Broken down NOW fuel pump starvation

[HastaAlaska]

Hey guys. I'm up in remote Yukon on the side I the highway and need some advice.

I have a Fuel Injection engine in my Bus but the Bosch inline electro fuel pump is suffering from starvation

The new Bosch pump is making a lot of noise as it runs dry. The pump is mounted under the tank. There is a pre-filter which converts the 7mm tank outlet to 12mm pump inlet.

I've confirmed that the gas flows freely from the gas tank and the tank is clean. I think that there is a bottleneck from the 7mm tank and the flow can't keep up with the pump.

I know similar issues are found on Vanagons and I'm wondering if any of you can recommend a solution?

Thanks
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[HastaAlaska]

Hey guys I'm going to try and hit the road again and make it to Dawson. I anyone has any advice about this 7mm to 12 mm pump being a bottleneck or can shed any light on why the pump might be running dry please post a message and I'll check in when I get service....if I make it out the other side that is
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[Merian]

filter blocked?

the Bus forum will be better - good luck
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[CanStan]

Check that filter. Maybe it's clogged? Often the pumps will have a mesh screen in then to act as a filter too. If you have crap stuck in the screen it will starve the pump. On a Vanagon you can switch the 2 wires on the pump, remove and clamp the line between the pump and tank, and run the pump backwards to flush that screen. No clue how similar that is to the Bays, but hopefully it should be a simple fix. If gas is flowing nicely from the tank, but starving the pump, you should be able to track down the culprit fairly quickly.

[nemobuscaptain]

I'd backflow the pump and also be suspicious of rust in the tank. Sometimes it moves around, intermittently blocking the outlet screen. I had some do that. I could clear it by blowing hard into the tank, but it would settle again, sometimes immediately blocking the outlet, sometimes being ok until I took a turn hard or something.

Did you change the filter already? How did it look? Did rust or dirt flow out?
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[chompy]

I would ditch your pre-filter and grab some brass fittings from your local hardware store to convert from 7mm to 12mm. The fuel pumps will cavitate trying to to pull that much fuel out of the narrow tank outlet. They would rather push the fuel into a nice big metal canister fuel filter instead of pulling from a pre-filter. Some of us also use a resistor to slow the fuel pump down. It's part number BWD RU4 and looks like this when installed between the ground of the fuel pump. Keep in mind the resistor gets really hot so I would space it away from your fuel lines.

picture from forthwithtx
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'81 Westfalia Subaru EJ22
Manual Transmission

[AKWesty]

Ben, how much flow are you getting out of the tank? Have you let it run and tried to gravity flow a full gallon of fuel. On the vanagon tanks there is a rubber hose inside the tank running from the outlet to the bottom of the tank. There is a screen inside the tank that gets clogged with varnish and rust particles. You may think you are getting full flow if you are only collecting a small amount but if you can't fill up a gallon jug in a short amount of time then you have enough restriction inside the tank causing the pump to cavitate. Also the rubber hose (assuming you have one in your tank) can dry out, crack and fail allowing it to suck air when you are less than 1/4 to 1/3rd tank. Are you having this problem with a full tank?

If you are out of things to try, switch your fuel line into the pump with your return line. You may only be able to drive your tank down to a 1/4 before running out of gas but you may be able to bypass a clog in your current supply line if that is the case.

I don't know how your buses gas tank is structured but these ideas may help while on the side of the road. Safe travels. -Chad
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84' Westy 2wd
EJ22 - 4spd - Peloquin TBD
GW +1.5 Springs
215/70-16's

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"Never go to Alaska as a young man because you'll never be satisfied with any other place as long as you live." -John Muir

[AKWesty]

After reading through the background info in the bay forum thread and seeing that you have already established fuel tank flow, I agree with chompy. You need to either get a slower pump or install a resistor to slow down the bosch pump. It is a common problem for vanagon owners to experience fuel pump noise and cavitation with new bosch pumps and 7mm outlets on the fuel tanks. The newer tanks are sized with 12mm outlets to remedy this restriction issue. Some pumps seem to do fine with the smaller restriction. It seems the speed of the pump is on the verge of too much and the fix is to slow the pump down.
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84' Westy 2wd
EJ22 - 4spd - Peloquin TBD
GW +1.5 Springs
215/70-16's

www.CatchTheKraken.com

"Never go to Alaska as a young man because you'll never be satisfied with any other place as long as you live." -John Muir

[boroko]

Another thought, though remote... When you went from 7mm to 12mm did you have to stretch a hose to make it work? Even without that, I have seen hoses delaminate internally and a small flap flops in and out of the way restricting the fuel. Not the most likely, but if you are grasping for straws...

Mark
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'87 SyncroWesty: Smokey the Turtle, '85 SubiWesty: Chappie, '84 GTI, '86 GTI in full Rally trim,
previous: 2 Syncro tin tops, 2 Vanagons, 3 busses, 3 Ghias, 2 Jettas, a 411, a gas and a diesel Bunny and about 25 Beetles, one that only drove left.

[HastaAlaska]

Hey guys,

Thanks very much for the replies.

I made it to Dawson city which was a full tank drive, with no breakdowns. Although I stopped over night at around half tank.

The pump still makes a lot of noise, so the problem still exists. That resister fix is a treat Chompy, thanks for that.

I'm planning on hitting the auto store in town to see if they have another fuel pump (or that resister)

Can anyone recommend a pump which is known to be OKfor a 7mm tank?

Thanks
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Around The World in a VW - Follow the Docuseries
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Latest Adventures - https://www.youtube.com/@kombilife

[Wildthings]

[boroko]

As a general thought on volume, we are running some of the smallest motors out there. It seems that if its good enough for almost any FI, it will have enough for our motors. Miles per gallon is determining how much fuel we need, and what actually goes in the motor vs. what gets pumped back to the tank is pretty small.
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'87 SyncroWesty: Smokey the Turtle, '85 SubiWesty: Chappie, '84 GTI, '86 GTI in full Rally trim,
previous: 2 Syncro tin tops, 2 Vanagons, 3 busses, 3 Ghias, 2 Jettas, a 411, a gas and a diesel Bunny and about 25 Beetles, one that only drove left.

[seventyfo]

Does napa have the resistor? My last new Bosch pump lasted about 10000 miles, I'm game to try the resistor because I have the 7mm outlet on my tank with the big filter and no prefilter.
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85 Vanagon GL Westy GW 2.2 (Rebuilt by YT)


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[Forthwithtx]

I believe the resistor is a part common to older (like '60's and '70's) vehicles. O'Reilly had mine, but it took a guy who had seen one before to know what I was talking about.
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Cheers!
-Karl

'84 GL with 2001/2004 Subaru 2.5L

[Wildthings]

The resister is just an ignition ballast resister that was used with ignition coils that took external resisters. I use them for several purposes besides their intend use and haven't had trouble finding them as of yet.

[HastaAlaska]

[Wildthings]

[Tristar Eric]

I'm just going to throw this out there...

It's worked for me and several others.

The fuel pump can and will run backwards if you swap the terminals. I've seen the screens in our old tanks break up and allow crud to make it's way into the fuel pump locking it up.

Reversing the flow and pushing it back into the tank is a temp fix, but will allow you to keep rolling. Just remember to keep your tank pretty full.
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[HastaAlaska]

[Merian]

Sgt. Preston would be proud - have fun.


BTW, You can order from Van-Cafe, etc. and have things waiting for you when you get to a post office.
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