Howdy. I've spent the last few days devouring the advice on this board--you guys are amazing. I'm hoping you can help me fix this problem and save some $$.

My '97 Ram 2500 Van isn't a morning person. What I mean is, when starting the van with a cold engine, the engine will turn over, start, and immediately die. If I keep my foot on the gas for a few minutes until the engine temp gauge comes up to the lowest mark (it starts at the bottom of the dial), the engine will idle and I can go on my way. Each time I start the van that day I'll have no problems. But the next morning I'm back to the same spot.

Based on what I read here, I thoroughly cleaned the IAC and port as detailed in the DIY post about it. Interestingly, the IAC itself was already pretty clean, but the port was filthy. However, this morning: same problem, no idle without gas for a few minutes.

Is my IAC faulty? Do I need to replace my TPS, or clean my throttle body?

Any help is really appreciated. And if you respond, remember that I know practically nothing about engines.

Thanks
Jon

 

Yes your IAC valve could be faulty. But I'm more inclined to think that your 2-wire coolant temperature sensor (CTS) is out of specs. There is a 1-wire one that controls the dash gauge, but the 2-wire CTS tells the ECM the engine temperature so that the fuel mixture will be richened when the engine is cold. This is the equivalent of what a choke does on a carburetor. Once the engine warms up a bit, the mixture doesn't need to be as rich for the engine to run, hence your stalling problem goes away.

 

Also check the voltage in your battery before you do the cold start. If the less the 12 volts, the van will not idle until the alternator has brought it back to full charge. Have the battery load tested for a possible cell going bad. May need to be replaced.

 

Thanks for the quick replies--I've just had a chance to look into this further and buy a new CTS sensor from the store. I should also say that I have a 5.2 V8 engine.

This morning, cold, the battery was at 12.36 volts.

I am having trouble confirming which set of 2 wires belongs to the CTS though. I've taken a picture (below) -- is the 2 wire version in front, and the 1 wire sensor in the background?



If so, the new sensor that I got from the auto parts store doesn't fit, and I'll have to get a different one. The two prongs on the new sensor are wider than what is currently installed.

Also, any tips for loosening/removing the CTS? It's really in there tight.

 

My brother in law helped me install the CTS today. For those out there who have difficulty, as I did, here's the location (because you can't see it easily): After taking off the doghouse, the CTS is located just behind the throttle body, in the gap. You must reach a deep socket down in there to get it out and replace. It's a bugger.