Hi all, I have some issues with a new to me 97’ 117k TJ Sport 4.0L
I’ll try to keep it short but I have a lot of data:
Jeep was losing power and wouldn’t go passed 35MPH after warm start. Hooked up my scanner and saw ETS at 400F , after driving. Dash gauge for engine temp is at the middle bar. I know they’re different sensors so I got a new Delphi ETS at NAPA no change. Looked up service manual and got MOPAR sensor one, same. Checked all 3 ETS against a resistance chart and they all check out good. Next day started checking other sensors on PCM and had some wild data. IAT at 200F and ECT at 200F, I hadn’t even started the engine since day before. Went to AllData and bought one month sub for the jeep to get the 5V diagram. Unplugged everything on the 5v bus. Cam, crank, fuel sender, both 02, VSS, MAP, batt temp, TPS, ETS, everything the diagrams showed had 5V.
All had 5V, all had ground enough to light a test light. Tried just plugging in just new ETS, same 200F without it being run.
Other results: TPS reads correct % according to scanner. As did VSS, I assume crank and cam are fine since it cranks and runs fine till warm and restart. Don’t know what MAP should be at when off so can’t say if that’s ok. Fuel tank is full and sender says 2.75 gallons. I don’t remember Bat temp but it was way off too.
The big question are: is this sufficient testing to say the ECU is toast ? does anybody have more ideas on tests to run? Or do I take it to a pro diagnostician?
Thanks for any help.
I’ll try to keep it short but I have a lot of data:
Jeep was losing power and wouldn’t go passed 35MPH after warm start. Hooked up my scanner and saw ETS at 400F , after driving. Dash gauge for engine temp is at the middle bar. I know they’re different sensors so I got a new Delphi ETS at NAPA no change. Looked up service manual and got MOPAR sensor one, same. Checked all 3 ETS against a resistance chart and they all check out good. Next day started checking other sensors on PCM and had some wild data. IAT at 200F and ECT at 200F, I hadn’t even started the engine since day before. Went to AllData and bought one month sub for the jeep to get the 5V diagram. Unplugged everything on the 5v bus. Cam, crank, fuel sender, both 02, VSS, MAP, batt temp, TPS, ETS, everything the diagrams showed had 5V.
All had 5V, all had ground enough to light a test light. Tried just plugging in just new ETS, same 200F without it being run.
Other results: TPS reads correct % according to scanner. As did VSS, I assume crank and cam are fine since it cranks and runs fine till warm and restart. Don’t know what MAP should be at when off so can’t say if that’s ok. Fuel tank is full and sender says 2.75 gallons. I don’t remember Bat temp but it was way off too.
The big question are: is this sufficient testing to say the ECU is toast ? does anybody have more ideas on tests to run? Or do I take it to a pro diagnostician?
Thanks for any help.
