Tom in Austin

Happy New Year all!

My intake refresh is creeping along, and I've noticed something interesting ... Porsche used identical connectors for the throttle position switch and MAF. I didn't mark them when I took everything apart ... only difference I can see is one wire is a little longer coming out of the harness than the other, by maybe an inch or two.

Is that a reliable indication of which goes where?

davek9

Hello Tom, are you certain you have only two unused connectors?
The TPS is a three wire switch and the connector is small like a Temp Sensor, the MAF has several connections and has a long connector, unless it is a different TPS on a GTS.
Usually the wires will lie as they came off as the harness gets hardened w/time.

Post a PIC please.

ROG100

Not the same

SeanR

ISV and TPS are similar under the intake. TPS is black and the ISV will be tan/white. (should be anyway)

Tom in Austin

Will post a pic later ... on my car, MAF and TPS are identical - black six-position connectors with 5 pins present on each ...

I think S4s might have had three-pin TPS connections.

Alan

They are the same connector on a '94/'95 GTS Auto since the TPS has extra functions for the dynamic kickdown.

Alan

SeanR

Oh yea, forgot about that......duh.

Tom in Austin

Thanks Alan, that explains it ... now, following the length of the cable theory ... in the MAF installed position, is it's connector on the driver or passenger side? If it's on the pass side, then the MAF connector is likely the longer of the two since it has to go under and around the air guide elbow, whereas the TPS is on the driver's side (and the two wires split out from the harness together more to the driver's side).

Mike Frye

I'd plug one into the MAF and then meter for MAF resistance at the LH harness. Not sure which terminals, but it's part of the LH test procedure. On the '85, stock resistance is about 382 ohms. If it's open before plugging and then MAF resistance after, you've got it. If not, try the other plug.

John Speake

The MAF connector only has 5 of the 6 pins fitted with wires.

Tom in Austin

Tell me what you think about this ... I assembled the MAF and throttle body and set them into approx installed position. One of the wires is about 10 mm longer than the other (measured from where they leave the harness), and has a sharp bend just before the connector. It appears to me that this longer one with the sharp bend most likely goes to the MAF as shown below. The connection to the TPS is 'straighter' and doesn't have, or apparently, need a noticeable bend.

Do I have the MAF in the correct orientation in this photo (taken leaning over the left fender)? If so, it seems very likely the longer wire with the sharp bend is indeed the one to the MAF, and I won't open it up to see if there are five wires inside.

Thoughts?

John Speake

Sorry, my bad, both only have 5 wires to the connector. But check out pin 2 of each one.

With ignition off, measure pin 2 of each one, the TPS connector with be a short to ground (chassis)

With ignition on (LH plugged in) Pin 2 MAF connector will have 12v.

Looking at the connector on the MAF you will see the pin numbers shown .

John Speake

Sorry, my bad, both only have 5 wires to the connector. But check out pin 2 of each one.

With ignition off, measure pin 2 of each one, the TPS connector with be a short to ground (chassis)

With ignition on (LH plugged in) Pin 2 MAF connector will have 12v.

Looking at the connector on the MAF you will see the pin numbers shown .

SeanR

Tom, that looks correct. Due to the angle, they pretty much form themselves with age. At least your boot isn't split at the bend.