03 Dodge Dakota doesn't start when it's wet

'03 dodge Dakota 3.9 v6 136k- I’ve had a variety of issues I’ve fixed over the last few months, mostly because she sat for about two years while I was out of the country. But I’ve been able to figure everything out and get it fixed pretty easily up until now.

It’s been wet and rainy recently and yesterday was the first time my truck failed to start completely. However, the issue has been ongoing. It turns over really rough if it’s a bit damp or humid, sputtering and idling really rough once it does start. I have to let it sit and warm up a bit before I drive it, and when I do it doesn’t accelerate well and sputters a bit when I stop. However, after it’s been running awhile the problem goes away completely, and there after starts up without a problem. Also, I have noticed a gas smell whenever it’s struggled (or failed) to start.

When it’s dry out, even when it’s cold, it starts up without a problem and might have a bit of rough idling when put in gear for just a few minutes.

I feel like this might be an easy fix if identified (though maybe not the cheapest and I’ll probably have to take it to a mechanic, don’t have a way to work on it myself). However, everytime I brought it up to mechanics previously, they couldn’t tell me anything because the problem went away because it was warmed up by the time it got to them.

Any good suggestions on what might need replaced and/or how to figure that out would be greatly appreciated. Thanks in advance.

How do the plug wires look? Poor wet starts might be related to faulty plug wires.

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More than likely the problem is with the secondary ignition components.

Replacing the distributor cap, rotor, coil, and plug wires usually solves this problem.

Tester

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You mechanic must be very young. To reproduce the conditions all he would have to do is use a spray bottle of water and spray the spark plug wires and distributor cap. You can go out after dark on a rainy night and have someone crank the engine and you will see sparks jumping to metal on the engine.

If it was my truck I would start by replacing the parts tester mentioned except maybe the coil. But I am cheap and would not have to pay myself extra to go back and replace the coil.

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Another vote for Tester’s advice. Additionally, check the seal on the cowl where the hood rests on it. The distributor is at the back of the engine, right under the cowl, so you don’t want water leaking past that seal. Also make sure the cowl area is draining properly.

Thanks for the advice everyone! I would definitely rate myself as a novice when it comes to cars but I’ve done some work on my own (especially lately), and have learned quite a bit during the twilight of my truck’s life. Glad that it’s fixable and I can keep it on the road.

If you are planning on doing the work yourself, be prepared for a bit of a hassle. The distributor cap and rotor are somewhat of a PITA to change due to the the location of the distributor. But do it/get it done anyway.

If you don’t find the problem in secondary emission, soak down the crank position sensor and its lead/plug. It has to have clean dry connections and an intact insulation shield to transfer that weak little pulse from the sensor to the ECU.

Good advice above. The reason you are smelling gasoline probably is that one or more cylinders are misfiring due to the wet ignition system, no spark in other words, so the gas just comes into the engine, and gets pushed right back out the tailpipe, and that’s the source of a the gasoline odor.

Quite some time ago we had a thread here titled something like “who’s the cheapest among us” and posteres would chime in with how they solved their car problems on the cheap. Micky mouse solutions I call them. Whatever the minimal amount of work it is that gets it running again. One poster I recall said he had this same problem, won’t start when it is raining. The only way he could get his car started was to set some sheets of newspaper on fire under the hood to dry out the ignition system … not that I’m recommending this method … lol …

If all else fails and the spray the engine with water doesn’t isolate the cause, try replacing the coil. Or at least remove it and inspect it on the bench with a magnifying glass. I had that wet ignition system problem on a VW Rabbit years ago and I could spray water all day and it would run fine. Drive over a little puddle, stall out. Turned out the ignition coil had a tiny crack in the ceramic on the underside.

Oh, do open the hood at night to see the arcing if you have plug wires. It can be quite a show.

I have the same truck , same year. It does the very same thing. Im going to change the plugs. Ill let you know if that fixes the problem.

When you pull each plug, inspect the condition and check the gap. If the gap is much wider than nominal, changing plugs will help.

If the hood/cowl seal is loose or missing rain water may drip onto the distributor.

In this picture you can see the cowl seal resting on the master cylinder.

Dakota%20cowl%20seal