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No Start... Please Help!!!


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New here and can really use some help. This might not be the right section to post this but i figured id have better luck here. I just recently finished swapping a 24v into my ford and have been having a problem getting it to start. Before I say this my heater grid is not hooked up and i know its horrible on the motor but the truck will only start with a small hit of ether.Once its started it runs perfect. Idles great sounds smooth and revs up like it should.Once you shut it off and try to start it right back up it wont start. It wont even sputter or sound like its trying to start. The vp44 is brand new and was part of the problem originally when i first started trying to start it. It has since been pulled off and sent back to find it had a defective computer on it. It was repaired and sent back to me but the truck still will not start without ether. I also just sent the ecm off to be checked and they found it had a bad apps and lift pump circuit. It was repaired and sent back and still the truck will not start without ether. Before the ecm was sent off I had a few codes. p0122,p0237,p0336,p1287,p1689. Now that the ecm was repaired im seeing no codes.I also replaced my brand new crank sensor with another brand new sensor just to be sure and still no change. Fass pump cycles on like it should with key on and im getting good pressure at the pump. If anyone has anything they think i can try or check please let me know. Ive been testing wiring and sending parts off for the past two months and im at my breaking point. Thanks for the help.

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Tried hot wire test and I got nothing. Not even a sputter. You can hear the pump click on when you connect it to battery but it still won’t start. I’ve now pulled the breather and nut on pump to check keyway and it’s still in place and looks fine. Not sure where to go from here now. I’ve already sent the pump back under warranty once and they found the computer was bad. Is it possible they didn’t test it and sent it back still broken. 

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I would definitely be contacting them again and telling them that you've done the hot wire test per blue chip diesel troubleshooting guide and everything points towards the pump. This is of course assuming everything else is functioning properly.

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That is my next step because I just cracked all the lines open at the injectors and cranked for about 30 seconds and I’m barely getting any fuel out of the lines. I put a rag under #3 and it didn’t even wet the rag and the nut was completely loose. #6 does seem to be getting more fuel than all the others though. 

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  • 2 weeks later...

Update. I wired the fass pump to 12v so it’s constantly running and putting out 17psi. I also hot wired the vp44 to the battery and it is now trying to start. I then unhooked the wires and connected the harness back to the vp44 and it just turns over with no attempt to start. I re-checked continuity of all wires from vp plug to ecm and all are good. I also have good ground and good voltage at the plug. I’ve also tried wiggling the plug while someone cranks and still no change. Any ideas ? 

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  • Owner

Return the FASS back to the lift pump circuit excess fuel pressure cranking is not good. 

 

Then I've got to ask is the WAIT TO START light working does it come on? I know this is a Fummins swap but I want to know if the ECM is even booting up. If there is no WAIT TO START then the VP44 will not fire up nor will the ECM command to start.

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When the fass is hooked up to the factory lift pump plug and the vp44 is hot wired to the battery it doesn’t try to crank like it does when the fass is connected to 12v. It also won’t come on after the starter is bumped. I’m not sure about the wait to start light. It comes on on the dash but I’m not sure if it’s turning on by the Cummins ecm or the Ford pcm. I’ve had the ecm repaired already and I’m hoping it’s working correctly. I did read something today about a security lock out within the ecm that could be preventing start up but I’m not sure if that’s actually true or not. 

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I just got it back from being repaired by Auto Computer Specialist. They repaired the apps circuit, lift pump circuit, and also changed out the cpu and processor and reflowed the pins. My vp44 was also sent back to Midwest fuel injection a couple weeks before that and they found it had defective electronics. The computer on it was repaired and sent back to me. 

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  • Owner

Lift pump should pulse during cranking. 50% duty cycle. The reason for this is to keep the VP44 from over advancing during startup. This why you don't want direct power to the FASS. Then you'll get hard starts hot later on. 

 

WTS light is the next thing I need to know if it's coming on. If not then the ECM is NOT booting up at all. The first instruction is to light the WTS light and fire the grid heaters if needed. 

 

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Ok that makes sense but with the fass plugged into the lift pump plug it’s not pumping fuel to the vp. It cycles on for 2 sec with key on but will not cycle on when starter is bumped. Also with the vp wired to the battery it was not even trying to fire up until I connected fass to 12v. Makes me believe the fass was not getting signal to pump any fuel at all during cranking wired to factory plug. The directions from auto computer specialist also says that I can only use a factory Cummins lift pump. Not sure why.

 

When I get a chance I’ll hook up a test light to the WTS wire coming from the ecm and see what I get. 

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