Injector Pump or fuel shut off?
 

Hey folks!

I've got a '93 P30 Van with the 6.2L (I think) diesel V8. I have good fuel at the lifter pump, good fuel at the filter box (black valve top left at the filter mount) and good fuel at some release valve on the front of the motor (I can't tell where it comes from... it comes up from under the intake manifold.)

But no fuel at the injectors. I've cracked 4 of the injectors and no matter how much I crank 3 are dry and one got a tiny bit wet. I pulled the return line at the injector pump and that's dry too. Not even a squirt.

The van ran last year and I had parked it for the winter. The fuel filter is newish.

Is it likely the injector pump is out? If so, can I rebuilt it myself? I've done my own seals on my TDI before.

Is there a fuel shutoff solenoid like on the TDI? Could that be failing to release?

Any other test I can do?

Thanks for your help.

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PS: The van is for sale — I don't use it anymore. :)

The injection pump could have failed. No you cant rebuild it your self. There is a fuel shut off inside the top of the injection pump. If you unplug the I believe its the red wire from the top of the i/p turn the key on and plug the wire back up you should be able to hear it click. I would take the fuel line off to the i/p and see if you have fuel there. The problem is you will have to remove the intake to remove the line.

2MuchJunk thanks. I don't hear a click from the IP at all.

I have two wires to the IP, both on the passenger side. I think one is green and the other is maybe red. I'll have to look again.

What's the other wire do, and how can I tell which is which? I'd like to jump it directly to the battery to test it but I don't want to damage it. I guess I better check my fuses too. =)

The green wire has to do with cold start stuff and should also be spliced a solenoid that pushes the throttle open a little when its cold. It's the red wire and I think its the one furthest back. It should be fine to jump it right to the battery.

Poke around some more.

Solenoids are good. Both click. Throttle pusher works too. I even pulled the top cover off and examined the solenoids. Both work when powered. There's a little bit of fuel in the IP. It was not full though.

I pulled the box filter and it looks good. Fuel came out all holes.

JUst for laughs I plugged the fuel line from the lifer pump, to the output nipple that the box filter sits on... basically sending fuel right from the lifter pump to the IP. With the IP cover off I cranked the motor. I could see a TINY amount of fuel being delivered... after for or five cranks I had maybe a 1/2 inch more fuel in the IP.

But when I pull the lifter line off and leave it disconnected, the lifter line really GUSHES. I am not getting that level of flow to the IP... it's just a trickle. But, the cracked injectors are now looking a little wet when I crank.

Does this low flow to the IP look right? Is it natural for the IP to only allow a little fuel in? Or do I have a blockage between the box filter and IP? What else could stop me from catching... it's HOT out, do the glow plugs even matter?

Brand new starter... and the batteries are topped off every time I try. So RPMs should be good. What am I missing?

I would guess you have a blockage. You should be getting a good amount of fuel in the i/p. I would check the line between the filter and i/p. There should also be a screen on the inlet to the i/p. You will have to remove the intake most likely to get to everything. The screen if it has one will be in the fitting going into the pump. If you don't have any problems up to the i/p you may have a problem in the transfer side of the i/p.

The glow plugs could matter it just kind of depends on the truck.

Thanks I will tear into the intake tomorrow. =)

Check for kink in the fuel line between fuel filter and IP

No kink. But I ran bio for a year and if it's a rubber line it might have been damaged. Strange to happen now though because I've run regular diesel all last year before I parked it.

I'm going to try to blast out the line from the IP end and see if any crud comes out. If that fails then I have the intake gaskets on order and I will pull it apart.

So what's between the box filter and IP... a nipple, a hose, another nipple, a screen, and a valve? I assume the cutoff solenoid operates some sort of valve because when I pulled the IP cover off I could see it actuated some sort of lever. And the second solenoid, activated manually with the throttle advance, just seems to open up the return line at the IP.

Does the IP regulate its own fuel intake? I see the throttle also moves the same assembly the shutoff solenoid seems to move. Lots of little metal parts and some springs.

It was probably just an airlock. It took days to finally reprime the pump and injectors, now it starts on the first or second crank every time.