MFI Mecahnical Fuel Pump - Help needed!

M491Cabriolet · 02-09-2009, 09:45 AM

I have some questions for the experts! I have a 1972 2.4 911T engine currently in my 1972 911T that is extremely good health, with 97% and 98% leakdown results on all six cylinders. The engine in the car has a 2.4 E (014) pump on it, but my mechanic (ASG in Fairfax, VA) tells me that pump might be in need of a rebuild soon. Notwithstanding the mechanic's prognosis , this car is really making me happy! It's quite cantankerous when cold, but when it's warm, it feels great to me. The idle even holds at 950 to 1000 RPMs. Hats off to ASG!

I also have another 2.4 liter engine currently on a stand being completely rebuilt with 2.4 911S heads, 2.4 S Mahle pistons and cylinders, E cams, magnesium 911S MFI stacks, and I'm currently planning to use a 2.2 911E,freshly rebuilt mechanical MFI pump.

OK, so here are the questions/problems: First, I am now having some untimely doubts about the 2.2 911E (010) MFI pump because I'm not sure it will have a fuel curve that will be useable on either my 2.4 liter 911T or the rebuilt 911E/S spec engine. Do you know if this pump would work OK on either or both engines?

Second, does anyone have one or two known very good or rebuilt 2.4 911E or 911T (014 or 015) (or even a 013 2.4 911S) MFI fuel pump(s) for sale? I say "two" just in case the rebuilt 2.2 911E (010) pump would not work on either of my engines. Any info would be greatly appreciated!

304065 · 02-09-2009, 10:37 AM

Why does he think it will need a rebuild? Why?

Most people think their MFI pump needs a rebuild which is why Gus has a huge backlog. In most cases the MFI is out of adjustment and there is nothing wrong with the pump.

The space cam matches the engine cams in terms of amount of fuel metered. Not recommended to mix them, although these days with reliable dual channel AFR sensing you might be able to.

M491Cabriolet · 02-09-2009, 10:55 AM

Hi. He said something about the idle mixture and the part load mixture screws/adjustments falling into a groove or something like that causing the idle and the part load mixtures to not be perfect. This guy is a true perfectionist, so for him it might need a rebuild while for me it will still give me 20 years of good service (exaggeration).

Regarding the second part of what you wrote, my proposed setup would be a 2.4 liter engine with 2.4 911S pistons, cylinders and heads, 2.2 911S stacks and throttle bodies, 911E cams, and a 2.2 liter 911E (010) pump. Do you think this sounds like it will work alright (in terms of the pump)? Thanks.

304065 · 02-09-2009, 12:45 PM

The space cam is hardened, I don't think it can "groove" but I would adjust it PROPERLY and then see what the AFR says.

See the thread "MFI Open heart surgery"- you CAN make a 911T pump power a 3,0 liter, it just takes a LOT of tuning and knowledge. That said in your combo the 010 pump will match the E cams so I would try it. The higher compression from the S pistons shouldn't make a difference and the S valve pockets are bigger than the E. TBs shouldn't make a difference, but don't put S throttles on an E head.

kenikh · 02-09-2009, 01:48 PM

Before you convince yourself that the pump won't work, read this:

MFI Pump - Open Heart Surgery

175mph951 · 02-10-2009, 06:19 PM

there is a good 015 pump for sale in the classifieds