pcm temp reads 253 degrees on cold engine 97 f150 4.2 engine 5v supply and signal ck good have cold start problem with flooding engine run fine when hot temp should make lean problem but remove plugs and soak with fuel.no codes fuel presser ck ok.reflash pcm and no change any one had this problem.gauge in dash reads fine just wonderabout high temp reading.

 

Did you check the signal at the sensor or at the computer? The signal wire may be grounded. There should be a separate sensor for the gauge and the computer. I think if the computer thinks the engine is that hot it adds more fuel to prevent preignition or detonation.

 

sean thanks for the reply used a jumper wire from temp to tps signal wire which ties in together and still no change i didnt think about the destortion your right .im going to try a new pcm today if you think of any thing else let me know thanks let you know what new pcm does.

 

You say the temperature sensor and TPS are hooked together? That isn't the signal wire. That wire is the power wire. Many sensors get power from the computer through the same wire and give varying degrees of ground as the signal. You need to check the signal wire for ground at the sensor and at the computer. I forget which way the sensor works, either full ground is hot and no ground is cold or full ground is cold and no ground is hot with varying amounts of ground being the middle readings. So if at the sensor you get full or no ground and running the truck doesn't change the amount of ground then the sensor is bad. If that checks okay then check at the computer, where the sensor ground goes in. Full ground with no change would mean the wire is grounded out, and no ground with no change would mean the wire is broken.

 

changed the ECM all is good now.Thanks alot for all the help.