White98LS

My car has run beautifully with my current parts list for thousands of miles, but for a week my car has been running super-rich and hesitating a lot, sometimes dying. I started with misfiring in cyl #2 which then progressed to eventually all cylinders. I replaced the cap, rotor, plugs and wires, which were all worn, but it got only a little better with the plugs, the rest didn't affect it. Compression test was fine.

Now I have a CEL code #3, non-functioning or disconnected MAP sensor, in addition to the other misfiring codes. I just got the MAP CEL today as far as I know, last time I checked the codes was Friday and I had just the misfiring codes. The S-AFC reads a constant 0.0% airflow, I dunno how long it has read that but my friend re-wired the S-AFC Friday night because I accidentally pulled a couple of the connections loose putting the ECU back (I had taken a look at the S-AFC connections to see if that was a problem, which is why the ECU was out). I understand that the MAP thing might be a loose S-AFC connection, but I got into it just now and the connections look and feel solid, and according to the wiring diagram it's all done right. I also don't think it's that because although I noticed the MAP sensor fault after my friend re-wired the S-AFC (though who knows if it was a day after or immediately after cuz I didn't check codes immediately after), the car was running the same before and after the rewiring and the MAP CEL.

My question is, could a faulty MAP sensor really cause my car to misfire and the S-AFC to read 0% airflow? My car has symptoms of a bad MAP sensor (shitty/stalling idle, runs very rich with a normal fuel pressure, hesitates, loss of power), but the MAP CEL came on after the cylinder misfire CELs and after my friend re-wired the S-AFC, which is strange. Also if the sensor itself was bad, would it really cause the S-AFC to read 0.0%, or just a lower number than usual? 0% makes me think bad connection, but we'll see. Also maybe the S-AFC itself is screwy? My cams idle really rich and usually the S-AFC compensates for that, so maybe the S-AFC's airflow signal is not working (since that's how it "tricks" the ECU into adding/subtracting fuel). Any tips??!!

White98LS

Well I swapped the MAP sensor itself from my friend's LS to mine, no change at all.

On the S-AFC voltage during the S-AFC's sensor check at idle, my Throttle is at 0.500 V or so, and In-1 (which I think is airflow input) is at 1.6xx V, but my In-2 (airflow output I think) is only at 0.035-0.040 V. Is this supposed to be so low? It only goes up to about 0.060-0.070 V when I floor it in neutral up to maybe 5k rpm. And the airflow monitor still reads 0.0% even when I floor it up to 5k.

Anybody PLEASE give me some ideas... I've been messing with this car every day, for at least a couple hours per day, for a week now. It's running really rich (droplets of fuel all over the inside of the exhaust tip, strong gas smell) and stalling often at idle. And then I still have this CEL code #3 for a faulty/disconnected MAP sensor, which may or may not be related to the S-AFC but the connections look/feel solid and the sensor itself is fine. I will see if any import shop will let me plug in a new S-AFC into my current S-AFC wiring harness.

I need help big time, I don't want to run the car even more when it's running so freaking rich, and the nearest junkyard or import shop that knows anything is at least 20-30 miles north and south from school, where I live. I don't want to take it to Acura, they already mis-diagnosed problems and generally made asses of themselves, and most import shops around here don't know jack either, my favorite one just went out of business too. So the questions are:

-What is the normal voltage for each sensor on the S-AFC at idle?

-Could it just be a tank of bad gas? But why would that make it run really rich and get the MAP problem?

-Why am I running rich and misfiring on all cylinders, AND get a CEL for a bad/disconnected MAP sensor? The sensor itself is fine, the wiring for the S-AFC looks fine, I replaced the cap, rotor, plugs, and wires (stock plugs, gapped properly) with no change. Compression is fine, already checked for head gasket problems, fuel pressure is same as always....

-Finally, what the hell do I do next?!!

Please, any help is immensely appreciated, if I drive to any shop/junkyard it's gonna be a good 20-30 miles one way, and the shops around here probably won't be able to figure out much at all, Acura sure didn't.... I don't want to drive it like this 50-60 miles and not solve the problem, and I don't have much time at all this week - two midterms. I am officially at my wit's end. Please help. Thanks.


Modified by White98LS at 6:44 AM 5/5/2003