Katman

Hello All!

Does anyone have a picture of, or know what the IAT sensor looks like, of the IAT sensor that goes with the MAC 11 ecu?

I've replaced the MAC 02 ECU and harness on my urq with the whole MAC 11 ECU and harness. What the heck! Previous owner had already swapped the motor to MC1..

Thing is, the old MAC 02 IAT sensor was a thin tiny thing suspended between two standoffs. Really delicate looking.

The IAT sensor that came with my MAC 11 harness looks a lot more substantial.
I didn't think anything of it at the time. Must have been an 'improved' version, right?

So today, I'm doing some troubleshooting to find my 'miss under boost', and wondering if it was associated with the intake temperature. I was testing to see how much the resistance of the intake air sensor changed in relation to temperature. Funny thing..

At room temp, its about 593 ohms. At boiling water temp it's 580 ohms, and at melting ice water temp, it's about 599 ohms. Not much change happening! (All measurements with the ECU disconnected)

Hmmm... Funny how the active part of the sensor look a lot like a resistor, soldered in across the standoffs!

I'm thinking that in a past life, the air sensor may have got broken, and someone substituted a fixed resistor.

So that's why I'd like an idea of what the MAC 11 air temp sensor (the actual part that measures the air temp) looks like.

Resistor, or skinny tiny piece of sensor wire?

Thanks!

MarkPan

0c should be about 450ohm,
100c should be about 625ohm

http://www.sjmautotechnik.com/trouble_shooting/10vcoolt.html#airt

Katman

Thanks for the link. Good picture and resistance graph.

Actually, I was expecting a lot more of a resistance change that I got! More like that of a water temp sensor. Maybe it is ok..

Weird that it's a positive temp coefficient too.

At least it seems that my sensor looks the same, except for the fact that I accidently stepped on it..

Further investigation required!