300Tdi injector pump - problems after adjusting - help!

[George Mason]

Hi folks

Have been struggling for the last couple of days with adjustments of my Bosch VE fuel pump. In the past I had someone fit a re-cored intercooler and at the same time they blanked the EGR and adjusted the fuel pump. I later found out that when they said they were "adjusteing the fuelling" what they were actually doing was screwing the smoke screw in a couple of turns. Yes it went better but also smoked up the road if you used the throttle off boost!

I decided to tackle this yesterday but I've made things far worse. I marked the Torx bit on the smoke screw and backed it off a little, then re-tested, smoking had reduced with little effect on power. Then I removed the top cover and checked the position of the diaphragm, and marked the position of the tick mark on the housing of the pump before making any adjustments. I turned the diaphragm through 90 deg and tested again.

This time I had absolutely no power and no smoke. I figured I must have trapped something somewhere or done something else stupid, but I've checked it 4 or 5 times since and can't find anything wrong at all. I've returned everything to stock - and I know this because my tick mark lines up with the wear mark on the eccentric pin surface. One thing I can't understand is that I can't see the pin that rubs against the eccentric shaft, even when I operate the throttle. Could the pin be stuck? If so how to release it? This would surely cause under fuelling?

Any help would be very gratefully appreciated. I need the car on the road in a couple of days time and at the moment I've rendered it useless!

Thanks

George

[BogMonster]

Yes the pin is probably stuck. In theory it's a specialist job to get it un-stuck but I know a couple of folks that have managed it. I'd fill up in there with lots of WD40 and see if it un-sticks. Otherwise you're probably into dismantling the pump and I've not done this but I suggest exercising caution if you don't want to end up with boinggggggg bits all over the floor and lots of swearing.

[George Mason]

Just found this: http://gnarlodious.com/vanagon/bosch_pump/-Rebuild

You're not wrong about boooiingg! Don't think I want to do that unless I *absolutely* have to. Reckon it'll take me a very long time and not convinced the car will work afterwards.

Is there any chance I'll cause anything else to go wrong if I blast the inside of the pump with WD40? I'm willing to try anything like that at this stage, as I really need to get her going again. I read somewhere that by actuating the throttle the pin should push into the chamber, but that isn't happening.

[BogMonster]

Don't think so, I had a 300 a few years ago with a bit of corrosion inside the pump diaphragm housing (water ingress due to wading I think) and I sprayed loads in there with no ill effects.

[George Mason]

WD40 is going to have to be the approach then. I will take the cone section out and clean it properly etc. and then drown it in persuading fluid. The logic I have for thinking the pin is stuck, is:

1. Under fuelling - so the fuelling pin MUST be in the housing

2. Can't see the pin when opening the throttle - again suggesting its stuck in there

3. No marks on the cone in any position other than where it started

I had a look at the process to replace the pump entirely as they come up now and again on fleabay but it looks like a big job.

[dave t]

ok I might be wrong here but if you operate the throttle without the diaphram in place the pin will fall out, I would check to make sure it isnt in the bottom of the diaphram chamber

also worth checking the boost hose to the pump might be coincidence but they do split sometimes and if there is no boost to the pump it with underfuel

HTH

Dave

[cackshifter]

_{I think this thread might help..http://forums.lr4x4....showtopic=74279}