Have a 2002 Caravan with the 3.3 V6 that runs rough until it warms up. There is no CEL. Once it warms up its OK.

It has new plugs, wires, and fuel rail. I am thinking a temp sensor might not be working right and hope it is not the ECM.

When I look at the Haynes book for the 2003 thru 2005 Caravan, I see 5 sensors that measure temp – Air Temp Sensor (IAT) – Battery Temp Sensor- Engine Temp Sensor (ETS) – Transmission Temp Sensor – and Ambient Temp Sensor.

I don’t know if the 2002 has all the same sensors but think that the IAT, ETS, and Trans Sensor would be the ones to look at.

Is the 2002 the same as the 2003/05?
Is the ETS in the same place on the 3.3 as the 3.8?
Does anyone have a suggestion as to how to test the sensors?
Am I overlooking something?

PS I have a scanner on the way but since there is no CEL I will most likely have to figure out which measuring blocks I need to look at for the signals from the various sensors. Does anyone know where I can get a list of the measuring blocks for the various dodge caravans?

 

'02 and '03 should basically be the same. Coolant temp and intake air temp are the 2 to look at. Check your fuel pressure too. The vehicle uses alot more fuel cold than warm. If the pressure is low, it will starve for fuel. Also check the EGR valve if it has one. EGR on a cold engine is way no good.

 

Would any these trip a CEL?

 

Only if they are open or shorted or are so out of whack that they don't make sense. If they just rear wrong, no code. Computor are pretty trusting.

 

We are about to find out what is wrong. My daughter could not get it started today and we are having it towed 93 miles to the guy that sold it to us to see if he can fix it. Thank God for AAA Plus!

 

update -- we found that some idiot pored something into the gas tank. After $800 to diagnose the problem, drain the tank, replace O2 sensors, the mass aflow sensor, etc. it began running great!

Then we began hearing a knock in the motor. The next step was to replace the motor. We found one with only 45K on it so we lucked out (the other one had over 120K)

We lucked out again when the insurance company said that they would cover all the costs because it was vandalism. They said that whatever was put in the tank did not compress and ruined the bearings.

I was not going to argue!! But we did spend another $800 getting the alignment correct, flushing the transmisson, and changing a balky starter.