MFI gurus, help me understand
 

Gurus,

I'm busy fine tuning my MFI set up. Followed all steps of CMA.

I have a AFR sensor connected to the left HE. I looks like idle is ok (13.5), part load a little too rich (14-15) and far too rich while cruising (10-11).

What are good values?

I was wondering, what if one of the cylinders sometimes misses, would that influence the AFR reading? The sensor is connected to the left HE, what about the right cylinders?

Thanks,
Ed

http://forums.pelicanparts.com/porsche-911-technical-forum/583345-whats-ideal-air-fuel-ratio.html
http://forums.pelicanparts.com/porsche-911-technical-forum/589355-afr-readings-lm-2-idle-speed-vs-partial-load.html

Thanks, now I re-read that thread I notice that it's about the same question; how to get WOT and cruising right. See below my reading. I already turned the main rack adjustment half turn CW. Think I put it back because WOT looks too lean now. What to do about cruising though....

http://forums.pelicanparts.com/uploa...1308084094.jpg

Here are few other links that I had stored on my home PC.
Optimum AFR for MFI
http://forums.pelicanparts.com/porsche-911-technical-forum/198561-f-ratio-meter-vs-co-meter.html
AFR Readings (LM-2) - Idle speed vs. Partial load
MFI main enrichment help
Air:Fuel Mixture, MFI Feedback needed
Hope they help some.

Thanks guys, a lot of reading to do!

This is my last reading. WOT, uphill (tip of Mark Jung).

I think I leave the setting for now until I learned more.
The cruising 11-12 still annoys me though....

Ed
http://forums.pelicanparts.com/uploa...1308156230.jpg

Your readings are very similar to mine 73 911 E. Your WOT is pretty good. I found max HP to be at 14.5 - 15. I get a miss and possible detonation at 15.5. So a fine line there. At 3k RPM's - Cruising, you are a bit rich. Idle you are rich also. I would add a notch or two of idle lean and a click of the main adjustment toward lean and you should be real close to right on.

Another trick to the trade is to give the linkage to the MFI pump a turn to shorten the rod and thus add lean to the whole spectrum. This is a quick, easy and easily reversible adjustment.

The AFR's are pretty cool!

Chris
73 911 E

Don't monkey with the rod. It throws off everything- the rod must be exactly 114.0 +/- 0.2mm.

Very tempting but I won't....

I'll play a bit with the WOT and Idle. Must accept the cruising richness I guess.

Ed

Do what you want, just keep track of everything so you can put it back to where it was. Shortining the linkage to the MFI pump a turn or two will solve your cruising richness issue. Just be mindfull that it will lean the entire specturm. Lean is good. Rich is safe. Too lean is BAD.

Chris
73 911 E