VP44 help...absolutely won't start after replacing!

ENafziger

ENafziger

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Hello!

I usually hang out in the 3rd gen section, but my brother is needing some help.

He has a '99 Cummins NV4500 with a BlueChip and Edge. Recently, he put a Walbro lift pump on the truck as the old pump would pull down to 0 psi at WOT. The new lift pump maintains 18 psi.

A few weeks after this, the VP44 started going out. Finally, it would only run at an idle, and wouldn't run with any above that. He bought a reman VP44 off Craigslist, and we installed it.

Now, we can't get the truck to start at all. We cracked the injector lines and have cranked and cranked and cranked...literally for over 30 minutes of time. Line 4 has fuel coming out. Every now and then fuel will spurt just a little from one of the other lines.

We bypassed the lift pump to let it run with the key off. We let it run for 2 hours straight with the lines cracked, turning the engine over a little every 15 minutes.

The truck will not fire at all. We bypassed the clutch switch and drug the truck down the road about 5 miles. Again, nothing.

Any suggestions? We've checked all fuses, and they're fine. I'm positive we timed things correctly when putting the new pump gear on. Even with the old pump bad, it would still start and idle. With this pump, nothing.


Help!


Thanks, Eric
 
ENafziger said:
Hello!

I usually hang out in the 3rd gen section, but my brother is needing some help.

He has a '99 Cummins NV4500 with a BlueChip and Edge. Recently, he put a Walbro lift pump on the truck as the old pump would pull down to 0 psi at WOT. The new lift pump maintains 18 psi.

A few weeks after this, the VP44 started going out. Finally, it would only run at an idle, and wouldn't run with any above that. He bought a reman VP44 off Craigslist, and we installed it.

Now, we can't get the truck to start at all. We cracked the injector lines and have cranked and cranked and cranked...literally for over 30 minutes of time. Line 4 has fuel coming out. Every now and then fuel will spurt just a little from one of the other lines.

We bypassed the lift pump to let it run with the key off. We let it run for 2 hours straight with the lines cracked, turning the engine over a little every 15 minutes.

The truck will not fire at all. We bypassed the clutch switch and drug the truck down the road about 5 miles. Again, nothing.

Any suggestions? We've checked all fuses, and they're fine. I'm positive we timed things correctly when putting the new pump gear on. Even with the old pump bad, it would still start and idle. With this pump, nothing.


Help!


Thanks, Eric
Click to expand...

Crack all the lines except #6 (because it is too hard to get too, if you don't have to)
When fuel starts coming out of the injector nut, tighten it back down. Do this for each injector until they are all purged.
It should start then.

We bypassed the lift pump to let it run with the key off. We let it run for 2 hours straight with the lines cracked, turning the engine over a little every 15 minutes.
Click to expand...
I learned that the truck will not start with full fuel pressure. Reconnect the fuel pump the way it is supposed to be and it might start.

I just installed a new pump in my truck and it took about 30 minutes of actual cranking time and two days to finally get it to fire.
Remember, your new pump and lines are all empty and it is going to take time to purge them.
Also make sure that your pump is connected. Just stating the obvious.:bang

There is a thread started by me about this very problem.

called "no start after new vp"
 
If all else fails, shoot it with some ether. That seems to help things along when there is a huge amount of air in the system.
 
pretty obvious but...did the key way fall out while pressing the new gear on? If you take the nut back off you should be able to see if the key way is there. Thats really what it sounds like to me. Ive never had to crack more than 2 lines to get it to fire up and even with installing a new pump or a severe air lock she'd always fire. Good luck.
 
I'd wonder about this "reman" first. If it wont start with ether, the pump is probably Junk.
 
pretty obvious but...did the key way fall out while pressing the new gear on? If you take the nut back off you should be able to see if the key way is there.
Click to expand...

I guess we're going to tear back into it tonight. I'll check this, and hope this is it.

I'd wonder about this "reman" first. If it wont start with ether, the pump is probably Junk.
Click to expand...

I'm starting to wonder this myself. I hope this isn't $700 down the drain.

Thanks guys...

--Eric
 
Spray the piss out of it, and if it wont fire, I'd try to get my money back.
 
Spray the piss out of it may = blow the motor...If it isn't starting within 15 minutes then something is wrong. Either the key fell out or was damaged or the pump was junk out of the box. Unfortunately, Craigslist may not be the best place to find a VP44 rebuilder.
 
Ive seen some ornery trucks take the better part of a can to fire off... although not in one spraying.
 
coon smile said:
If all else fails, shoot it with some ether. That seems to help things along when there is a huge amount of air in the system.
Click to expand...

I remember that one day....man thats been awhile ago
We also learned that day only crack 2 injector lines.


Make sure you unplug the grid heater relays before you hit it with ether, that could go bad in a hurry.
Also, just get some cheap ether DO NOT USE JOHN DEERE PREMIUM 80% ETHER, and if you do, use it very sparingly, its hot stuff...

When used properly, there is nothing wrong with using ether to light one of these engines off after pump replacement.
 
Well, wired the VP44 manually with a hot and ground directly from the battery to pins 7 and 8 on the pump. Still no start, and only getting fuel out of one line. It looks like the rotor is siezed and the pump is garbage.

Moral of the story...don't buy pumps off of craigslist! :doh:

Thanks guys, Eric
 
FWIW, I only crack #3 and #4 on my truck until I can wiggle the line freely. Then have someone crank it. Once fuel comes out, I tighten it up WHILE cranking. Normally, just these two will light off in about 20 seconds. Works everytime for me on my truck and my neighbors. And don't run your lift pump while cranking the IP. The factory is set up to bump the pump on key on then relax it until the motor fires. This will cause hard starts from my reading and experience. $.02
 
Hey Jory, is it the same with the in-tank and motor mounted lift pumps? With the hard start that is.
 
roskoe115 said:
Hey Jory, is it the same with the in-tank and motor mounted lift pumps? With the hard start that is.
Click to expand...

I don't know. I've only had the "motor" mounted ones until I installed the FASS. And as far as hard starts, I have only read multiple threads on it and with luck, have never had the issue personally. I am a injector primin' fool, but that is all. :D
 
Erik@LCD said:
Unfortunately, Craigslist may not be the best place to find a VP44 rebuilder.
Click to expand...

X2.. I myself would rather spend 1500 or whatever they are costing for a blue chip, than spend 700 and be out 700 with still a non running truck. At least then you will have them standing behind a well put together product.
 
You can buy a good, stock type pump from half a dozen reputable places for $1050-$1100.
 
Start tracing your fuel path to determine where the hold up is. I.E. start cracking the lines before the lift pump, after the lift pump, before the injection pump (after the lift pump) then go to the outlet side of the injection pump per cyclinder then work your way toward the motor... You should find the reason.

-Rob
 
I never had a problem after a new pump install, i just crack # 3 and put some gas on a rag over the intake and it fires up every time.
 
samuel642000 said:
I never had a problem after a new pump install, i just crack # 3 and put some gas on a rag over the intake and it fires up every time.
Click to expand...

AGREED... Ether without diesel in the mix is a bad idea. I have torn into more than a few engines that died because farmers would give them a snort of ether before they bothered cranking the engine. I should find some of those pistons with the tiny pieces of rings embedded in the top and snap some pictures.

Our 6.2 was a pain to start after sitting too long (months on end) and a gas soaked rag always worked.

Either way, I'm having the same problems with a 99 that I swapped a used pump onto. My question is wouldn't a junk pump not move fuel up to the injectors at all? I get a little more than a teaspoon worth of fuel per squirt while trying to bleed it, I've got fuel at 1 and 3-5 (I already put the intake horn on so 2 is a b^#$@ and 6 is just plain evil)

I haven't popped the nut off to check the key yet, so I'll try that yet. But I still think we should have p-pumped it :hehe:
 
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