jcorenman

I need some advice, looks like our fuel-pump died (90GT). We were literally on the last leg of a 2-week 3000 mile trip that took us to the bay area, Anaheim for S'Fest, San Diego for some business, back to the bay area and then home.

We stopped at Safeway in Anacortes for a snack before heading to the ferry, pulled out of the parking lot, made a left and the car died. We coasted into a parking spot and started trouble-shooting.

First curious sign was no fuel pressure on the Roger-gauge, zero. Checked the fuse (#38 on a '90), was OK. Disconnected battery and pulled the brains to get the relay out, swapped it for a spare, still nothing. Swapped in the spare LH, nothing. Substituted the relay for a test-switch from 30 to 87, shows volts at the switch but no fuel pressure, no "whirring". it's drawing a lot of current- I don't have a ammeter but the voltage at the switch dropped from 12 to 9.5 and the (skinny) wires to my switch got warm. All I can hear from the pump is a quiet "click" when the switch is closed.

It looks to me like a jammed pump. Are there any other possibilities? Any quick fixes? Call it a VW starter and whack it with a hammer??

Possibly related: I think we might have gotten our gas siphoned in the parking lot-- Gauge was around 1/4, while we were troubleshooting Sue noticed it was zero, and the digi said "--" miles to go, for sure hadn't displayed "call range". But we were parked on a slight uphill incline, which may have fooled the gauge. We added two gal's, gauge now reads just under 1/4. Still no fuel pressure.

If we did get siphoned that would explain how it ran for 2 blocks (although the fuel dampers may provide that much), but not the fuel pump behavior.

Ideas??

The plan right now is to grab a room for the night and then get it flat-bedded home tomorrow, but if anyone can think of anything else to try, I'm all ears.

Thanks!!

Mrmerlin

remove the wires from the pump and run it backwards,
Since you know that you have no fuel pressure ,you know the pump isnt pumping if it will run backwards then you will get it unstuck, there will not be any fuel other than whats in the pump to lube the pump so dont let it run for long

jcorenman

Stan, Thanks!! Are you thinking that something is stuck in the pump? Or that the pump itself is stuck? My only concern is getting it unstuck and then having it stick again, in a worse spot (like on the ferry...).

This car does have the second fuel pump, which was re-done a couple of years ago. This does sound like the classic second-pump failure though...

Thanks,

docmirror

I think you fuel pump has failed completely. You can try running backwards a bit, it might clear. The fuel pump is one of the fairly easy fixes on the 928. It helps that your car is low on fuel now. Finding the right fuel pump is an issue. Roger has them in stock, but it's a long way west to you.

dr bob

Jim, check the voltage at the pump under for grins. The FP, IIRC, feeds off of one of those extra red wires at the battery, with cooling fans and injectors. I'm sitting in a bar after a couple glasses of wine so memory is not most trustworthy; others will chime in I'm sure. Anyway, I found that my perfectly maintained battery connections were in need of just a little cleaning and tightening. 10 MM wrench us weapon of choice on that positive battery bolt, on the small end.

dprantl

Apart from the above, sometimes you can revive a stuck pump by rapping on it with a rubber mallet.

Dan
'91 928GT S/C 475hp/460lb.ft

the flyin' scotsman

I'd try the reverse fuel pump idea as wellas well as tapping the FP. You've confirmed power at the relay with the wire getting warm so trace the power back to the pump...........if its there, bingo.

Perhaps with the fuel level so low some crud got jammed in the pump..........good luck.

jcorenman

Thanks, everyone, for the thoughts. Dr Bob, you are correct that the fuel pump is fed by one of the "extra" red wires direct from the battery, along with the LH. And definitely worth checking-- the drop to 9.5 volts with the fuel pump trying to run seems fishy. I'll check that in the AM along with reversing the polarity and giving it a whack or two.

If still no-go then we're well within AAA-plus distance of home, but I would much rather finish the trip properly.

Thanks, all!!

heinrich

Jim I have a spare pump if you need.

heinrich

I once owned a Mercedes Benz 123 series. When the fuel pump died one day, the car kept running. WOW??? Turns out the car has a pump bypass emergency circuit

IcemanG17

Jim
I also like the run backwards briefly and hit it with a hammer...

worf928

Yup. Seems to work more often than not.

But, why did the pump jam. In a '90. With the in-tank fuel pump?

One guess: The main pump jammed on bits of the in-tank pump.

So, replace the in-tank pump too. If it is original equipment there a virtual 100% chance that it is already in two pieces anyway because the little hose inbetween the two pieces died a couple of years ago.

FredR

Jim,

The possibilities have been well covered in the threads above but most likely a failed pump- just a quesiton of why it failed but indeed they do from time to time. The voltage drop suggests it is trying to start a pump that will not turn. If you can get the pump off and back flush it [remove the check valve on the discharge]- maybe with a garden hose and/or reverse the polarity briefly it may well help. I assume the motor part is well isolated/sealed.

Just in case it helps- the Bosch part number for the main pump is 0580.464.017 according to the manual if there is a local Bosch agent. The pump may be available as a VW/Audi fuel pump if there is a local agent- I know nothing of your location other than it is an Island in Washington State according to Google Earth so presumably time wise you are not too far from Seattle.

An internet search for parts in your location came up with a company called parts highway tool free 1.888.533.9119. They offer both fuel pumps at around $215 each if they are located anywhere close to you. Their part reference numbers are BOS-67807 [in tank-$218] and BOS-69475 [external $214].

Just remmember that external pump failure can be caused by in-tank pump problems [already covered]

Hope the above helps a bit- I will send a copy to your private e-mail as well.

Fred

John Speake

Hope you manage to fix the problem Jim !

I agree most likely cause of crud getting into the main pump, most likely due to the low fuel level. It seems unlikely the intank pump assembly would fail after only a couple of years ?

If you can clamp the hose to the external pump, undo the connection to the ext pump, then release the clamp enough to drain a little fuel from the tank to get any crud from there, the briefly reverse power the main pump.

Good luck !

Mrmerlin

Warning be careful reversing the leads, with the fuel line disconnected or raw fuel in the area, otherwise a big fire can ensue from an errant spark of touching a seized pump.( this happened on my free Euro,PO almost burned down the house as well as burning up the car)

Best to swap the wires without opening any fuel lines,(safest method)

Next best remove pump from car and work on it away from the car.

Next, replace both pumps and fuel filter and check valve and sealing washers, inspect the metal hard line for deformation, place the sealing washer area on a flat surface it must be flush all the way around on either side, it usually deforms from overtightening ( where the banjo bolt goes through) if you see any deformation then replace this part as well