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Thread: Fuel pump relay control voltage low.

  1. #1

    Default Fuel pump relay control voltage low.

    I have a 550-601 on a tuned port engine. It ran fine when it came out of the other car a year ago. Do these computers lose their base tunes after along time? Engine has spark, but no injector firing. Fuel pump running, the voltage on the relay computer control side is only two volts and the fuel pump will not come on. I jump the relay, fuel pump comes on, but still no injector fire. Had similar problem at another shop where the control voltage was low, but jump the relay and would have fuel pump and it would run. No cranking RPM. I did update the firmware in the computer, could that cause problems? I'm going to do a new download and update. I did a TPS Autoset.

  2. #2
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    Default

    Quote Originally Posted by wagonmaster View Post
    No cranking RPM.
    Well that's why it doesn't start or run the fuel pump.
    http://forums.holley.com/showthread....5760#post45760 (Scroll down to "Typical No-Start Checks".)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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 can get the fuel pump to come on, still no injector fire. Do you know how to test the distributor ignition module at the Holley computer? Not sure what Holley wants to see, I do know it's different then what GM wanted. Thinking could be no signal from distributor or it's related to not having 12 volts at the fuel pump relay.
    What is the Crank Input supposed to be?
    What is the Cam Input/Bypass out supposed to be?
    What is the EST/Spout Out supposed to be? Does Holley use this to control injectors or just for the tach?
    Does the computer supply 5 volts to the distributor like GM, or is it like a MSD magnetic pickup.
    Last edited by wagonmaster; 06-17-2019 at 06:59 PM.

  4. #4
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    Did you upload the Global File into the ECU after the ECU firmware update? Is this a GM small cap HEI distributor? If so, ensure it has a genuine GM ignition module inside.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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

    Which file? I do not have the old file. I soon as I hooked the laptop up, I was prompted to update everything. I got everything to use handheld on it today, after I updated everything again. Yes, GM small cap HEI with dual plugs.

  6. #6
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    Quote Originally Posted by wagonmaster View Post
    Which file? I do not have the old file.
    Has your Global File (engine file) or a base calibration been uploaded into the ECU?
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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.

  7. #7

    Default

    I don't know, I couldn't link up. I had V4, wouldn't do anything, had to update to V5. It had one because the car ran before the engine was pulled. That's why I was hoping to see with the handheld.
    Last edited by wagonmaster; 06-18-2019 at 05:11 PM.

  8. #8
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    If you don't have your previous Global File, then you must start over by uploading a base calibration.
    http://forums.holley.com/showthread....ents-Read-This (Initial Checks & Adjustments - Read Step #1)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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.

  9. #9

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    That's where I'm at, but I must of done something wrong. It's been awhile since I've done it, I'll try again today. Thanks for the links.

  10. #10
    Join Date
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    Connecticut
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    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, 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.

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