Ok, got a 2007 Corvette that does not respond to what has been adjusted.
No matter what I change for airmass (VE or MAF) the car spikes the values. Also randomly changes spark values, and idle throttle control feels almost nonexistent.
I know this is vague, but it's not something I've been able to nail down. Heck, the coolant temp will swing all over the place.
Feels like a bad ECU, which would be my first.
Anyone ever seen this happen?
I've included the original tune, and my attempt to start over. Neither will give positive results.
Checked how? I would really want to see good voltage drop readings taken at a time I knew the glitch occurred. Specifically, between battery ground and ECM C1-73, as this would test across the actual bolted connection at G106.
G106 is the common gnd point for both the ECM and the MAF (separate wires, same ground point).
Go to the middle of a run of stranded wire, strip back the insulation, snip away all but one strand of the conductor. This wire will test A-OK on an ohms test, but fail miserably when you ask it to carry any meaningful current. Static vs dynamic. An intermittent makes the static ohms test even less relevant. Ohms test is really good at tricking you into believing it's good though, if that's all you're interested in.
Meaning, you have not yet checked for a voltage drop across G106. You need to do some research. Youtube videos or whatever. Voltage drop is a specific test that finds problems the tests you have done will not.
Also, being this is intermittent, you must be watching the meter when the glitch occurs. Testing it when everything is working will tell you only that it works when it works.
Voltage across the ground wire of the PCM to the ground of the battery showed a max of 0.1v. No spike when the ECU commands different airmass values than those in the MAF table.
I took a video of the DMM while performing a dyno pull. That is where the value range came from. The peak was 0.1v across the grounds.
On one of the pulls today, the ECT jumped from 199 to 253, and then back to 199 again. I was recording the DMM during that pull. No jump in voltage.
I have also added an additional ground wire from the ECU directly to the battery, and still the random changes in temp and airmass. Also the two do not coincide. Temp changes sometime have no effect, and sometimes pull timing.
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