[ktvaughan]

This is a '02 Dodge Grand Caravan Sport with 3.3L V6 and 92k miles.
Recently replaced trannie filter (Wix) and fluid (ATF+4), belt with tensioner and idler pulley, alternator and water pump, idle air control motor and spark plugs/wires.
Engine runs strong but has started to stall at startup when cold/wet. Starts right up but there is something happening when it is cold/wet outside.
I have replaced the throttle position sensor once already. Is that a wear item?
Any other candidates?
Recent tune-up with spark plugs/wires and IAS motor was because it was stumbling at idle.

 

[chuzz]

Have you tried cleaning the throttle body? That may help, but it sounds more like an electrical problem to me. Maybe a faulty EGR transducer?

 

[ktvaughan]

I did clean the throttle body.
How do I check the EGR transducer?
This engine doesn't have a typical EGR valve above the alternator.

I also noticed that it seems to stumble when the AC compressor cycles on/off for the defroster.
Is the engine supposed to increase RPM when the AC cycles, or can this reflect binding in the compressor?

 

[ImperialCrown]

Binding in the A/C compressor was an issue for '01-'03 Chrysler minivans. See TSB # 24-004-04 which included an extended 7/70 compressor warranty.
It addressed replacement of some plumbing to prevent refrigerant oil 'pooling', the compressor assembly and a PCM software change. If metallic compressor debris has entered the plumbing, then further system cleaning/replacement may be necessary.
An over-charged or over-oiled A/C system can also drag the engine down.

 

[keithsketchley]

You need a service manual to get information on how system operates, typical engines depend on many sensors, computer uses them at various times.

Idle of 1994 3.3L could in theory be affected by solenoid on EGR transducer failing to prevent EGR operation at idle, see
http://www.allpar.com/forums/topic/146614-egr-valve-could-case-startidle-problems/ , don't now if your engine has that lashup (there is more than one even in 1994 model year). On 1994 the EGR valve is behind the throttle body whereas alternator is on other end of engine.

Computer should accommodate added load of A/C, but others have noted high probability of much higher than normal load on your particular vehicle.

Cold weather is upon most of us (northern hemisphere) so fuel doesn't vaporize as quickly and there is more friction, when engine cold. On the mid west coast it is now very wet, some vehicles get condensation on engine parts if not run every day - spark plug wires in bad condition are a common suspect.

IIRC the ECM uses coolant temperature to set initial mixture for start, if open circuit the ECM would probably provide less fuel (typical temp sensor is high resistance when hot so open circuit would be hot - beware there may be two, a simple one for the gage and a somewhat more complex one for the ECM).

 

[David Eidell]

Similar problem had me re-inventing the wheel until I dumped a can of Chevron Techron in the tank and drove the car fifty miles.

 

[ktvaughan]

Thanks for the suggestions.
Looks like this engine doesn't have an EGR valve.
Others have written that use of EGR valves differs based on state.
Here (Indiana) they didn't use them on the '02s.
Regarding AC binding, does a flush and refill with new gas/oil help?
It's working fine but has not been touched in ~ 10 years..........

 

[ImperialCrown]

Fresh R-134a and PAG oil won't help. Verify that your A/C compressor is hard to turn first:
http://forum.chryslerminivan.net/archive/index.php/t-19173.html
http://www.dodgetalk.com/forums/archive/index.php?t-166722.html
If it turns stiffly, the damaged compressor needs replacement. If compressor debris has entered the system, you may try flushing and receiver/dryer replacement while the system is open. Every trace of contaminant must be removed or subsequent compressors will continue to die.
The plumbing should also be upgraded to the newer design in order to do this right.
It can get expensive. Google Chrysler TSB# 24-004-04.