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Air dog, pcm, I'm lost.


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long time looker, first time poster. Kinda at my wits end. Installed an air dog 150 a couple months ago. The wiring in the truck from the previous owner was kinda messed up but I finally figured out the wires for the fuel pump to kick it on. So I've checked those and everything else, fuse, relay and grounds. And it won't kick on when I turn the key on. Truck runs but seems like it's getting lack of fuel. Especially on start up. Idles up and down and up and down. And I just changed the filters so I know that has nothing to do with it. Lights have also been flickering at night and voltage jumping around alittle, not sure if that's related. But any help would be appreciated. 

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Welcome...

On start up, the truck powers the pump relay from the ecm 50%.  

You may have issues with pressure,  but do you have a gauge?  Are they're any codes?   

The flickering is kinda scary.   That could be a loose connection,  bad alternator, bad batteries... hard to say,  but I would check those.

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Pull the alternator have it bench tested. Make sure to test for AC noise also.

To correct CSM a bit there is no relay for the stock fuel pump circuit it just a direct feed from the ECM. Now you aftermarket pump will have a control relay. So you want to check the stck connector from the ECM and see if the ECM is coming on. If not the wild alternator noise could be what killed the ECM.

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I'll pull the alternator and have it tested. I have a bhaf and my alternator wires are not wrapped or anything so the noise issue may have something to do with it. Unfortunately I do not have a fuel pressure gauge. So il try that route and see. I read something on another page about a ripple test for the alternator? Could this have something to do with it?

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The oe harness for the oe fuel pump is the one that needs to used for the relay to run the AD you installed. If those wires are not used then it wont give the pump the initial bump at key on. If you do have the  right wires and dont have the bump at key on it is most likely ECM related. Does the pump run after start up? I lost my lift pump a few months ago and the engine will idle fine with out the lift pump working. Surging at idle could be other things as well. Check for trouble codes. If you dont have a scanner a local auto parts should be able to scan it for you and tell you what they are. There is more than one thing that can cause a surging idle. The codes will help point you in the right direction. And as Mike says, rampant AC voltage can be the root of many issues. Fuel pressure is another cause of problems, and needs to be known.

 Also it would be good if you would go to your profile and fill out your signature with info on your truck so we know what we are dealing with. Different year models of these truck work a little different than others.

 By the way welcome to the forum. This place is the sole reason my truck is still on the road 355k mile after buying it. 

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Ok so update on my situation, pulled the alternator, plastic melted off the clip that the harness plugs into, so I just went ahead and throw on a new alternator. Fixed all electrical issues. Not the pump. Tested my connections EVERYWHERE down the harness for the air dog. I have power to the pump, pump won't kick on. Gotta assume it's the pump right? And I bought it used off a guy, bad idea to begin with, but does the warranty transfer through the serial number? Thought this thing was going to save me a lot of trouble down the road and just ended up creating more.

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i want to heIp,but if the wiring is a mess like you said originally and the pump is used, who knows what is wrong. If you have power to the pump and it wont come on, the pump is probably toast. As Mike says the warranty most likely will not transfer. Plus if the pump is wired to something other than the oe harness, who knows how it will act. I dont.

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