Re: 2003 dodge Dakota with 4.7, 2wheel dr.

so I was driving in pouring down rain the other day. The truck idled up to 2000 rpm on the 50 mph hiway, and downshifted out of overdrive. It would not go under 2000 rpm. Pulled off on a side road, took a lot of braking and put it in nuetral, came to a stop and shut it down. Tried restarting, same thing, but the third time was a charm and it ran fine for another 10 min into town. Got back in to it about half hour later, started right up and ran fine for 10 min. In small town city driving. Then just died. No coughing, no sputtering, just like someone turned the key off. Was stuck there for about half an hour. Tried restarting a few times every 10 min. Turned over great, but nothing. Finally on the third try it started, ran ok, and I made it the 20 miles home with out any trouble. Weird thing was, when it was shut down, the left blinker/hazard lights wouldn’t work. But once it started back up, they worked fine.

I got this message along with a purge issue message. Put a new purge valve in there next to the battery and a new TPS in. The purge valve did the trick there, but not the TPS.
at first, after removing the neg. Battery terminal, then holding key in start position for 30 sec, then reconnected and relearned the pedal movement. All was fine and reset. Drove for about 10 mi And it acted up again. Wouldn’t idle under 2000 rpm, and it would come out of overdrive. Just like before.

reset pcm again, but neither that or my scanner would reset the code. The check engine light would blink 5 times, and the scanner says sent successfully, but it wouldn’t reset.

so checked voltage again. I get 5 v in on #1, but no matter if the plug is in or not, I get 4.99 volts out. Ground is good.

So I’m stumped. Why am I getting almost 5 v on the sensor #2 wire with no tps plugged in? Shouldnt it read 0. Can it back feed from somewhere, possibly the pcm?

it now runs fairly good for at least 20 mi. That is as far as I dare go. Idles just a bit high, maybe 800-900 rpm. Takes 1/2 sec longer to catch when starting. Otherwise has power, etc.

Looking for any help.

On second TPS.

thanks

Gary

 

Has to be a short in the sensor wiring somewhere. The orange/dk blue wire should NOT see voltage with the sensor unplugged.

 

Yes. But what are the most likely candidates? What about the pcm?

 

Unplug the connector at the PCM, then measure resistance between the two wires. Should be infinite.....

 

Depends on what kind of meter you are using. An "input" circuit typically has some diodes and resistors on it to protect from various electromagnetic flux. In theory, it should read low rather than high, but a "low impedance" meter could reflect that; Most meters are "high impedance" meters though.

What does the middle wire show for voltage with the TPS plugged in? Should sweep from 0.7-1.5 volts through to 3.5-4.2 volts or so as the throttle moves.

 

After replacing the first TPS I got with a different one, she runs pretty good. No codes. The only issue I have is I idles just a bit high. More like 800 instead of 600. It wants to do almost 5 mph on a level street all by itself. When on the highway, takes a LONG time to slow down. Just a little bit of jerk when putting it in gear,but barely noticeable.

i have .57 volts on the sender wire. If I remove the TPS, it goes down to .37 volts and the idle goes back down to 600 again where it should be. I guess I ll try resetting everything again

 

Reset the PCM, and let it relearn the zero values of the various sensors. Basically, disconnect the battery, turn on the headlights, turn off the headlights, hook the battery back up, turn ignition to On, (don't touch anything) count to ten, then start the engine. PCM should figger out idle pretty quick.

 

Thanks. It pretty much worked.
i did as you said, but also held the ignition key on start for 30 sec. Like I did before, but this time I let it idle for 5 min. Before I did anything. Idled back where I wanted it to be….until I turned on the AC. Then it goes back up a bit. It did want to decelerate a bit better though. It wasn’t too far off before. But this is better, especially without the AC on. But here in Hawaii this PNW guy has the AC on almost every time I drive it.

 

The computer will indeed bump idle when the a/c is running. The compressor puts an additional load on the engine, and without that little bump, it would likely stall.