Hi everyone, my son's 1992 929 cranks but doesn't start after a rainy night. This is the second time it's happening in the last 2 weeks. Battery is brand new and fully charged. The next day it starts fine. Cap and rotor look fine but they are 13 y/o and 130 miles. I did clean up all inside the cap.
Plugs are this old too. The car does get fuel, and I do see spark when I plug a screw driver in one of the spark plug wires. Should I start with the rotor first, and then cap etc or am I missing something? This car won't be around much longer so I don't want to put anymore money into it. He hit black ice and the front fenders and hood are all bent. Nothing happened to the engine thankfully. Appreciate any help you can give me.

 

Your way past expected life for ignition components, Bite the bullet on this one. Replace the cap rotor plug wires and maybe even the ignition coil. It may seem a bit pricey for a car that your planning on getting rid of, but what's it worth when it wont start and your stranded?

 

Thank you Sparky. I agree with you. I went ahead and ordered cap and rotor from Tasca. I still have the original cables that I replaced at 80k miles back in 2003. If the cap and rotor don't make any difference I'll try the old cables and take it from there. Coil would be the next one but it is over $200. Thanks again. I'll update the group with the results.

 

I found a fuel leak coming from the Fuel Damper. The top plastic part was cracked and leaking. The car had been smelling like fuel for a while. I've read this can cause starting problems so I cancelled the cap & rotor order and purchased a new damper. I also had to get the intake manifold gasket since it had to come off...$160 for both parts! I should get them in a few days. Hopefully this was it.

 

Granted the damper had to be replaced but, if the hard start was only in damp weather? The damper would cause a hard start, extended crank time, all the time and not be related to rain.

Try this old trick. locate a empty trigger type spray bottle like the one for glass cleaner. fill it halfway with water then add a couple tablespoons worth of liquid dish soap or Simple Green. With the engine running, spray the cap, ignition wires and coil. The soap breaks down the surface tension of the water and allows it to "soak" in rather than roll off the ignition components. This will simulate a damp, rainy day. If you have any ignition components that have lost their insulation factor, you will develop a rough idle and may even see spark jumping from the failed part to ground.

 

Sparky, I agree. I am just hoping it was a coincidence and wasn't really the rain the problem. But like you said, it had to be replaced so it became a higher priority. I am planning to let him park in my garage when it rains. He'll be buying his own car in a month or two so we don't really need this car much longer.
I like your test. I'll go ahead and do it once I get it running again.
Does anybody know the size wrench I need for the damper? I bought an open end wrench size 21mm and it is too small. I assume it is then a 22 or 23. Each one is about $13 at Sears. I tried using an adjustable wrench but there isn't enough space. Thank you for your help.

 

Cheat, take the replacement damper to the store with you and match it that way

 

Well, I was hoping to have it out by the time it got here. Looks like it will be a few days.

 

Got the fuel damper and gasket. I bought them at Autozone of all places. Faster and cheaper than anywhere else. The fuel damper is Part Number: 800-4012 and it was "only" $99.99. It is exactly like the original except it doesn't have the plastic top. I just pulled the one from the old one and snapped it on the new one. FYI, it is a size 22mm and I had to use a crowfoot wrench since there isn't much room to use an open wrench.
The Intake Manifold gasket is Part Number: MS16082 and it was $18.99. You can find some on ebay for $12 but they come from California and I didn't want to wait for it.
It was pretty easy to install except the vacuum hose under the intake manifold was a pain to connect back. Car is running great again and no more gas leak and smell. We'll see what happens next time it rains. If I still have the issue I'll order a new cap and rotor and see what happens. Thank you Sparky for all your help.

 

Glad to. Hope that takes care of it for you but, the rain condition still has me skeptical.