MFI questions

[goldsc78258]

just finished putting a MFI engine on my 72 (it had a 2.4 CIS from a 73) but anyways I have spark and this engine was running perfectly before.

I think I have isolated the problem to the electrical pump it was a used one I had and I think it is not puting out enough pressure because if I put gas down the stacks it will try to start and then die. My questions are the folowing

What is the pressure that the pump should be putting out?

What is the volume?

Please feel free to chime in with any ideas and thanks in advance

Fred

[rs dreamer]

Here are 2 links to great threads on the fuel system:
1973 911T fuel noise?
Braided Fuel Hose for a 72T MFI



You need the pump shown for the E,S in the table. The T is the carburated version.

Here' another link:
1971 911E Fuel injection problem

Gary

[rs dreamer]

I think this is what you're looking for (from 72,73 technical specifications book)



Gary

[goldsc78258]

Thanks this is very usefull

Fred

[goldsc78258]

Any of you guys know if you could use an aftermarket pump that puts out 14# pressure?

Thanks

[goldsc78258]

I found a good electrical pump here in town and the preassure is good as well as the flow, but the car won't start.

Is there anyway to check if the injector are working good?

Is there anyway to check if the MFI pump is out of timming? or maybe something wrong with it?

I'm sure is fuel because I've got a good spark

Any of the MFI experts care to chime in?

Thanks

[MikeDL]

I've been researching MFI stuff for a week or so, and there's tons of great stuff here. Try searching for "mfi AND newbie" and you'll get several pages of introductory threads.

[Grady Clay]

I recommend you have a Forum Moderator combine your recent thread with this one. Too many little threads make for difficult searching.

Speaking about searching. Much of your questions have been thoroughly debated and solved on other threads. The Search Function is your best friend.

Here are only a few links:

Check Measure Adjust (CMA)
http://www.scatliff.mb.ca/pelican/MFI_Check_Measure_Adjust.pdf

CMA

Ultimate MFI resources thread
Ultimate MFI resources thread

MFI Message Board Index
MFI Message Board Index

“MFI Size Chart”
MFI Induction Chart

“MFI thermostat spacers”
p. 1 end has CMA extension, p. 3 has nozzle, fuel flow, and fuel pressure.
MFI thermostat spacers

“More Fun with MFI and LM1”
How to use protractors for correlation.
More fun with MFI and LM-1
“More MFI”
More MFI
“MFI Problems” Furl filter console plumbing error.
MFI Problems
“MFI Speed Switch”
MFI Fuel Shut off solenoid questions
MFI tools
MFI tools for DIY'er
“MFI electrical”
A different MFI thread - electrical
“'72 Hose from engine tin to MFI WUR - what material?”
http://forums.pelicanparts.com/porsche-911-technical-forum/201734-72-hose-engine-tin-mfi-wur-what-material.html#post1715584
trouble shooting “Grady/ Sherman(72 Guys) Ok now what?”
http://forums.pelicanparts.com/porsche-911-technical-forum/203301-grady-sherman-72-guys-ok-now-what-post1729700.html#post1729700

http://forums.pelicanparts.com/porsche-911-technical-forum/306631-mfi-pulley-mark.html#post2836726
MFI Pump Timing Mark

“Cleaning MFI Throttle Bodies”
Cleaning MFI Throttle Bodies

Motor break in with MFI
Motor break in with MFI

“Mechanical Fuel Injection” site with OK stuff:
http://www.my930.com/MFI/TipMFI.htm

A really good thread on MFI fuel supply:
”Braided Fuel Hose for a 72T MFI”

Fuel tank cleaning procedure.
”Water in fuel“



Best,
Grady

[goldsc78258]

I checked the fuel pressure at the inlet and it is 14# and yet the car won't eve let a peep out

I disconected the tubes that go into the injectors and you can bearly seee a drop coming out every so often during cranking

if I disconect the tube with the injectors there is nothing coming out of them, any ideas? I read mostly all the threds and none of them cover any issues like this

This engine ran perfectly when I took it out of the other car(about 6 months ago) do you think anything could have gone wrong between now and then?

Thanks

[Grady Clay]

try this again.

[Grady Clay]

try this again.

[goldsc78258]

Grady, I think I have solved the problem! the timing was off by a tooth, it fired right up. I'll try to make it run smoothly tomorow and will report back

Thanks again

Fred

[goldsc78258]

OK the car has been running smoothly for a couple of days now, the CMA really helps, if you go thru this list you'll find your problem mine was

1.- the fuel pump pressure was low about 7#

2.- Ignition timing was off (way off)


Thanks everybody