iamcvr
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- Thread starter
- #1
Hey all, I've looked through the forums quite a bit as I am having a similar issue to others here. My idle RPMs are acting a bit weird, and after I go WOT a few times, the problem gets worse. I've considered these "symptoms group 1" and "symptoms group 2" when I describe it to people, lol.
For some background on the car:
Tunes I have tried:
Symptom Group 1:
Symptom Group 2:
During both symptom groups, the car does NOT shudder or act as if it is stalling out when coming to a stop - the easiest way to explain it is the car acts as if it is falling asleep; it's a clean RPM drop, and when it "bogs" it simply revs again and then goes to the idle issue. If it shuts off, it is a clean RPM drop all the way to around 300 at which point the car shuts off.
I can turn the car back on immediately, with no CEL. It as if the car does not realize what has happened at all.
Things I have tried:
1. Cleaned throttle body w/ TB cleaner
2. Cleaned MAF sensor w/ MAF cleaner
3. Unplugged VCT solenoid connectors 1 at a time (plugging back in the previous one) to see if it evens out - all done with the car on ONLY. So, unplug solenoid 1, check RPM, plug it back in, unplug solenoid 2, etc., etc.
4. Smoke test to check for vacuum leaks
5. Checked physical fuel lines for kinks/bends
6. Flashed to all tunes I have to recreate issue
Notes:
I have attached a Google Drive link to the HPL file of my idle (not allowed to attach HPL files apparently), with as many relevant parameters as I can. I have also linked a YouTube video of the same log file. One thing that's weird to me on the log file - the O2 reading bounces between 60 and 800 mV or so; this rise and fall is almost EXACTLY in line w/ the RPMs dropping and rising. Unsure if this is an EFFECT of the RPM issue, or the cause of it.
I have new exhaust coming, and am planning on checking the O2 sensors then, all though outside of swapping the sensors I am unsure what effect "checking them" is going to have.
I am also going to remove the supercharger lid and check the O-ring and gaskets, as well as the spark plug health/gaps/etc. when I install the exhaust.
Any ideas are welcome, thank you taking the time to read!
HPL file:
For some background on the car:
- 2023 MANUAL Mach 1 with a Whipple Stage 2 kit
- The car only has 3400 miles on it
- SC Foster Sound Tube
- UPR Supercharger Catch Can
- Kooks catless LTH
- Steeda H-Pipe
- OEM Active Mufflers
Tunes I have tried:
- Base Whipple
- Lund
- Wengerd
- Ortiz
- My own tune (nothing crazy just adding a couple degrees of timing and messing around with MP0 to get a ghost cam)
Symptom Group 1:
- Idle fluctuates between 790 and 850 RPM when the idle RPM is set to 800, or 850 and 910 if idle RPM is set to 850 or 875
- "Bogs" (drops to 400 RPM) when coming to a stop decelerating above 5MPH/s - only happens if I come to a full stop.
Symptom Group 2:
- Idle fluctuates between 500 and 950 RPM regardless of idle RPM target
- "Bogs" (drops to 400 RPM) when coming to a stop decelerating up to 3MPH/s - only happens if I come to a full stop.
- Completely turns off when coming to a stop decelerating above 5MPH/s - only happens if I come to a full stop.
During both symptom groups, the car does NOT shudder or act as if it is stalling out when coming to a stop - the easiest way to explain it is the car acts as if it is falling asleep; it's a clean RPM drop, and when it "bogs" it simply revs again and then goes to the idle issue. If it shuts off, it is a clean RPM drop all the way to around 300 at which point the car shuts off.
I can turn the car back on immediately, with no CEL. It as if the car does not realize what has happened at all.
Things I have tried:
1. Cleaned throttle body w/ TB cleaner
2. Cleaned MAF sensor w/ MAF cleaner
3. Unplugged VCT solenoid connectors 1 at a time (plugging back in the previous one) to see if it evens out - all done with the car on ONLY. So, unplug solenoid 1, check RPM, plug it back in, unplug solenoid 2, etc., etc.
4. Smoke test to check for vacuum leaks
5. Checked physical fuel lines for kinks/bends
6. Flashed to all tunes I have to recreate issue
Notes:
- Cold start is stable - when the oil temp and CHT are both under 140F, the idle is stable at 1100, 1050, etc. as it goes through the warmup process. The issue only presents when the car is at operating temps.
- There is an intermittent popping sound during cold start, as if there is a single misfire every 200-300 rotations. It is just ONE pop, every 4-5 seconds, until oil temp rises above roughly 100F.
- When turning it on while warm, there is a SINGLE pop after it hits the RPM limit (like 1200 or so) of the startup process. It sounds cool as hell, but it's a new development. Unsure if related, or if a product of my exhaust configuration. Not taking this as a symptom of anything, just a different behavior that began roughly around when these idle issues did. I can only recreate this single pop if the car is turned off for 5+ minutes. I cannot turn the car off and on and have it pop every single time. Thus why I think it is exhaust.
I have attached a Google Drive link to the HPL file of my idle (not allowed to attach HPL files apparently), with as many relevant parameters as I can. I have also linked a YouTube video of the same log file. One thing that's weird to me on the log file - the O2 reading bounces between 60 and 800 mV or so; this rise and fall is almost EXACTLY in line w/ the RPMs dropping and rising. Unsure if this is an EFFECT of the RPM issue, or the cause of it.
I have new exhaust coming, and am planning on checking the O2 sensors then, all though outside of swapping the sensors I am unsure what effect "checking them" is going to have.
I am also going to remove the supercharger lid and check the O-ring and gaskets, as well as the spark plug health/gaps/etc. when I install the exhaust.
Any ideas are welcome, thank you taking the time to read!
HPL file:
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