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Thread: HP ECU - No +5V Sensor Out

  1. #1
    Join Date
    Jun 2016
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    Finland
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    3

    Default HP ECU - No +5V Sensor Out

    Hi. Having a strange issue with new HP ECU HW, does anyone know is there anything SW related, why cannot get A26 pin 5V out for Sensors. Problem issue:
    - Cannot get 5V our from pin A26/orange ==> only 0.110V output is coming.
    - No TPS Autoset cannot be performed.
    - TPS Autoset gives error: Not enough Voltage difference (need at least 1.5V).
    - No correct readings coming to TPS, MAP, MAT, CTS.
    - MAT & CTS is showing some 300F value, TPS & MAP is "low error".
    - No extra sensor connected to A26 5V feed.
    - We also remove All connectors, Crank Signal, WBO2, TPS, MAP, CTS, MAT, IAC, Injectors, if there might be some Ground connect, but still no 5V ref out from A26 pin.
    - Engine do not start.
    - USB connection is OK & PC can control and see all data related to Holley SW.

    We switched back older HP ECU Serial: 0D8D to same Power & Main wiring set, with this one:
    - TPS give values, TPS Autoset can be performed.
    - MAP, MAT, CTS gives correct values.
    - When measuring A26 pin from for E.G. TPS pigtail, orange wire gives 5.001V.

    Cannot have more ideas what might be issues except something inside ECU or damaged "A26/Sensor 5V output" somehow?
    We had some battery issue at beginning no voltage coming out and replaced a new one, but cannot believe that could cause some permanent issue to ECU.
    Esa

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    28,245

    Default

    I would contact Holley Tech Service (LINK) about this.

    EFI Software Problems:
    Often times, when EFI software related functions don't work properly, it's caused by a corrupted software download/installation.
    I suggest completely removing the Holley EFI software from the "Control Panel", "My Documents" (Holley folder) and
    the "C:Drive" (Program Files, Holley folder) and install a fresh EFI software download. Save your Global Folder somewhere.
    ECU Firmware Problems:
    Conversely, often times, when actual ECU related functions don't work properly, it's caused by a corrupted ECU firmware installation.
    As a last resort, you can try reflashing the ECU firmware version (LINK). The ECU firmware is in with the software download (LINK).
    Also, try completely disconnecting the battery for 20 minutes (or 2 hours for some severe faults). This "resets" some unusual ECU issues.
    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
    Join Date
    Jun 2016
    Location
    Finland
    Posts
    3

    Default

    Hi. Could try once again installing Holley EFI V4 software & firmware again, but remember we did this one already. Battery had been removed couple of times for overnight to reset ECU issues. BTW, is it actually possible to downgrade ECU Firmware from V4 to V2?

    I have V2 in old ECU, which seems to work quite well with all sensor, except that ECU chassis has not so good EMI protection as newer ECU serial/date code ECUs. Old ECU has issue if you connect something to CAN Bus EMI noise can cause total ECU reset, if close to noise source like spark plugs, coils, alternator or other EMI/RFI noise generator. Esa

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    28,245

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    Contact Holley Tech Service (LINK).
    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

    Default

    I realize this is a nearly ancient thread, but I'm having the same issue with my Terminator Stealth installation. I was on the phone with Holley Tech Support because I could not get the TPS Autoset to complete.

    ECU, LCD & laptop all at V5. I've unplugged and tested the TPS independent of the system, works great. So does the second Holley TPS I have.
    Checked continuity of the throttle body harness to TPS - no issues.
    Checked for +5V going into the throttle body harness - measured 4.9V.
    Grounds all good.
    Power and ground for ECU direct to battery.
    Fuel pump comes on with key-on.
    CTS & MAT both read 302°F with key on.
    FPS and MAP no reading.
    Battery steady at 12.3V.

    Holley Tech unsure about the issue, asked me to send GCF and we will discuss Monday. Seeing this thread I'm curious what Mip713 found to be the solution to his issue? Open to suggestions to investigate. Thanks, Andrew

  6. #6

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    Have you tried unplugging the 5V sensors one by one to see if the issue goes away? I had a customer who had a faulty oil pressure sensor and it was having these same problems intermittently. Andrew
    Instagram: @projectgattago
    Offering remote Holley EFI tuning.
    I deliver what EFI promises.
    Please get in touch if I can be of service.

  7. #7
    Join Date
    Jun 2016
    Location
    Finland
    Posts
    3

    Default

    Hi. My case was that HP ECU 5V Sensor Out got burned out or something inside ECU got damaged. I had another working Avenger ECU unit (same as HP), so wire & sensors check was easy, just to replace ECU and check everything works.

    Holley ECU 5V sensor out is actually quite accurate 5.00V, not 4.7-4.9V or something lower. Also when measuring 5V sensor out, you need to use Sensor Ground pin to get accurate measure, which is a different port/wire. If recall correctly TPS sensor out should give 3.3V at WOT, but it's difficult to measure due to pigtail rubbers and need to be careful not to shortcut any wires.

    I swapped to Dominator ECU with new order, which has multiple 5V Sensor Out ports for extra/additional sensors and you can then leave main TPS, CTS, MAP, MAF as engine main 5V sensor feed.

  8. #8

    Default

    Hmm, have you, or any customers verified the average load on the 5 volt reference line and attempted to fuse it? Could maybe save on some of the ECU failures that have been reported because of sensor failures? Just a thought.

  9. #9

    Default

    First, thank you for your responses and suggestions to try and sort this out. Spent some more time with Holley Tech Support including disconnecting the two +5V sensors, Fuel Pressure & TPS. No improvement. ECU is heading back to Holley for evaluation.

  10. #10
    Join Date
    Jan 2018
    Location
    SEVERN, Ontario
    Posts
    118

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    What I've done on a few Honda and Ford ECUs with the same problem is cut the +5 volt wire from the ECU then install a +5 volt supply from another source I made a 5 volt regulator for under $10.00 for Holley ECUs. Get the power to turn on the regulator from the pink wire so you have power while in crank and run the regulator with power up all the sensors. As long as the ECU gets the reference voltage from the sensors, it should work. ECU doesn't care about the +5 Volt supply. I used a 3 amp regulating transistor and the output is dead on 5V. This can save you from buying a expensive ECU. Hope this helps. Joey.S
    Last edited by Joey.S; 04-21-2021 at 07:42 AM.

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