And this was with the fan on? Did the idle drop at all? If the headlights were on, which creates load on the engine and the fan or AC on full and the BAC plug pulled the idle should at least drop to around 500 rpm. It might not sound like it should die but at least drop in rpm some. If it doesn't then perhaps the BAC is in the stuck open position. Again, place voltage to one terminal from the battery and a ground to the other terminal and the BAC will click. Do this repeatedly to see for one if it clicks or not and perhaps unstick the solenoid just in case it is stuck. And you do this w/the engine off.

 

It's still a clutch fan, and it's hard to tell if it was engaged. I'm getting it up to operating temp, not trying to actively overheat it. I don't know how easily I could even do that around here. According to Clokker, his e-fan only comes on about three months out of the year. I didn't turn the headlights on either. Adding load was not on the agenda to my mind. What does this device do exactly? Maybe it's been working all along, I just didn't test it well. The resistance spec could require some state I didn't induce out of ignorance.

 

Not the e-fan but the fan in the cabin which blows air out of the vents. That one. The BAC prevents load from dropping the rpm to an idle speed which is too low so placing load on the engine via the headlights, AC fan on high will sufficiently place load on the engine. And I really don't want to have to repeat the "get the BAC to click" trick any more.

 

About that clicking... Does it matter which terminal is positive and which is negative? Could I just jump it straight off the battery?

 

Just as long as one terminal gets the positive and the other gets the negative is all that matters. Secondly, yes, you can use the battery directly.

 

I've got about an hour between one gig and the next today. I just did the click test, and it passed. Moving on to trying to suss out the MAF temp sensor.

 

I pulled the MAF, opened it up, and dug a little deeper into the temp sensor there. What I'm getting is an initial flash of the correct reading, then it goes to a non-conductive state. It showed just under 2Ω, which makes sense because that's what it should read at 68°F, and it was slightly cooler than that. Immediately after it flashes the correct reading though, it goes to no conductivity. I can repeatedly tap connection on the leads of the sensor itself inside the MAF, and each time it reads slightly lower than the last. It's like it doesn't want the current I'm sending it, and it causes it to heat up. Lower readings = hotter temps. So either it's intended to see a lower current than my multimeter is producing, or the temp part itself is shot. It looks like I could probably replace just the temperature sensor part if I could get my hands on a known good one where the rest of the MAF is bad somehow. Might even make for a good writeup. This finding jives with the ECU reading. The ECU is seeing a lower voltage than it wants, which translates to a higher resistance, which indicates a much colder temperature than it's really seeing (and probably beyond what it's capable of compensating for). I'm not sure what the ECU does with that information, but I'd be willing to bet it enriches the mixture to compensate. I could be wrong. Surely someone knows better than I do on that one and can chime in.

 

Sure you could find previous posts on the issue. Often its best to do a search immediately followed by a member name who has much experience with these cars such as Hailers and so and so on.