How to wire GM IAT to e30 AFM plug?

[CorvallisBMW]

All questions MS2 v3.4 related:

I've been searching but can't seem to find the answer. How do you wire the GM IAT to the stock AFM wiring? Which wires to to which wires?

Also is there anything that needs to be done wiring wise when switching to an e36 variable TPS? Or just plug in and go?

[CorvallisBMW]

Also what's the deal with the e36 variable TPS? I thought it was a direct plug-n-play? The shaft receiver and the screw taps are totally different, it definitely will not bolt up.

[ak-]

2 wires on the IAT.
4 wires on the AFM connector. (The AFM plug has 5 slots but one of them is empty).

Splice the IAT wires to AFM wire #1 & #4 to wire from the connector.
It shouldn't matter which IAT wire goes to which AFM wire.




For your TPS, shit, the e36 vTPS 100% slots it's shaft into the receiver of the M20 so whoever recommended the e36 vTPS for your M30 could of been mistaken that you were M20 Turbo (I'm sorry if it was me).

Since MS requires a variable throttle position sensor, one will need to be purchased. For m30 engines, the easiest solution is to use the 6 pin TPS from an automatic e32/e34. Make sure you also source the plug with some wire to solder to.

[CorvallisBMW]

OK, AFM/IAT makes sense.

I was under the impression that m20 and m30 TPS' were identical... apparently I am wrong. How "necessary" is a variable TPS? Sounds like it's just an option for easier tuning?

[ak-]

Your other option is to do it MAP based and that sucks because it lags.
MAP based is vacuum.

I had to drive this way for a couple months because I was having TPS calibration issues (forgot my WOT wire was cut from installing Miller's crap) and I hated it. Feels like your driving a car with an AFM again - snap throttle, 2 second delay, THEN the engine reacts.

[CorvallisBMW]

So vTPS is pretty important it sounds like. Ok, off to the yards to find a round pigtail.

[Nitro Nick]

It seems like you have the IAT sensor figured out. Simple terms the two outer wires are used for that.

You can check my thread for the TPS issue I had the same problem but you can use the existing plug from the stock wiring you just have to cross two wires. The other thing with using the M50 TPS is that you need an adapter because it is slimmer than the M20 TPS. Source one on the forum here or one of the other E30 forums. They are pretty cheap but necessary. Let me know if you have any other questions I literally just did both of these.

[nando]

Also what's the deal with the e36 variable TPS? I thought it was a direct plug-n-play? The shaft receiver and the screw taps are totally different, it definitely will not bolt up.

the sensor on the right isn't the right one at all. I don't even know what that's from, but it's not an E36.

[CorvallisBMW]

It seems like you have the IAT sensor figured out. Simple terms the two outer wires are used for that.

You can check my thread for the TPS issue I had the same problem but you can use the existing plug from the stock wiring you just have to cross two wires. The other thing with using the M50 TPS is that you need an adapter because it is slimmer than the M20 TPS. Source one on the forum here or one of the other E30 forums. They are pretty cheap but necessary. Let me know if you have any other questions I literally just did both of these.

You mean this thread? http://www.r3vlimited.com/board/showthread.php?t=378973

the sensor on the right isn't the right one at all. I don't even know what that's from, but it's not an E36.

I pulled 2 identical TPSs off m50tu-powered 325i e36s. This is one of them. If it's incorrect, then what does an e36 TPS look like?

[ak-]

Now that I think about it, my vTPS from the E36 doesn't look like that either.
The snap connector is centered on my unit like this:

[nando]

You mean this thread? http://www.r3vlimited.com/board/showthread.php?t=378973



I pulled 2 identical TPSs off m50tu-powered 325i e36s. This is one of them. If it's incorrect, then what does an e36 TPS look like?

I think you got the TPS off the ASC unit, rather than off the throttle.

[CorvallisBMW]

Now that I think about it, my vTPS from the E36 doesn't look like that either.
The snap connector is centered on my unit like this:

hmmmm that definitely won't fit on the m30 TB, the bolt holes are much too close together. Looks I may have to use an M30 AT TPS

[nando]

It does. you just need an adapter plate.

One guy got smart and used the old TPS, he ground it down until it was the right thickness and screwed the E36 TPS into it.

[Nitro Nick]

yup thats the right thread for the wiring. Now you just need the right TPS and adapter