out again. No change.
I jumpered the the biggest 2 of the 3 wires at the inertia switch plug with a mini blade fuse. The fuse popped, so its getting power to the inertia switch at least.
Pump will sometimes make a clicking sound every few seconds, but wont "run".
I have the tank ready to drop in the morning. Ill stick the other pump in and see if it will buzz before putting the tank all the way back on.
Friend thats a former mechanic came and checked it out and agrees its probably the pump. Really dont know much else to try at this point.
Thanks

black_demon69 · Sep 28, 2015

nbates55 said:
The pump is a little older than I thought. Put it on new 19 months ago.
The plug and wires are a l;il melted at the inertia switch, but not enough to keep it from working. Switched relays out again. No change.
I jumpered the the biggest 2 of the 3 wires at the inertia switch plug with a mini blade fuse. The fuse popped, so its getting power to the inertia switch at least.
Pump will sometimes make a clicking sound every few seconds, but wont "run".
I have the tank ready to drop in the morning. Ill stick the other pump in and see if it will buzz before putting the tank all the way back on.
Friend thats a former mechanic came and checked it out and agrees its probably the pump. Really dont know much else to try at this point.
Thanks

if replacing the pump pull bed and DON'T drop the tank.. pulling the bed is much easier I know just had to replace my fuel pump yesterday.. it took me about 45 min...

Spott · Sep 28, 2015

What size was the fuse that you popped? It sounds like your pump may either be drawing too much power, or you've got a dirty path to ground of some sort that shouldn't be there.

nbates55 · Sep 29, 2015

(Bad) Update

:shok:

Tank dropped and pump out. The pump runs, hooked it to the battery for a couple seconds. Whats happened is the wires from the pump melted in two where they were connected together, so it wasnt getting any power. Also, the plug at the top of the plate, which I assume is for the sending unit, is partially melted. New assembly is $250 plus tax. And it may melt it too. Pump could still be going out, just because it ran a few seconds hooked to battery doesnt rule that out I dont think. I may be able to rewire the assembly I have. I still have a new pigtail that came with the pump thats in it. If the other plug isnt melted too bad.....
On the fuse that shot, it was yellow. Im thinking it was a 20 amp. But it blew too late. Maybe its supposed to have a smaller fuse?
Either way, something is drawing too much power. Help!

enjr44 · Sep 29, 2015

Fuses are used to protect the power source. They are not there to protect what they feed (it is already screwed up or the fuse would not blow). However, if the wiring went before the fuse, the circuit was over fused. It was too big for the wiring.

That doesn't mean it was larger than called for. It could have been a bad fuse that did not cut the power when it should have or the engineer that specified it screwed up (wouldn't be the first time).

Anyway, I would make sure that pump is good before putting it all back together. Try hooking it up to a battery with say a 10 or 15 amp fuse and see what happens.

Spott · Sep 29, 2015

enjr44 said:
Fuses are used to protect the power source. They are not there to protect what they feed (it is already screwed up or the fuse would not blow). However, if the wiring went before the fuse, the circuit was over fused. It was too big for the wiring.

That doesn't mean it was larger than called for. It could have been a bad fuse that did not cut the power when it should have or the engineer that specified it screwed up (wouldn't be the first time).

Anyway, I would make sure that pump is good before putting it all back together. Try hooking it up to a battery with say a 10 or 15 amp fuse and see what happens.

He was using a loose fuse as a temporary jumper, which blew. I wasn't referring to the proper fuse for protecting the circuit.

Problem Dying

New Member

Member

New Member

New Member

Senior Master Grease Monkey

Member

New Member

New Member

Member

New Member

Well-Known Member

Member

New Member

Active Member

Member

Sponsored Ad

Sponsored Ad

Today's birthdays

Member & Vendor Upgrades

Truck of The Month

Recently Featured

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals