Injection pump question.

[Quantum TD]

So, I thought I'd see if anyone else has these symptoms.

1987 Golf motor. Hydraulic lifters, about 185K original miles.

I had the injection pump resealed about 3 years ago.

Since last winter, I've had trouble starting it sometimes. I always attributed it to the injection pump, but I thought it was just normal wear. The compression is great, the glow plugs work great, the injectors were rebuilt a year ago. So, what's left?

Well, this winter, it really didn't want to start one day, when it was about 14 degrees outside. So, I tired a little ether. Well, that was a bad idea. Motor didn't want to turn over. So, I pulled the injectors, cranked the motor over to blow out any residual fumes, and I checked the glow plugs. They look fine. So, I noticed I had a weeping return line from the pump to the tank. So, I replaced it. In the process, I discovered that one of the return nipples on the #1 injector had broken, and was hanging by a thread. So, I swapped the guts into another injector body I had laying around, that I had thoroughly cleaned beforehand.

In the process of replacing the return hose, I noticed that the pump was not full of fuel. The feed line was full, but the pump was about a pint low. Hmm. So, I topped it off, glowed the plugs 2-3 times, and the truck fired right up. Ok, great. I figure somehow, the pump was pulling air instead of fuel through the weepy return hose and broken nipple.

Until today, it's started fine. Not great, but it always started. Well, we had another night in the low 20s, but it warmed up to the mid 40s today. When I went to start it, it did not want to start at all. I mean nothing. So, I checked the pump, and again, it's down about 1 pint of fuel.

So, at this point, I'm thinking there's probably only one or two possibilities:

1) The input shaft bore is worn, and the shaft is moving in an elliptical orbit, making the seal leak.

2) The cold temps make the seal stiff, and the input shaft shrinks, causing fuel to leak out of the input seal. I'm not sure how this could be the case. I had this pump resealed by (ebay user name) red---rider. he'd done a few pumps for me before, and claimed to use Bosch seals.

Anyways, I've yet to pull the timing cover and inspect if it's leaking, but that's about the only place it could be leaking. There's nothing on the front of the block, on the top of the pump, or in the bracket area. There is however, some oily residue on the lower edges of the timing cover. I'm almost assured that it's diesel fuel, and my belt now needs to be replaced.

This pump has been a bit of a turd since day one. I haven't gotten over 40MPG out of it: ever. It's retarded down to .76, and it STILL sounds like marbles in a can at certain RPMs. It also makes a "squeegee" like noise sometimes. It pumps like a biyotch, but sounds like poo. Ive got a couple pumps I rebuilt myself. It may be a good time to see how I did. I rebuilt those about 2 years ago and filled them with ATF. Most of the ATF leaked out of the rubber grommets I stuck in the fill holes, but I'm hoping they're still good inside. I may pull a cover off just to check for surface rust.

Just seeing if anyone else has expericienced this: resealed pump starts to leak out of the input shaft later on. I don't think the shaft is worn, as I checked it before I installed it and there was no play.

[zukgod1]

I've rebuilt my share of pumps and had a couple shaft bushing wear out at what I would call an accelerated rate.

Pretty much EVERY time I can attribute that to an over tightened Timing Belt.

Sounds like your timing advance piston is stuck in the full advance stage as to the noise your hearing.

[jseeley]

Not sure about the quantum, but on my Mk2 Golf there are check valves back by the tank on both the send and return lines. The one on my send line was shot (fuel flowed freely in both directions) and I replaced it with a generic one off ebay. You could be loosing prime that way in addition to a faulty seal sucking air...

[Rabbit TD]

That is where a boost pump in the rear will tell you a lot of things along  with a good clear fuel line going from the filter to the pump.  My 1.6 TD will crank over 2 or 3 turns at times even when warm before it starts but run the pump 2 or 3 sec.s and it starts instantly.  A boost pump helps diagnose things a lot.  They aren't needed if everything is perfect throught the whole fuel system but it almost certainly never is and the clear fuel  line usualy proves that, it doesn't take much at all and a little air sucked in can make you think it's something else.  I recomend every desel having one if for no other reason to make things easier when you change a filter, pump ect. just put a push button switch on it or a toggle if you have real problems and just use if when or if you need it, they do make a difference and are easy to instal and don't cost much at all..

[Quantum TD]

I've rebuilt my share of pumps and had a couple shaft bushing wear out at what I would call an accelerated rate.

Pretty much EVERY time I can attribute that to an over tightened Timing Belt.

Sounds like your timing advance piston is stuck in the full advance stage as to the noise your hearing.

Well, the belt isn't overtight. I've been working on them for years. That's not to say it might not have been before I got to the motor. I pulled this motor from a junkyard car. The only reason I bought it was because all of the signs were good (great compression, clean, low miles, etc.). Someone must have junked it for a reason, and I assumed it was due to bad plugs or injection pump, because, when I installed new glow plugs and primed the pump, it fired right up on my shop floor.

In the coming weeks I'm going to swap the pump and do an autopsy. I don't think the advance piston is stuck. You can feel the resistance in the cold-start lever when cold, and it eases up when running. I think the pump is just worn out and needs a complete rebuild. I'm gonna see if any of my hillbilly rebuilt pumps doesn't run as well or better, and get me better MPG.

I should also note that I'm running an AHU camshaft. I snapped the nose off the original one, and bought a TDI camshaft to run in here since I couldn't find any good, used hydro cams. I doubt that it makes a huge difference in MPG, but it seems to be better at high RPMS than any other diesel I've owned.

So, I may replace the pump and see MPG, then replace the camshaft, as I now have about 3 spare hydro camshafts. Might be a good idea to check the intermediate shaft bearings. If the input shaft bushing is worn, the intermediate shaft bearing might be worn too.

Ah, fun times....