Rav4 stalls when rainy and put in Drive, not when in Reverse or Low Gear.

[lilrayray69]

I have a 1996 Rav4,

A year or two after I got it I noticed it had a problem starting up on rainy days. It would take a second or two longer to start, and have kind of a "dirty" start. Then it would often stall out when put in Drive and given some gas. It would idle just fine. However, after some time running in park or trying to drive it, it would eventually sort of fix itself and be fine from there on.

I first fixed that by just getting the distributor cap replaced, I guess the old one was bad and water was getting in or something...

But today it was again a rainy day, and I went to start the car and had another dirty sort of start. I got about a mile down the road though, when it started to sort of sputter and shake and then once I got to an intersection and stopped it died there. I could start it up, but as soon as I gave it gas while in drive it died again. I got the car out of the way then started sort of testing it...it would idle just fine in park, then I found it would drive in reverse just fine too. Then I found it would even drive just fine in either Low or 2nd gear (L and 2 on my gear stick)...so that's how I ended up getting the car home. Once I got it back, I found I could now put it in Drive and give it gas, no problem.

Any idea what's going on here?

 

[tortillasoup]

Your car is over 10 years old, time to clean up the electrical grounds in your engine bay. I'd start off with isolating about 5 of the major electrical grounds in the engine bay, starting off with the ground that runs from negative battery terminal to varios parts of the body. When cleaning up the grounds, scrub/sandpaper down the metal until COMPLETELY SHINY, Eyelits, washers, bolts, etc. DON'T SCRAPE PAINT!!! You say you replaced your distributor but did you replace the ignition wires? Do you have a multimeter? If you can measure the ohms of both your electrical grounds and your ignition wires, that would be helpful. Ohms shouldn't exceed 15K for the main ignition wire from coil to distributor and like 20K ohms for each spark plug wire. You've also probably got some frayed wires here and there that are partially shorting out at inopportune times, inspect carefully. Maybe post super high resolution pictures of your engine bay?

 

[phucheneh]

Right...when I hear 'stalls in the rain,' I always think 'dirty ground wires.'

OP, I think the differences in drive/low are probably a red herring that your mind has kind of invented. There's just no way that locking the trans out of third and fourth gear should alleviate the symptoms you're describing.

Said symptoms kinda sound like you pushing a misfiring engine until it dies. You should probably avoid that.

Plug wires are a possibility, but a resistance test will tell you something between 'jack' and 'shit.' Your problem would be the high voltage inside the wire arcing to ground. Best way to test that is with a spray bottle full of water. Before you bother doing that with the wires, though...spray the ignition coil. Which IIRC is mounted on the firewall.

An epoxy coil mounted on the firewall is undoubtedly the number one cause of rain-related misfires.

 

[Meghan54]

If the plug wires are really arcing, a quick and dirty way to check is run the car at night. Make sure it's in a dark area, pop the hood with it running and you'll sometimes be able to actually see the faint arcing from the wires. Pretty cool when you can see it. Light show! LOL!

 

[tortillasoup]

Right...when I hear 'stalls in the rain,' I always think 'dirty ground wires.'

OP, I think the differences in drive/low are probably a red herring that your mind has kind of invented. There's just no way that locking the trans out of third and fourth gear should alleviate the symptoms you're describing.

Said symptoms kinda sound like you pushing a misfiring engine until it dies. You should probably avoid that.

Plug wires are a possibility, but a resistance test will tell you something between 'jack' and 'shit.' Your problem would be the high voltage inside the wire arcing to ground. Best way to test that is with a spray bottle full of water. Before you bother doing that with the wires, though...spray the ignition coil. Which IIRC is mounted on the firewall.

An epoxy coil mounted on the firewall is undoubtedly the number one cause of rain-related misfires.

Well when you listen to how OP explains the problems, the symptoms and conditions for when they happen it is all over the place. I did forget to mention to inspect the spark plug wire boots to see if the rubber was cracked/brittle which would cause a short to ground. Not disagreeing with any of your advice but don't dismiss my advice either. Don't say a resistance test wouldn't prove jack shit because if the wires are too high of resistance, that would cause partial or total misfire.

 

[lilrayray69]

Well I ended up taking it to a local mechanic I know, and turns out it the plug wires were arcing. He got it fixed relatively cheaply.

Though he thinks the catalytic converter may be clogged now...always somethin.

 

[zaydq]

I was about to say. My old 99 Mustang was doing the exact same thing. Replaced the plugs and wires and it never happened again.

 

[tortillasoup]

Well I ended up taking it to a local mechanic I know, and turns out it the plug wires were arcing. He got it fixed relatively cheaply.

Though he thinks the catalytic converter may be clogged now...always somethin.

Well you can have the catalytic converter removed and cleaned in laundry detergent then left over night... I've also heard of using Citric acid/water solution could work as well though I don't know as much about the latter rather than the former.