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OT Buick Spark problem- HELP

Discussion in 'Uncategorized Threads' started by Frank C, Mar 27, 2008.

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  1. Frank C

    Frank C Well-Known Member

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    Girlfriend has an 03 Buick Century, approx 80K. Today the check engine light started blinking, engine running rough, exhaust puffing like a plug misfire. I borrowed an OBD-II and it gave a code of #2 cylinder misfire. sure enough that plug was wet. I swapped two plugs and cleared the codes and restarted, again #2 misfire code. plugs are original, but don't look bad. So what next? Looked at the wire, not burned or damaged, nor corroded etc. it appears that two plug wires come from each "coil" or what was formerly the distributor cap.

    So what goes bad in there these days? Thanks in advance for the help- Frank C.
     
  2. blizzard

    blizzard Active Member

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    I beleive that "coil pack" is commonly the problem.
     
  3. Frank C

    Frank C Well-Known Member

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    Looked it up at Autozone. $24.99, seems simple enough, any tricks to installing? Disconnect battery?? Etc.
     
  4. halfmile

    halfmile Well-Known Member

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    NO juice on there unless the key is on. If you disconnect your battery your clock will go to 12, your radio presets will vanish, and your shorts will melt.

    HM
     
  5. sako2115

    sako2115 TS Member

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    Hope it all works. Now if the plug is wet, could it not be due to valve guide problem or bad compression, bad ring, etc.? What happened to mechanics that know how to run a "good old leakdown test"?

    I hope all turns out fine with the part replacement.
     
  6. Frank C

    Frank C Well-Known Member

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    I s'pose it could be a more serious issue, but it is doubtful to me....engine well cared for, oil changed at 3000 miles, the problem happened suddenly, running purrfect b4! my standard compression tester isn't long enough to reach down to the plug opening...
     
  7. AveragEd

    AveragEd Well-Known Member

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    Coil pack failures causing misfire codes (P030-) on all cars are approaching commonplace these days, so I think you're on the right track. Fortunately, on a 3100 V6, they're inexpensive and easy to access.

    Ed
     
  8. todd farris

    todd farris TS Member

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    Howdy

    If the car has 80000 and hasn't had plugs or wires, I would start there. I know the coils can fail but you don't see it that often. As well, if it is a 3.8, the intakes are prone to fail internally and allow water into the cylinder. If this is the case, change it IMMEDIATELY as water is not compressible and when the intake really fails it will fill the cylinder and you will bend a rod/break a rod. You will need to replace the intake which you can buy from Napa, Carquest, etc. If it is a 3.1/3.4, it could need a new intake gasket. These generally don't cause misfires, they allow coolant to leak into the oil and to the atmosphere.


    Hope this helps.

    Todd Farris
     
  9. Frank C

    Frank C Well-Known Member

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    Tis a 3.1, no water in the oil. Bought the coil pack at lunch, will replace it tomorrow after the SNOW MELTS!! I thought it was spring in Massachusetts??
     
  10. motordoctor

    motordoctor Shoji Tabuchi in Branson

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    I would recommend replace all the plugs and wires along with a fuel filer. Clean the injectors wiht a cleaning machine and/or put some blaster fuel injector in the tank. you could also have a stuck fuel injector with too much fuel in the cylinder.I believe it has port injection take a look at those. motordoc
     
  11. Frank C

    Frank C Well-Known Member

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    Well, installed the coil pack.....cleared the codes and the engine still missfires. Swapped out wires, one for another, cleared the code, swapped plugs for another cyl......and still runs rough and has the SAME code. Will likely take it down the street.....running to crappy to try and wait out injector cleaner, and too cold to screw around with it any further....Thanks for the help all, will post the reply on Monday hopefully FC
     
  12. sammyd95

    sammyd95 TS Member

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    I put brand new plug wires on my 2000 lesabre ,and was still having trouble,took it to the garage ,and it cost me $184.00 to find out that one of my new wires were bad,good thing they had a warranty,i got free wires.(its suposed to be a joke)but it is the truth!
     
  13. austin fatts

    austin fatts TS Member

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    Sounds like your intake manifold gasket is leaking. Common problem.

    Austin Fatts
     
  14. JPK1957

    JPK1957 TS Member

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    A simple spark tester will tell you if the cylinder has spark. Auto Zone or the like should sell one. Just ground it, plug the wire on and fire it up.
    Do only one at a time. If no spark, check the companion plug and wire also, as they fire together in pairs. If one's bad neither will fire.

    Try some carb spray at the manifold/cyl head parting line and see if rpm changes. Also, measure the resistance across the injectors. If the coil pack or wires ( probably wires at 80k )were bad it's also possible that the ignition module is faulty, but it will normally fail on both companion cylinders. This is a waste park system where the plugs fire in pairs. Is the companion plug or wire bad. At 80K I'd check compression on the bad cylinder before hunting another problem.

    If the OBD-II is only showing one cylinder mis-firing, I'd lean to an injector or vacumn leak.

    An injector drop test would be in order. I've been away from driveability and autos for a while, but I believe the OBD=II will do the drop test. Just put a fuel pressure gauge on and record Key on eng off pressure, cycle each injector 1 at a time and record the fuel pressure drop, key off and on to rebuild fuel pressure between each injector.

    Hope this helps a little, John
     
  15. Frank C

    Frank C Well-Known Member

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    Plenty of spark, I put a plug in the wire and ran the engine (got whacked too) I an leaning towards a prob with the injector.

    I didn't touch it today, it was TOO nice....finally! we shot some practice and just enjoyed the 50F weather! It'll go to the mechanic for him to skin his knuckles on in the morning!

    I'll report back on the cure!
     
  16. Frank C

    Frank C Well-Known Member

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    they had a look at it today......preliminary report is......no compression.....they will pull off the valve cover for a closer look tomorrow
     
  17. Frank C

    Frank C Well-Known Member

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    We finally have a diagnosis! Before she bought this car they replaced the intake manifold gasket (2 yrs ago) to do this job required removing the rocker arm assemblies...well apparently the mechanic over-torqued the steel bolts in the aluminum head and nearly stripped out the threads on at least two of the bolt holes. One set of threads finally let go and as a result the intake valve rocker arm was loose, upon intake stroke, the valve stayed closed, and upon the compression stroke, there was nothing to compress.....so there was no compression on the gauge.

    Now the question.....what is the fix for these two stripped holes?? Heli-coils? Will they be strong enough to withstand the constant vibration of the engine?? The mechanic is worried that he has no idea IF the fix would be permanent or not?? He wants to drop an engine with 18K into it (from salvage)for $2300!!!!
    Without further disassembly of the other head we won't know if one of THOSE is ready to let loose as well. IT took two yrs for this one to loosen, and the mechanic loosened one more and after just cracking it loose, it popped out stripped...

    Comments pro and con please!! Frank C.
     
  18. Texas Ton

    Texas Ton TS Member

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    Properly done, a Heli-Coil is stronger than it's ever been.
     
  19. Jim101

    Jim101 Active Member

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    I would heli-coil all of the rocker bolt holes. It's not difficult to do correctly and will be stronger than new. I've used them in acft engines turbine and recip, Car engines, Outboard engines and never had one fail.




    Jim
     
  20. Frank C

    Frank C Well-Known Member

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    Thanks, this is the news we were hoping for- FC
     
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