Fuel pump on 911E 1973
06-10-2011, 01:25 PM
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Fuel pump on 911E 1973
Hello
I´m putting the MFI mechanical injection pump back on my car, which has been running with a set of Webers the last two years it was driven (2006-2008). The fuel pump was changed at the same time.
My question is, does the MFI require a special pump (the original bosch unit) or can the one be used which the car had with the carburattors? Does the MFI pump need a specific output, or does it lift the pressure to the required standard by it self?
I´m putting the MFI mechanical injection pump back on my car, which has been running with a set of Webers the last two years it was driven (2006-2008). The fuel pump was changed at the same time.
My question is, does the MFI require a special pump (the original bosch unit) or can the one be used which the car had with the carburattors? Does the MFI pump need a specific output, or does it lift the pressure to the required standard by it self?
06-10-2011, 03:07 PM
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This is a very good question. The answer is yes, you need a specific fuel pump for this Bosch MFI. Your best bet is to try to find a used one or rebuild a leaking one. These fuel pumps have three inlets/outlets and feed the MFI pump a specific fuel pressure. The fuel pressure is regulated at the MFI pump. Should there be to much pressure, the MFI pump sends fuel back to the fuel pump(hence the third inlet) and back to the tank for normal over-pressure.
The major difference between the carb fuel pump and the MFI fuel pump is that the carb fuel pump is a one-way fuel system. The MFI fuel pump is a circuit fuel system.
I would advice you to start looking on ebay to find a used pump. Bosch may still sell these new, but they cost a hefty $800!
Best regards,
Erick
The major difference between the carb fuel pump and the MFI fuel pump is that the carb fuel pump is a one-way fuel system. The MFI fuel pump is a circuit fuel system.
I would advice you to start looking on ebay to find a used pump. Bosch may still sell these new, but they cost a hefty $800!
Best regards,
Erick
06-10-2011, 04:45 PM
#3
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this is a very good question. Erick is spot on. I went thru the system on my 73S and came to the same conclusion. I did get a new pump, but remember having too look hard for the right deal. Can't remember where it ultimatly came from, but it was a substantial savings. I may suggest contacting some of the major suppliers to get a referance on what they cost, then getting in touch with some of the smaller shops. Somebody may just have one on the shelf and willing to let it go for a bargain.
Be sure to pull the fuel tank outlet and clean the filter "sock" inside the tank...if you hav'nt already.
Be sure to pull the fuel tank outlet and clean the filter "sock" inside the tank...if you hav'nt already.
06-11-2011, 03:33 PM
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Thanks for the answers, not maybe what I wanted to hear but that gives an explanation to the extra fuel line that is plugged for the moment... Must check through the PET for the pump model and try to find references on where I can find one...
The idea was to make a quick service and then enjoy the car during the summer... Well there was a lot of work to be done with rust etc. I checked and serviced the engine and it looks to be in good condition (well I drove it 4 years a ago...). The car had also a plastic fuel cell, which either is a RS unit or a replacement, thought to swap that to a normal fuel cell from another project car and leave it for an R-Gruppe projetc in the future.
The idea was to make a quick service and then enjoy the car during the summer... Well there was a lot of work to be done with rust etc. I checked and serviced the engine and it looks to be in good condition (well I drove it 4 years a ago...). The car had also a plastic fuel cell, which either is a RS unit or a replacement, thought to swap that to a normal fuel cell from another project car and leave it for an R-Gruppe projetc in the future.
06-12-2011, 08:21 PM
#5
The Bosch MFI on your car is an excellent system. Throttle response is incredible. It was discontinues due to cost and emissions requirements, but can hold its own with modern systems in terms of performance.
Your 911E is very rare and valuable car. I suggest restoring the MFI system bak to factory. Pacifit Fuel Injection is a specialist that understands these systems and is reasonably priced.
I own a 1970 911S and fully understand the costs of restoration. This is not economically feasible for me, so I understand that others may not be able to do this either, but at minimum, "freeze" your car as close to stock as possible, and do any repairs as close to stock as possible.
As in art preservation, do no further damage.
If you want to do an "R-Gruppe" project, I suggest using a post '74 car... there are plenty of these doomed for the crusher and can be saved... plus, you;ll just lose $20K of value doing this to your car.
Have fun
Your 911E is very rare and valuable car. I suggest restoring the MFI system bak to factory. Pacifit Fuel Injection is a specialist that understands these systems and is reasonably priced.
I own a 1970 911S and fully understand the costs of restoration. This is not economically feasible for me, so I understand that others may not be able to do this either, but at minimum, "freeze" your car as close to stock as possible, and do any repairs as close to stock as possible.
As in art preservation, do no further damage.
If you want to do an "R-Gruppe" project, I suggest using a post '74 car... there are plenty of these doomed for the crusher and can be saved... plus, you;ll just lose $20K of value doing this to your car.
Have fun
06-13-2011, 01:45 PM
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Found a restored pump at Vertex auto for 399usd, I wrote to them and hope they have one available...
Discovered that i might also be lacking the fuel filter element, will go through my parts this evening. Special part (expensive), again... There might be lying parts in peoples garages in Finland, hope I find one.
The 911 E will be left original, no modifications here. It will receive a 911 S front spoiler (they were options in 1973 for other models as well) for stability, but that is all.
The R-gruppe will be build from another car.
Discovered that i might also be lacking the fuel filter element, will go through my parts this evening. Special part (expensive), again... There might be lying parts in peoples garages in Finland, hope I find one.
The 911 E will be left original, no modifications here. It will receive a 911 S front spoiler (they were options in 1973 for other models as well) for stability, but that is all.
The R-gruppe will be build from another car.
, I did not find the Fuel filter element either... Any advice on where to look? Part number 901 110 232 00.
