Just fixed my plenum. Started her up, ran funky for a while but its getting better. I was told that the pcm had to relearn. Anyways I noticed that the temp gauge isn't changing at all just sits at 130. What would cause this? I did put in a new 180 tstat. Im really concerned because when I got home from work I smelled something weird so I checked my motor and saw a little bit of smoke coming from the TB. Any ides?

 

early years had 2 temp sensors in the intake manifold, later years had 1. i think your 99 has only 1, and its on the front of the intake.

is it plugged in ? unplug/replug to check.
if thats not it, just replace it. its not very expensive and the old one likely got screwed up during the repair.

if the temp never gets above 160, i'd expect you to be throwing a code P1281.

reset PCM by disconnecting negative battery cable and turning on headlights for 30 seconds. engine should run pretty good following this reset, not funky.

need more info on smoke from TB..... might be oil burning off, maybe from PCV?

 

turn on the headlights? really? i have never done that, just disconnected the battery for like 5-10 min. but that was on my VW, not the dodge.

 

The idea of turning on the headlights while the battery is disconnected is to put a load on the electrical system, to discharge the various energy reserves some of the electronics have. This makes sure your computer is indeed reset. Is it necessary? Probably not. But, its just a bit of added insurance.

 

if you didn't plug the coolant temp sensor in, it should have thrown a code. When you replace it, be very careful you don't over torque the new one or it'll sheer clean off in the manifold, ask me how I know that one.

 

Its definitely plugged in, but could it be backwards? When I start the truck it goes up to 140 but I can watch it fall down to 130 in less than a minute. Will recheck everything and reset the PCM. The truck was running FUNKY when it was idling, it had a really low idle and would occasionally stall out with very little throttle. This problem has disappeared within a day or so. The smoke seems to be coming out of the TB not sure how to describe it, seemed like maybe it was just running to hot or maybe like it was burning oil. Could this be caused by a bad water pump? Mine hasnt been replaced and it wouldnt surprise me if it died during the fix.

 

i had the same problem when i did my plenum. i brought a new coolant temp sender from advance auto and it was bad when i first started the truck but the check engine light was on and the gauge didnt move one bit

 

its the responsibility of the thermostat to open and close properly to maintain internal engine temperature of 180 or 195. if your temp gauge is registering anything other than 0, and the temp is low (130-160), then you have a bad t-stat, or maybe its in backwards. (sorry, had to say it - brass colored temp sensor goes down, and dome side is up).

temp sensor electrical connector is keyed and can't be plugged in backwards.

you've got me stumped on the smoke from TB.

bad water pumps leak or overheat. not overcool.

 

Tstat is in correctly, triple checked that due to a little ocd. Sounds more like the temp sensor is bad, there was a lot of crap that I had to clean out sounds like that may have messed up the sensor. You said that the waterpump failing would cause it to overheat, would that cause the motor to smoke? Also would the temp gauge still get hotter even if there isnt any coolant running through it, if my tstat or waterpump are failling will it still have an accurate reading?

 

If you are seeing a bit of vapor come out of the TB when you shut it down, I really don't think it is anything to worry about. (if its just a bit.....) When the engine stops, there may still be some air/fuel mixture in a cylinder, and if the valves aren't completely closed, it will tend to escape.

The temp sensor will still read temps, even if there is NO coolant in the engine. It won't exactly be accurate...... but hey.

Water pump failing will cause the engine to run hot. All it does is circulate the coolant. If it isn't doing it's job, you will find out quickly.

If the engine isn't getting up to temp, or, what you think temp should be. Stick a thermometer in the radiator, and see what coolant temp is, when the thermo opens. (you will see the flow, should be fairly obvious) Take it from there.