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Calibration Module indications are all over the place (with Video)

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  • Calibration Module indications are all over the place (with Video)

    Calibration Module indications are all over the place (with Video)

    Here is the video of the problem that I am having. Notice that the numbers on the calibration module are fine when the engine is not running. When the engine is started the numbers are all over the place and the engine runs terribly:

    I took my SBC Pro Flo XT to a shop (Performance Prep in Federal Way WA) to get it tuned. They said they would not be able to tune it because the calibration module indications are fluctuating too much. The shop said that they checked all of the ground wires and they are fine. The technician said that he tested the water temp and it works fine. He also said it is reading fine at the sensor and at the ECU. He advised me to send the ECU into Edelbrock to be repaired.

    I talked to a Peter at Edelbrock Tech Support and he had me send in the ECU to be evaluated/tested. Peter said the ECU was hooked up to their simulator and was working fine.

    I ordered a new water temp sensor and replaced it. No change.

    Nothing is plugged into the ‘user interface’ plug.

    I have the standard Pro Flo XT ECU, not the ‘PLUS’.

    I have noticed that the voltage to the water temp sensor is about 3.3 volts. Should this be 5 volts maybe?

    I have a wide-band O2 sensor and I made sure that the jumper is in place.

    Thinking my alternator is spitting out bad current, I disconnected it and started the engine. No change.

    I moved all of my plug wires away from other wires to try and isolate them.

    I pulled the plug to the ECU and made sure that the proper pin grounded out ok.

    Any ideas would be greatly appreciated. I would really like to enjoy the car this spring and summer.

    Thank you,
    Matthew Cannon
    Normandy Park, WA

  • #2
    Looks like a sensor ground problem since that's what's common between all those channels that are fluctuating. If ECU was tested to be okay then it's likely a harness, wiring or install problem. What's a common cause of this is having sensor ground tied to a chassis ground that also has something noisy grounded to it. This can happen when ancillary items (like wideband O2 gauges or ignition boxes, etc) get added into the harness. If it only happens when the engine is running then that points more towards the ignition being the problem.

    How about some more background info? Has this problem always existed? Or did it recently pop up? How long has the kit been installed?


    • #3
      It looks like it was the O2 sensor. I took out the wideband and replaced with a stock one that would have come with the kit. No I need to figure out why I'm having a problem setting the base timing.