Fuel basics

[imbodie]

Ok, Same scenario that I've read about a couple of times on these forums already. Car was running fine, parked it, two days later would not start. Local mechanic said the injector pump was dead and it wasn't worth fixing.

A couple of days later the car was given to me because I had lusted over it since my friend had bought it. There is no fuel getting to the filter. I thought there was an electric supply pump. A post on this site implied that there was not a transfer or supply pump. So how does the fuel get to the injector pump?

I get the feeling I'm in for some priming of the fuel system, but where do I start?

Thanks,
Tim

[freds83]

On the VE pumps on our cars there is a vein pump in the pump that sucks its fuel from the tank. Some times they dont pump that well or if you just loose prime in the fuel system they cant suck enough to re prime the injection system. What I have done to get a prime back all the way to the pump is crack the return line at the pump take the fuel cap off and with an air line and some thing to half way seal it to pressurize the fuel tank and it will push fuel all the way up to the pump and fill the pump. then crack the injector lines at the injectors and crank until there is fuel squirting out the lines close each one as they start to squirt fuel by the time you get to all of them it should start.

[imbodie]

So the injector pump actually pulls it's own fuel supply from the tank?

Would it be strange for prime to be lost on it's own?

So I need to put 5-10gallons of fuel in the tank and crack a couple of injectors and start cranking?

I tihnk I read one of the posts that talks about puting diesel in a return line that had a banjo bolt that could be cracked?

Thanks in advance AGAIN
-Tim

[freds83]

ya the inj pump pulls its own fuel on our pumps.

ya I would put some fuel in the tank just incase it may have ran out and the fuel guage isnt working. You never know on a 20+ year old car plus it cant hurt.

you can put fuel in the return its just kinda messy and takes a while cause its not just a large hold once you remove the banjo bolt its a tiny hole that you are trying to put fuel down into. if you just loosen it and have an air compressor take a rag and the air nozzle and take your fuel cap off and stick your air nozzle down in the fuel tank and seal it the best you can with the rag and pressurize the tank it will force fuel all the way to pump and out the return and then you can tighten that return back down and you know you have fuel all the way up to the injection pump and the pump is full also.

then start cranking on it with the lines open make sure you have a good bat and the bat charger hooked up also. Also take it easy on the starter we burnt one up trying to get one running.

[imbodie]

Fred (guessing thats your name)

THANK YOU
I'll post how it all turns out after saturday... But I bet you just "fixed" my car.

I know she had let the tank drop to below a quarter of a tank and we had one of those weather systems move through that dropped air pressure in tires, so I wouldn't be shocked if it de-primed the fuel system, have seen stranger things happen.

If this is any indication I am gonna LOVE my vw powered volvo, my dodge has to have 10psi to the injector pump or the injector pump becomes scrap metal. Having an mechanical pump intergrated into the injector pump is going to be interesting.

-Tim

[Jason]

Its the same pump pretty much found on the earlier 1st gen dodge 12 valve cummins trucks. These pumps are pretty bullet proof, if you run out of fuel the engine just shuts off. They aren't nearly as finnicky as the VP44 on your truck. They do require some special maintenance not needed on the Cummins though, and thats the timing belts. If you don't know any service history or their condition is questionable replace them before you start driving it, or the engine will be a pile of scrap!

Originally Posted by freds83

What I have done to get a prime back all the way to the pump is crack the return line at the pump take the fuel cap off and with an air line and some thing to half way seal it to pressurize the fuel tank and it will push fuel all the way up to the pump and fill the pump.

You mean what I suggested we do?? Trying to take the credit for my genius!!!

Jason

[imbodie]

I made one small change to your suggestion.

Instead of cracking the banjo bolt, I pulled the return fuel line off. With the return fuel line in hand, I used my air compressor to pump air down it instead.

Obviously not opening the air nozzle full blown but putting just enough pressure that I could hear it in the fuel tank bubbling. Within a few moments I had frothy fuel coming out of the return banjo connection... just a few seconds more and I had good non-frothy fuel running out at a good rate.

I'm still debating on cracking the lines at the injector, the manual says it should be self priming and I really don't want to crack the lines unless I have too.

Will decide what I should do when I go back to the car in a bit. Seems my battery discharged quite a bit in the last week.
-Tim

[imbodie]

Ok
my brain won... figured I wont know if the injector pump is working if I don't crack the lines.

When I cracked the lines and cranked, I got dribbles instead of spray's of fuel.

What does this mean?

The mechanic that the car was initialy taken to said the injector pump was bad. I am about to come full circle on my volvo experience and agree with their conclusion.

I've still got the car on charge and will try again tommorrow when it's not raining and the battery is fully charged.

On another note, put a test light on the glow plugs and there is power to them for as long as I choose to leave the key at the glowplug position. It will go off after cranking though. I KNOW I'm going to have glowplug issues too, but I would like to get the car started first.

Thanks in advance for all your help.
-Tim

[IceV_760]

Okay, change fuelfilter, it might be bad.
Otherwise, pump is bad, and in need of rebuild mostly.
That will cost ~1000$, if they change all seals and
other things. Atleast on my car it costed about that.
There also might be something trash on fuel lines.

[ngoma]

Originally Posted by imbodie

When I cracked the lines and cranked, I got dribbles instead of spray's of fuel.

What does this mean?

Dribbles out of the injector lines pre-injector should be about right. Think about it-- each shot is a tiny amount of fuel. Next thing to look at are the glow plugs themselves.

Originally Posted by imbodie

On another note, put a test light on the glow plugs and there is power to them for as long as I choose to leave the key at the glowplug position.

Good, you have power to the glow plugs. Now you need to check the glow plugs themselves. Remove the bus bars and test each GP independently for continuity. Mine would not start no way in the morning with three bad GPs (they tested open). Replaced them and it starts first try.