fuel pump noise, how to fix?

[dabaron]

this noise in my 1991 Westy is driving me bonkers for wankers... happens with just key on when the pump primes, when idling or when driving and under load. temp does not matter. sometimes the noise stops for a few minutes, sometimes it takes a few minutes for it to happen at key on...


Link


it's the fuel pump right? i replaced it with a brand new Bosch... noise still there, zero change. i've replaced the fuel tank, the fuel filter (post, no pre pump), the fuel pump, the rubber mounts for the fuel pump... zero change.

is this the sound people are using the resistor mod to eliminate?
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1991 Vanagon GL Camper
i had no idea i wanted to be a mechanic
"burnin oil and cookin coils" -- Destructo

BiWerks Design, LLC

[CanStan]

Hard to tell for sure, but it does sound like cavitation to me. The resistor should fix that. It also sounds like a vibration issue. How do the mounts look?

[dabaron]

[Ahwahnee]

Mine has the pre-filter (white cube) and makes a lot of noise when the filter needs to be changed.

How does the status of the after-pump filter affect the pump noise (I really don't know)?

[djkeev]

What confounds m3 is the old fuel pump and the new fuel pump make the same noise.

I think it is external from the pumps.
A common vibration cause point in the system, not the pump itself.

I've got a pump if you want to try it, if three pumps make the same noise (and I know my pump doesn't make that noise) that would confirm my suspicion.

Dave
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[oceanair]

Be absolutely sure that the pump is NOT contacting the frame. If it is, it's loud. My pump 'holder' was bolted on backwards and the pump was touching the frame. Turned it a round and silence ever since!
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[GreggK]

I knew a guy with the same issue, went through the same trouble shooting and swears when he bought the Pierburg one that BD sells, it went away. Not saying it was the true solution, but he swore by it. https://www.busdepot.com/251906091
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[J Charlton]

Several of our NAHT hightop installer / distributors, along with doing general vanagon service or retrofitting and modernizing customers' vans - i.e. everything from front to rear, road to top, power trains etc etc - also periodically buy vans that they renovate from bumper to bumper and then sell. When they do so it is critical, in their eyes, that the vehicle that they sell be be as sound and trouble free for years as possible. To that end and to start "with a clean slate" they all pretty well have a common systems approach. Rather than chasing gremlins they proactively routinely replace some critical systems components to rule out potential causal future problems. The most common proactive measures seem to be:

1. Replace the 30+ year old fuel tank. The fuel tank has a screen at the bottom over the outlet - this screen gets plugged or obstructed with 30+ years of crap from just "life" of being filled, going through years of internal rusting, gum residues from fuel sitting for long periods etc etc - Not replacing it can lead to hours and hours of gremlin chasing - including fuel pump cavitation, plugged filters, dirty injectors etc etc etc/. As an aside - it baffles me that folks think that replacing a fuel filter plugged to the point of restricted flow "solves" anything - where did the "stuff" that is plugging the filter come from?

2. Replace the rad and coolant pipes. Chasing overheating and / or overcooling issues can be a frustrating and ongoing process. The coolant pipes are a "while You're there" spin off on the fuel tank replacement but the radiator replacement issue and therefore starting with a clean 100% effective rad - not one that is 30 years old and probably more than partially filled with crap - presents a known starting point to sort out any emergent issues. This is even more important with engine conversions - the wbx engine is relatively inefficient ( if a wbx powered van gets 15 mpg and a suby powered same van gets 22mpg - then the difference in fuel consumed (energy) has to be accounted for - in the wbx case it is the form of heat - therefore the relatively huge cooling system in a vanagon - a cooling system that overcools in most engine conversion - the overcooling can be solved with bypasses or feedback routes - each specific to the particular conversion power plant but, again, working from a known"clean: starting point is important.

3. Replace the heater core, blower motor and whatever else needs redoing WRT the heater, defroster blower - this is such a PITA job and one that is critical for safety certification that it is far better that the vehicle is sold with it operating at 100% than having to deal with the unhappiness of buyers who have to deal with a faulty heater or blower a year or so in the future.

There are other procedures that the pro's do as a matter of course but these 3 are done as a matter of course even if the systems are "working" in the van when they start.
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[revolution337]

Bumping this thread, I have the exact same noise coming from my fuel pump as well. Brand new fuel tank and lines. Pump (Bosch) and filter (OE post filter, no pre filter) only have about 500 miles on them. Rubber isolator mounts are new as well, and no part of the pump is contacting the frame. Just started happening a few days ago, and seems intermittent (but it is mainly present). Its very loud and I can hear in the van when idling.

Were you ever able to solve your noise issue?
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[DuncanS]

Had a fuel issue when in Belfast, Maine. The Beetle Shop is a serious T3 place with knowledgable guys. In checking everything out, he noticed I had a replacement fuel pump. His comment, "I guess we can rule out a crappy Bosch fuel pump problem as you don't have one. We've had a ton of Bosch fuel pump problems and we never put them on anymore."

Duncan

[AtlasShrugged]

Had a brand new made in EU Bosch fuel pump installed prophylactically, replacing the OEM 120K mile original fuel pump on my vanagon.

That darn new Bosch pump was noisy all the time. I tried all the usual electric motor audio solutions without success.

The Bosch finally became silent as it died after about 20k miles leaving me stranded.

I used a new $49 Hayg Walbro fuel pump from eBay as a replacement

That Hayg Walbro pump is completely silent and has worked well for several years.

No more Bosch fuel pumps.
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[dobryan]

[AtlasShrugged]

For the 1986-1991 Vanagon: https://www.ebay.com/itm/321874536438?fits=Model%3...Swo4pYKhH4
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'Let's Go Brandon'

[dobryan]

[danfromsyr]

agreed, when you are on the side of the road.. is the last place I want to pull out a old pump that 'ran when pulled' and hope.

I do keep old pumps around the shop, toss them on a project/carcass to move or test it.. but not on a vanagon built for roadtrips and MY leisure time activities.

worth far more than $50 at that time..

[Andymon]

Ours always has had a static sound.
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[DuncanS]

That's because it runs on static electricity with the hidden and rarely seen Van De Graaff generator.

Duncan

[dabaron]

i have ordered this fuel pump, recommended by Marco Mansi. i have not installed it yet, but once in, i will report back.

https://www.ebay.com/itm/353134701388

i tried a number of things with my replacement Bosch, adding the ballast resistor did not resolve the issue. i hope this solves it.
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1991 Vanagon GL Camper
i had no idea i wanted to be a mechanic
"burnin oil and cookin coils" -- Destructo

BiWerks Design, LLC

[revolution337]

[skills@eurocarsplus]

walbro for the win

Botch is junk these days.

I agree that a tank should be replaced. they are (were) dirt cheap.

i'm running the large outlet to the pump and a post filter. literally can't hear it run
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