MFI Problems

[Guest]

Perhaps someone out there has some wisdom in this area !!

The story goes like this:
- I put an Ansa 911 R exhaust system on my car (it is for sale) that has no heat riser for the MFI pump.
The system was installed by a local dealer in Chicago. He short cut the cold start solenoid, and I think adjusted the low and high fuel delivery settings on the pump, and short circuited some of the other electronics. I don't know the settings.

- When I got the car in the UK, I installed SSI heat exchangers, and the car ran much better.
My mate who got the car going after 15 years, adjusted the butterflys so they all opened simultanously. Prevously, someone had f...ed up the butterfly settings. The car ran better.

- I then gave the car to someone who I was lead to believe was an expert in setting the MFI. All of the rod settings were not to Porsche specs, and the car did not seem to run well at all. I now have the car being worked on by a local technical expert.

- The rod settings are now per Porsche spec. Only issue is the idle. It is at 1200 to 1400 rpm, which is 300 to 500 rpm above the factory spec of 900 rpm.
In their static state, the butterflies are open a few degrees (we don't have the protrators to measure the degrees), and the bleed screws are closed. The rod setting is at 114 mm as it is supposed to be.
The bleed screws should be open some turns and the butterflies closed completely.

- Logic tells me that we can just shut the butterflies, and open the bleed screws to the recommended spec, and the motor will probably run better than it does now. I think the butterflies will be then be in sync with the main pump.
No Porsche spec talks about how to set the butterflies in a default situation.

- Can anyone shed a bit of light on what to do here?


Thanks
_________________
domtoni
1969 911E

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[early 911]

I realise this link has been posted over on DDK, put I think it's useful to post it over here:

MFI - Check Measure Adjust
http://www.scatliff.mb.ca/pelican/MFI_Check_Measure_Adjust.pdf

I've heard that Tower Diesels are supposed to be 'experts' (let me know if these are the one's that worked on your system):

Tower Bridge Diesels
93 Endlebury Road
Chingford
London
E4 6PX
02085242973

Russel Lewis (PCGB tech guru) know's a fair bit about MFI (I'm a carbs man myself).

RSR Engineering
Rardley House,
Headley Road,
Grayshott,
Hindhead,
Surrey GU26 6LB
Tel 01428 602911

 

[Guest]

Thanks Phil for your kind reply.

 

[Guest]

Phil,

Thanks for posting the info and thanks to Russell Lewis for his comments on the MFI unit. The car is now running as it should. The butterflies will need a rebuild at some future point, but I am not worrying about that today.

Thanks again.

Dom