Lift pump questions

[Kevin 007]

I got a one way check valve hooked up and ready to install tomorrow. And will post my results.

Ok, I will check all the return lines, all injector lines appear to be dry. Yeah I suppose the crush washers could be a culprit.


Thanks for all the help Lindstromjd!!

 

[Kevin 007]

Hopefully the lift pump is strong enough to overcome the check ball pressure....
It is a fuel check valve so it "should" be ok......

 

[lindstromjd]

Hopefully the lift pump is strong enough to overcome the check ball pressure....
It is a fuel check valve so it "should" be ok......

Should be. The fuel pumps on 6.2's are designed to put out way more fuel flow than the engine actually needs. I think they put out about 8psi or so.

Just as an afterthought... you can install a clear fuel line as your main feed line to the IP and the main return line from the IP to the return rail... it will let you know right away if you have air bubbles in the system.

 

[Kevin 007]

I put the check valve in, and ran the bus for about an hour. shut it off for 10min, no longer, and it cranked and cranked but no start. gave the injectors a bleed and then a shot of WD-40 and away it went.
Driving me nuts.

Being a van configuration its really hard to acsess the IP to put clear lines on, but thanks for the great idea.

Im leaning towards the electric lift pump not having enough pressure, it has lots of flow however.....

 

[lindstromjd]

The lift pump only needs to be putting out around 8-11 psi of pressure. 11 is on the high side. 8 is normal.

Since you've ruled out the lift pump, the check valve, and glow plugs, there are really only 2 things left I can think of. You may have a "heat soak" issue with the IP, or your return lines might be bad.

If you have a "heat soak" problem, it's pretty easy to identify. When you shut if off, pour cool water over the IP and see if that does anything. If it does, that means the internals of the IP are shot and you need a rebuild.

If the return lines are leaking air/fuel, then it's cheap and easy to fix them.

You're absolutely positive the glow plugs are working? It just doesn't seem right that the engine would fire with wd-40 but not on it's own. Also, when you're bleeding the injectors, there's not going to be very much fuel coming out of them at all, because 6.2's don't hardly use any fuel at idle.

 

[Kevin 007]

When I shut it off hot, I will restart up a minute or so later, but not after 5 minutes or longer, is that still typical of a heat soak issue?
But it never did this before I put that electric lift pump on, always started instantly when hot

And when I bleed, I have my throttle foot to the floor and still see very little fuel.

Under normal circumstances, should I apply some throttle when starting these things. I have been with this one just because its such a pain to start.

 

[lindstromjd]

You're supposed to have your foot at least halfway to the floor on starts with these old things. All the way shouldn't hurt it, but might be indicative of some other problems. Either way, you should be giving it at least half throttle on start up, hot or cold.

Mine always starts right up after I hit the GP's, but when it's hot and I don't use them, it doesn't like starting after a couple hours. I have to use the GP's again. But mine are on a push button.

It really beats me, as far as why you're having starting problems. I just don't know what else it could be anymore.