Waking up an old CUCV (long post)

[k20]

Hey guys, tryin to get my m1008 started today. I finally got it turning over late today by replacing all the battery cables. She is still setup for 24v cause I cant afford to swap to 12v. Anyway, current problem.

I had the bleeder screw on top of the filter housing open, turn it over and it would spray a little, then nothing, spray a little, then get nothing. When I say spray a little it might be a 1 second shot, might shoot horizontally from the drain hose....4-6" maybe. But I could never get a consistant stream of fuel.

Im not sure if I am supposed to or not. So then we closed the bleeder screw not really sure how it was supposed to shoot fuel out, and tried starting it, didnt have any luck, thought ok, injector lines need to be bled, opened em up, didnt hardly leak out anything. Probably 5 of em dribbled out a little fuel, the other 3 didnt do anything but get a little damp. And yes we were sure to hook up the pink wire when we did this.

My question to you guys, does this sound like a fuel pump, or an injector pump? Or is there a possibility there is a hole in a fuel line somewhere making it do all this crap. Never did see a hole in a line, or any drips under the truck, but I could have missed something.

This is my first time ever working on a 6.2, or any diesel other than routine maintenance on a powerjoke.

Thanks for the help guys.

 

[tRustyK5]

Remove the fuel line downstream from the filter, but before the IP. Make sure the pink wire is unplugged first.

When you spin the motor over you should get a pretty decent stream of fuel coming out of the line...if not your lift pump is dead or you have a bad fuel line somewhere.

Once you verify you have good supply to the IP, then hook the line back up, plug the pink wire back in and crack the lines at the injectors. Unplug and remove the glow plugs for this part...it'll help to not kill the starter or the batteries.

A 6.2 will run with a dead lift pump, but you'll never be able to get the air bled out with a bad lift pump. My K5 has a dead lift pump, and it runs still...just not very well.

Rene

 

[k20]

How consistent should the stream of fuel be? Should it be a solid stream or should it 'surge' like an old hand water pump does?

Oh and trusty, when you are saying lift pump, are you talking about the fuel pump bolted to the side of the block or the injector pump? Ive seen lift pump used in place of those 2 terms, so trying to be sure.

 

[k20]

If it is the injection pump, can it be rebuilt? A quick look at advance/autozone/napa and what they want for an injection pump, is almost what I paid for the whole damn truck.

 

[BKinzey]

It should be a solid stream. Sounds like you are getting air in the lines. Check your fuel lines from the tank to your lift pump. Check your electrical connections on the pump as well.

If you have a box type fuel filter the pump is mounted to the back of it. They have been known to crack on the backside and let air in the system so check for that.

The lift pump feeds the IP and they are seperate parts.

IPs can be rebuilt but they need to be metered so it is best to leave that to the pros.

 

[k20]

I have the box style filter on the firewall. There is no 'pump' on the back of that housing, there is however, a carburetor style fuel pump bolted to the passenger side front of the block. I also see no electrical connections on the fuel pump.

 

[tRustyK5]

Lift pump is always the pump that supplies fuel to the injection pump. The majority of guys here have the stock unit which is the mechanical fuel pump on the passenger side of the engine. Quite a few guys have added an electric fuel pump for better reliability, and i've heard easier starting too.

Even with an IP in need of rebuilding you should be able to get the fuel system bled out and get the truck started.

Get the fuel supply problem fixed first, then you'll be able to at least get it started and see what else you might need. In the event you do need to have the IP rebuilt there are places that do so for very reasonable money. My rebuilt IP (and 8 rebuilt injectors) cost me less than $350.

Rene

 

[k20]

Ok, I had a buddy helping me yesterday and he was saying that it seemed like it would almost start getting fuel up to the filter, and then when I would stop cranking it would all drain away. Then I would try cranking again and it would take several seconds before fuel would make it back up there.

 

[tRustyK5]

Sounds like a weak lift pump. A good lift pump will supply plenty of fuel at 5-7 psi to the injection pump. It's a bastard job to change the lift pump out, not very much room to work...but it's not a spendy part. I recall paying about $22 for the last lift pump i did.

Rene

 

[k20]

Yeh I noticed there aint any room down there......at all....but is it just like doing a fuel pump on a gas motor, have to align the pushrod & all?

 

[imiceman44]

Yeh I noticed there aint any room down there......at all....but is it just like doing a fuel pump on a gas motor, have to align the pushrod & all?

Look at the 3rd sticky post for a full write-up on changing the lift pump.

 

[rich]

Yeh I noticed there aint any room down there......at all....but is it just like doing a fuel pump on a gas motor, have to align the pushrod & all?

Yes - same style with pushrod like gas engine.

My block-mounted mechanical lift-pump was such a pain to get out (such little clearance working in there) that I put a block-off plate on it (same as SB Chevy) and used an electric pump instead. I used a Mr Gasket 12V pump from Advance Auto that was like $38. But it stopped working after only 300 miles. I had a spare used electric pump (same size but had a square body) that I used as a replacement, and it has been working since. Took the broken Mr. Gasket pump back to Advance and got a refund.

If you are thinking about going electric, you may want to leave the mechanical pump in place and use the electric to "push through it". See if this works, especially to save you time while you're just trying to get this truck running. I did not have this option, as my mechanical lift pump was leaking and I had to remove it.

 

[k20]

hey guys, just walked in from checking the fuel lines, one rubber section is kinda cracked up, seriously doubt its lettin any air in, but I'll replace it just for peace of mind. What kind of hose should I use? I dont know if diesels req the fuel injection hose, or regular carb hose, or if there is some diesel fuel safe hose.

Also, on the crossmember all the lines run across from the fuel tank, there are 3 ports at the tank, 2 have lines connected to, and the third has a vacuum cap & a clamp on. I assume that is the tank vent, and if so, should it be capped off, or should it be run somewhere?

Final question, I read in another thread about a 2nd fuel filter somewhere on the back of the manifold, where is it located?

Sorry for the noob style questions, but again, its the first 6.2 Ive worked on

 

[imiceman44]

hey guys, just walked in from checking the fuel lines, one rubber section is kinda cracked up, seriously doubt its lettin any air in, but I'll replace it just for peace of mind. What kind of hose should I use? I dont know if diesels req the fuel injection hose, or regular carb hose, or if there is some diesel fuel safe hose.

Also, on the crossmember all the lines run across from the fuel tank, there are 3 ports at the tank, 2 have lines connected to, and the third has a vacuum cap & a clamp on. I assume that is the tank vent, and if so, should it be capped off, or should it be run somewhere?

Final question, I read in another thread about a 2nd fuel filter somewhere on the back of the manifold, where is it located?

Sorry for the noob style questions, but again, its the first 6.2 Ive worked on

I don't know if yours has the same filter but the early ones had it under the intake behind the IP, it's a spin on filter, right under the spider style intake.
The fuel tank is ine the way it is, just replace fuel lines that are cracked, there are fuel lines specific to Diesel that will last longer but gas fuel lines will do fine for long enough.

 

[DukeBoy88]

You should only have the one fuel filter on your M1008, unless someone altered it from factory. I replaced my mechanical lift pump with the $25 electric when it started leaking. works good for me.