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Thread: Missing data points with engine not running.

  1. #1

    Default Missing data points with engine not running.

    Hello. I think I'm missing a lot of data points with engine running or not.
    Can you confirm it is not normal?
    Sometime I have no point during 3/10 seconds.
    It follows a pattern, this is weird. Thanks.
    The following datalog is with engine not running.
    If it's not normal I'll do the classic check:
    - Grounds.
    - 12V with relay.
    - ...
    Sniper_0039.zip

  2. #2

    Default

    Are you capturing the datalog on a laptop or the touchscreen? Sometimes a data dump to a laptop can be wacky depending on the USB config and other activities in the computer. Otherwise I would look at loads in your wiring. The alternator/regulator, for example could produce a pattern depending on their condition. I would try taking the pink wire directly to the battery for a quick test without the ignition on. If it happens with key-on then I'd start disconnecting loads until you find which is affecting the data. A strange ground loop between the battery, frame, engine, and firewall/body could also produce a strange voltage pattern. It it does it with the pink wire (key on 12 volts to Sniper) without the ignition switch turned on it could still be grounding or the charging circuit. If the datalog look good when wired to the battery, turn the key to "on" and take another datalog. That would also help determine if the problem is related to other loads.

  3. #3

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    I'm battling this exact same situation. I've tried cleaning grounds, adding grounds, moving the handheld wire, running with the belt off, and putting the pink wire on a relay. I haven't been able to figure it out. It's getting super frustrating. My car is running really well, but I just think about how much better it'll be when I'm getting all 60 data points per second. Hopefully one of us will be able to figure out a solution.

  4. #4

    Default

    Quote Originally Posted by Bcsader View Post
    I'm battling this exact same situation. I've tried cleaning grounds, adding grounds, moving the handheld wire, running with the belt off, and putting the pink wire on a relay. I haven't been able to figure it out. It's getting super frustrating. My car is running really well, but I just think about how much better it'll be when I'm getting all 60 data points per second. Hopefully one of us will be able to figure out a solution.
    At least your engine is running well. Mine is not at all. The right frequency is 60 points per second?

    Quote Originally Posted by GPatrick View Post
    Are you capturing the datalog on a laptop or the touch screen? Sometimes a data dump to a laptop can be wacky depending on the USB config and other activities in the computer. Otherwise I would look at loads in your wiring. The alternator/regulator, for example could produce a pattern depending on their condition. I would try taking the pink wire directly to the battery for a quick test without the ignition on. If it happens with key-on then I'd start disconnecting loads until you find which is affecting the data. A strange ground loop between the battery, frame, engine, and firewall/body could also produce a strange voltage pattern. It it does it with the pink wire (key on 12 volts to Sniper) without the ignition switch turned on it could still be grounding or the charging circuit. If the datalog look good when wired to the battery, turn the key to "on" and take another datalog. That would also help determine if the problem is related to other loads.
    It's captured with the touchscreen. You're right, I'll do exactly what you said, plus rewiring all my grounds (00 AWG battery to engine, 4 AWG engine to frame, 4 AWG frame to firewall, 10 AWG body to battery).

  5. #5

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    So I've rewired the grounds: 00 AWG battery to engine, 4 AWG frame to firewall, 4 AWG body to battery, 10 AWG engine to frame (first gen Camaro, very little frame, nothing on it). Same issue. Then I changed the SD card and now it works fine when engine not running. But when I start the engine it's working fine for maybe 30 seconds (almost 60 points per second) and then it starts missing points per second, a lot. I tried to route the temp sensor a different way, but it's the same.

    In the datalog you can see I have blank spot of several seconds. It is new. At the end of the datalog I tried to remove the temp sensor, but not change. Do you have any ideas? Next things I'm going to do: Connect to pink wire directly to the battery. I can try to remove alternator belt too. It's making me crazy. I don't even want to drive the car anymore. The datalog: Sniper_0058.zip

  6. #6

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    I'm having the same kind of issue, however, I'm losing minutes at a time and the ECU is acting erratically. Holley has told me it's RFI noise and I need to keep trying to find the source. None of the telltale signs of RFI noise are in the datalogs (spiking in RPM or passive sensors). I've added grounds, replaced wires, run with the alternator belt off, etc. I've attached one of my datalogs, my AFR is also stuck about 15 right after the gap.
    Attached Files Attached Files

  7. #7

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    Speaking of spike in RPM, my RPM is always okay in handheld, but my tach sometimes acts crazy. The cable runs close to water temp gauge and oil pressure gauge. Can it be a problem? It's not high frequency so it shouldn't be.

  8. #8

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    You said that the datalog is with the engine not running. Please clarify, it looks like the engine was started and was warming up with some small application of throttle during the run. I do not see any abnormal spiking in the RPM signal or TPS that's indicative of RFI noise. Does the engine run well? It looks like RPM takes a dive several times when you give it throttle.

  9. #9

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    I'll take a look when I get a chance. Data point loss does indicate RFI noise and to the handheld. While the CAN Bus cable is shielded, it can still be affected. The main cause is the power wires and ignition system. I'll have a better idea after looking at the datalog.

  10. #10

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    Datalog 039 is with engine not running. But this issue is addressed. It was a problem with the SD card. Datalog 058 is with engine running, and it's not resolved.

    Yesterday I tried to disconnect my additional tach. Drive for 10 minutes and it was horrible. Then I stop the engine. Check wiring, wait 10 minutes and drive again. The driveability was absolutely perfect. Check the datalog: 60 points per second. Perfect. Then I stop, refuel, restart. It was good at the beginning then it was okay. Check the datalog: 60 points per second first, and then 15 points per second. This is really weird. Good thing is when I have the 60 points per second it runs good. An other strange thing, I disconnected the tach signal wire (other tach wire still connected) and it doesn't always show 0. It's a sign of RFI noise.

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