Of Mice & MFI (not for the squeemish)

[svandamme]

.3 difference, that's 6%, but it's even on both sides
that's at idle, and will not affect WOT

imho, my flow meter (similar to yours, but different brand)wasn't even that precise to come up with values that sharp, also , the needle always fluctuates up and down, it's not steady...

you could try opening up the adjustment screw on the throttle bodies a liiiittle bit on #5 and #6, but take notes about what adjustments you make so you can fall back

personally i wouldn't tinker with it if it runs well, smooth, feels strong and idles well
don't fix if it ain't broken

that it runs a bit hotter, could be the ignition timing, mixture, but it might just as well be coincidence, aircooled temp behaviour changes as temp outside is warmer or colder... especially if there is no front oil cooler (does yours have one?)

besides ,you'de need a exhaust o2 tester like an LM1 to get a clear picture of the mixture, if you want to get it really right...

[svandamme]

oh , yeah, with adjustment screws i mean the air correction screws, the ones accessible from the top, with springs under

not the throttle stop screws

[mhackney]

Stijn, the thing is that I noticed my idle speed is not dropping back down like it was last night. Even on the hotest days, my temp is pretty much right on the thermometer tick mark (180 F) but today (and it is not a super hot day here) it is just slightly above and the idle speed was not dropping down once I was up to temperature (it was earlier in the drive). I do have a Gastester Pro gas analyzer that I do plan to use. I do want to check the timing first though since I have been able to get the idle down from 1600rpm where it was before.

Other than the fast idle, it runs pretty good but I feel like it has been running rich since I have a fair amount of carbon in the exhaust and the plugs were black and sooty when I changed them last year.

cheers,
Michael

[svandamme]

then yes, continue with the CMA...
although has to be said , mfi does like to be a tad on the rich side to run well

but if you have the gastester, you got the right gear to do the cma from start to finish

[mhackney]

Great. Unfortunately, I am away in CA for business all this week so I won't be able to work on it until next weekend.

cheers,
Michael

[mhackney]

Just out of curiosity, what sort of gas mileage should one expect from a 2.2L MFI engine?

cheers,
Michael

[svandamme]

not much
don't know it in miles
but mine got something like 7 km per liter average
and that was definitely not when doing spirited driving


fuel economy is not an mfi characteristic

[mhackney]

Ok, I am back from my business trip and picking up my fast idle diagnosis. It was really hot here the last few days - upper 90s - and yesterday and today cooler in the 70s. I'm still idling at 1500-1600rpm after warm up. I did get a temperature probe so I plan to test the thermostat today. I did have to take the thermostat apart because of the "mouse issue" described in this thread. It actually looked very clean and reassembled with no problems. But I still have to wonder if it is related to the problem. Basically, once the engine temperature is in the 160 to 180 range the idle is spot on at 950rpm. But as it warms up it goes up to 1600rpm. I have not checked the timing since removing the mouse so I think I need to do that too - but it is tricky when the idle is so high. I still have not rulled out a distributor problem since it seems that if I slow the engine down by laboring it a bit, the idle speed drops down and seems to stay there.

Any ideas/suggestions to help diagnose this are greatly appreciated.

cheers,
michael

[svandamme]

when it goes into high idle
have you re-tried the "disconnected linkage" trick again, to make sure it's not sticking in the back somewhere?

i've had that on mine, where the rack was fine when i moved it from full open to full closed

but while driving, i generally don't always do full open/full closed
there's the intermediate position to closed, and in my case it wouldn't close fully from there...

[mhackney]

Stijn, yes I did make sure the linkages were all free and the throttle linkages do go all the way closed.

thanks,
Michael

[mhackney]

Ok, I started a new thread to diagnose my idle speed problem: At whit's end with high idle

cheers,
Michael