ENGINE RUNNING ON 3 CYLINDERS, SOME OF THE TIME

  • Tiny
  • knhgn
  • 1999 Honda Accord
  • 140,000 miles

My 1999 Honda Accord has inconsistent firing plug 2nd from left. Mechanic told me to try Aldor non fouling plugs. I researched and learned it could be a bad PCV valve or camshaft cover seal. Only one cylinder affected, no exhaust smoke and compression is 150 + on that cylinder. What do you think it could be?

Thursday, July 12th, 2012 AT 3:31 AM

9 Answers

  • Tiny
  • rasmataz
  • Member

Recheck the plug and injector for that cylinder-start here-let me know-

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Thursday, July 12th, 2012 AT 3:39 AM
  • Tiny
  • knhgn
  • Member

I was told seal was leaking oil into that cylinder, which was fouling plug, yet no smoke.

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Thursday, July 12th, 2012 AT 3:49 AM
  • Tiny
  • rasmataz
  • Member

If its not smoking what make them think its a valve seal/stem/guide-Are you using OEM part on the plugs-if its fouling use a hotter plug and see what happens

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Thursday, July 12th, 2012 AT 4:48 AM
  • Tiny
  • KHLow2008
  • Expert
  • 41,938 posts

If it is the plug tube seals that is leaking, there would be no smoke as oil is not getting into the cylinders. Instead the oil is causing bad conductivity and could have damaged the coil wire.

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Thursday, July 12th, 2012 AT 5:58 AM
  • Tiny
  • knhgn
  • Member

Is the plug tube seal you mention, the same as the valve guide seals. The original was missing on ALL cylinders, later determined to be loose wires on contact pin of ignition module. Before that the car ran great, no problems. Afterwards, one cylinder doesn't fire, and leaking inside head was given as reason, with repair of $1200 as solution.

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Thursday, July 12th, 2012 AT 1:37 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,938 posts

No, the plug seals are those under the valve cover. There are O'rings under the cam carriers as well.

How can the valve guide seals be missing? They are not easily removed unless someone forgot to reinstall them when cylinder head was worked on.

What are the compression on all cylinders?
Were the valve clearances checked and adjusted?
Do you have oil in the plug tubes?

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Thursday, July 12th, 2012 AT 10:10 PM
  • Tiny
  • knhgn
  • Member

The valve guide seals are not missing. I didn't say it well. I meant the original PROBLEM was the engine was missing all cylinders because of loose ignition module wires. The problem is now pretty much solved. Your advice to check the fuel injector was good, as the cylinder wasn't getting fuel, so thanks. Another, better mechanic found there was a pulse through the injector and agreed with you that was no oil leak in the missing cylinder. The problem turned out to be a faulty wire connection in that part of the wiring harness just behind the valve cover. When he moved the harness slightly, all cylinders fired again, including the bad one. He explained that the loose wire was the one activating the fuel injector for that cylinder, so it wasn't getting fuel, even though it was getting spark. It's running fine, although I may have to eventually take apart the protective shield on the wiring harness and check the connection for the affected wire. Thanks for all your help; you definitely pointed me in the right direction.

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Saturday, July 14th, 2012 AT 4:05 AM
  • Tiny
  • KHLow2008
  • Expert
  • 41,938 posts

Ensure the connectors are good. Quite often the locking tabs breaks off as they becomes brittel due to age. This would result in the connectors not being locked securely into position and can cause a break in the circuit.

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Saturday, July 14th, 2012 AT 1:49 PM
  • Tiny
  • knhgn
  • Member

Will do. The original problem of loose wires on the ignition module caused the engine to run very rough, which probably jiggled the connection inside the harness loose and caused the 2nd problem. Thanks again, for pointing me in the right direction.

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Saturday, July 14th, 2012 AT 3:02 PM

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