Injection Pump problem too

[BlueDog]

I suspect my injection pump on my '89 1.6 has stopped pumping. It was rebuilt at a Bosch Service center 15 months ago and been working great. Running dino-diesel ever since.

Last Friday it coughed a couple or three times as I was going down the road starting off for work. I turned around and brought the car home and took my wife's old van to work.

On Saturday I drove the Jetta again on some errands and it ran just fine; except for later in the afternoon as I drove home. It didn't have the usual power, seemed to be starving for fuel. I had no tools with me so I nursed it the 12 miles back to home. I was on the highway and could get up to 60 mph but that was all.

It turns out that the fuel filter inside the tank was very plugged up, some kind of snot-like stuff . Cleaned it all off and reassembled the hoses at the tank. Then I primed the IP with a squeeze bottle of diesel fuel until it was full and fuel coming out the outlet side of the pump. That's a standard way of priming it, right?

Stuck the infeed hose into a glass coffee carafe of new diesel and started the engine. The IP just doesn't pump. It will idle like that until the fuel I bottle fed to it is gone.

Did I damage it running it at 60mph for that 12 miles to home?

[TylerDurden]

I'd run Diesel Purge through the pump. You know the drill... both hoses (inlet/outlet) into the can or carafe of DP.

[CarlosA]

Yep purge is good for tons of things, also see if that sludge clogged up your spin on filter and is causing the pump to suck air or just really work for fuel.

[Fatmobile]

See now this is what a vacuum gauge is for.
By the time you actually stop the car you are pulling a very high vacuum.
Suck fuel through the whole pump and lines by pulling it from the output of the pump.
You might need some RPMs to get the vanes to pull fuel again.
You might have to pull-start if it doesn't start pulling on it's own.
Remember to floor it while cranking.
I don't want to recomend disconnecting the glow plugs and spraying something in the intake but have heard good things about dry silicone spray as starting fluid.

[Dakotakid]

Couple of things come to mind here:
1) you're sure you reattached those two lines at the fuel pickup/sender correctly?

2) does this car still have the big plastic fuel seperator down there ahead of the tank?
It may be cracked and drawing air now. Additionally, you probably sucked it dry as the intank screen clogged. Your pump may be getting a little weak in the first half of the pump and having difficulty drawing so much to re-establish prime.

3) Were the ends of those two lines (at the pickup unit at the top of the fuel tank) still in good shape (after you removed them) or were they cracking under the original (or current) line clamps?

4) The screen at the bottom of the tank was clogged. What shape is your fuel filter in? There may have been moisture in the bottom of that plastic seperator (if it is still in the car) and you drew it forward into the filter as you ran things dry.

And, before you dismiss these ideas....take a good look at them.

[BlueDog]

Thanks for the ideas guys.

The fuel lines and the fuel tank aren't really in the picture at the moment. I'm attempting to run the engine from a glass container of fuel. The fuel intake hose is disconnected from the filter. It goes from the IP direct to the fuel a distance of a foot and a half. I wanted to do this first so that I fully prime the pump and test that all is well. It's not.

The big plastic fuel separator was discarded a few years ago.

I'll check out the condition of the lines where they connect to the tank. But later, after I see the IP works properly in the present mode.

There has been no problem starting the car. It starts fine. I rev it up even. When the fuel that I bottle fed to it runs out the engine begins to lose power and won't rev beyond idle so I shut it down.

[82vdub]

I was going to say to rig up a bottle of fuel and bottle feed it and rule out the fuel distribution system, but that's what you've done. Run some diesel purge through it (bypassing the fuel system as you have already) and post results.

[BlueDog]

I thought it was fixed. Last night I ran Diesel Purge through it. The pump wouldn't draw it in so I bottle fed it. Still nothing was happening until I saw a dribble of liquid on my vacuum gauge line. That wasn't supposed to be there. I disconnected the tubing for it, went back to the stock set-up for fuel in-feed to the IP. The IP IMMEDIATELY started drawing Diesel Purge. So I switched over to drawing diesel fuel from the glass coffee carafe. It worked great. Then I hooked up the lines to draw fuel through the fuel filter and the fuel tank. Worked great. Ran an errand to Menard's just to see how everything was going and it was like old times again, ran like new! Idled smooth, accelerated strong, cruised smooth.

Today I drove it to work. Went fine. Lunch hour I started the engine and it was surging. Fast, slow, fast, slow. Stalled out. Found that if I gave it some accelerator it started right up but had to keep it at a pretty fast RPM to keep it running. Same thing going home after work. Just stalls out if left to idle.

Now when I start it at home in the garage I must give it plenty of accelerator to even get it to start. Then it will surge right up to a pretty high RPM and die off and stall. I can give it some accelerator and I get it to stay running at a fast RPM but it sure won't idle without stalling.

Went back to running it from the coffer carafe bypassing the fuel filter and tank. Same thing.

This just baffles me and I'm stumped.

[Dakotakid]

I don't know.....why don't you try running a hot wire directly from your battery to the pump solenoid electrical attachment (or other source of juice).
Or, screw it out and remove the spring and plunger for a minute.

Almost sounds like this could be the problem. Running out of ideas.

I am impressed with you describing what efforts you have put into this. Now days, these new guys only want to say, "help me.....you figure it out." I have no patience for them.

I will say this, when they surge like this, it has been my 30 years of experience it is an air-suck problem.
I'm done!

[TylerDurden]

You got clear lines on the inlet and outlet? (Bubble report, please.)

[BlueDog]

Yes, clear lines; no bubbles.

[82vdub]

It seems that the pump isn't sucking fuel like it should. Is there any way to rig up a low pressure (less than 10PSI) pusher pump and see if feeding fuel to the IP leaves it running? It's weird that it would run for a night and part of a day, then go back to how it was. If you're bottle feeding it and having the same problems, likely not something with the fuel system. Would be interesting to know if you ran diesel purge through it again if it had the same results or not. How clean is the rest of your fuel system? I'd be tempted to rig up something to slightly pressurize fuel and push it to the IP to see if that helps.

[Caerbannog]

...Stuck the infeed hose into a glass coffee carafe of new diesel and started the engine. The IP just doesn't pump. It will idle like that until the fuel I bottle fed to it is gone.

If I read this right, you're only feeding the IP from the carafe, not taking the return line and refilling it, right? You'll get a lot longer run time if you return it, though you should have a filter on the inlet side. Maybe give that Diesel Purge a longer run time to work its magic.

[BlueDog]

Whatever is wrong is showing much different symptoms now than at the beginning of this post. Presently, the engine will race upon starting, very high RPMs guessing 2500 or more but just for a couple seconds and then run out of fuel and stall. This occurs without even touching the accelerator. If I use the accelerator pedal to start it I can keep it running at this very high RPM. Otherwise it stalls. I see no bubbles in the inlet side of the pump. I'll check this evening the outlet side.

[Quantum-man]

Try bottle feeding the pump, but this time use longer supply and return lines, and from a position like 1 ft off the ground. If the pump copes with that then your issue may well be back towards the tank