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The I-3 Camry

So my wife was driving our '86 Camry grocery-getter (2SFE engine) and the idle smoothness and available power suddenly start to feel like it was hitting on three cylinders instead of the customary four.

I pulled the plugs and #3's spark gap is zero. Grounding bar mashed right down onto the center electrode, and a piece of its end seems to be missing too.

Since the engine (unopened original) doubtless has its share of carbon on and about the head -- it's a bit of a known predetonator under load on a hot day -- I'm guessing that a chunk came loose and bounced around until it smacked the plug. What do you think of that? Or do you think the bit of plug came off and then performed a friendly fire incident?

(Single-electrode Bosch Platinums, properly gapped, that had been sparking unremarkably along for many thousands of miles.)

My plan is to apply the Shop-Vac to each plug hole, just in case some bit of evil still lurks within, and replace all the plugs... Thoughts?

--Joe

Reply to
Ad absurdum per aspera
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"Ad absurdum" wrote: '86 Camry (2SFE engine)

Rough idle. Low power. Number 3 spark gap is zero. (Single-electrode Bosch Platinum). The grounding bar is mashed onto the center electrode, and a piece of its end seems to be missing. I will Shop-Vac each plug hole in case some particle remains, and replace all the plugs.

The engine is a known predetonator under load on a hot day -- I'm guessing that a chunk came loose and bounced around until it smacked the plug. Thoughts? ____________________________________________________

I had this happen in a V8 engine with a vacuum leak near one intake port. The extreme heat from the lean mixture softened the plug bar until it twisted up into the center electrode. Part of the tip of the bar was gone but there was no chunk in the cylinder; just some fine slag articles stuck on top of the piston. I guess they sputtered off in small amounts as the bar began to short the electrode.

The top of the piston was wavy from overheating and I was worried about the engine so I had it rebuilt. Since then I am paranoid about vacuum leaks.

Good luck.

Rodan.

Reply to
Rodan

Thanks. Guess I should run a vacuum gauge up the flagpole and see who salutes. Previously though the engine was a smooth idler by four-banger econobox standards and topped 30 highway -- blew a little oil, probably past valve stems/seals, at startup, but that's about it for misbehavior -- so my initial simplifying hypothesis is that there's nothing horribly wrong with the engine.

Cheers,

--Joe

Reply to
Ad absurdum per aspera

I think you nailed it. The carbon didn't necessarily have to come loose, it could have been getting thicker over time, finally hardening to a ground tab bending degree.

I would suggest you use a top engine cleaner like GM X-66 and several applications at that. With the engine at idle you can use a long section of vacuum hose, attach it to a common vac port, and suck the contents of the X-66 right out of the can (pourable version). If you want to use the spray version, you will need to hold open the vane in the airflow meter enough to keep the engine idling while spraying X-66 into the throttle body. Shut off the engine as soon as you empty the contents. You may want to try both methods because each has it's benefits. It would be wise to do this at night so the solvent can soak in, but you can start the engine in 15 minutes if need be. Also, be sure to park outside before doing this as the resulting steam cloud is quite voluminous.

Someone with textbook or google skills will probably reply "don't do it or you'll ruin your converter!". It won't cause any problems, I've done this a hundred+ times with success. Use Nippon Denso or NGK plugs this time when you replace the set.

Toyota MDT in MO

Reply to
Comboverfish

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