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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
There are a lot of fake ones out there that were made in China.
I used to think if it had the right number and letter markings stamped into it and said Bosch and made in Czech Republic it's a real one. Now I'm not sure if the Chinese ones might say that too and there may be no way to tell them apart unless you know you have a real one in your hand next to a fake one and can see a difference.
If you can return it, do it. and do it again and again until you get a relatively quiet ones.

I've returned two or three made in Czech Republic Bosch 044 pumps I've had because they were ridiculously loud after 10 to 20 minutes of running. You could hear them buzzing/screaming from over 200 feet away and it's unbearable inside the car.
After replacing the second front pump I just leave the heavy steel cover off the bottom of the car because I got tired of unbolting it and bolting it back on to access the stupid pump. Don't need it anyway.

I think part of the problem is they're made for current day EFI that runs around 40-50psi and not 30 year old CIS that runs up around 100psi and that puts a lot more strain on the fuel pumps. Another words they are the wrong fuel pumps for CIS.

The noise may be fuel cavitation or fuel vaporizing into little tiny bubbles in the rollers of the pump as it overheats and the internal pressure valve opens and some of the fuel is recirculating around and around inside the pump and getting hotter and hotter while it does it.. The fuel pump is cooled by the fuel flowing through it. Fuel flowing right around the spinning motor armature, the brushes, and the bearings.
If the pump overheats the fuel partially vaporizes and you get the buzzing noise.

Anyway, after returning 2 or 3 of them and getting new replacements I've got two of them that are not too bad at the moment.
Old 11-04-2014, 02:48 PM
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