Looking for MFI speed switch: options??

[Ho Hum 74]

Folks,

My fuel shut off solenoid is not working and I’m looking for a speed switch for a 73 MFI. This is the switch which controls whether the shutoff solenoid is activated or not.

What suggestions do you have for where I might look for a used one?

Thanks

[derek murray]

I had mine repaired by fellow Pelican 'Cornpanzer'... if you still have your's he may be able to help out.

[Ho Hum 74]

Thanks but mine is AWOL!!

[Tspringer]

Mine is long gone as well. In fact, so is the shut off solenoid!

I have yet to hear of any negative effects of running without the shut off solenoid and micro switch other than difficulty passing emissions testing if you are so required where you live. Here in GA my '69 is exempt.... so no reason to bother with it.

[derek murray]

for me anyway, a working speed switch, et al. virtually eliminated backfiring on over run... and it backfired alot.

EDIT:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2484285445&category=34205

[Ho Hum 74]

I also think that it increases fuel efficiency (a good thing these days) and more importanly stops getting fuel past your rings.

T

[jpnovak]

Post a pic and some part numbers for the speed switch. I may have an extra one.

Where is it located on the relay board?

[Ho Hum 74]

Hi,

Part number is 901 615 111 00

OR

901 615 113 00 (which is the one from 73S)

Thanks
T

[Halm]

Before I did my transplant to a 2.7 with Webers, P-Thomas used a Gunston on my system to set the mixture and we also backed off the needle for the speed switch. The motor ran great. Well, as good as a POS MM motor can run . In any case it was smooth and mileage went way up, so I'm not sure about the effects on mileage.

[Tspringer]

Well... my car does dilute its oil with fuel washing past the rings if driven hard. Dieter at Franz Blam here in Atlanta is going to tune it and try to solve that.... well see if I end up needing to re-install the speed switch and solenoid. I believe I have the parts in another complete MFI setup I have in storage.

[Ron,K]

If you're willing to part with about 300 bucks, Stoddard Imports s
should still be able to order one for you

[Ho Hum 74]

I just got one from Otto's Venice. They are very reasonable (did I just say that?). $175 for a recon and $75 if you have a core to return.

Nice.

"Well... my car does dilute its oil with fuel washing past the rings if driven hard. "

Mine is mainly track so its driven hard almost exclusively!

Tristan

[Grady Clay]

Terry,
Your MFI should never run so rich that it dilutes the oil with gas when driven hard. Check this thread and other MFI.
MFI thermostat spacers

There are two possibilities:
First is the oil dilution is from cold running where the thermostat is too rich, the thermostat doesn’t turn off properly, the cold start solenoid is leaking, the main mixture is too rich, or it doesn’t get sufficiently warmed up each time its driven.

If it is diluting the oil while hot and driven hard (very unusual) you will find an outstanding performance increase by correcting the problem.

What is your gas mileage on a highway trip?
The guys in Atlanta should get you fixed. Just do it ASAP, gas in the oil is not good.

Best,
Grady

[lcjjbeav]

Check out the answers by Early_S_Man. He knows the MFI systems and the electricals as well as anyone. Here is the results of a search using speed switch and Early_S_Man. Don't forget the underlines in his name.

http://forums.pelicanparts.com/search.php?action=showresults&searchid=756474&sortby=lastpost&sortorder=descending

[Tspringer]

Warren is indeed amazing. His knowledge on these early cars is astounding. I have no doubt that I could fix the issue myself just by using Warrents prior posts and following the "check,measure,adjust" procedures but my problem is time. I am just so swamped with work right now that it would cost me more $$$ to work on the car myself than it costs me to pay an expert like the guys at Franz Blam Racing.

Franz Blam and Dieter are going through the car now. They already did a leakdown test and it came back good. I should know more before weeks and and hopefully all my running issues will be fixed.

[1972 911 T]

How much did it cost to have the speed switch repaired/replaced???

Alex

[Tspringer]

Franz and Dieter got my car running fantastic. They took it and tested CO after adjusting and its right on at about 5% under load at 4000rpm on the dyno. It runs great.... and they said it should no longer foul the oil.

No speed switch. Franz said no need. If you need to pass emissions that may not be the case, but if no emissions required (as here in GA) then the car will run/drive great without the speed switch and cutoff solenoid. When I originally asked Franz about installing those items, he just looked at me real funny and asked "vy vould you vant to zoo that?"


Terry

[derek murray]

Originally posted by 1972 911 T
How much did it cost to have the speed switch repaired/replaced???

Mine was repaired for about $75.00, if my memory is right.

[82SC]

also try Supertech...harry schmidt posts in the rebuild forum all the time. They like to specialize in MFI engines...

MJ