Can't Find TPS
 

I have a 96' 1.8 and I finally got my Megasquirt hooked up but I am having a bit of trouble. It is a Megasquirt 1 btw. Everything goes smoothly until I try to get my tps, then both open and closed always read the same (like 255 I think) Is there something I need to hook up to get this on the 1.8? Thanks!

The TPS is pretty straightforward, however there are a grand total of three wires that need to be connected within the factory ECU harness for it to work.

The first, ground, is obvious. And I'm guessing you already have this crossed over or else your CLT sensor wouldn't be working. The ground in question is a B/L wire at pin 3O of the ECU harness. Note that this wire isn't a ground itself, rather it's a wire that needs to be connected to ground. Simplest thing is to connect it to one of the many ground pins of the MS's connector.


Next, and equally obvious, is the TPS signal. This is the R/B wire at ECU position 3F, which goes to the "TPS" pin of the MS (pin 22.)


The one I suspect you may be missing is VREF. This is a supply of +5 which is sent out to the TPS, to give it something to work with in order to produce a signal. It's light green/white wire at position 3I of the ECU harness, and it wants to be connected to pin 26 of the MS.

Can I have the ground hooked to a ground point on my car instead of going to the harness? I accidentally broke the ground pin off. It was pin 30, I know there are other grounds but my wires are too short to reach them.

Thanks!

Well, as I said, the B/L wire coming up into position 3O of the factory ECU connector needs to be connected to ground. If it isn't then some of the analog sensors will not work properly. You can ground that wire to whatever point is most convenient- ideally it will be connected to the ECU's own ground at a point near the ECU.