zetec wiring help

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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focus dan
MegaSquirt Newbie
Posts: 1
Joined: Sat Jan 01, 2011 10:03 am

zetec wiring help

Post by focus dan »

i cant find a wiring diagram for my car (1.8 mk1 focus) does anyone know were i can get one?

also im fitting k1 gsxr 1000 throtle bodies to it and cant find a good diagram for the TPS wiering?

thanks to anyone that can help
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: zetec wiring help

Post by Matt Cramer »

It's not a whole wiring diagram, but we have some Zetec hints here:

http://www.DIYAutoTune.com/tech_article ... _zetec.htm

The easiest way to check a TPS is to unplug it and put an ohmmeter on its pins. Observe the resistance as the throttle opens and closes. Each pair of pins will behave differently:

The resistance between the VREF and ground pins will remain constant.
The resistance between the ground and signal pins will be low with the throttle closed and high with the throttle wide open.
The resistance between the VREF and signal pins will be high with the throttle closed and low with the throttle wide open.

If your sensor behaves like this, it will be pretty straightforward to connect it to Megasquirt.

If the resistance jumps from infinite (or near infinite) to near zero, you have a switch type throttle position sensor, or possibly a seriously defective potentiometer type TPS. These do not provide very much information that Megasquirt needs, as it can tell if you are at idle or full throttle by the MAP sensor information. You can still use MAP based acceleration enrichment and ground the TPS signal pin through a resistor.
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