Dead Fuel Pump--Testing Double Relays

[LynnsABCs]

I had a decent running vanagon when I put it away in the garage for the winter. A warm last Saturday and the van wouldn't start.

Checked and no voltage to the pump. Tried a 12 volt motorcycle battery hooked to the pump and the pump would not click or anything.

Checked the relays per Bentley with a digital voltmeter.

The Current Supply Relay has full battery voltage ground to 30 and 87. 85 shows only .04 volts. 30 and 86 show .07 volts. 86 and 87 are dead and Bentley says replace relay.

Fuel Pump Relay shows full battery voltage ground to 30 and 85. 30 and 86 show .04 volts.

I'm thinking the pump died and took out the Current Supply Relay. Did it kill the Fuel Pump Relay too?

Haven't tried cranking test until my Son is available later. Am I on the right track? or is it the Red wire from the Starter?
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LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe

[crazyvwvanman]

Not likely to be the relays. Try tapping on the pump, gently. Then hit it even harder.

Mark

[morymob]

U already found problem with M'cycle batt,it's the pump. Try removing both leads from pump,take batt jumper and touch seversl times forward and reversed,this sometimes loosens a stuck pump.If this fails remove pump, sit with inlet up and squirt some penetratin oil/leave for few minutes and repeat with batt/jumper test, i have done this several times to loosen and refurb the pump insides,have ran into a couple that had bad motors. If this works 4 u,re-install and let run for awhile and a fuel press test,if ok then pump is probably ok. U only get power to pump 4 a couple seconds when ign 1st turned on but runs all time eng runs.

[Dogpilot]

Mory's suggestion is a good one. The best fluid to refurb a pump is diesel. Get a quart or so and pump that back and forth several times using the reversal trick. Diesel lubes and is a great cleaner.

The relay is a #53, about $5, unless you have an 88 or newer, then it has a diode installed for an extra $40. The relays do get burnt and get fuzz on the contacts.
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Geology with a Syncro rocks!
86 Syncro Westy AKA "The Bughunter"
98 Disco I
08 Range Rover SC
08 VW Rabbit S
1951 O-1G

[crazyvwvanman]

The fuel pump should not have power to it just because the key is on. The ECU logic controls the fuel pump relay and only turns the relay on when the engine is turning, or for about 2 seconds right when the key is turned on to prime the fuel system. Without someone else there to keep turning the key on and off while you measure voltage at the pump you just can't properly check at the pump.

You can hot wire the fuel pump relay socket with a small jumper wire after taking out the relay, to directly provide power to the fuel pump for purposes of seeing if power can get to the pump and if power will make the pump spin.

Mark

[LynnsABCs]

Thanks for the good info. I already tried reversing the MC battery leads to the pump to try to get it come back to life and it didn't so the next step is to remove and try the diesel fuel cleanout.

I forgot to mention that I did the fuel tank reseal in Oct and drained the tank and saw no sediment so I don't think the pump is clogged. Also replace the filter.

Where can I buy the relay for $5? None of the online vendors have it listed for sale. Is it available at local parts chains?
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LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe

[crazyvwvanman]

The FP relay is pretty basic but the VW one has a voltage spike protection device inside of it. Lots of cheap replacement won't have this and should not be used!

If your van has factory air conditioning you already have a spare relay in the main relay panel. Relay location 5 should have a type 53 relay in it. You can borrow it to replace any of the type 53 relays in the engine relay box. The one in socket 5 is only used occasionally by the A/C and can be left out while the A/C is not used. Do not leave it out forever if your A/C will ever be used again. Do not leave it out at all if your van did not come with A/C but you can still borrow it for this test but don't take any trips without it

Mark

[tclark]

[LynnsABCs]

Decided to order the Bosch pump that was on sale from Bus Depot. Now I know what the pump is supposed to sound like when it runs.

Oh, and the Van runs again too. Thanks for the help.
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LynnsABCs
Knoxville, Tn
1990 Vanagon Westy
1961 Porsche 356 B Notchback Coupe