1.6L diesel injection pump leak/change

Sep 11, 2003 2 Replies

Hi all,



My brother has an '85 Jetta with a 1.6L diesel engine. The injection pump is leaking diesel fuel at a pretty good rate (enough to make it not driveable)... It appears to be coming from the bottom of the pump, but I haven't identified exactly where yet. It does not appear to be an injector or line, it is almost certainly coming from the bottom of the pump.



He has a spare pump that is said to be in good working condition. I haven't looked at the spare yet (to see what the bottom looks like), but he says there's a small metal 'plate' on the bottom that looks like it could be the source of the leak on the one on the car... Anyone have any idea as to if that may be the case, and if so, can it be fixed with the pump in place?



Failing that, what's involved with changing an injection pump? Could I just lock the cam in place (as if I were doing a timing belt), then line the replacement pump up using the same tool (a 10mm deep socket IIRC) to align it?



I don't really know how to ask this question, but does everything "happen" inside the pump in one revolution of the gear? In other words, is a fixed point in the rotation of the gear (say the place where you lock it in place when doing a T-belt change) the same on every single rotation? It seems to me that if this is the case, we'd be able to change the pump and 'time' it using the method mentioned above.



Am I on base here, or is there something I'm mising?



Thanks in advance, Craig

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First off check the seal right behind the sprocket. It's replaceable and is cheap. The fuel could be running out and down from there. Regarding changing the pump. Yes, one revolution is just like a revolution of a distributor on a gas car. However make absolutly sure you know the correct way to time the pump, crank and cam. If you get it wrong and you crank the engine with the starter valves will be bent! There's a pin that fits in and holds the pump pulley. There's a slot on the backside of the can that a piece of metal is put in and holds the cam aligned. Then you must make sure the crank shaft is a top dead center with the marks on the flywheel lined up with the pointer inside the bellhousing. Make sure your looking at the right marks! Also make sure the belt is tight enough but not too tight.

Thanks for the tips (and the ones that came via email as well)...

It sounds like the seal is a likely culprit, we'll take a look at that first. I've done the timing belt on my diesel, so I'm good in that department... if I end up changing the pump, I'll set it up as if I was just doing a belt and then change the pump without moving the crank/cam.

Now to find some time to get back over there and have a look...

thanks again, Craig

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