TPS connector voltage??

[jprocket]

Long story short.... the engine swap I'm using in my 2002 came from a 1990 325ic. It ran well with a chip for 17# injectors (as I waited for the bigger injectors) then I switched out injectors to green tops and now it idles poorly after reaching operating temp. It now has a new ICV, fuel filter/pump, working TPS and no vacuum leaks. Before I go through changing a bunch of parts and switching back to my original injectors, I did a bit of electrical testing and found the TPS connector has 11.6v - key on and 2.7v key off. I swapped out the DME with a known good one and I'm getting the same key on/off voltage.

QUESTIONS

1. Should the voltage be ~5v?
2. Could both DMEs be bad?
3. Did the injectors damage the DME and cause this voltage change?
4. Should the TPS connector even have voltage with key off?
I'll go back and switch to my original injectors and see what happens. Kinda bummed cause my research showed that this injector change shouldn't cause any issues.

[Chris Spiegl]

"**** Here’s how you test the switch. First make sure that the battery disconnected. This is crucial. If you fail to do this, you could send a spike through the system and fry the ECU. Now open the hood, and look under the throttle body. You will see a small black box with a plug going into the side. Press and hold down the metal clip on the outside of the switch and pull it off. You will now see three terminals on the inside of the switch. These are the terminals that go to the idle control valve. What you need to do is get a hold of a multi-meter, set it to check for continuity. It will be a tight squeeze getting the terminals under the intake air boot, but it is possible. Now, check for continuity between the left outside terminal and the center terminal. While holding the test probes in place, slowly open the throttle. Just after opening, there should be no continuity. Now test the outside right terminal and the center terminal, and slowly open the throttle to the full position. As you come close to full throttle, you should see continuity return. I you fail to see any continuity return, try loosening the two screws under the switch and rotate it until you have continuity when the throttle is fully closed. If you still fail to see continuity, the switch is bad and must replaced."

[jprocket]

Thanks for the post back, but I adjusted the TPS correctly but it still idles poorly. That lead me to checking voltage cause it only idles bad after reaching operating temperature. Can you someone help me out by pulling the connector from the TPS and check key on/off voltages and get back to me?

[packratbimmer]

There is some chat here and there about the green pops. Some say they are 17 or 17.5 at 3.5 bar and lower at 3.0 bar. I would check with your chip provider about the issue. There are 17# injectors that were tested at 3.0 bar.

[jprocket]

I'll search and read up on the green top thread. Thx

Can anyone give me feedback on key on/off voltages at the TPS connector? I want to know if I have a bad DME.

[wilholl]

I'll search and read up on the green top thread. Thx

Can anyone give me feedback on key on/off voltages at the TPS connector? I want to know if I have a bad DME.

The voltage at the TPS should be battery (~12V) according to The Bentley manual.

[jprocket]

Thanks wilholl!!! Now I guess I'll swap out the injectors for the original ones and see what happens.