Replace mech. fuel pump w/ electric?

taylorcom

taylorcom

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The mechanical fuel pump on my '72 3.0 CS seems to have failed and these pumps are getting hard to find.

However, I see that some electrical fuel pumps are advertised as replacements for mechanical pumps. Here are 2 examples: http://www.oreillyauto.com/site/c/s...sal&year=1972&make=BMW&model=3.0CS&vi=1011070

Is converting to an electrical pump a good idea? If so, how do you make the switch? Is any other stuff required besides just the pump?

Thanks,

Steve
 
Taylor,

Rebuild kits were available the last I checked. New mechanical is best for that original look.

Electric as Steve says can be noisey. They usually come with a check valve to prevent drain back. The fast way is mounted to the firewall. The best way is near the tank or left wheel area.

If you can afford a rotary pump; that would be my recommendaton. But they cost about twice relative to what you can get at less cost.

Not all heads have the provision for the pump and at sometime we may all be facing this issue.
 
I used the low pressure electric pump out of a 633csi in my Bavaria. It fits right in place of the existing gauge sending unit and is pretty quiet.
 
My old 2800 had an electric pump. It was an airtex (sp?) unit similar to one in your link. It was a low pressure system that made a slight hum when on, but was not noticeable when the car was running. All in all, the pump worked fine, was mounted near the gas tank and proved reliable.
One little word of caution is that my pump had a filter mounted to it which was impossible to locate replacement for, and that the car would only run well if both the stock, and the one attached to the pump were in line.
 
Mike, I am interested in the set-up you describe for your Bav but not sure what you mean by"It fits right in place of the existing gauge sending unit"?In the trunk or on the head?
 
PaulinPa said:
Mike, I am interested in the set-up you describe for your Bav but not sure what you mean by"It fits right in place of the existing gauge sending unit"?In the trunk or on the head?
Click to expand...

Me too! I have looked up 633 csi fuel pumps and they do not look anything like what might fit in place of the fuel gauge sending unit. Also, would this unit then also act as a fuel gauge sender?
More description would be greatly appreciated.
 
Mike,

can you post a pic of the 633 in fuel tank unit? i think that might be what the previous owner did to my car when they put a 3.5L injected engine in ... the car doesn't have a csi tank ...it has a standard cs tank, but the fuel gauge sender is different. i think it is an in-tank pump / sender unit.

can anybody identify it? its a vdo unit - i see a stamped number on the perimeter 1179423
 

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well i figured out what i have ... its from an e21 320i. i guess i need to find out what the wiring diagram to a 320i fuel tank is supposed to be. anybody have a wiring diagram?
 
rsporsche said:
Mike,

can you post a pic of the 633 in fuel tank unit? i think that might be what the previous owner did to my car when they put a 3.5L injected engine in ... the car doesn't have a csi tank ...it has a standard cs tank, but the fuel gauge sender is different. i think it is an in-tank pump / sender unit.

can anybody identify it? its a vdo unit - i see a stamped number on the perimeter 1179423
Click to expand...

I chose the 633csi unit because it is about the same length as the stock Bav gauge sending unit. A 3 series unit is somewhat shorter than the Bav unit, which would leave me with fuel I can't reach. The pump proper is used in lots of models, like the 3 series cars. The wiring is pretty straightforward, the sending unit has the gauge wire, the fuel light wire and a common, while the pump has 12v and common. My stock gauge works just fine with the 633 sending unit, but I have noticed that the fuel light comes on sooner, perhaps because the injected cars don't have any cushion like a carbureted car.
 
This is great info. I've read that electric pumps work best when installed at the tank, not in the engine compartment. This could be a more-complicated install than just plugging in a new mechanical pump.

Beside AutohausAZ.com, I've found 2 more sources for the mechanical pump, one in the UK and one in Spain:

http://www.jaymic.com/shop/parts_CS_products.asp?grp=CSFU&page=4

and

http://www.oscaro.es/ficha.asp?ID_O...7&ID_GENERIC_ARTICLES=458&ID_ARTICLES=1870493

Has anyone bought from these guys before? Can you tell me what happens to those prices when VAT and shipping are added?
 
Steve,

Your profile doesn't show where you live. If in the U.S. there is no VAT added, that is for European Union only. I have bought items from Jaymic, they are fairly priced, ship extremely fast at a fair price, conversion to British Pounds is easy and fair and use Paypal. Couldn't be easier. I know Mesa Performance can get these pumps as well.

Chris
 
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