No 1 Cyl not firing

Discussion in 'Engine Tech' started by wahoo50, Oct 10, 2010.

  1. wahoo50

    wahoo50 Member

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    Engine began running rough, cleared up, back to running rough. Is missing on No. 1 cyl. Have replaced coil, module, plug, plug wire, compression balanced throughout @ 115psi. 220 cam w/1.65 rollers. Removed valve cover, good rocker action so cam appears OK. Replace injector on No. 1, no help.

    While cranking the engine over today I did get a loud backfire through the exhaust twice. Although I haven't readjusted them, the rockers don't appear to be too tight.

    Wondering if I may have a voltage problem to this one injector? Is there a proven way to confirm? Running a Fast system.
     
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  2. turboclam

    turboclam Well-Known Member

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    I would double check the valve springs on #1. Are you using the bee-hive springs or the single coil with an inner spring. I had a single spring break on the coil but the inner spring held it together enough that I missed it when I pulled the valve cover off. What does the plug look like?
     
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  3. wahoo50

    wahoo50 Member

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    I looked pretty closely at the springs, didn't spot a break. These are GN1 Aluminum heads with Champion springs.

    When first removed the plug was a bit wet. Doesn't look like it is firing.
     
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  4. TurboBuRick

    TurboBuRick Moderator Staff Member

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    Backfire when cranking sounds like the cam sensor is off. Remove the cap and check the wheel. Make sure it's tight.

    HTH
     
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  5. Black Power

    Black Power Well-Known Member

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    How did you determine it was #1 that was missing? The FAST doesn't have the data for each cylinder, does it?
     
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  6. wahoo50

    wahoo50 Member

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    Removing the No. 1 plug wire as no effect on the engine, all others do.
     
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  7. Black Power

    Black Power Well-Known Member

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    Gotcha.

    Have you checked out that plug wire and the terminal on the coil pack?

    I think you are on the right track, you have compression so it's not mechanical...all you need to have fire are spark and fuel.

    If you run it for a little bit (not too long, hot aluminum heads don't like you taking spark plugs out of them) and pull out #1 plug, does it have fuel on it?
     
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  8. wahoo50

    wahoo50 Member

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    All six wires read the same resistance, even switched places with the No. 2 wire, still missed on no. 1. When the wire is pulled from the coil terminal, it pops voltage so I'm assuming it's firing the plug.
     
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  9. Black Power

    Black Power Well-Known Member

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    Sounds right.

    Have you tested the individual wire for #1 injector for juice? It seems like the wiring harness is getting power to all the other ones, so if there is a short it would almost have to be between the plugin from the main harness and the #1 injector.
     
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  10. chopped39

    chopped39 Well-Known Member

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    Im no expert but being that a 100psi is min spec for a gn engine do you think 115 is good. If timing was off it would effect compression on all cylinders. if the chain jumped it would cause all kinds of problems low compression and backfiring would be two of them. first check cam sensor timing like Rick said and make sure engine is at tdc then I would pull the rockers and do a leak down test to verify its not a mechanical problem. Like I said I am no expert but if I saw 115 lbs I might be concerned. good luck
     
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  11. Black Power

    Black Power Well-Known Member

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    While the cam sensor could be off, it wouldn't just move on its own.

    Has it always run goofy or is it something new?
     
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  12. turbot990

    turbot990 A member since 05

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    no it cant move but the key way can break and move alittle however is the plug white in color check your coil tower noid light on that no,1 inj plug end and see whats happening there bud im in a fix it mood lol.
     
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  13. 87Regal168W

    87Regal168W Travis Wiley

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    I deffinately agree with this one. Buy yourself a set of noid lights from matco tools or someone that will work for your application. It will deffinately come in handy anytime you have this issue.

    Also look into a spark plug tester. Also from matco its like 10 bucks. If its intermitten i could even see a cracked plug doing this. It only take a smalllll amount of force to crack a plug very slightly. did you try swapping plugs?
     
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  14. wahoo50

    wahoo50 Member

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    Certainly do appreciate the replys. I have replaced the plug with a new one, no help. The plug is not white, appears black, almost wet looking.

    The car is not driven much, but has been running well the last 2-3 yrs. It's a Stage II with all the good stuff.

    Gonna do a leakdown test on this cyl today. Am not familiar with the noid test light, what is it and can you get it from the auto parts stores?
     
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  15. whitehot1

    whitehot1 Well-Known Member

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    Here is a set of noid lights that autozone sells that they normally have in stock but you can buy them seperately. The noid light just plugs into the injector wire connector after you disconnect / remove it from the injector,then you crank the engine over and if the connector is getting power the noid light will flash / blink.

    OEM/6 pcs. noid light set (27161) | Injector Signal Tester | AutoZone.com
     
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  16. wahoo50

    wahoo50 Member

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    This is good. Will get some and test the wiring harness. Thanks for the replys.
     
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  17. pajo

    pajo Member

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    ""The plug is not white, appears black, almost wet looking.""

    That is a tell tell story of no spark at plug - need some more troubleshooting around that area leaning towards cam sensor ..:cool:
     
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  18. wahoo50

    wahoo50 Member

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    Thanks for your comments Pajo. Although I have not tested the cam sensor, I have replaced the plug and wire with one from a cyl known to be firing. The miss stayed at no. 1. Has me stumped.
     
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  19. Phoneguy

    Phoneguy Cometic HG stress tester

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    If the plug is wet it would indicate that fuel is getting into the cylinder. Do you have a coil pack you could swap out? Anyone close that you could borrow one from? Also check your crank bolt to see if it is loose, this will cause erratic issues with the crank sensor.

    Bryan
     
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  20. RmvBfrFlght

    RmvBfrFlght Well-Known Member

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    With the plug being black and wet, sounds like the injector is stuck open or leaking badly.

    If the spark plug wasn't firing the plug will still look new, and wet.

    RemoveBeforeFlight
     
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