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240 Running on 3 cylinders when cold/wet

esmth

esmth

The member
Joined
Jul 13, 2016
Location
MA/NH
2 weeks ago I went to start the car and it straight up wouldn't start. I pulled and dried (condensation everywhere) the distributor and wires and it started fine. Then for a couple next starts it started and ran fine.

Now, the past 3 days, the car clearly runs on only 3 cylinders, and as it warms up the last cylinder slowly misfires less and less and then comes fully online. This morning it did the same and I stopped on the side of the road to do some quick diagnostics, and found that I get zapped when I have my hand near the distributor at all. Tried wiggling the wires and distributor cap but nothing changed. As it warmed up the cyl came back as expected. I didn't have time to perform more diagnostics, but by pulling wires i found it's always cylinder 4 that is doing this.

What should I look for tonight to figure out exactly what is causing this and what to replace/fix? I don't have much time as it gets dark very fast once work gets out and I need to work fast with the light i've got.

Thanks :cool:
 
Caps can get fine cracks that hold moisture and provide a path for sparks to misbehave along.

It could also be some other less likely things (iffy injector?) but it's almost certainly the cap. Or wires.
 
I have experienced this many times with Volvo’s. The distributor is a very poor design that they used, and they are extremely sensitive to humidity and moisture. A new cap, rotor, and wires would likely help. On my 93 245, it runs on 2 or 3 on cold starts and completely falls on its face under load. 1-2 minutes later it clears up.

(Here we go again)
I just park it and drive my Camry. I think Toyota used a proper rubber seal on the distributor caps so humidity doesn’t matter.
 
JohnMc said:
Caps can get fine cracks that hold moisture and provide a path for sparks to misbehave along.

It could also be some other less likely things (iffy injector?) but it's almost certainly the cap. Or wires.
Click to expand...

This. OE Bougicord, blue NGK, or the NAPA dark blue plug wires are all good quality. Get the Bosch cap and rotor. Might as well plop new spark plugs in there too, they're dirt cheap and easy to replace. And don't forget a smear of dielectric grease inside the plug wire boots to keep moisture out.
 
Similar issue I had in the past was a plug lead with a connect clip that was broken in two... it'd fire intermittently, was worse cold than warm.
 
Also good to replace the plastic plug wire guides. The plastic gets brittle and cracks. This lets the wires lay on top of the valve cover and short out over time.
 
Thanks all for your suggestions. I used my key and scratched up all the points under the distributor cap. and it started up mint last night and this morning. I'll buy another cap and rotor and have it in the car just in case it happens again.

The plug cables are ~2 years old, the blue IPD ones with the metal shields. Are those known to last? I might also still have one step colder plugs installed still from when it was turbo.:lol:
 
My K-Jet 244 2.3 NA used to kinda start on 2/3 when it was a hot day out and then slowly pick up the fourth in about 30 seconds or so. Haven't had it happen since I put new leads on (Bosch Brand)
 
You could use a spritz bottle full of water and start spritzing wires to see if a cylinder drops. Then spritz the dist cap and see if it drops.

Cleaning the 'contacts' inside the cap won't do much - the spark has already decided to jump over to that, a little schmutz isn't going to stop it. It's when the spark finds an easier path from there to the distributor body via a small water-filled crack or surface trail that it stops working.

But using a water bottle like that could help rule out wires being the issue. If they keep working when wet, it's much more likely to be the cap (and not the rotor because it's one cyulinder - but replace both).
 
esmth said:
Thanks all for your suggestions. I used my key and scratched up all the points under the distributor cap. and it started up mint last night and this morning. I'll buy another cap and rotor and have it in the car just in case it happens again.

The plug cables are ~2 years old, the blue IPD ones with the metal shields. Are those known to last? I might also still have one step colder plugs installed still from when it was turbo.:lol:
Click to expand...

Total junk. If you saw how those IPD wires are constructed you would toss them in the trash and buy a good set of Bosh or Bougicord.
 
It happened again this morning, but only for ~20 seconds on start. Hopefully my new cap comes in today or tomorrow
 
I’m going through the same thing still. About to sell my 245 so I ordered a full ignition tuneup with plugs, wires, cap, and rotor.

All OE except wires. Anyone have experience with the NGK wires? Part number 54213 or EUX017
 
ignition0011.jpg
 
dl242gt said:
I've used the NGK, and they were ok. Lasted about three years like most wire sets.
Click to expand...

That sounds like a terrible run time! I have been on my set for at least 5 years now. But They've probably been 'bad' for a while now. Car runs fine usually. I think they're bougicords.
 
Do what JohnMC said, mist the ignition system with water. If you do it in the dark it will be pretty obvious what the problem is, you will see the arcing. Just don't touch anything while the engine is running, it kinda hurts if you have a problem.
 
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