So I recently purchased a 96 sport and at first it would start with no problems. Now it has decided that when it's freezing out it doesn't want to run. I have done a full tune up and replaced the crank sensor with no luck in correcting the problem. I have heard that the coolant temp sensor can cause this issue and I am awaiting the arrival of the part. I would like to confirm this before throwing it in and waisting more money so any info towards fixing this would be greatly appreciated.

 

When it won't start, are you missing fuel or spark?

 

When I was able to test it yes that's why I was told crank sensor

 

So...no fuel or no spark? Or not both?

 

I had nothing when I checked it last it just cranked

 

Where did you get the new cps? If not OEM that can still be your problem.

 

Yeah, apparently it must be a Jeep part. The reliability of others is a crap shoot.

 

I don't remember the brand but it wasn't a cheapy like some people put in. I do work in a shop so I have access to quality parts and plenty of material to go through were all just stumped as to what the problem is. If it's around 40 outside I'm good to go all day below that I'm screwed. If I can't figure this out soon I may have to part with the damn thing.

 

How would temperature affect the crank sensor

 

I know it may sound weird but any chance it could be the battery temp sensor? its located under neath th battery.

 

I didn't even know it had one

 

It doesn't seem to matter how much or little you spend on an aftermarket sensor. The fact that it is not a factory part seems to make the difference.

If you sell it, make sure the temp is over 40.

 

The guy I work with has done many crank sensors none of which where from jeep all aftermarket and he has never had a problem.

 

Next time it's cold and won't start, grab a hair dryer and heat stuff up one by one until you find the problem. I'd start with the PCM, then each of the sensors, even the relays in the PDC.

 

Did you actually TEST for spark when it won't start? That is the first thing I do for every no-start. It's not clear if you did that or not. It's critical for troubleshooting.

Remove a plug, keep it attached to the plug wire, place the plug electrode near a good engine ground. Have a buddy crank the engine while you watch. You are looking for a strong, BLUE, snapping spark. Yellow/orange/white indicates a weak spark which may not be strong enough to start the engine.

This quick and dirty test takes about 15 minutes of your time. It will absolutely help narrow down the suspect list! If you have good spark, then things like coolant temp sensor, etc. could be in play. If you have weak spark, then ignition coil, etc. Let testing lead the way. Anything less is a guess. Report back what you find.