I have a 97 Dodge 4x4.. The truck starts well when the weather is warm, even if it sits a week or two, thus eliminating bad battery.. But when the weather turns cooler, around 40, it turns over slower, & hard to start.. Acts like my 92 Ford when 1 or 2 glow plugs were bad.. I usually have to turn the key off & on again a couple of times when the wait to start light goes off.. I wouldn't have a hope in h--- of starting this truck if it went to 10 or 20 below zero.. Is there a fuel or engine pre heater that might have gone bad? if so where do I find it, & how do I go about testing it?? What is the proper name for it, so as to find one on the net??
Thanks,
John

 

Intake Air Heater Grid, it's a rectangular grid of metal that is inside the intake just before the manifold - powered through two little electrical blocks that feed direct off battery hot, they should be mounted either on the fencer below drivers side battery tray as our truck has it, OR (as my FSM shows it) on the lip of the battery tray. I think these are relays of some sort. The Cummins doesn't run glow plugs, it relies on heated air to the intake.

Now, none of this may be what's causing your problem - but that's what springs to mind first for me!

 

Hey, you're not that far from me. My sister bought a horse from PA once. :P

I would check the starter - after a while, the solenoid contacts fry and increase in resistance, which makes it difficult to turn over a cold motor. Often you can take it down to a starter/alternator shop and they'll tell you exactly what you need to put 'er back together and get many more miles from it. (aka, while it is out, check the rest of it, brushes, bearings, etc.)

After that, I would load test the batteries. They might hold a charge, but if that charge isn't strong enough, you could be hooped. There are many weird battery problems that can become more apparent in cold weather, such as shorted cells, etc. If one is pooched, replace them both.

The intake grid heater rarely fails, and shouldn't affect the crank speed, although it does stay on a bit after the wait to start light goes out, and consumes quite a bit of current. You can see the current from the heaters pull down the battery voltage, and thus confirm they are working.

I'm pretty sure by this point you'll have found something that fixes your problem.

 

Also: anytime you remove an electrical contact involving the starter (including the starter itself as it grounds through the drivetrain), make sure to clean the contact surface with some emery cloth/sand paper. You may want to check the ground strap, also, for high resistance (can't really measure with a multimeter as the resistance only becomes a big deal when hundreds of amps are rushing through the connection).

 

Thanks for the replies.. Scott, I had starter out as my contacts were fried, & most of the time the starter only clicked.. I got a kit from Napa & replaced the copper contacts & plunger.. I did clean the connections good..
When I say it turns slower, what I mean is like a cold engine.. My Ford used to turn over slower if I had 1 or 2 glow plugs not working.. I will go & put a load test on the batteries, although I put in new ones last winter in Texas.. Got them from Wally World, so they're probably still under warranty.. Don't know if Walmart in Canada would warrant them if they're bad..
I hope it wasn't a horse from me, mine only lasted for a short while, then up & died, lol..ha ha