Got pinging issues

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  1. #1
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    Got pinging issues

    Sorry, this first post is a bit wordy, but I need to explain the situation.

    So our family wagon is a 2001 Chevy Suburban 2500 4x4 with the 6.0L engine that we have had now for around 4 years. The previous owner had installed some Edelbrock Headers. He also had the ECM reprogrammed for economy and towing. I'm not sure how that is possible, but he said you get one or the other, not both at the same time. He said when towing just put your foot into it when climbing a hill and the vehicle will pull hard. Otherwise, just normal driving will produce the economy. His acid test was the commute his wife made with it everyday to work. Before the mods they were filling the tank every 5 work days, after the mods they were filling every 7 to 8 work days. Not bad.

    Anyways, I have found that when driving up a grade at speed, especially with the whole family aboard, the engine would ping a little. Typically I would back off the throttle or cause it to downshift to eliminate that. I always suspected the econo tune was the culprit.

    So a few weeks ago we needed to make a trip to the coast from the interior. I decided it was a good time to replace the spark plugs and air filter before our trip, I had never touched them since we bought it and it had a bit of a rough idle and hesitation as of late. I also did a Seafoam treatment of the upper intake to clean things up before I changed the plugs. The plugs that came out were the NGK TR55 plugs that have a factory setting of .050" gap. As far as I know, these plugs were never recommended for this engine. The plugs looked good with a clean burn. I checked the gap on the old plugs and they seemed to be anywhere from .061" to .065" gap. I checked the manual and it said to use .060" gap. I have since learned that GM has updated their recommendation to a plug with .040" gap. I went to Lordco and their computer suggested using NGK TR5GP, a platinum plug with .040" gap. I bought them and installed them. On our trip to the coast, as we passed through Kamloops by climbing the steep hill out of town, the engine pinged very badly like I had never heard before and even caused the check engine light to come on (knock sensor code). I pulled into Canadian Tire and bought a few bottles of octane booster, one for the way down and one for the way back. No more pinging during that trip.

    I have since filled up with regular gas a few times since the trip and notice some pinging when the engine labors up a hill. It is certainly more pronounced now then from before I changed the plugs. The rough idle and hesitation is gone too, but the pinging is not good. I cleared the engine code but it has since returned, even when the engine is NOT pinging.

    Not sure what to do. I am considering opening up the gap to .050" and see what happens. I understand that too small of a gap will result in an incomplete burn. Anyone else have similar issues? Did you find an solution to the problem?
    1972 FJ40 & 1984 BJ60 - to be merged into one vehicle: a BJ40 with 4 cyl turbo/intercooled diesel and 5 spd tranny
    1996 FZJ80: was killed by a Moose, I barely felt the impact
    1982 Toy 4x4 ShortBox
    1948 Willys CJ2A
    Fond rememberances of: 1977 FJ45

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  3. #2
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    Re: Got pinging issues

    How is it with just higher octane pump gas? Those knock sensors sit in cups under the plenum that often collect water and then they corrode, leading to bad or missing info to the ECM. They will eventually need doing anyway so maybe pull the plenum and have a look (or watch them on a scanner). I wouldn't change the plug gap. I have installed those plugs in 5.3s and 6.0s with no problems many times.

  4. #3
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    Re: Got pinging issues

    I would get a PCM reflash from a place like Westers Garage and get them to do a dual tune
    you can have a economy or stock tune,press the tow haul button and the PCM will switch over to a 2nd tune or performance tune
    99 silverado RCLB,6inch lift,9k winch,35 bfg m/t,4.10's,5sp
    92 s10,fs jeep d44,ford 9",38s,sm465,duals,4.56's,spools,exo,212 crawl ratio
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  6. #4
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    Re: Got pinging issues

    Quote Originally Posted by sloweryota View Post
    How is it with just higher octane pump gas? Those knock sensors sit in cups under the plenum that often collect water and then they corrode, leading to bad or missing info to the ECM. They will eventually need doing anyway so maybe pull the plenum and have a look (or watch them on a scanner). I wouldn't change the plug gap. I have installed those plugs in 5.3s and 6.0s with no problems many times.
    Haven't tried it with higher octane gas. I too have begun to suspect the sensor itself has gone bad, as it will send a code during normal driving around our neighborhood. I will check into that ASAP. Took the vehicle to Kelowna yesterday and drove it up the big hills outside Vernon and Oyama. Still pinging more than usual, but if I backed off the throttle a hair it seemed to be not bad.
    1972 FJ40 & 1984 BJ60 - to be merged into one vehicle: a BJ40 with 4 cyl turbo/intercooled diesel and 5 spd tranny
    1996 FZJ80: was killed by a Moose, I barely felt the impact
    1982 Toy 4x4 ShortBox
    1948 Willys CJ2A
    Fond rememberances of: 1977 FJ45

  7. #5
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    Re: Got pinging issues

    Quote Originally Posted by 99silverado View Post
    I would get a PCM reflash from a place like Westers Garage and get them to do a dual tune
    you can have a economy or stock tune,press the tow haul button and the PCM will switch over to a 2nd tune or performance tune
    That is essentially what this vehicle has I believe. The previous owner never said anything about the tow/haul button, but when the tow/haul button is pressed, no light comes on on the dash. So I wonder if that is how this one is programmed? Will have to test it out on the next big hill.
    1972 FJ40 & 1984 BJ60 - to be merged into one vehicle: a BJ40 with 4 cyl turbo/intercooled diesel and 5 spd tranny
    1996 FZJ80: was killed by a Moose, I barely felt the impact
    1982 Toy 4x4 ShortBox
    1948 Willys CJ2A
    Fond rememberances of: 1977 FJ45

  8. #6
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    Apr 2009
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    Shuswap/North Okanagan
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    Re: Got pinging issues

    Ok, thought I would give an update. So I ended up opening the gap on the new plugs to just over 0.50" and the pinging issue got slightly better, but the check engine light would still come on. So I resolved I would take the vehicle in to get the knock sensors replaced as soon as I have some disposable cash. However, after about 2 or 3 weeks of driving the check engine light went away, and so did the pinging! The engine runs great now. Very strange. Is it possible it took the computer that long to adjust to the "tune up"?
    1972 FJ40 & 1984 BJ60 - to be merged into one vehicle: a BJ40 with 4 cyl turbo/intercooled diesel and 5 spd tranny
    1996 FZJ80: was killed by a Moose, I barely felt the impact
    1982 Toy 4x4 ShortBox
    1948 Willys CJ2A
    Fond rememberances of: 1977 FJ45

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