Check the gap on the crank sensor. Look at your logs. Your in open loop idle yet the O2's are erratic. I don't think the issue is the motor is running lean. What your looking at is a misfire causing the O2's to show lean. I wasn't saying your mains were bad just that the issue could be the crank sensor contacting the damper.
His idle is very erratic until the radiator fan comes on. Shifting the trans into gear does nothing to change his idle. Something bad is happening until the radiator fan comes on,then it runs as it should. As soon as the fan turns off,it idles erratic again. If the crank sensor was the problem,the fan turning on wouldn't fix it.
Correct , I guess I'll start with all the wiring.. ugh lol
I think a good place to start would be at the connectors at the computer. Use a jumper to supply a known good ground to every terminal that should have a good ground one at a time.
I wouldn't make that assumption. When the fans come on that puts a load on the alternator which puts a load on the front of the crank. I'm not saying this is definitely the problem but checking the crank sensor clearance is a quick and easy check. His problem looks like a misfire...not a lean fueling condition. It's ignition related.
When the fan comes on,the problem goes away.
You didn't read my post thoroughly! The fans turning on loads the alternator which puts more load on the nose of the crank which could slightly move the crank enough to touch the crank sensor if the sensor is set too close. Bottom line....CHECK THE CRANK SENSOR TO MAKE SURE IT'S NOT LOOSE OR TOUCHING THE DAMPER. After looking at his logs he has an ignition misfire issue.
You are saying that when the fan comes on,the generator becomes harder to turn which could cause the crankshaft to move slightly causing the reluctor wheel to contact the crank sensor causing a misfire which causes his engine to idle rough. At least that is what you've written several times. Is this correct.
I’m sure this has been mentioned already but I would double check your grounds and positive leads to your fans .
That is a possibility
Do you understand that the problem goes away or is greatly improved when the fan turns on?
Yes I do. That was my bad when I was explaining my theory
My brain was thinking one thing but my fingers were typing the opposite. dank GN brought up a good point. What if his damper is loose. The engine is externally balanced so the damper is not neutral balanced. If the damper is loose it could have a wobble in it contacting the crank sensor. When the fan turns on the increased tension in the belt caused by the load on the alternator reduces the wobble enough so it doesn't hit the crank sensor. Looking at the logs the OP posted everything points to a misfire. The engine is in open loop idle which means the fueling should be fixed. The injector duty cycle only changes slightly. When the fans kick on there is a slight drop in fuel pressure. Not enough in my opinion to cause such a drastic change in fueling. My opinion is he has an ignition misfire. That's the only thing I can see that would give the O2's an erratic lean condition in open loop idle when everything else remains relatively constant. I would be looking at the ignition system. The crank sensor would be the first thing. It's easy to check. Make sure the gap is correct...make sure it isn't loose...check the damper to make sure it isn't loose. I would then look at the ignition module. What I see as odd is if it was strictly an electrical problem caused by the fan you would think the problem would show up when the fan turns on, not when it is off. Of course the OP could have made some bizarre wiring connection when he wired in the fans but at this point who knows.Yes,if your other scenario could happen,this opposite could also happen,but the erratic idle never occurs during the first many seconds of a start up. According to the theory,it would if the fan didn't come on at start up as it does with his car if the coolant temp is 168 or higher.
Yes,and even more interesting is that the cross counts vary only a few points which shows that the program is fixing the idle air/fuel ratio at a certain ratio as it should in open loop. If you look at the closed loop file,the cross counts move from 0-155 and repeats as is should in closed loop.
Yes,and many people have noted this with their cars,but never that the fan coming on helps a bad idle. Very odd. Did I mention that I find this to be very odd?
I agree with you mostly except for this part. The car I had with the bad mains ran perfect from off idle to WOT with no noticeable issue. The only time it reared it's ugly head was when the engine was idling. If you look at his log labeled "Idle bad until fan turns on" even at the start of the log before the idle goes to crap you can see the O2's are not stable...kind of erratic but not going lean enough to cause an idle problem. The O2's then go to crap. The engine with the bad mains did the exact same thing. When we first started the motor it seemed to idle ok. The longer it ran the worse it got. I know this is really a bizarre problem. I have never encountered the exact problem the OP is having but do you agree it looks like an ignition misfire. I'm not sure what else could cause the O2's to get that erratic when the fueling looks good.
I don,t know what to think about that.
