Engine/Transmission (1998.5 - 2002) Engine quit

[JMLambert]

The engine quit, I looked at the fuel pressure gauge and had no fuel pressure. I bumped the starter and I could not hear the fuel pump running. I changed the air tex fuel pump and fuel filter. I bled the system and still can not get the engine to fire. When I turn the key on the pump comes up to 20 lbs of pressure. When I crank the engine with the starter I loose fuel pressure and the pump quits. As soon as I let off the starter the pump activates. There is no engine light. I have ordered a code reader but I have not ricieved it yet. Any suggestions on what is wrong? Thanks John

 

[JLandry]

John,



What exactly did you do to bleed air from the fuel system? I ask because you need to make sure air is purged from not only the low pressure side of the system (lift pump to Bosch VP44 fuel injection pump) and the high pressure side (VP44 to injectors). The easiest way to purge air from the low pressure side is to loosen the fitting at the inlet of the VP44, pack a wad of rags under it, and bump the starter to activate the lift pump. When a steady stream of fuel comes out of the loosened fitting, snug it up. Next, to purge air from the high pressure side, you'll need to loosen 2 or 3 injector fittings at the head (loosening more fittings is better than less) and crank the starter for 5 to 10 seconds. If you have a helper, you can have that person crank while you observe the loosened fittings for strong squirts of fuel. Retighten these fittings.



Next, make sure your batteries are fully charged, hold the accelerator pedal to the floor, and crank the heck out of it! After some cranking you should at least get a cough from the engine if she's gonna start at all. If you get nothing, then the VP44 could be shot from being starved of fuel.



Please keep us posted.



John

 

[JMLambert]

I did not bleed the high pressure side as you indicated. I will bleed the system again tomorrow when my son is here to help. Thank you for the reply and help.

 

[JLandry]

Any luck getting her running?



John L.

 

[JWiegel]

Lift pump!

 

[JMLambert]

I bled the system from the lift pump to the injector pump. When you bump the starter there is 21 lbs of pressure. First let me say this is the first time I have bled a diesel system. I loosened the injector lines 1,3and 4 to the point of being finger loose. I then had my son bump the starter for about 10 seconds. The back injector line was spurting fuel out of it but not the other two. I tighened that line and had my son bump the starter again. I had to rock the lines back and forth to get any fuel out of them. I know little about the injector pump but would figure the pressure it is suppossed to have I would of had diesel all over the place. After getting fuel out of those two I tighened the lines and then cranked the engine 3 to 4 times for 30 seconds each time with out it firing. There still is no engine light so I must be doing soethig wrong.

 

[JLandry]

I then had my son bump the starter for about 10 seconds.

Do you mean you had your son CRANK the engine?

I know little about the injector pump but would figure the pressure it is suppossed to have I would of had diesel all over the place.

If your son was indeed cranking the engine (not just bumping the starter and releasing the ignition key), then yes, you should've seen lots of diesel squirting from the loosened fittings.

After getting fuel out of those two I tighened the lines and then cranked the engine 3 to 4 times for 30 seconds each time with out it firing.

Were you cranking the engine with the accelerator pedal held to the floor? If yes and it's not even trying to start, then it's very likely that the loss of fuel pressure to the VP44 fuel injection pump has damaged it internally. It's probably time to order a replacement.



How many miles do you have on this VP44 fuel injection pump?



Do you have access to a code scanner to see if there are any trouble codes stored in ECM or PCM?



Regards,



John L.

 

[JMLambert]

After I loosend the injector lines my son cranked on the starter for at least 10 seconds each time we were bleeding the system with the pedal to the floor. The number 4 line it pulsated, the other 2 lines there was very little fuel coming out of them. Also when we attempted to start it the pedal was to the floor and we cranked on the starter for 30 seconds 4 times. A question I have when you crank on the starter the fuel pump shuts off and there is no fuel pressure. As soon as you release the starter the pump starts and the pressure goes up to 20 lbs. is that normal? The truck has the original VP and it has 198K on it. The code scannner will be here by tomorrow. Thank you again for the help and answers.

 

[JLandry]

A question I have when you crank on the starter the fuel pump shuts off and there is no fuel pressure. As soon as you release the starter the pump starts and the pressure goes up to 20 lbs. is that normal?

Yes... that's perfectly normal.

The truck has the original VP and it has 198K on it.

That's a lot of miles for a VP44, and being starved of fuel, it's very likely the internal accumulator diaphragm was ruptured and so the pump is effectively dead. This is why it's so critical to supply positive fuel pressure to the VP44 at all times. If the lift pump quits while the engine is running, then the engine needs to be shut down quickly to try and save the VP44.

Thank you again for the help and answers.

You're welcome and good luck. Please let us know how things work out.



John L.

 

[JMLambert]

John, I recieved the scanner yesterday it showed a P 1688 code, Fuel Injection Pump Controller Failure. I have an appointment next week to get it fixed. Thank you for the help and information. John Lambert.

 

[JR]

Just make sure the replacement VP has new electronics on it. There Are some rebuilders out there that will bench test the ecm that is mounted on the pump and providing it passes you will end up with someone elses with unknown mileage. There there is a large gap in prices of rebuilt pumps ranging from roughly $900 all the way up to $2400 depending on what has been replaced on the pump. Most of the issues that plagued the early VP's have been addressed but the weak link is generally the ecm so it is important to make sure you get a new one.

 

[klcammie]

check with blue chip diesel they have good pumps and a variety from oem to high horse p[ower. they also have test on there web site to confrim that vp is dead. also you can call and talk to a live person with questions.

 

[Vaughn MacKenzie]

John if you do any wrenching it wouldn't be too tough to swap out a VP44 yourself. Heck if you bought me pizza and a rootbeer I might even wander over to Wally World and give you a hand

 

[Sticks]

Do a search in this forum section. I did a complete write up and tool list on doing a VP swap. A first timer can get it done in about 3-4 hours.

Still can't find the original thread, but here is a thread with a copy

https://www.turbodieselregister.com/forums/showthread.php?228089-Injector-pump-replacement

 

[JMLambert]

Vaughn and all of the others that offered help and advice, thank you. I took it to a local shop and had it done. I just did not want to do it in the heat outside and needed the truck. The one thing I can pass on to others: I was getting a hesitatiion and thought it was the torque converter unlocking. I feel now it was the injector pump on it's last legs. Thinking back, the difference to me between the two is when the torque converter unlocks there is a difference in several hundred rpm, I was getting a hesitation which did not show on the tach or fuel pressure gauge. Hopefully this will help someone else in the future. Again Thanks to all John

 

[Vaughn MacKenzie]

Glad to hear you're back on the road John. Can't blame you about the heat, I've done more wrenching than I care to in triple digits this summer in the driveway with no shade!

 

[Joseph Donnelly]

I have heard that you don't want more than 16 psi from the lift pump or you can damage a diaphragm in the VP44. 16 at idle is what a new OEM pump delivers.

 

[JR]

Out of the half a dozen or so block mounted Carters I've dealt with, I've never seen them above 10-12 at idle, even the new pumps right out of the box. Once you get them under load, I've seen them drop down to as low as 6 psi. Alot of the pressure drop has to do with the small oem fuel lines, but even with 1/2" lines when I had to hook up my Carter for a week until I got a new AD I was still seeing 3-4 psi drop under load. I have my AD adjusted right at 17psi at idle, and generally don't ever see it drop below 14-15 psi which is the point that the overflow valve at the vp opens up.

 

[JMLambert]

Where can I purchase a pressure reducer that will get it down to 16, thanks?

 

[Sticks]

I have heard that you don't want more than 16 psi from the lift pump or you can damage a diaphragm in the VP44. 16 at idle is what a new OEM pump delivers.

30 psi would not be good, but IIRC there was a pump that came out for a while that ran off a belt on the dampener that put out over 25.

I've done many a dual pump mod on trucks when I worked for Central Motive Power in Denver CO (we were the VP44 rebuild and warranty shop for central US - supplied dealerships with theirs among others). Dodge in tank transfer pump, and block mounted Carter pump in series. 20-23 psi idle, 17-20 psi WOT no load. Never had a return, never had one shell a VP44 due to over pressure.