MAF Temperature Sensor appears to be dead

[Three Dee]

With the onset of cold temperature my i-spec '86 325 (1989 325i engine) has been giving me issues. About two weeks ago, on the way to work (of course) it began to misfire and then quit running just before I got to a parking place. After work it would not start and I had to tow it home. Today I was finally able to spend some time doing some diagnostics, and discovered on checking the MAF that there is continuity across the connectors to the temperature sensor. In short, it looks like the temperature sensor is dead.

Will this cause a no start problem?

The car has had cold start issues for awhile, in that it has to crank a few times before starting and it idles rough when cold and sometimes a bit too fast when warm. This led me to think the cheap Chinese-made IAC was giving me fits, but replacing it made no difference on the no-start issue.

I already know nobody carries a replacement temperature sensor for the air flow meter, and this probably means I will have to replace the entire AFM. I just want to be sure it is why the car won't start before I drop the bucks. I can't afford to throw money at it.

For the record, the IAC is brand new and TPS is only about a year old and test within specs. The coil is also within specs and the spark plug wires are less than three years old. Static fuel pressure is a solid 40 psi, and while I haven't measured it, flow seems to be excellent. The O2 sensor may be dying, but I'm not sure. I have been wondering for awhile if the AFM has been dying a slow death. At somewhere in the neighborhood of 300,000 miles, that is a possibility.

[Bimmerknut]

Wrong group friend. E21 group doesn't have MAF sensors. Good luck!

[Three Dee]

Yeah, I just discovered I was in the wrong group. I don't know how I did that.

[Somjuan]

Welcome to the wrong forum! (You might find help here anyway).

First question, does it still turn over? Follow up, have you checked the fuses?

Have you tested for spark? Honestly my first jump would to be to check the distributor cap and rotor...which I'm pretty sure you still have in an '89, unless you moved to a different setup. When my distributor cap got dirty from a failed seal I had the same symptoms. I mainly have worked on the generations before and after yours though, so take it with a grain of salt here.

As far as the AFM causing a no-start, I don't think it would by itself just by a cursory running through the ETM, but you should check for resistance across pins 24 and 25 on the ECU (Or 26 and 44 on the sensor itself). Should be around 3000 ohms of resistance when cold. Infinite resistance implies it's being flooded and the sensor is bad/disconnected, below 3000 means it's too lean. After that if everything checks out go for broke and check for vacuum leaks.

I'd check the crank position too while I was at it. Run back to the basics, see if it runs on starting fluid, has a good spark at all six, and is getting air. My money is on something simple being fouled. M20s like to keep kicking.