Hard Starting After Airdog Install
06-30-2010, 05:47 PM
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Hard Starting After Airdog Install
I just finished installing an airdog 100 a couple days ago and ever since, it is hard to start. Takes 2 or 3 tries and then runs fine. I was reading that hard starts can be caused by excessive fuel pressure. So I unplugged the airdog and it cranks right up. Plugged it back in and the hard starting returns. I did this twice and it was consistent. I don't yet have a fuel pressure gauge but is there a way to adjust down the fuel pressure? Or some other solution? I'm hoping I don't have to jerry rig something to cut out the airdog when starting.
07-01-2010, 06:13 AM
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It may be adjustable on the pump you have. You need a gauge to set it. You can use the trigger wire that hooks to the stock lp wiring and hook it to the fuse for power windows instead. Under crank it will not turn on pump, just sends power in run position.
07-01-2010, 08:11 AM
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Not sure I know what wire you are talking about. Are you talking about the two conductor plug that goes to the airdog? Where is the power windows fuse? I assume I would be connecting to the power input side of the fuse.
07-01-2010, 09:04 AM
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I have seen this before with VPs that have been run on low fuel pre. a cheep fix for this is to run a hobbs 4 psi pressure switch off the oil feed port on the filter and to the relay so the A/D is off till you build oil pres. this works very well with hard starts after an A/D or FASS
07-02-2010, 10:30 PM
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I'm having trouble envisioning the set up you are describing rebal. What relay would the pressure switch be going to? What kind of fitting would I need to install the pressure switch?
I've called airdog support and apparently they have some kind of a re-wire for this problem. Still waiting to find out what it is.
I've called airdog support and apparently they have some kind of a re-wire for this problem. Still waiting to find out what it is.
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07-11-2010, 10:15 PM
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Spoke with airdog support for a while. They are telling me the ECM should not be telling the pump to run while starting. I'm not 100% yet but I believe mine is. I'm hoping there is an ECM reflash that can be done so that the pump doesn't kick on while cranking. I believe that would solve my problem and would be preferable to a rewire through a relay, etc.
07-11-2010, 11:54 PM
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Do you have the bypass plumbed back into the filler neck? I have the Draw Straw V installed in my tank (dealer installed tank lift pump) and forgot to cut the line above the check valve on the old supply (now the return) in the module and had 25psi. No hard starts however. After cutting this line my pressure dropped to 15 psi. BTW I have the same fp100 you have.
07-12-2010, 06:29 AM
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Not sure I'm following you sixpack. I have the return line from the AD going to the filler neck. Is that what you're calling the bypass? There were two lines going to the top of my fuel tank. One was the fuel supply. That was removed and installed the snap on connector installed to supply fuel to the AD. The other line on top of the fuel tank was left untouched.
07-13-2010, 09:59 AM
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Find a local member with a Smarty programmer. If they have the latest software, you can flash the newest factory software load into your ECM by loading a Smarty program then restoring it back to stock. The Smarty has the latest factory load for going back to stock.
07-13-2010, 12:16 PM
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07-13-2010, 03:12 PM
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Spoke with airdog support for a while. They are telling me the ECM should not be telling the pump to run while starting. I'm not 100% yet but I believe mine is. I'm hoping there is an ECM reflash that can be done so that the pump doesn't kick on while cranking. I believe that would solve my problem and would be preferable to a rewire through a relay, etc.
I would venture a guess that none of the third party manufacturers actually makes the pump that is smart enough to use the 50% decreased drive voltage and reduce pressure on VP when starting. That would require putting in some circuitry to monitor the voltage... much easier to just throw in a on-off relay.
I personally chose to run my aftermarket LP from a Run-only circuit (relay power is from Run only, relay switch is from the LP harness). This way, VP44 starts up with zero pressure. Once the engine starts, the LP kicks in. This eliminated hard starting for me. This is a much easier solution than the one with an oil pressure switch, that gives exactly the same result.