1997 Nissan Truck will not run in the rain. It chugs and chugs...

[osu9400]

Anytime it rains, my truck is useless. When I finally do get it started, it chugs and coughs as I try to drive.

Any idea what is wrong here?

[Big-Bird]

Sounds like moisture either in the fuel system or in the distributor cap ( it could also be a weak spark plug wire).

Purchase some gas-line antifreeze ( methyl-hydrate ) you need about 4 oz. Pour 4 oz the fuel tank. The methyl-hyrate will bind with any moisture in the fuel and help it burn in the engine.

Second: Remove the distributor cap and check the condition of the cap's base seal. A cracked seal will allow moisture into the cap and cause the sparks to go everywhere at random. (water is the perfect conductor for high voltage electricity) Especially a coil that snaps off 30,000 volts or more with each firing of a cylinder.

If you do have a bad spark plug wire, or even a bad cap the moisture will cause the spark to ground on the outside of the engine instead of at the spark plug.

This is real easy to check, but you need a dark place to do it so you can see any sparks jumping.

Get a spray bottle filled with water.Run the engine.Spray the spark plugs, wires and distributor cap with a mist.Listen for the arcing ( a snapping sound) and look for a spark being where it shouldn't be.

Look for sparks at the wires boot ends, possible cracks in the distributor cap, old dry cap seal, cracked ceramic on a spark plug.

IF these items don't help you find your problem get back to us here.

[osu9400]

thanks. I'll give your suggestions a try. I should also add that the truck has the same symptoms on really humid days when there has been no rain at all. Does this give any additional insight?

[Big-Bird]

Humididty is a funny thing. If you have any kind of wire,cap, plug issues even small amounts of moisture can cause you some trouble. If the misting test doesn't prove any thing then there could be other issues at work thaty in my opinion are still electrical in nature. But I did remember something about my old 1986 720 Pickup I used to have. It had a hairline crack in the cap. The truck ran fine until I washed the motor. So I would run the engine while I cleaned it. That's how I found the tiny crack in the body of the cap. It looked like it ad been dropped or smacked with something. A new cap fixed the issue.

[Ajax77]

What's funny is that I came to this forum to pose the same quandry.

I also have a 97 Hardbody and have serious problems on wet and humid days. It won't stumble when the truck is first run, but after a few minutes of driving, it will start to chug. After a while it will stop (probably when the moisture has burnt off) and it will only really do it at low RPMs. Usually, once I get to 2500 or 3k RPMs, it will run normal. As soon as i shift and RPMs drop, though, it will chug until they go back up.

I was fairly sure that it was probably a distributor problem, but I though I'd check in here to see if there could be any other causes. The spark plug wires are all in good shape (Magnecor wires), but I haven't pulled the distributor or plugs yet to look at them.

I'll check it out and post the results.

[Big-Bird]

I went back to the trouble shooting guide for my D21 Manual.

These are the things the book says to check for:

Engine 'lopes' while idling or idles arractically:

1. Vaccuum leaks at the intake manifold or vaccuum lines.2. Leaking EGR valve or plugged PCV valve.3. Clogged airfilter4. Fuel pump not delivering proper fuel volume.5. Leaking head gasket.6. Timing chain or belt worn.7. Camshaft lobes worn.8. Valve clearance out of adjdutment.9. Ignition timing out of adjustment.10, Ignition system not functioning properly.11. Thermostatic air cleaner not operating properly (carbed only).12. Choke not operating properly (carbed only).13. Dirty or clogged injectors. (Carb is dirty, clogged or out of adjustment)14. Idle compensator not operating properly.15. Idle speed out of adjustment.

Hesitation or stumbling during acceleration.

1. Ignition timing incorrect.2. Ignition system not operating properly..3. Dirty or clogged carburator or fuel injector(s).4. Low fuel pressure, Check for proper operation of the fuel pump and for restrictions in the fuel filter and lines.5. Carb out of adjustment.

Engine surges while holding the accelerator steady:

1. Intake air leak.2. Fuel pump not working properly.

[chemao]

I have a 1998 Nissan Frontier and I have the EXACT SAME problem and is actually why I came here!!!! What the **** is wrong with these trucks? I did throw a code that might help us to find out what's going on. The code was "Cylinder 4 misfire". That's rather obscure but after I cleared the code I finally threw codes again yesterday during rain here in Texas. I'm going to pull the code and see if it's still cylinder 4 or another cylinder this time. If it's a different cylinder then it may be the distributer. What's wierd is that when I upshift and the RPMs drop to a couple thousand it chugs and sputters again, no matter what my actual MPH is, or how long the truck has been running. On dry days it runs great. *sigh* does NO ONE know the answer to this problem?

[osu9400]

I think it has been solved. We had some crazy rain here last week and the truck purred better than it has in a loooong time. I had the plugs, points, wires, and cap all changed. There was no misfire in my case.

[Big-Bird]

As for the 98 Frontier. I probaly do have the answer. But I am off to bed and will post stuff up on Friday.

[Ajax77]

Well I finally changed my distributor cap but it hasn't been rainy or particularly humid (amazing!) so I didn't have a chance to really test the results. But we had a really good rain yesterday and now it's back to good ol' humid Missouri weather and my truck has been running smoothly. I checked the old cap over and couldn't find any cracks, but it's possible it might just be worn out.

So I'm crossing my fingers and hope it's all fixed and I don't have to be pissed off every time it rains. Hopefully this helps anyone who is having the same issue.

[proudpapatwice]

Same Truck, Same Problem. I'm going to give the distributer cap a workover and I'll post my findings too. Just so you all know, this is the best base of info I have found in my last 3 hours of searching the net. Thanks.

[MufflerBearings69]

I would check and make sure all the connections over at the coil are clean and tight- I have had some issues with that on my older hardbodies... All of the above is where to begin for sure, but I would check these connections also

[Joe67]

I also am having a sputtering problem with my 97 nissan pickup... it chugs along with serious power loss, and moves real slow unless i flow the pedal and get the RPMs above about 3000 or so, it chugs all the time, not just with rain or moisture in the air, just all the time. and it gets worse the warmer the engine is... i have replaced the spark plugs, check the plug wires, the distributer, the fuel injectors, the fuel rail, and the fuel filter... and i can't figure out what it is... what would you suggest??

[RT22]

To check moisture problem on distributor cap easy troubleshooting before buying parts is WD40. remove cap when it is messing up spray the entire under cap area, and under the cap, pop it on and see if it goes away, that will tell you if it is in that area. WD stands for water dispersant. if it is water and dampness under the cap wd will clear it up for the time. Then do as said above as far as replacing and checking seal. MY 4x4 buddies use clear silicone on base of cap so when they hit a big water hole it does not allow water to enter, also some dielectric grease on the inside of wires under tthe plugs on cap keeps water out in the water hole thing.

[seang]

Distributor caps need should always be nice and dry, but I have had this problem with both my old 86.5 and now my 97 D21's. I think it has something to do with the electrical connections at the fuel sending unit because I have already been through the distributor cap. I could be wrong, but it sounds feasible.

[bwilliams6992]

I have a 2000 pathfinder. It runs good when its dry but when its wet it starts to miss and slowly gets worse. We changed the cap and rotor and it worked for 25 min then died completely. Replaced the distributor and it fired right up. However when i was driving today in the rain it started missing again. It got worse as i drove. What could it be?