AirDog 100 Woes.

[Drewhenry]

1st one lasted 10+ years. 2nd one installed in May/June 2018. Now it keeps popping the 20amp fuse. I cleaned everything and removed the cover plate to inspect the gerotor. It was clean with no debris. I replaced the filters. Comes on for 45sec-1 minute then pops fuse. On a suggestion from a local diesel mechanic, I replaced the relay. Popped the fuse in 45 seconds. I am going to try pulling the connector from the motor to see if it is a wiring issue. I have not been able to find any bare spots with any exposed wire. The only other thing I can think of is the seal between the motor and the pump may be compromised.
Such a pain in the ass.

 

[sojoe]

Why not go to a NOS IN TANK PUMP and be done with it?

 

[Drewhenry]

Why not go to a NOS IN TANK PUMP and be done with it?

Because stock sucks! Haha!

 

[Drewhenry]

Let me add another variable. The pump runs fine as long as the engine is not running. 10-15 seconds with the engine on blows the fuse. I'm electrically ignorant. Would using a 25amp fuse be dangerous? Could my voltage regulator be on the way out?

 

[DavidC]

What is the pressure doing during this ?

 

[Drewhenry]

What is the pressure doing during this ?

I dunno. I don't have a fuel pressure gauge.

 

[DavidC]

It sounds like a motor bearing/bushing heating up and loading the armature causing the overload to blow the fuse.

 

[petersonj]

Is there another electrical circuit activated from the same fuse when the truck is started? I can't think of why there would be, but I thought I should ask the question anyway.

- John

 

[Drewhenry]

It sounds like a motor bearing/bushing heating up and loading the armature causing the overload to blow the fuse.

A motor bearing/bushing WHERE? The electric motor on the AirDog runs fine as long as the engine is not running. I am starting to think I have charging system issue and not an AirDog issue. I've noticed it takes longer to start the truck lately. A records check shows the EXIDE AGM batteries installed Oct 2012. Still on the original alternator. If a battery is on the way out and the alternator is trying to over charge and for some reason I have more than 12V in the system, I'm led to believe that could pop the fuse. But why only the fuse for the AirDog and nothing else?

 

[Drewhenry]

Is there another electrical circuit activated from the same fuse when the truck is started? I can't think of why there would be, but I thought I should ask the question anyway.

- John

No. Only the AirDog on that fuse.

 

[petersonj]

If a battery is on the way out and the alternator is trying to over charge and for some reason I have more than 12V in the system,

That would be simple enough to check with a multimeter, assuming you have one. Check battery voltage before and after starting the engine. Then check voltage at the fuse before and after starting the engine.

- John

 

[cerberusiam]

Fuses don't pop because of voltage, they pop due over amperage draw. You should already have charging at 14.8 volts and have since it has been on there.

If the batteries are weak and the system as a while is pulling them down a load close to the limit will likely pop the fuse or breaker. 8 years is outside a reasonable life expectancy with the load the trucks put on the batteries. Have you replaced battery cables\ends and cross over cable at any time? Have you check the ground and battery draw cable to see if they are getting really soft and pliable?

 

[DavidC]

There are a few reasons for a fuse blowing and it all comes down to the load pulling to many amps or the fuse not sized accordingly. Running the pump without the engine see's the pump just sloshing the liquid around and no real load. With the engine running the liquid has somewhere to go which means the pump is loading with liquid flow and higher amps will occur. Get another pump (you should have a spare anyway) put it in and see what happens. Or, you could just keep chasing non existent/maybe leads.

 

[p-Bar]

It's the pressure regulator not shutting off the pump

 

[cerberusiam]

On the AD\FASS the pressure regulator doesn't turn the pump on or off, it just bypasses fuel back to the tank when pressures exceeds its setting. That happens whether the engine is running or not, the AD\FASS delivery almost always exceeds demands so the regulator is always in play engine running or not.

The only real difference between engine running or not is the electrical system load. It may also depend on how the AD is wired; direct to key-on power and always on, or, run thru a relay that the ECM is activating. The latter adds wiring components and the ECM lift pump circuit to the equation, the former is just a battery draw with fewer components.

 

[Ozymandias]

Because stock sucks! Haha!

Nope that's simply no true.
The OEM in tank unit is proven reliable and most of the time lasts longer then any aftermarket pump.

 

[AH64ID]

What does your dash voltmeter show when running?

Is it cold where you are? With the engine running in the cold the grid heater will do a post-start her cycle that draws the voltage down. Lower voltage means more amps for the same running wattage, more amps means the fuse can blow easier... that also assumes the motor is drawing more than normal.



Several things to check thou. Crossover cable, voltage, batteries, etc. I’d be replacing 8 year old batteries either way.

 

[Drewhenry]

Nope that's simply no true.
The OEM in tank unit is proven reliable and most of the time lasts longer then any aftermarket pump.

One look at your signature about your truck.....how come its not STOCK?

 

[Ozymandias]

One look at your signature about your truck.....how come its not STOCK?

Bad influence, wouldn't do it again.
Lots of trouble.

 

[AH64ID]

Bad influence, wouldn't do it again.
Lots of trouble.

Same thing. Many of my 05’s mods were not worth the hassle, time, or money. Main reason my 18 is basically stock with a few bolt ons.

Ya live and learn.