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davlance01
Samba Member
Joined: May 10, 2013
Posts: 224
Location: Ohio
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 Posted: Tue Mar 30, 2021 6:18 pm Post subject: Fuel pump cavitation, which is my fault |
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I installed a (canister style https://www.summitracing.com/parts/aei-12319) 100 micron pre filter and my fuel pump cavitates because of it.
The way I see it I have 5 options
1. Lift pump to keep the pre filter full.
2. In tank fuel pump with a big sock and eliminate the filter.
3. Put the filter on the shelf and forget about it.
4. Carry a extra fuel pump and swap it out every time they fail.
5. Get a larger pump that is capable of keeping the canister full.
I travel all over the country with this thing for work and get fuel at some pretty shady gas stations and the filter picks up all kinds of crap so I hate to get rid of it.
Any advice from people that have made this upgrade?
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dobryan
Samba Member
Joined: March 24, 2006
Posts: 16503
Location: Brookeville, MD
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 17123
Location: Retired South Florida
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| Posted: Tue Mar 30, 2021 6:58 pm Post subject: Re: Fuel pump cavitation which is my fault |
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You could tie in the return with a small reservoir that would refeed the pump inlet and excess would return to the tank.
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davlance01
Samba Member
Joined: May 10, 2013
Posts: 224
Location: Ohio
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| Posted: Tue Mar 30, 2021 7:06 pm Post subject: Re: Fuel pump cavitation which is my fault |
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Truth to be told after 31 years of delivering fuel to gas stations...they are all questionable. Most racks you load at have a strainer with no basket and if the gas station has one the chances of that $8 an hour cashier cleaning it is slim to none, they just leave them out too. I have no way of knowing the actual condition of their underground tanks.
I use it to deliver new semi trucks and sometimes I'm pretty far off the beaten path and have to fuel where I can.
The stock filter was not lasting and would cavitate as well just not as bad.
The metal shavings that this thing picks up that the square filter didn't was enough to convince me to try to keep it.
Clean fuel is always a good idea. If I could do more I would.
What would you do?
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davlance01
Samba Member
Joined: May 10, 2013
Posts: 224
Location: Ohio
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| Posted: Tue Mar 30, 2021 7:09 pm Post subject: Re: Fuel pump cavitation which is my fault |
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| MarkWard wrote: |
| You could tie in the return with a small reservoir that would refeed the pump inlet and excess would return to the tank. |
I thought of that but afraid I would create a vapor lock condition by not allowing the fuel to cool off in the tank.
I may try that though but I would have to have a easy way to reverse it out in the field. A shut off valve maybe.
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32598
Location: Reading Pennsylvania
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mikemtnbike
Samba Member
Joined: March 26, 2015
Posts: 2795
Location: North Carolina
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SCM
Samba Member
Joined: January 26, 2011
Posts: 3115
Location: Bozeman MT
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| Posted: Wed Mar 31, 2021 10:08 am Post subject: Re: Fuel pump cavitation, which is my fault |
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My cavitation problems went away when I replaced my rusty old gas tank and I don't run a pre-filter and am on the same pump for over 10 years now. Are you sure that's not the problem?
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'91 Westfalia GL Automatic (GTA "Turbo" Rebuild w/Peloquin) and 2.3L GoWesty Engine |
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oceanair
Samba Member
Joined: June 09, 2013
Posts: 720
Location: Victoria, BC
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| Posted: Wed Mar 31, 2021 12:07 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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^^^^^^^^^^^^^^^^This^^^^^^^^^^^
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84 Vanagon Pop Top Conversion from Tin Top, 1970 Ghia - all sweet rides! Love em!
Previous: Green 72 Tin Top, White 72 Westy, Blue 64 Beetle, Yellow 71 Squareback, 2014 Jetta TDI Wagon - wish I could have them all back! |
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hardway
Samba Member
Joined: January 03, 2012
Posts: 416
Location: Fidalgo Island
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| Posted: Wed Mar 31, 2021 12:59 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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I have a filter from Napa installed before the fuel pump. Part number 3248. No idea of what the micron rating is. !/2 inch nipples. I use BMW 12 mm ID fuel hose, 16 12 1 176 440. I have no cavitation.
While chasing an issue in a Vanagon recently I was surprised at how much trash I removed cleaning the inlet screen in the pump. I am going to make this a standard modification from now on.
Napa claims it is a gold filter. But it was only 3 or 4 dollars. It says made in China on it. As long as it catches the chunks I think it is a worthwhile investment. |
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Nuthin2It 
Samba Member
Joined: December 31, 2011
Posts: 306
Location: Marietta, GA
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| Posted: Wed Mar 31, 2021 1:46 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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Option 6: Slow down the fuel pump with a resister.
Many people have done this successfully. I did it after trying everything else I could find in TheSamba, and it worked. Here's a link to the thread that I got the idea from: https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0
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1985 Westfalia 15 degree EA288 Boxeer |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32598
Location: Reading Pennsylvania
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Abscate
Samba Member
Joined: October 05, 2014
Posts: 22648
Location: NYC/Upstate/ROW
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| Posted: Wed Mar 31, 2021 2:19 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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A simple glass filter from West marine will run you about $15 and have real fittings
A more expensive one to drain water will be about 4x that
The few times I’ve had long term issues with shady fuel ( Central America, Africa, Central Asia) I’ve used plan B
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50338
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| Posted: Wed Mar 31, 2021 4:06 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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| On my '83 1/2I went from cube prefilter that clogged almost daily on a long trip to a canister filter after the pump about a dozen years ago. Changed the canister once since since then, just cuz. |
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puchfinnland
Samba Member
Joined: December 26, 2005
Posts: 279
Location: Deale Maryland
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| Posted: Wed Mar 31, 2021 5:25 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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Im in the same situation
I have new fuel lines, tank,pump, all canisters are resealed w new roll-over valves, the thing is air tight!
12mm outlet, no pre-filter,
I just checked the vapor canister plumbing and all is working as it should.
I just ordered a new charcoal canister as this may cause too much vacuum when its clogged or not breathing properly.
On Friday I filled the tank and listened to the very noisy pump on our trip camping, on our return trip with half a tank it was quiet as a mouse.
I also want to throw into the discussion the voltage,
before my trip I charged the batteries, so the alternator was pumping out over 13.5v as they were full,
on my trip home my house battery was very low, raining and headlights on, and the volt meter was around 12.6-12.8 trying to keep up, so I have a test concept
when the pump is making noise, turn on some heavy consumers
wipers, lights, rear defrost, blower motors and see if that pump shuts up
I would be interested in a voltage stabilizer for the pump, not just a resistor as my pump was quiet on return trip
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ABYC marine master technician , EX European auto technician, new business- EASTCOASTWEST , custom work on campers, only systems, no mechanical |
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82westyrabbit
Samba Member
Joined: March 02, 2015
Posts: 969
Location: Ma
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| Posted: Wed Mar 31, 2021 6:39 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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| I ran a prepump to fix that problem. I changed my fuel tank and it was no longer necessary. I run a square prefilter and the can filter after the pump. I don’t have any problem with pump cavitating any more. Just my experience. John |
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dgbeatty
Samba Member
Joined: October 26, 2006
Posts: 702
Location: Sacramento
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| Posted: Wed Mar 31, 2021 7:03 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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A very major problem is the incorrect pump being installed. Without naming offenders suffice it to says that many "similiar" pumps are being installed. They are too good with much higher flow which in this case is not a good thing.
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davlance01
Samba Member
Joined: May 10, 2013
Posts: 224
Location: Ohio
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| Posted: Thu Apr 01, 2021 3:48 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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My tank is new but has the smaller 7mm outlet.
All the numbers on the pump are correct (psi, flow) and the car runs fine. Just noisy.
I do have A3 injectors, maybe that's affecting flow?
When I get back to Ohio I'll try out some of you guys ideas and get back with the results.
Just went from ohio to Iowa up to Minnesota back to Ohio and now I got to pick one up in Ohio and take it to jersey then back to Minnesota then Ohio then I'm putting this thing back on the rack for new engine seals, steering rack boots and deal with this noisy pump!
Whatever I end up with has to work rock solid cause the down time kills my profit margins and my wife is whining about bills for the month! 
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davlance01
Samba Member
Joined: May 10, 2013
Posts: 224
Location: Ohio
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| Posted: Thu Apr 01, 2021 4:21 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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The pump I have in is running at 3000 rpm, I'm having a hard time wrapping my head around what slowing down the pump is going to do.
Affect flow, lower psi, what is it doing that lowers cavitation?
I'm going to try it, I'll hook a transducer to the fuel line and show before and after waveforms and post it.
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davlance01
Samba Member
Joined: May 10, 2013
Posts: 224
Location: Ohio
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| Posted: Thu Apr 01, 2021 4:32 pm Post subject: Re: Fuel pump cavitation, which is my fault |
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| dgbeatty wrote: |
| A very major problem is the incorrect pump being installed. Without naming offenders suffice it to says that many "similiar" pumps are being installed. They are too good with much higher flow which in this case is not a good thing. |
Got me wondering if that is what the resistors are solving?
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