Fuel pump problems

944TurboHB · 08-01-2005, 07:44 PM

First off I have a 1986 944 turbo, fuel pump is outside next to the tank...OK here's the thing...try starting car: engine turns but won't start...checked for fuel, no fuel coming out (from hose where the injectors feed from) Ran a long jumper cable directly to fuel pump and checked for current...there is...checked ground...also fine...but fuel pump will not turn on (doesnt make noise). After this I jumped the fuel pump from the relay by jumping terminals 30 to 87b as per Haynes manual instructions and nothing still at fuel pump, but I do get a whirring sound in the engine compartment coming from a small looking motor of some sorts on the drivers side, sorry still dont know what it does...can someone fill me in on this please? so fuel pump I presume is definitely dead, Also the car sat for about an year and it was in a lot where someone may have added water to the gas tank...I read this corrodes the fuel pump...basically my question is can I salvage this fuel pump? can I take it apart? (I have a decent knowhow of taking things apart and trying to fix them) or should I just get a new one, or maybe even a used one, anyone have one they would be willing to part with, I'd also be willing to pay for it of course, what else can I do?? please help, sorry for long message...late night...thanks to all who reply and also those who read this...

MixMasterK · 08-01-2005, 08:13 PM

Get a new pump. I took apart my pump on my 83 and put it back together. Leaked like a drain basket. Not worth the time tinkering with it and there are a few springs that can go shooting off into nowhere if you are not careful.

Lawrence Coppari · 08-02-2005, 03:12 AM

The little pump (if it is near the coolant reservoir) is the circulation pump for the turbo. It is controlled by a timer relay as well as a thermostat mounted in the turbo's water jacket.

It should ALWAYS run for about 20-25 seconds as soon as you turn off the engine. It can also restart for another 20-25 second run when or if the turbo rises in temperature from heat conducting in from the exhaust piping.

Its purpose is to prevent oil degradation due to heat in the turbo bearings.

944TurboHB · 08-02-2005, 11:28 AM

Thank you everyone for your quick replies, MixmasterK the fact that you took your fuel pump apart actually makes me want to go ahead and do it as well, I'll definitely do it if i get another one by the way. As far as the turbo oil circulator, I was trying to jumper terminals 30 to 87b and as i stuck one blade into the relay socket (cant remeber if it was 30 or 87b) that is when this little motor turns on, I remember the first time I tried to jumper the relay it turned on after I had put both blades in, but the second time it turned on after putting just one blade in, is this indicating a problem with the ECM? Could it be fried? Why is turning on anyway? Also I read on another post where someone also had a problem with their fuel pump and had tried directly jumping it from the battery, and someone repsonding asked them if they tried jumping it with it off or with it still on the car, would this make a difference?? In other words hooking it straihgt from the battery while it is still on the car may not really be a good way to test it? It didnt turn on when I did it but does this necessarily mean my fuel pump is blown?? Please help I was hoping someone could give me some more insight into testing the fuel pump, besides trying to jump terminals 30 to 87b...thanks everyone.

MixMasterK · 08-02-2005, 07:12 PM

In regards to the fuel pump. I did a direct test with a charger hooked onto the fuel pump with it still installed on the car. It definetly would not pump and thus I new it needed to be replaced. When I removed the pump and took it apart, there was a lot of rust and varnish that had siezed it.

I also replaced all the injectors since I wasn't too sure on the health of the originals (whether they would have the same fate as the pump).