MFI running too rich for emissions test?

HELP!!! I just failed the first of three chances I get to pass the emissions test for my '72 911T ('S' Spec engine). The only portion of the test that failed (and by a long shot) was the hydrocarbons, unburned gas coming out of the exhaust. My guess is that the MFI system needs adjustment to make it lean enough to pass the test. Is this something that is relatively easily done? Can a good 'weekend' mechanic do this? Where can I get documentation? Any other thoughts? This is a wonderful car and I feel it should be able to pass. It looks great in my garage but I want to DRIVE it!!!

What kind of gas are you using? I can E mail you a copy of the tech manual for the MFI. But you need to be able to accept fairly large files. Where do you live?

mackgoo, I typically use Shell Premium Gas - 93 Octane (US), is this appropriate? If you could e-mail the manual it would be greatly appreciated the file size should not be a problem under 2mb, I have a DSL connection. I live in the Chicago (IL) area, which currently has the distinction of the highest gas prices ($2.40+ / gal for premium) in the contiguous 48.

I got your E mail. i'm going to the movies now, I'll get back to you on the manual. The whole thing is about 50 meg. I have it broken up into 5 meg packets for a previous delivery. Do you think 2 meg is your max? The reason I ask about the gas is the manual is very specific about that. any thing over 87 will make the CO content run high and very hard to adjust. There are a bunch of things to check before you want to start adjusting. One would be gas. Two your warm up regulater, is the hose clear of obstruction and the regulater itself if dirty and sticking it may not lean out with warm up. As I say i'm off, when I get back we'll figure out how to get the manual to you and you'll pass in no time. Acctually what are they doing checking emissions on a 72 car?

[This message has been edited by mackgoo (edited 06-23-2000).]

Actually, I did some checking and I think a 5 meg file should work OK.

Start checking your E mail.

I have always felt that the MFI on my engine was running rich. I am fortunate that in CA, isn't it good that something about emissions in CA is good, the '72 engine does not need to be smogged. Don't get me wrong, I want to save the atmosphere but sometimes they get a little sticky about those things. We now have smog III and the car actually has to be run on a small dyno as well pass visual inspection. Anyway I digress. I found that the heat regulator is critical. I checked the tube running from the heat exchanger was cracked and I also cleaned the inside. Good 1/2 hour or so job but real easy with carb cleaner and a little wire brush. Be sure that the internal components are put back in correctly, little plates that are concave '()()()()()()' like so and it will change how the car runs tremendously. Good luck.

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John Birkett
72'T Targa

Well this was before my engine & MFI rebuild, but last time I had to pass smog (am exempt now, hurray!) my mechanic tweaked the MFI so much that supposedly it passed, but the car wouldn't even drive down the block. I have no idea what he did, but it worked and was easily adjusted back into drivable form.

Good luck w/ yours,
Chris C.

mackgoo, received the tech manual for the MFI system. No problem retieving it from my e-mail and it printed out beautifully. Thanks much for your comments and for taking the time to get this to me.