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Thread: knock counter

  1. #1
    Electronic Ignition!
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    knock counter

    I wish to zero out the knock counter each time I start a new data log run. Could someone tell me where to find info on how to do that, please?
    87 chevy truck ecm 1227747
    Thanks,
    Dave

  2. #2
    Electronic Ignition!
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    I have another question... can anyone offer a reason why my battery voltage shows 16.9 to 17.1 volts on the TunerproRT dashboard while datalogging. It shows normal (13.5V or so) on the actual (real) gauge. Truck runs terrible (lean spit / cuts out) when virtual gauge goes red, runs good when virtual gauge goes back to blue. All the while the real gauge stays the same. I checked and cleaned battery cables and grounds. found no burned or hot wires indicating high current draw, yet it acts like there is not enough juice to fire the coil, backfiring through the throttle body. Shut it down, check for loose connections, fire it back up and it's normal again for a while. Maybe a battery with an intermittent internal short? Suggestions? I'm baffled.

  3. #3
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    Hello Dave,

    The knock counter is not set to zero in code. Changing this would require writing code specifically to set the counter to zero on start or restart.

    I would look at the Tunerpro RT definition file to ensure it is translating ecm data correctly, then I would check voltage at the point where the ecm is sensing voltage.

  4. #4
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    Thanks, that sounds like good advice. I'll do that and report back.

  5. #5
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    regarding the knock counter ... I'll not bother with it as it has no particular value toward making the truck run better. As to the other issue "very high battery voltage" I think I agree that it is a software problem. I checked voltage at pin A6, B1 & C16 and found 12.4 at each, although the engine was not running at that moment. I tried a drive test of around 35 miles to see if it would clean up and run right. Alas, no joy! when cold, it would hardly move from a dead stop. just would not take any pedal without the lean spit. Unless stomped wide open, then it would accelerate well until high gear. I was not logging during the drive, but it was definitely lean at freeway cruise. fully warm, it would take off better, but still not smooth. After returning I obtained another pressure gauge and checked fuel pressure at the throttle body inlet. it was a solid 13psi on one tank and 12 1/2 on the other. Voltage was also checked at the relay and at both pumps and was nominal at 12.4 volts. Finally I took a hard look at the injector cone spray pattern and saw a steady dribble from the center of each cone. Cleaning did not improve so I ordered a new pair of injectors. They should be here next week. I hope they do the trick. I'll try to post a log file showing the High Battery reading and the definition file if anyone wants to take a look. I tried to see if I could tell what was going on, but don't have any experience. Anyway, thanks. I'll post the files in my next reply.
    Dave

  6. #6
    Fuel Injected! PlayingWithTBI's Avatar
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    Quote Originally Posted by ddiamondav View Post
    I wish to zero out the knock counter each time I start a new data log run. Could someone tell me where to find info on how to do that, please?
    87 chevy truck ecm 1227747
    Thanks,
    Dave
    When I start a log on my 88 5.7L it resets back to zero every time but, as soon as I start it when cold I get ~19 KO.

    I'm using ADX file $42-1227747-V5.ADX

  7. #7
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    Quote Originally Posted by PlayingWithTBI View Post
    When I start a log on my 88 5.7L it resets back to zero every time but, as soon as I start it when cold I get ~19 KO.

    I'm using ADX file $42-1227747-V5.ADX
    I was using $42-1227747-V3T.ADX, I will try a later version and see how that works. I installed the new injectors but truck still runs lean. From a stop it just won't take any pedal. It backfires thru the throttle body several times then takes off only when held wide open. Gets a little better when fully warmed up. I have replaced CTS, IAC, TPS, MAP, both fuel pumps, tank switch and valve, plugs/wires/cap/rotor, injectors, made the fuel pressure regulator adjustable and cranked it all the way up. Fuel pressure checks 13psi on one tank/pump and 12 1/2psi on the other. it has a new air filter, oil filter, clean oil, fresh antifreeze, and all new vacuum hoses. The only things left are the O2 & EGR.
    I need to get it smog tested to complete the registration process this month as all the fees are paid for last year, but the new year starts the end of April so I will be delinquent May 1. I'm worried if it fails smog they will label it as a gross polluter. I will drive it 50 miles to get it good and hot then take it in to the smog test shop tomorrow afternoon. I asked for a pre-test first, then, if it passes, take the official test immediately thereafter. I hope this works, 'cause I don't know what else to do.

  8. #8
    Fuel Injected! PlayingWithTBI's Avatar
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    Quote Originally Posted by ddiamondav View Post
    I was using $42-1227747-V3T.ADX, I will try a later version and see how that works. I installed the new injectors but truck still runs lean. From a stop it just won't take any pedal. It backfires thru the throttle body several times then takes off only when held wide open. Gets a little better when fully warmed up. I have replaced CTS, IAC, TPS, MAP, both fuel pumps, tank switch and valve, plugs/wires/cap/rotor, injectors, made the fuel pressure regulator adjustable and cranked it all the way up. Fuel pressure checks 13psi on one tank/pump and 12 1/2psi on the other. it has a new air filter, oil filter, clean oil, fresh antifreeze, and all new vacuum hoses. The only things left are the O2 & EGR.
    I need to get it smog tested to complete the registration process this month as all the fees are paid for last year, but the new year starts the end of April so I will be delinquent May 1. I'm worried if it fails smog they will label it as a gross polluter. I will drive it 50 miles to get it good and hot then take it in to the smog test shop tomorrow afternoon. I asked for a pre-test first, then, if it passes, take the official test immediately thereafter. I hope this works, 'cause I don't know what else to do.
    I'm also using this .xdf if that helps
    Attached Files Attached Files
    Last edited by PlayingWithTBI; 04-19-2019 at 03:43 PM.

  9. #9
    Fuel Injected!
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    If I'm not mistaken, 'V3T.ADX is for a TH-400.

  10. #10
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    Quote Originally Posted by PlayingWithTBI View Post
    When I start a log on my 88 5.7L it resets back to zero every time but, as soon as I start it when cold I get ~19 KO.

    I'm using ADX file $42-1227747-V5.ADX
    I think there's a GM service bulletin for this...

  11. #11
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    Quote Originally Posted by tayto View Post
    I think there's a GM service bulletin for this...
    A TSB for what, the ADX file or Knocks?

  12. #12
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    Hey Dave, how did the smog test go?

  13. #13
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    After a 50 mile run down the 405 to El Toro and back, I rolled into the check station. I left it idling to keep it warm, but before the tech arrived (20 minutes or so) she started smoking just a little bit blue/grey. When I revved to clean up, a big cloud enveloped the truck. So I told the reception gal I changed my mind, and split.
    A couple days later a friend suggested a smog tech he knew to be a highly skilled artist might be able to fix the problems. He wasn't cheap but it's running good now. Passed smog and registered a couple days ago, so am good to go. Thanks to everyone for the help.
    Dave

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