Just Replaced VP44 And Still Won't Run
#13
09-14-2008, 11:02 PM
#15
09-14-2008, 11:29 PM
Diesel Wrench
check the apps sensor first, but even when unplugged if should still idle.
there are 3 other things im thinking.
bad ecm- find someone with a smarty nearby and see if they can load it on your truck then put it back to stock...this will install the latest cummins flash into the ecm if its a software issue, but wont work if something int he ECM hardware is damaged.
injectors damaged- the truck needs the IP and injectors to make it run...if the vp44 is good, maybe the injectors sustained some damage which may have caused the damage to the last pump. if it will start and ile rough for a few before shutting off, then it could be an injector issue since bad vp44's either wont start or will start but throw codes and be low on power with dead pedal 99.9% of the time. never heard of one that will start but not stay running.
and kinda of a long shot here...
fuel return system in the head from the injectors- extra fuel not injected that has made its way to the injector exits via a return system, there is a banjo bolt fitting on the back of the head, its its somehow clogged maybe there is too much pressure in the fuel system, but thats just a wild guess.
there are 3 other things im thinking.
bad ecm- find someone with a smarty nearby and see if they can load it on your truck then put it back to stock...this will install the latest cummins flash into the ecm if its a software issue, but wont work if something int he ECM hardware is damaged.
injectors damaged- the truck needs the IP and injectors to make it run...if the vp44 is good, maybe the injectors sustained some damage which may have caused the damage to the last pump. if it will start and ile rough for a few before shutting off, then it could be an injector issue since bad vp44's either wont start or will start but throw codes and be low on power with dead pedal 99.9% of the time. never heard of one that will start but not stay running.
and kinda of a long shot here...
fuel return system in the head from the injectors- extra fuel not injected that has made its way to the injector exits via a return system, there is a banjo bolt fitting on the back of the head, its its somehow clogged maybe there is too much pressure in the fuel system, but thats just a wild guess.
The following 2 users liked this post by GetBlown5.9:
Justinlhc (09-15-2008),
turbo20psi (02-14-2012)
#16
09-15-2008, 04:26 PM
Ok, down to basics.
LP. It may or may not be bad but even if it were it would take time to kill a brand new VP, so that's not gonna be the issue here. Even if the LP was completely dead the VP will still pull the fuel it needed to run it would just be a pain to get it primed. If it's starting though then it has a prime.
Did you change the Pressure Regulator on the VP44 when you installed the new pump. If it is bad the VP will not hols the right internal pressure and won;t feed fuel right. It is the Banjo Bolt on the outgoing fuel line from the VP, it has a spring loaded ball bearing in it. This could be the problem.
Since you say that pushing the go pedal has no affect I would bet that you forgot to plug the APPS sensor back in when you put everything back together. Check this out. It is the plug that goes to the underside of the throttle assembly. It's easy to miss.
The other issue here is, are you sure you got the key way lined up exactly in the slot. It will go in wrong and the nut will suck it into place just like it's right. If you missed by even the smallest margin your timing is off and the new pump is now bad.
We'll start here and see what comes up.
LP. It may or may not be bad but even if it were it would take time to kill a brand new VP, so that's not gonna be the issue here. Even if the LP was completely dead the VP will still pull the fuel it needed to run it would just be a pain to get it primed. If it's starting though then it has a prime.
Did you change the Pressure Regulator on the VP44 when you installed the new pump. If it is bad the VP will not hols the right internal pressure and won;t feed fuel right. It is the Banjo Bolt on the outgoing fuel line from the VP, it has a spring loaded ball bearing in it. This could be the problem.
Since you say that pushing the go pedal has no affect I would bet that you forgot to plug the APPS sensor back in when you put everything back together. Check this out. It is the plug that goes to the underside of the throttle assembly. It's easy to miss.
The other issue here is, are you sure you got the key way lined up exactly in the slot. It will go in wrong and the nut will suck it into place just like it's right. If you missed by even the smallest margin your timing is off and the new pump is now bad.
We'll start here and see what comes up.
The pump I bought came with new banjo bolts with the new regulator. I didn't check it to make sure it was infact good so I will give that a try next.
I did actually forget to plug the APPS back in at first, but after seeing the check engine light come on I looked things over before I started it and found the harness and plugged it in.
The key way slid in by hand and gave no resistance so I'm pretty sure I got that in the right position. I painted a mark at the end of the pump shaft where the slot is so I can tell where it needed to be. That seemed to work pretty good for me.
Thanks for the suggestions.
---AutoMerged DoublePost---
check the apps sensor first, but even when unplugged if should still idle.
there are 3 other things im thinking.
bad ecm- find someone with a smarty nearby and see if they can load it on your truck then put it back to stock...this will install the latest cummins flash into the ecm if its a software issue, but wont work if something int he ECM hardware is damaged.
injectors damaged- the truck needs the IP and injectors to make it run...if the vp44 is good, maybe the injectors sustained some damage which may have caused the damage to the last pump. if it will start and ile rough for a few before shutting off, then it could be an injector issue since bad vp44's either wont start or will start but throw codes and be low on power with dead pedal 99.9% of the time. never heard of one that will start but not stay running.
and kinda of a long shot here...
fuel return system in the head from the injectors- extra fuel not injected that has made its way to the injector exits via a return system, there is a banjo bolt fitting on the back of the head, its its somehow clogged maybe there is too much pressure in the fuel system, but thats just a wild guess.
there are 3 other things im thinking.
bad ecm- find someone with a smarty nearby and see if they can load it on your truck then put it back to stock...this will install the latest cummins flash into the ecm if its a software issue, but wont work if something int he ECM hardware is damaged.
injectors damaged- the truck needs the IP and injectors to make it run...if the vp44 is good, maybe the injectors sustained some damage which may have caused the damage to the last pump. if it will start and ile rough for a few before shutting off, then it could be an injector issue since bad vp44's either wont start or will start but throw codes and be low on power with dead pedal 99.9% of the time. never heard of one that will start but not stay running.
and kinda of a long shot here...
fuel return system in the head from the injectors- extra fuel not injected that has made its way to the injector exits via a return system, there is a banjo bolt fitting on the back of the head, its its somehow clogged maybe there is too much pressure in the fuel system, but thats just a wild guess.
I'm not sure what a smarty is, but I'm pretty sure I don't know anybody with one.
I can't get it to idle for longer than 5 seconds. Pumping the gas does nothing.
It's looking like one of 3 things.
Cam sensor
Injector(s)
ECM
I really hope it's not injectors or the ECM.
Last edited by Justinlhc; 09-15-2008 at 04:26 PM. Reason: Automerged Doublepost
#17
09-15-2008, 06:32 PM
#18
09-15-2008, 07:43 PM
How do I check it? I unplugged it to see if it would make a difference and it didn't make any difference at all in the way it acted. It didn't even trigger the check engine light. Do you think that could cause something this extreme? I'm located in LHC, AZ.
#19
09-16-2008, 09:22 PM
The LP is working without a doubt. I know this for an absolute fact now. I'm going to see if I can find a cam sensor tomorrow and see what happens. I have a feeling it's not going to help, but I'm running out of options here. I'm no diesel mechanic, but I'm going to have to assume that it's not getting spark or ignition or whatever they call it in these motors. I have fuel, compression and air so it has to be ignition related.
#20
09-16-2008, 09:35 PM
Nope, it's fuel/timing related. Your fuel is not being moved through the system with either enough pressure or at the wrong times to crank the engine.
So the next questions are:
What has been done to the truck as far as Mods.
What Fuel pressure is it reading.
What codes is it showing.
Are you sure you put the regulator valve on the right line.
So the next questions are:
What has been done to the truck as far as Mods.
What Fuel pressure is it reading.
What codes is it showing.
Are you sure you put the regulator valve on the right line.
