I think that my 66 smallblock may be fouling plugs because of its running poorly. I can think of a few ways to determine if a plug is fouling i.e. pulling the wire out of the cap or off the plug and watching a tach to see if the RPM if affected. Is there a easier way? Maybe a test lite or something? Bill
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What are the symptoms?
Rather than saying that it runs poorly could you give us some details? A service writer or mechanic can always drive the car and make their own judgement as to the specific symptoms, but it's tough to do over the net. If you state more specifically the operating anomalies you engine is exhibiting, the folks on this board can more accurately diagnose your problem and suggest corrective action.
Duke -
Re: Detecting Fouled Plugs
Try this one. Some tool companies sell a infrared or laser termometer, but that isn`t nesessary. While the engine is running drop a little water on the exhause manifold on top of each exhaust port. It should sizzle if not you have found the culprit.Comment
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Re: Detecting Fouled Plugs
(1) Disconnect plug wire. (2) Apply socket wrench to each spark plug and remove. (3) Visually examine plug tip. (4) Electrode/gap should be clean and un-blacked from oil/soot. (5) Plugs that are black are fouling.
If fouling continues after clean-up or replacement of plugs in a given cylinder, consider a compression test and leak-down test to verify piston ring integrity and valve seal, respectively.
If compression and leak-down tests show acceptable, look into your engine ignition electrical for erratic spark (or do this prior to compression/leak down). Best way is to put engine on diagnostic machine and watch the waveforms of each cylinder/plug firing. Could have spotty coil, condensor, points, as well as intermittent plug wire(s).Comment
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Re: Detecting Fouled Plugs
Bill,
Hook up a good tach/dwell meter to it and pull off plug wires one at a time to see if a spark plug is firing. If a plug is firing, there will be a noticeable drop in the rpm's when you pull its wire off. Once you figure out which ones are not firing go ahead and pull all the plugs, making note of which cylinder each comes out of. What do they look like? Are all the plugs on one side of the engine fouled or just one or two on opposite sides? There are lots of reasons a plug fouls: 1. It wears out. 2. It is improperly gapped 3. It is not getting any spark from the ignition system 4. It is getting too much fuel 5. It is getting fouled by oil (rings, valves) 6. It is getting fouled by something else (antifreeze-blown head gasket)
Let us know what you find.
BTW: I am assuming you have an old point type distributor, if you have a modern, high-voltage, electronic ignition system installed DO NOT PULL OFF PLUG WIRES! OK, pull off one just so you can see the pretty stars...Comment
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Re: Nice tip Wayne ..........NTX
TerryComment
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Re: Nice tip Wayne ..........NTX
I liked this tip so much I e mailed Wayne at home to tell him I thought it was very clever.
jerryComment
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