Diesel Injection Pump '85 1.6L VW, suddenly not pumping

[Michael]

I just finished rebuilding an old Bosch pump, with a new supply pump, head, rebuild kit (gaskets) and front shaft seal (same old nozzles though). After bleeding the system and timing this pump, this new engine started right up for the very first time; way cool!
The engine will only idle, with a few slight surges, but the throttle doesn't seem to do anything; must have made a mistake with the rebuild, but it will keep idling.
Anyone know this pump well enough to know where I went wrong?
Thanx, and have a great week! - Michael, Seattle

[Vincent Waldon]

99% of the time it's a linkage problem.. either you didn't quite get the pin at the bottom of the governor relay lever firmly into the small hole in the control collar or the throttle lever is disconnected from the governor spring assembly.

Happens often... if you pull the lid off the pump you should be able to sort out if this is the case.

[Michael]

Wow; immediate answer. I'll do it in the morning, let you know what I find, just in case you're keeping score. Thanx again - have a good week.

[Fatmobile]

Turning the max fuel screw in can sometimes give you enough fuel to get it off idle.

[Michael]

I apologize for my poor use of nomenclature; I'm uncertain of the correct descriptors for these various intricate pump parts. I'll study my Bosch manual in the meantime.
The throttle linkage is the problem. The governor spring assembly has no slot in the end of it. It goes through a round hole in the lever assembly. The "spring loaded capsule" is supposed to be on the governor side of the "lever plate", as usual, but I'm not certain about the configuration of springs, clips and washers that may go on the other side of the lever assy. ( max load adjust screw side).
This appears to be the only weak link in the chain.
This pump was given to me as a non-functional pump, which I've otherwise rebuilt with the parts previously mentioned.
I could take the lever assembly out of my other pump, but that's a hassle, and I'd still need to know how this thing's supposed go together when I decide to rebuild it.
I'm sorry that I don't have pictures to give you right know, but I'll try to figure out how to do that.
I'll be standing by to clarify; thanks.

[Michael]

I rechecked the throttle connections today, then started the engine. Wouldn't idle well so I retimed it and tried starting it up - found that I'd left the plug out of the end, so put that back - still not luck, even after bleeding. The thing will idle, there's fuel, but it's running worse after the timing. It was at 10 before timing, is at 98 now, am thinking about turning the pump while engine's running to see if that helps.
I'm wondering if Hagar's hillbilly tuning would work for me, even though it's not a turbo. Still haven't figured out how to do hillbilly tuning, but suppose it means, partly, turning the pump while engine's running; am ready to give it a try. I'll let you know.

[82vdub]

It was at 10 before timing, is at 98 now

What are these numbers? If these numbers are from an IP dial gauge reading after "timing" the engine, you have not properly timed the engine. If you don't have a Bentley manual, this is where one comes in really handy. Locking the IP and cam and aligning the TDC mark to set the timing belt is only the initial timing setting to set things up right. To properly set the timing, you set the timing of the internals of the IP according to a dial reading, only by adjusting the position of the IP. Hillybilly tuning can be done on any engine, turbo, NA, diesel, gas. It's done not using any tools and timing the engine by ear or based on it's performance.

[Michael]

The "10" I had mentioned was from a dial gauge reading; this is where the timing was at, after setting to TDC (static timing). What I meant was, that the engine ran better than when I fine-tuned the pump using the dial-gauge and set the pump so that the dial setting was about 95 (which is what my Chilton's guide recommends - I'll get the Bentley guide when affordable). This timing procedure is something I've done many times. Since the engine ran better at the advanced setting, I'm tempted to tune it "by ear", but first mark where the proper dial setting position is so that I can use it for a reference.
So: I've static timed it properly and then fine adjusted with a dial gauge; now I will tweak this setting by moving the pump slightly with the engine running; I realize that I can't move it very far with the injector lines tightened, but I'll give this a try. If this doesn't work, then I'll turn the pump with the engine off and the lines loosened.
At this point, I'm happy the engine runs and there are no apparent oil or water leaks, since this is a totally rebuilt engine. Now, I'll either get this freshly rebuilt pump going or Ill borrow/but a different pump just to get me moving again.

[Michael]

Assuming I've done everything "by the book", with no "joy" (positive outcome), I've enlisted the aid of "professionals". I've taken the pump to the local Bosch rep./fuel-injection specialist, with the technician's foreknowledge of the work I've done (new supply pump, new head/piston, new gaskets/washers) and with the agreement that I would be charged for labor: 1.5-2 hrs. at his going rate and he would look for things I didn't do, such as head-return spring shim thickness (I'd like to see that descriptor as a conjugated German noun!)fuel metering, pressure regulation, and etc.
I'll let you know everything that I've paid for, for your own edification, when I get the results; check back Monday - latest!

[Fatmobile]

Maybe he will bench test it for you.
that tells alot.

[Michael]

Got the pump back, about a week after last post. They'd replaced all of the bushings.They said the drive shaft bushing was probably the "primary cause" of the surging I was experiencing. In the future - like when I rebuild my other pump - I'll be more thorough and assess these areas with a more discriminating eye.
They also replaced the governor shaft. When I asked about what could go wrong with this, was told that sometimes new parts come together as part of a package including a set of parts - this was likely the case here. Something I also found in the bag of replaced parts they gave me when I picked up the IP: a couple of very squashed aluminum washers. When I'd rebuilt this pump I used new Al. washers and removed the old ones - or so I thought. Apparently there were some very old and very thin ones that I didn't see, also, which were well-forced into the sides of the governor housing.. Be on a lookout for these r/t increased risk for pressure leakage.
"Penny wise and Pound foolish!" Word to the wise, but lost on me; gotta get over it! If you're gonna do a rebuild, don't mess around with a 0.5-donkey job; consider the service life of the pump and replace all of the parts you can, and especially those that come into contact with or which include any moving part.

[reddogracing]

hijack but i have similiar problem. My 81 rabbit ran great, but was leaking from cold start. I did not have time to do all work myself, so i had other mech remove pump for me. he did not follow my instructions to use clamps to hold timing in place. Well i rebuilt pump, no problems seemed easy enough. I give it back, and they install it with new belt. tell me that pump wont pump. I go check it out. i pull bolt off top, and fill pump with trans fluid. pull filter and its full.

loosen every injector line, and crank and crank, i get a trickle from middle two injectors. check everything, pump still full,

so i spray some diesel into intake, nothing . i keep increasing sprays and cranking until i find saturation point where i get hydro lock, get it cleared, and try several times, but never hits once.

still only trickle on middles injectors.


so they say it is in time, that it has to be pump,, i suspect timing what do i do now??

i am in south central ky near clarksville and nashville tn if anyone knows an experienced mech. i need help.

[Michael]

first off, I'd repost your cry for help as its own thread; more people likely to see it there and help you with it. You can, of course, take the pump apart and see if the heads clogged, or - as with mine - the distributor piston is broken. Hard to know what to advise unless I know what's been done to it so far. An injector pump is not something that any old VW or diesel mech can help you with, not if you need fast results (like it's your only car!). You might want to send it out (UPS) to someplace that does these if no one's around your neck-of-the-woods, otherwise there is good tutorial available; I can email it to you as an attachment. Good Luck! - Michael -

[reddogracing]

thanks for the reply.

did your break after you put it back in car?

My car ran great, just leaked fuel.

I took pump apart 100%, myself and reassembled.

There is a place in nashville that does pumps.

After doing this pump, i was kinda surprised at how straight forward it was to tare down. I did buy a video and tutorial.

[WAgrower]

How much did you guys pay to get the pump serviced? and what was done to it?