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Thread: Knock Sensors

  1. #1

    Default Knock Sensors

    I am having trouble verifying that my knock sensors are recognized by the HP ECU.

    Configuration - SC BBC marine:
    - 2 single wire early GM sensors
    - threshold at 50, although others tried

    I tried tapping on the block with a hammer, but see nothing in the ECU logs.
    Should the ECU recognize that knock sensors are connected? Since these are standard, there is no way to Pin Map them that I have found.
    All other sensors, oil pressure, etc. show up on my laptop. Maybe I don't have logging set up right. I could put a scope on the wires, but I doubt that both sensors/conn are bad.

  2. #2
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    Quote Originally Posted by conmax View Post
    I am having trouble verifying that my knock sensors are recognized by the HP ECU.
    The Data Monitor & Data Logger need to be "Edited" to display the "Knock Retard" & "Knock Level" channels.

    I tried tapping on the block with a hammer, but see nothing in the ECU logs.
    Have you tuned the knock sensors? Read this thread:
    http://forums.holley.com/showthread....ors-Holley-EFI (Connecting & Tuning Knock Sensors)

    Should the ECU recognize that knock sensors are connected?
    Yes, you can monitor them on the Data Monitor and record them on the Data Logger.

    Since these are standard, there is no way to Pin Map them that I have found.
    Pin-Mapping isn't involved with the knock sensor wiring or function, because they're prewired in the main harness.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  3. #3

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    I am still struggling to get the system to recognize the existence of the 2 knock sensors. I don't believe that they are both bad or miswired. The original sensor is connected to the prewired knock sensor connector that came with the harness. I added an extension wire and connector to knock sensor #2 in the harness.

    I left the default Frequency value alone. I set the Ignition Parameters to 2 single wire sensors. The 2 wire sensor ground is left unconnected since I have only 1 wire sensors. When I turn the key on, no knock sensors show up in the Data Monitor. The other sensors like WBO2 and CTS are active.

    I must be missing something very basic. To think that I have been able to setup far more complex things like 2 bar MAP and idle optimization and something so simple as recognizing the knock sensors is really frustrating. Maybe you could walk me through a step by step on the sensors. I have read the manual many times and looked at all of the knock sensors posts on the forum, but they are mostly about tuning and I can't even get beyond the system recognizing that the knock sensors are even present.

  4. #4
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    Quote Originally Posted by conmax View Post
    When I turn the key on, no knock sensors show up in the Data Monitor.
    The knock sensors aren't displayed by default, even when they're installed and selected in the EFI software.
    The Data Monitor & Data Logger need to be "Edited" to display the "Knock Retard" & "Knock Level" channels.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  5. #5

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    Maybe mine are working. How do you edit the Data Monitor to display knock status? Also, I guess that some knock event must occur, so I will have to force that. I was expecting it would display the presence of the knock sensors, but the feedback must only be based upon a knock event.

    Also, somewhat different topic; if I click Send to ECU, will the Learned values be erased?

  6. #6
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    Quote Originally Posted by conmax View Post
    How do you edit the Data Monitor to display knock status?
    Click on the "E" button at the upper left corner of the Data Monitor. This opens a setup window where you can select which channels are listed.

    I was expecting it would display the presence of the knock sensors, but the feedback must only be based upon a knock event.
    Once you add the knock sensor channels, they'll always be listed (0%-100% Knock Level & amount of Timing Retard), whether or not a knock event occurs.

    ...if I click Send to ECU, will the Learned values be erased?
    Not exactly; the Learned values will be overwritten (not erased) with whatever is in the Global Folder you sent to ECU.

    "Get From ECU" & "Send To ECU" - ECU Sync window:
    When you connect a laptop and go "Online" with the ECU, you first want to click "Get From ECU". This updates your laptop with the latest ECU "state of tune". If you click "Send To ECU", you overwrite all the Learning the ECU has performed since the last time that laptop was connected (because you're not sending the latest, up to date values to the ECU). The only time you should click "Send To ECU", is if you're just sending a Global Folder change to the ECU and you haven't driven the vehicle since the last time the laptop was connected.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  7. #7

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    To be clear, the HP can run a pair of the single wire GM knock sensors and does not need the ESC module like the old C950 does when using the single GM 1-wire knock sensor?

    Just Pin Map each sensor wire, setup to their rated Hz and basically they're installed?

  8. #8
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    Quote Originally Posted by Bill C View Post
    To be clear, the HP can run a pair of the single wire GM knock sensors and does not need the ESC module like the old C950 does when using the single GM 1-wire knock sensor?
    Correct, no ESC module.

    Just Pin Map each sensor wire,...
    No, knock sensors aren't Pin Mapped. They're predefined & prewired Inputs.

    ...setup to their rated Hz and basically they're installed?
    Correct, just wire the knock sensor(s) to the Knock sub-harness connector and tune them.
    http://forums.holley.com/showthread....ors-Holley-EFI (Connecting & Tuning Knock Sensors)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  9. #9

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    Danny, I hate to keep making new threads and or plaster old ones with repeat questions. However, my application and needs are somewhat odd. Let me explain.

    I have the early release 550-406 that has the extremely basic harness. I'll do my new ring block break-in with it as is, but then will need to swap to a MPFI harness, and essentially it will be a TPI setup, but will use two knock sensors, oil and fuel pressure sensors, as well as the Holley Dual Sync distributor with MSD 6A for a while. But then over this coming winter I'll swap to LSx Coil-Near-Plug setup.

    I hate to buy two different harnesses. The Universal Unterminated harness that has 15 foot flying leads looks like the best choice for me, but would require I remove the can connector as well as a couple others, so then my Terminator harness would be incomplete. I notice now, and in the past your setup is quite custom.

    What did you use for a main harness as your setup progressed and changed? I have no problem spending the money, yet do not want to waste money or render the current TBI harness I have unusable. What do you suggest I do to save money and get the best bang for the buck?

    The Terminator harness I have is so old it doesn't have the basic main harness that they now ship with, it is the old one without oil pressure sensor plug, without knock sensor plugs, and the entire TBI wires come off one plug vs the newer setups that have a separate ignition and injector plug.

    The ideal situation would be a main harness that is plug & play with the Terminator TBI too, can be plugged in, and later the CNP can be plugged in. Eventually I'll buy another HP ECU. And I'll use the HP for a couple different cars, and the ability for it all to be plug & play from one setup to the other allows me to have a backup ECU, as well as injection setup. Confused yet? I am. Ha Ha Ha

    558-126 looks like the cheaper option. Or buying extra wires and ECU pins. Which way did you go? Modify your existing harness, or start with a fresh one? I'm just unsure of the most economical way to do it.

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