Hi everyone,

2003 Dodge Dakota V6

I am having problems with my truck starting when there is high humidity. I replaced the distributor cap and rotor, but it did not seem to have any affect on the problem. I am pretty sure it is spark related and not fuel. When it acts like this I have been successful in getting it started by attaching jumper cables and after a lot of cranking it will finally start. After starting it runs perfect no coughing or sputtering. After it is running I could drive through a monsoon with no effect. I have not replaced my plug wires, and in all of the reading it does not make sense that it would be a cracked coil as I have no problems once it is started. So it seems like the little bit of extra juice I get from the jumper cables is getting me the spark I need to get it started.

It is just not obvious to me what next step to take to cure the issue. Everything outside of starting is normal once running and moisture does not seem to affect it when its running.

Help please

 

Go to AutoZone they can test the battery for free as I'm thinking its the battery.

They can also put a scanner on it and look for error codes

 

Sorry, I should have stated Battery is only 3 months old. Also it is not an immediate start when the jumper cables are attached, probably 2-3 miuntes of cranking before it slowly starts to fire.

Thanks for the reply though.

 

Well I have seen loads of new stuff that's bad. New means nothing these days

But

What engine is it 3.9 or 3.7?

It could be a dirty throttle body has it been cleaned?

I believe the older 3.9 engine had an intake plenum leak problem.

 

The reason the jumper cables help is that they get your cranking voltage back above 10 volts (minimum firing voltage) after several minutes of cranking.

To verify spark, grab a known good spare spark plug, pull a plug wire off and stick it on the spare, put some welding gloves on, and hold the spark plug's threads up against a solid piece of metal on the motor, like an accessory mount or a ground bolt on the core support or firewall, and spin the motor over.

 

To go along with what Magnet is saying, monitor the voltage while cranking, not just at the battery but at the PCM.

 

I had a similar issue - truck wouldn't run after a rain storm.

Turns out the seal between the cowl and hood was worn out letting water drip directly on top of the distributor.

As a quick test I sprayed the distributor posts with WD40 then ran the hose over the hood for 10 mins with the bad seal still on but the truck started no issue.

As a safety precaution I sprayed the spark plug boots and coil as well and drove it for a month with no issues... Then I finally replaced that rubber seal.

Try some good ol fashion WD40 on your spark components and see if that helps.

 

Since there is a consensus about the battery being the problem, I'd be interested in exactly what you do find. I tend to disagree with the battery idea but I'll tell you that mine (3.9) has a severe miss when it's damp, but more generally rain damp, not humidity damp. It starts no problem but misses quite a bit until it "dries out". I haven't spent any time looking for issues since I can live with the problem, at least for now. My truck has only 60K on it but is still running the original plugs and wires, which while low mileage, are almost 14 years in age.

 

I would replace those plugs that's probably your problem gap has widened by now.

 

I think you'll find that your plugs were due to be changed at 30k, by the FSM.