Former VWDieselParts.com Forum

on my 81 vw diesel caddy ...it set for about 6 months and now i have no vacumm coming from the injector pump...it wont pull any fuel from the tank...i have cleaned both fuel lines and still nothing..i put a vacumm gauge on the pump and no vacumm..any ideas on a cheap fix?

First I'd try priming the IP... get it full of fuel and see if it loosens up while running the engine.

You can also bottle-feed the IP like an IV bag, hanging the bottle up high, so gravity keeps the IP full while it runs and hopefully loosens up.

If it doesn't just loosen up, I'd fill the IP with ATF and let it sit for a day or two and try again. The ATF may do a better job of loosening the pump vanes (and it will burn as good as diesel, so no need to drain/replace).

thanks for the reply...i tried filling the pump with atf and ran it for a while..then let it sit...still no vacuum ,,would it hurt the pump to fill it with marvel mystery oil and let it sit for a day or two...would the motor run on marvel if i wanted to run it through the pump for a while?

Not sure about the Marvel oil... the IP wants thin runny stuff like diesel. Also, ATF is thin and should creep into the vanes of the lift-section better.

Did you give it a good few revvings when running on ATF? The centrifugal force should help extend the vanes.

You might need to let it soak for a few more days... if you are in a hurry, then the lift-pump suggestion on the other site should help.

But, before anything else, I'd check that the OUT bolt is not plugged. It has a screen and a tiny hole, that if plugged, might cause the IP to not draw fuel... and a host of bigger problems that could kill the IP.

tyler..thanks for the reply....i took the out bolt off and it was plugged...looks like there is a screen..but it is staked in...i dont think it comes out....does that hole have to be that small?...i have cleaned it twice and plugs back up again

The tiny hole helps the IP develop internal pressure for dynamic advance and suppresses cavitation. It is usually about a half mm.

Did the engine ever get a dose of veggie oil? Bad/cold veggie can wreak havoc on IP guts. Maybe the tank got crap in it.

Use surgical cleanliness around the open IP lines... a speck of crap can plug the bolt or stuff an injector.

The good news is your pump still mostly works. If you have a spare IN bolt, you can test the lift section and ensure the IP sucks plenty of fuel.

You might try bottle feeding Lubro-Moly Dieselpurge to clean the IP and clean the OUT bolt with brake parts cleaner. When all is well and the OUT bolt is clean, the IP still circulates a generous amount of fuel... like a liter a minute or such at 1000rpm.

Bottle-feed with lines going to and from the can or jar of cleaner. Sometimes I use a 50-50 mix of naptha and ATF. A clear container let's you see the circulation.

If you can rig up a bigger bottle feed setup and drive around normally, the filter, lines and tank are suspect.

thanks for the reply...i think i'll try to half naptha and half atf...is it ok to fill the pump with it and let it set a couple days or will it hurt the seals?

auag wrote:thanks for the reply...i think i'll try to half naptha and half atf...is it ok to fill the pump with it and let it set a couple days or will it hurt the seals?

Won't hurt the seals a bit. Some folks store pumps filled with ATF.

is it ok to run the engine on naptha and atf for a little while?...soaking in the solution did help but i think it would really loosen up if i could run it with the solution..thanks in advance

auag wrote:is it ok to run the engine on naptha and atf for a little while?

Yep, That's how I clean my IPs.