Have something strange happening. I have my TPS set to 0.52 volts, using my scanner. Recently changed the ECM, used a rebuilt AC Delco unit. Went for a ride today and car likes to stay at 35-40 MPH. Have to lightly apply brakes to get it down to a lower speed. Base idle is set at 650 rpm. Engine has been modified, vortec heads, GM LT4 cam kit, SLP runners and 24 lb injectors. I had the prom retuned for the mods. I checked the TPS setting , using the scanner, and the reading is 0.52 volts, engine off and 0.60 volts engine running. I dont recall this type of voltage change before changing the ECM. Anyone seen this before?

 

With the engine idling or the key forward, the TPS voltage should be consistent.
You want a minimum of 0.54 volts (the factory setting).

It sounds like something isn't right... just my 2 cents.

Hope this helps!

 

Yesterday, I checked battery voltage ( after leaving car hooked up to a battery tender for 12 hours) and it was 12.2 volts. TPS was at 0.52. Started car , TPS jumped up to 0.56 and battery voltage was 14.4 volts. I readjusted the TPS ( engine off) to 0.50, started the car and it jumps to 0.54. So TPS is within limits, but I dont recall this happening before I replaced the ECM. When I get some time, I will check and see what the 5 volt reference voltage looks like. Since the range for the TPS is +/- 0.08 volts, I am still in the operating range, just dont recall this problem before.