xyz12383318

My injection pump started to go erratic last week. It started by not wanting to idle with my idle dropping to 400 or 500 rpm's and the vehicle wanting to die. I am running a P-pump lift pump and just added a set of 330 injectors. The pump is still virgin and has no mods. Did the p-pump lift pump hurt it? The new injectors? I drove home today from Salt lake City and the thing died in my driveway when I finally limped home. It is completely erratic at less than 1500 rpm's at this point and smokes whit smoke at lower rpm's. When the problem first started it was fine when I got on the pedal and got the RPM's up. As I was driving home today it got worse and worse, and I lost power as well as speed. Toward the end of the trip 67 mph was my top speed. Am I missing something and this a small problem, or do I need a new pump? A rebuild? Where and who? Are there mods I need to ditch? I would like to run a smoke free to low smoke 300hp and I'm wondering what to do I do next?

kawi600

I dunno how the chevys are timed but Id check that as well as look for boost leaks if it has a turbo.
Have you researched the max pressure the chevy injection pump should see, and made sure the lift pump isnt over-pressurizing? You can pop seals like this.
How long do you purge going back to diesel? Have you run on hot VO since?

NYCEGUY01

his burban is running a 93 12v cummins with a ve pump.

wannadiesel

Check the fuel filter first.

xyz12383318

I changed the fuel filter and have the same symptoms. I can start it with some pedal and can keep it running over 1000 rpm's, max rpm is 2200. I suppose ulsd has struck again, or perhaps it is my high pressure lift pump, veggie, an old pump. What is your guess?

G1625S

Man, that's an awful lot of variables. I think ULSD is out since there are so many old pumps running it now with very few if any confirmed failures associated with the fuel. The worst that could happen with the P-pump LP is a blown seal on the VE shaft, resulting in fuel being pumped into the timing case---have you checked your oil since the problem started? Sounds like a dead VE, but maybe running straight diesel for a while will clear things up...

xyz12383318

You don't think the extra pressure could ruin an IP? I suppose I will rebuild it and give it a go.

bgilbert

Exactly what piston lift pump did you install, the low pressure 3936320 or the high pressure "p-pump" piston lift pump?

Seems 99% of the dead injection pump threads I read are when guys run veggy oil. I'll stick with good ole foreign oil/fuel.

dpuckett

If you have distilled the veggie oil into actual diesel, you should be ok.

If you installed the high pressure p-pump LP, that WILL take out your front IP seal. You want to keep fuel pressure at <16psi I have been told. Some guys run higher LP pressures with modified seal holders in the front housing.

I would venture a guess of old age, bio fuel cleaning everything out and crudding up the fuel system, combined with ULSD eating old seals. I know of 2 pumps personally that have been affected by ULSD. Or they started leaking last fall, noticed mine in NOV; Mom's in DEC, and it was pouring out the AFC vent. VERY coincidental timing, if you ask me. though I'd think it a little late to be noticing it now. But if you had just started and driven it, it could be just getting worn out enough by now.

I'd say remove the pump and take it to a Bosch shop.

Daniel

xyz12383318

The shop said both return springs were broken inside the pump. They said it was a common problem with VE pumps. They said everything else looked ok and please send us $570 bucks because it took our rebuilder a whole hour to repair your pump, ouch. I asked about all the variables and they said that I have a 1 year warranty on the pump unless I use veggie which will void it. Oh Well!

timb

Or if you break the cute little paint seals they put on the adjustments. That will void the warrenty also.

Cowboy_Customs

Sorry to hear of your troubles, however the question remains, what piston pump r u running?

JD730

Had it happen on one of my trucks, rebuild cost $740 a few years ago. I also have one off a truck that did the same thing only worse, broke the springs in several spots.

xyz12383318

I told them I wanted a lift pump for a second gen 12 valve. I guess it is high pressure.

Cowboy_Customs

You need to find out lift pump u got cause your going to blow seals on the IP. The acctual second gen LP pushes something like 40 PSI i think. (someone correct me if im wrong here)
but either way its too much for the seals on the VE. The most common seal to blow is the one that seals the pump from the crankcase, u blow that one, n yer gunna dump fuel straight into the oil.
The VE is made for <16psi