Idle return springs for 71 MFI car

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rft218
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Idle return springs for 71 MFI car

Post by rft218 »

Hi All,

I am struggling with the final setup of my 2.2s. I cant get the idle running correctly but the start point of my trouble is that the throttles dont return back to the stops properly. I have looked at what returns them and there is a spring at the pedal and then a circular spring on the end of the throttle bar that goes between the two inlet stacks and that seems to be it. That is a new spring but it doesn't seem strong enough to return to the idle stops.

Have I missed anything, is there another spring somewhere else?

..and has anyone had experience in getting a MFI car set up in the south west, not sure who I go to, Roger Bray @ Exeter?

The pump and injectors have been fully refurb'd so hopefully it is just tweaking!

Cheers

Roger
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hot66
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Re: Idle return springs for 71 MFI car

Post by hot66 »

with the 2 link rods from the cross bar to the throttle bodies disconnected , do the throttle plates close fully then ?

with the link rods reconnected ot the cross bar, but then the throttle rod from the pedal to the linkage disconnected, do the throttle bodies return back to fully closed ? If not , then doisconnect the rod from the mfi pump to the cross bar and try

In other words, can you identify which part of the system has the resitstance to prevent the spring back ?
James

1973 911 2.4S
1993 964 C2
2010 987 Spyder
1973 MGB Roadster

Its not how fast you go, but how you go fast ;)
jwhillracer
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Re: Idle return springs for 71 MFI car

Post by jwhillracer »

rft218 wrote: Mon Oct 31, 2022 8:30 am
..and has anyone had experience in getting a MFI car set up in the south west, not sure who I go to, Roger Bray @ Exeter?
The best guy by far on MFI in the South West is Crispin at Oak Tree Garage, as long as you’re not in a hurry.

JW
Life's a single timed run with no practice....
1970 914/6 2.4E/Webers
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1972 911 Hillclimber 3.2 MFI. Part of the family for 30+ years!
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rft218
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Joined: Wed May 16, 2012 9:24 am
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Re: Idle return springs for 71 MFI car

Post by rft218 »

Thanks both, I am been trying to identify where the issue is but I will try unplugging different bits!

I will try Crispen and see how long the wait is!
ken c
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Re: Idle return springs for 71 MFI car

Post by ken c »

I would speak to Mike Burgess, if he's not too far away - Somerset - he wrote the book on MFI! Also, he did a fantastic job with my car - quick and v methodical.

http://www.911mfi.com/index.html
rft218
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Re: Idle return springs for 71 MFI car

Post by rft218 »

Hi Ken,

Thanks, yes i know him, he rebuilt my pump and injectors but he is currently too busy with his surveying business and sadly not doing MFI work. He has pointed me in the direction of useful materials which I need to work through,

Cheers

Roger
rft218
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Posts: 487
Joined: Wed May 16, 2012 9:24 am
Location: Cornwall

Re: Idle return springs for 71 MFI car

Post by rft218 »

...Update on this, was booked in with Crispin and was doing a final check on how I had set it up. I discovered that I had set the injection pump without the extra turn required on the crankshaft so it was 360 degrees out. Ran beautifully when I set it up right. Now doing some final tweaks before I let Crispin finally set it up.
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