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When the car was idling in the garage this morning (hooked up to HP Tuners), I saw a spike on the "Spark" graph at the same time as the car stumbled. "Control Module Voltage" also went from > 14 down to 13.69. Not a massive difference, but I don't know what the operating range for the computer is, so I can't tell if that's a real problem. It's weird that voltage would drop, though.

RPM also dropped from 850 down to about 740, then came back up.

Here's the chart:enter image description here

It did this twice more over the course of about 10 minutes.

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  • This is on your Solstice?
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Commented Feb 11, 2017 at 19:50
  • @Pᴀᴜʟsᴛᴇʀ2 yes. And now I'm getting a p0107 (MAP sensor)
    – 3Dave
    Commented Feb 11, 2017 at 19:54
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    When are you just going to drive that thing off a cliff? :o)
    – Pᴀᴜʟsᴛᴇʀ2 ♦
    Commented Feb 11, 2017 at 19:55
  • @Pᴀᴜʟsᴛᴇʀ2 very very soon. :(
    – 3Dave
    Commented Feb 11, 2017 at 19:55
  • @Paulster2 And I have apparently managed to ruin my MAP sensor. Now it shoes only 1.2PSI always. Car runs fine until I rev it, then it stumbles and dies. Start it again -stumbles and tries to die, reset codes (while running) and everything runs fine, util I rev it again. WTF.
    – 3Dave
    Commented Feb 11, 2017 at 21:55

3 Answers 3

Reset to default
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That is a lot of spark advance. It looks like its sitting at 5-7ish degrees, then pulls up to almost 30 suddenly. Thats way higher than any normal adjustment I've seen.

his data with a line added I added my own line onto your graph, and it looks like the voltage drop coincides with the start of the spark advance. Based on this, the fact that the MAP is suddenly blown, and the stalking I did on some of your previous questions where you mention sticky valves... It sounds like it could be a misfire that went back into the intake instead of out the exhuast. That could/would blow your MAP and maybe set off the knock sensor (which would violently pull timing, as we see here).

But those are pretty rare from my understanding. Maybe it was just a Gremlin.

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To get this off the unanswered question list:

There was an intermittent break in the wiring harness near the MAP sensor. I removed the damaged section and lineman-spliced it, and this particular problem disappeared.

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Doesn't this car have two MAP sensors? See this discussion forum for more information. Seems like one of them involves temperature, so you may have replace them as a pair.

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  • No. One MAP, one MAF with integrated IAT.
    – 3Dave
    Commented Feb 13, 2017 at 11:39
  • The GXP (LNF 2.0L factory turbo) has two MAPS, but my car is a 2.4L with aftermarket turbo. Good call, though.,
    – 3Dave
    Commented Feb 13, 2017 at 14:06

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