'86 AE82 4AC: Stalling in the rain

[Criard]

I've been having problems with my car stalling. Most often it happens when it rains overnight. If it rained hard enough or if there's enough moisture in the air, starting the car is near impossible and takes quite some time.

When I get it started on these rainy days, I make sure I let the engine warm up. engaging the clutch, the engine first idles very rough and sloppy and I can listen to it warm up to a nice sounding hum. However when I put it into drive or reverse the engine will start running very rough and will often stall unless I quickly shift into neutral and rev the engine before shifting back into gear.
Other times after warming up, the car will seem to be running fine at first as I pull out of the driveway and do a lap or two around the block. So I'll head out onto the road and be driving along, when I approach a red light. I brake to slow down, and the engine goes rough and stalls. Not only that, but for some reason at this point the engine will not start back up!! Only thing I can do is wait 5-10 minutes and then the car will start. Another common place for the engine to stall under these moist conditions is while turning, it will just cut out if I'm turning at a moderate speed.

These problems only happen when it's rainy/extremely moist air. On a sunny day the car runs perfectly fine. My thoughts are the problem is with the carb. I don't think it's been replaced yet, and the car has under 97,000 miles on it. Is there anything I can try to adjust or replace before I start looking for the best place to blow $200 on a new carb?

[OEMonkey]

If it only happens during the rainy season, then it's most likely an ignition related problem. A minor tune won't hurt especially if you haven't done it in a while. plugs, cap, rotor, wires, and the gasket that goes around the distributor cap. if it's worn, moisture can seep in and cause a bit of annoyance.

[retiredat44]

yopu can get a tube of rtv silicone and run some around the cap where it meets the base. Do it on the outside only. You can also by some selaer spray and srpay the ignition wires. That should help water proof the ignition. Oh yeah, you can also buy some gel to put on battery terminals too, if you think it might yelp you.

[Criard]

ok. first off, when I said 'clutch' I meant 'choke'. I have an automatic, for the record.


also, I was just wondering your thoughts on this as well. it rained overnight, and I went to use the car in the evening (the ground was dry, but the air was heavy still). I pumped the gas twice, engaging the choke, and started the car.
You see the problem with the stalling only happens for the first few miles, then it runs like normal. So I decided to just let it just sit there and warm up until the choke clicked off before moving it. The engine went through its usual sounding wakeup stage (sputtering and slightly shaking the car, slowly winding up to a smooth high idle) and was running nice and strong. I put the vent on high for a little while too, thinking more airflow would help the engine air out.
the choke clicked off, and the car stalled. I try to start it back up again, but to no avail. I notice the starter is turning over a lot faster and lighter sounding/feeling compared to normal, like the engine's warm and should be running. the engine indeed was quite hot. When I finally got it to start about 10 minutes later, I had to pump the gas pedal several times while turning over. The engine 'fired up' a little with each pump, then finally started.
I had to keep keep shifting in and out of neutral while backing out and pulling out of the parking lot, but once I was on the road I was fine and didn't stall.
which actually brings me to a new question. why is it more likely for me to stall when I'm stopped and idling in 'drive' (even moreso if I go to accelerate from a dead stop), as opposed to idling stopped in neutral (and revving the engine slightly before putting it into drive to accelerate)?


I realize that this is just a webforum and that I'm better off going to a mechanic, I'm just curious.

[90 GP]

Replace your spark plugs/ cap/rotor and wires. Also check all your vacuum hoses ( and there are alot of them) for vacuum leaks. In particular check the PCV valve hose which mounts low on the carb and gets cooked by the heat from the manifold. You also have 3 hoses on your vacuum advance on the distributor that can leak. The rough running during warmup sounds like an ignition problem. The stallout when warm sounds like a vacumm leak.

[Criard]

thanks, I'll look into those!

[fotosepp]

Did anyone find a final solution for this problem? I have exactly the same issue and have checked everything. My Mother in law also had the same problem when she used to have the same model. I am thinking it was an inherant problem with this model of this age so there should be one solution....I hope.....any help

[Criard]

no solution yet over here. I haven't really tried working on it much yet though