Injection Pump Problem

[coke]

Gone through 2 pumps on my 86 Jetta. The 2nd pump it wont fire or even run. I did a test tonight, and had a friend watch for me. Disconnected the fuel unions on the rear of the pump and cranked the engine over several times while holding the throttle to the floor. Fuel was only dripping out two of the injector ports on the rear of the pump. My impression is that fuel should spray out the rear of the pump under pressure, am I correct?

And for those of you who dont know me, I am coke from the vwdieselparts.com forum. Hello to all.

[vwmike]

fuel isn't really going to shoot out of there. The piump doesn't move high volume it just moves a small amount which is enough to increase pressure so the injectors will break open and dispense what fuel has been displaced by the cycle of the pump.

[coke]

Right but it should do more than just drip fuel out, and it wasn't coming out all the unions either.. it was only coming out two.

[vwmike]

Right but it should do more than just drip fuel out, and it wasn't coming out all the unions either.. it was only coming out two.

Yeah, ya got me. Are you sure it's properly primed?

[Justin]

i have heard of check valves going bad it might be possible that you have two bad check valves, you would pull all of them out and put them in chem dip and dissasemble them to make sure that they work.
hope this helps
or you can pull out the check valves and turn the pump over and see if it comes out all four holes, if it does then i would suspect the check valves
later
justin

[chrissev]

Right but it should do more than just drip fuel out, and it wasn't coming out all the unions either.. it was only coming out two.

actually on mine all it did was drip.  I never got more than that, and it was rebuilt.  Things to check:  1. is the timing exactly right (I believe on a non turbo it should be set around .032, but the engine will run anywhere from .032 to .045.  Above or below that, nothing will happen when you crank).   2. is the pump primed?  To prime, fill pump at OUT hole (return hole) then turn pump by hand, while filling at OUT hole, until fuel comes out IN hole.

[coke]

Yeah, the pump was primed. Everything was as it should be. No idea why it doesn't work. Oh well, I have another pump I'm going to try.

[watsongs]

Coke, I have been having the same problem on my IP, only fuel hsn't been coming out of any of the unions.  I pulled two of the unions, and fuel comes out when I pump an outboard primer bulb I installed between the filter and the pump, but nothing with them installed and the engine cranking.  I've filled the pump with Sea Foam and let it set for a week; tonight will be the first test.

Greg

[Justin]

upon dissasembly of a non working pump this weekend i found that the vane pump didnt work since the vanes were corroded in, sea foam might be enough to loosen them up and make if work, but just to let you know i let the vane pump set in Chem-Dip and I still had to use a screw driver to nock the vanes out, so good luck, and i still say pull the check valves out and see if you get any fuel to come out

later
justin

[watsongs]

The pump must be completely trashed - I pulled out a union, removed the check valve, re-installed the union, and fuel comes out when I squeeze the primer bulb, but not when I crank - lots of cranking, lots of squeezing, no luck.

[Justin]

take it apart if it is junk, figure out how it works and see if you can find anything obviously wrong with it, you will need a special 3 sided 13 mm socket to for two pivoting posts, and one of the allen headed threaded rods is a reverse thread, other than that see if you can get it apart and find bad parts, i have a parts pump sitting to home if you can find the main cause
later
justin