73-87chevytrucks.com
General Site Info => General Discussion => Topic started by: Bubba13 on January 24, 2009, 12:42:18 pm
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On my second truck that I have for my daily driver,( 96 gmc sanoma, 2.2 4 cyl. ) The check engine light went on just shortly after the engine started tapping, not a knock but heavier than a tick. the oil pressure before all this was normal, 20 lbs at idle and 40 on hwy. Now once warm, the oil pressure is 20 hwy and 5 ish at idle. I use mobile clean 5000 oil with a can of Restore in it. The engine light code is " number 4 cyl missfire detected" It's been too cold here to attempt working on it yet. Yea I know it's later than 87 but there has to be some diverse mechanics on here to help. Any ideas will help.
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Probably time for a tune up, plugs and wires.
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changed plugs, still tapping. Also left old plug in block, attached new plug into boot , grounded to block, started engine, have spark, but engine doesnt sound different even with plug there.
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Do a compression test
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Unplug the injector connector and see if it has injector pulse using a test light
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sorry, it has a tbi
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Almost sounds like a weak coil. Does it have the four pac coil or just the single. You can have a spark outside like you tested, but if it is weak, it wont fire under compression.
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sorry, it has a tbi
You might wanna double check that. You should have SFI not TBI.
Are you hearing a mechanical noise with no load on the engine?
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you said 2.2?
almost every 2.2 i see breaks the timing tensioner, which in turn makes a tap louder than a lifter but quieter than a rod.
id check that first.
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I had a 97 s-10 with a 2.2 and it done exactly what Chris said, so you might want to check the timing tensioner.
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Just an observation but I would be very concerned about any engine with only 5lbs. of oil pressure.