5.7 Liter Sputters After Rain

gmoneyword · September 17, 2009

I have a 3500 Savana with a 5.7 liter. The truck started to misfire randomly. I also got the code that says random misfire. The truck had 130k so I changed the plugs, wires, and distributor cap. Now it runs fine except when it rains. I wonder if I could be getting moisture in the d-cap. It seems unlikely because it is at the rear of engine. Any help is appreciated.

txab · September 17, 2009

Sounds like you ought to check all your ignition system connections. Pull the cap off and examine it thoroughly. Water/moisture can still get to the back of your engine. Check to make sure all your plug wires are properly seated at both ends

2COR517 · September 17, 2009

There are two vent holes in the base of the dist. One at about 8 o'clock, one at about 3 o'clock - looking down from the front of the truck. Make sure they are clear.

And your coil could have a crack and pickup moisture.

asilverblazer · September 17, 2009

Try checking it at night with a spray bottle of water, might see the arcing.

gmoneyword · September 18, 2009

The truck idles fine, the misfiring occurs during accelleration. I have checked all connections but not the coil. The wires are clear. Maybe I should have a look at the coil.

2COR517 · September 18, 2009

What kind of plugs? And what are your gaps? Should be .040"

233monte · September 18, 2009

Does it kick back ever on start up?

gmoneyword · September 18, 2009

Does it kick back ever on start up?

It never has kicked back but sometimes when starting the solenoid will only click, but I think that is a seperate starter issue.

gmoneyword · September 18, 2009

What kind of plugs? And what are your gaps? Should be .040"

Plugs are whichever ones NAPA gave me and they are gapped correctly

jerseymike68 · September 19, 2009

interesting information

Nytemare · September 19, 2009

Easiest way o trouble shoot this is break the engine down into sections. you take a spray bottle or a garden hose on mist and spray one side of the engine, drive around and see if the problem is there. ensure you get the water all over the plugs on that side.

let the water dry up, than test the other side...if nothing happens than you spray the top of the engine, but don't get any water on the distributor. Drive around and do the same test. If nothing than spray the distributor, test again.

even if you do get a stumble out of one of the first tests, carry on to find out if its the only issue.

one thing I would do first is remove all the plug wires, and place dielectric grease in each of the boots, this is usually the remedy for a lot of wet weather issues.

gmoneyword · October 6, 2009

Thanks TXAB you nailed it. I haven't driven the vehicle for a couple of weeks, so today I pull my 3 month old d-cap off and all the contacts were green and it seemed kinda rusty in there. I cleaned everything up and was wondering what I should do to keep this from happening again. Maybe there should be some good sealant where the cap meets the distributor. If so what works best. Thanks everone for your help