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Thread: Bad HP ECU?

  1. #1

    Default Bad HP ECU?

    Bought this HP about a year ago for a motorcycle converted to EFI about seven years ago. Have run three different versions of MegaSquirt systems on it. Decided to switch to Holley after some persistent problems with running large shots of nitrous for one mile land speed racing.

    Purchased the HP and a wiring harness through a motorcycle performance shop specializing in Holley EFI and dry nitrous on race bikes. The project got put on the back burner when the event we normally run was permanently cancelled this year. I’m back on the project and completing the wiring.

    I think I have an issue with the sensor 5 volt output. I was getting only 1.5 volts or so. In order to get the wiring done, I decided to use the 5 volt output from a datalogger I have. I unpinned the sensor 5 volt wire (pin A26) and connected it to the 5 volt source from the datalogger. The datalogger was grounded at the battery negative with the Holley HP. TPS & MAP and fuel pressure seem to work well - TPS calibrated and is very stable and consistent, MAP agrees with baro and increases/decreases when blowing/sucking, haven’t hooked up the fuel pump, but it reads 0 or 1 psi.

    Temp sensors - both MAT & CLT are giving me fits. Using GM sensors and get very high readings from both. Each sensor checks for proper resistance for the temperature. But both show temp readings corresponding to about 200 Ohm resistance (actual Sensor resistance being 4,000 to 5,000 Ohms).

    Battery voltage is correct in the software. Everything appears normal to this point except for the low 5 volt sensor power output and the skewed temp sensor inputs.

    Started troubleshooting. Removed all sensors one at a time, removed the solid state relays for the nitrous system, removed the arming relay for the nitrous, removed the relay for the fuel pump, eventually removed everything from the ECU and everything from the battery. Consistently through all this, if I plug main power into the ECU, I get 1.2 volts between pin A26 (sensor 5V) and pin A18 (sensor ground). If I put 12 volts to pin A10 (switched 12 volt input) the voltage between A26 and A18 goes to 0.8 volts. Voltage between A26 and battery negative will show About 2.7 volts (will jump around some). It seems as if there is stray voltage or something on the sensor ground - maybe that is causing the gross error on the temp sensors?

    Is there anything I’m overlooking before I try getting it serviced or warrantied? Thanks, Chris

  2. #2
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    23,064

    Default

    http://forums.holley.com/showthread....2193#post72193 (EFI Software/ECU Firmware Problems)
    https://forums.holley.com/showthread...ensor-Problems (Also check Pin Mapping. See post #5)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  3. #3

    Default

    I’m on V4 now (same as delivered when purchased). Should I update to V5? Or is reinstalling V4 fine? Thanks.

  4. #4
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    23,064

    Default

    V4 should be fine. The point is to reflash the existing ECU firmware, not necessarily to update it.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 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, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 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 tires.

  5. #5

    Default

    Reloading the firmware failed, usually with an error [29]. Also some error [1] and error [1024] thrown in for good measure. Looks like I’m calling tech in the morning. Hopefully they can work with it.

    UPDATE: Very pleased with Holley tech line. Called them first thing this morning, waited less than 10 minutes. Explained the issue, waited a couple more minutes, got a “tech return” number, and shipped it out this morning. Holley should have it by Thursday. Hopefully they can sort it out!

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