What Am I Missing on my TPS?, It couldn't have been important, right? Options

[BeatNavy]

Ok, so I was doing some intake work this weekend on my stock 72 D-Jet 1.7L trying to eliminate vacuum leaks, and I took the throttle body out to clean and inspect the TPS board as a candidate for replacement. While I was gently cleaning the traces I notice that one of the traces had broken and separated from the board. Because it was interfering with the movement of the TPS I just removed it. As shown in the picture below (where the red arrow points), I now no longer have that inner most trace.

Anyway, I put the TPS back in the car and it ran fine all day yesterday and this morning. This afternoon after work I started the car up and while the engine was cold I had ZERO throttle response or power and could not put the car in gear. Finally after pumping the accelerator I managed to limp off the busy commuter road and to a parking lot. After warming up for a few minutes, everything ran fine and I drove home.

Not sure if my experience this afternoon is related to that TPS, and in any event I'm going to order a new one, but WHAT am I missing with that inner most trace gone?

TIA

[davesprinkle]

That inner-most trace is your idle-switch circuit. Its absence probably didn't cause the issue you describe.

[BeatNavy]

That inner-most trace is your idle-switch circuit. Its absence probably didn't cause the issue you describe.

Ahhh...ok. But could this be related to the original problem I was trying to solve? I get popping during overrun. Its most noticeable when the engine is cold but it also happens when warm. From Paul Anders' site:

"The OS circuit prevents injection during over-run to reduce emissions. When the throttle is fully closed, the idle switch is activated, grounding terminal "B" in the over-run shutoff circuit. This ground is one of the inputs to the base of T807, along with the output of a low-pass filter circuit that uses the basic injection pulse from the PL as an input. When the engine speed is above a threshold level (>2000 rpm?) and the throttle is fully closed, T807 is turned off, forcing T301 on, which inhibits injection."

I know some ECU's don't have that circuit (not sure about mine). I have been chasing small vacuum leaks and a lean condition as well as looking for exhaust leaks. One or more of those may still be the issue, but this sounds interesting (or maybe I'm just grasping at this point). I'd like to know if anyone has an answer. In the meantime, off to buy a new TPS...

[BeatNavy]

That inner-most trace is your idle-switch circuit. Its absence probably didn't cause the issue you describe.

Ahhh...ok. But could this be related to the original problem I was trying to solve? I get popping during overrun. Its most noticeable when the engine is cold but it also happens when warm. From Paul Anders' site:

"The OS circuit prevents injection during over-run to reduce emissions. When the throttle is fully closed, the idle switch is activated, grounding terminal "B" in the over-run shutoff circuit. This ground is one of the inputs to the base of T807, along with the output of a low-pass filter circuit that uses the basic injection pulse from the PL as an input. When the engine speed is above a threshold level (>2000 rpm?) and the throttle is fully closed, T807 is turned off, forcing T301 on, which inhibits injection."

I know some ECU's don't have that circuit (not sure about mine). I have been chasing small vacuum leaks and a lean condition as well as looking for exhaust leaks. One or more of those may still be the issue, but this sounds interesting (or maybe I'm just grasping at this point). I'd like to know if anyone has an answer. In the meantime, off to buy a new TPS...

So I went back to find the member who recreated these and realized it was you (duh). Do you still make and sell these for the 1.7? (IMG:style_emoticons/default/smile.gif)