Brad5502

For the last two days, I shut the truck off, go inside, and anywhere from 30-60 mins later, I go out and the Airdog is pumping away.

I took the Airdog wiring harness apart, cleaned the connections and put dielectric grease on them. Rechecked the grounds/fuses to the battery. I even reloaded smarty to Stock SW and then back to 1.

Went back out 10 mins ago and the pump was buzzing away. Turned key to on and shut it off. Pump went off.

Any ideas what to troubleshoot. Anyone else had a similar problem?

pmtg

Has it always done this? You said the last two days, but is that since you noticed it or noticed a change?

A relay powering the pump could be wired incorrectly...normally closed vs. normally open.

edit: read your post again....think you need to insure it is being powered from a key-on only wire...is it being powered off the original fuel pump wiring or from a different source?

Or a faulty relay.

Brad5502

Airrdog has been in for 3 years. It is wired to the original fuel pump harness, which I took apart today, cleaned the connections and added dielectric grease.

This has only been happening for the last two days.

Can't figure where/why it's getting dc power, something with the original harness going bad?

Any ideas?

tantruck

If it is wired similar to my FASS, I would replace the relay. My relay is hot, (powered direct to the battery) and is triggered by the wire from the switch when you turn on the ignition.
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My setup had me remove the power wire form my existing fuel pump and have it trigger the relay to power the FASS pump. I don't know how yours is wired but it's an idea to check out.
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Just my 2 cents

jhenson

My thoughts too. The relay should be powered by key on.....if it goes bad it can power at any time......not good for the pump. Check your relay and verify that it hasn't shorted.

Brad5502

The Airdog used the original fuel pump electrical harness and I spliced into a 12v power cable that is only hot when the ignition is on.

Guess I have to trace that cable to the fuse box and replace the relay.

Drove it to work today. Pump wouldn't shut off until the third time I shut the truck off. Hasn't come back on yet...something is definetly shorted so I'll try and find the relay I'm hooked into.

Spooler

I would say you have a bad ignition switch. Not uncommon.

tantruck

Well with the responses above I would pull out the VOM and be ready on the next occurrence.
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Just a thought but ---->
If the ignition switch was powering the pump wouldn't the truck continue to run when you shut it off? I don't have a wiring schematic handy but wouldn't the faulty ignition switch power-up more than just the pump?
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First off I would certainly try to pinpoint which wires could be the power source. It's obvious the pump is running so maybe isolate wring in the switch or if it even has a relay involved isolate the relay trigger wire to see if it's causing the relay to activate.
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On my FASS install the directions had me remove the switched power lead from the pump and route it to a heavier duty relay, (that FASS provided), to trigger it. I also had to run a heavy wire, (10 or 12 AWG??) from the positive battery terminal to the relay and another from the relay to the pump because the existing wiring could not handle the increased amperage of the new FASS pump. I mounted the new relay near the driver's side battery near the hood hinge. I'm wondering if yours may be hidden out of sight. Also wondering if these things are waterproof. I could imagine that if the original pump power wire was used to power your Airdog pump, the relay could have burned up with the increased load. Just thinking out loud here.

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Have you been removing a fuse to prevent the condition when you leave the truck parked?

Brad5502

Well, last week I traced the hot wire and it goes straight to the battery. I also traced the original harness that controls the pump. Didn't see any shorts or frays.

After doing that, the pump has been acting normal for the last week. I've got my fingers crossed that all the tracing and moving of wires fixed whatever was shorting/bad connection...wish I'd have found the problem.

Brad5502

I traced the problem to a small relay (fuel shutoff relay). Every time i jiggled it, the. pump would come on (or shut off if it was running). $3.98 at Pep Boys for a new relay and hasn't come on after I turn the ignition off for the last week....

tantruck

Was that a relay in the fuse box or an additional unit someone added when the Airdog was added. The reason I ask ----> is that the stock relays will not handle the additional current of the heavier aftermarket pumps and fail like yours did..
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Would probably be a good idea to carry a spare in any case. Just my 2 cents.

Brad5502

It was original equipment on the truck down by driver side frame rail. Airdog harness was designed to plug into it. I've got the original one in the truck, in case this one goes bad I can always put the one that stays on back in.