4.2 BFM fuel pump trouble
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AudiWorld Newcomer
Joined: Apr 2023
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4.2 BFM fuel pump trouble
Hello, about the situationFew months ago right side fuel pump started to fail, after measuring pressure was about 2.7 bar. Since I heard bad reviews about aftermarket pumps, and the original one is expensive, I decided to try to put a left side pump.The only difference was that the left-hand pump has only one outlet, while the right-hand side pump has two outlets. I used a hose tee, to make two outlets, checked with compressed air, everything was tight.After putting it in the car, with working engine pressure was 3.4 bar, if pressure regulator vacuum tube was removed - 4bar.
The problem is that as soon as the engine is turned off, the pressure suddenly disappears, feels like somewhere pressure is leaking.
What do you thing about it, thanks for the answers.
The problem is that as soon as the engine is turned off, the pressure suddenly disappears, feels like somewhere pressure is leaking.
What do you thing about it, thanks for the answers.
AudiWorld Wiseguy
Joined: Aug 2012
Posts: 4,073
Likes: 322
From: Chicago
Right side type fuel pump probably has a check valve in it to retain pressure whilst it’s off, and the left side one doesn’t.
As you’ve put a left type in for the right type, there is no check valve to retain fuel pressure whilst the pump is off.
Id recommend taking the pump units apart and swapping/replacing the actual parts that have failed if you can source new or used components.
Although a new OES (VDO) one is only $200 so not really worth the hassle unless you’re really on a budget or enjoy the challenge of fixing things.
As you’ve put a left type in for the right type, there is no check valve to retain fuel pressure whilst the pump is off.
Id recommend taking the pump units apart and swapping/replacing the actual parts that have failed if you can source new or used components.
Although a new OES (VDO) one is only $200 so not really worth the hassle unless you’re really on a budget or enjoy the challenge of fixing things.
Last edited by dvs_dave; Oct 22, 2024 at 03:06 PM.
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