GQM
Active Member
- First Name
- Quinn
- Joined
- Jun 10, 2023
- Threads
- 4
- Messages
- 36
- Reaction score
- 37
- Location
- Connecticut
- Car(s)
- 93 RX-7, 06 RX-8, 03 S2000, 07 Z4M Coupe, 99 Miata
- Thread starter
- #1
Hey Fellas,
I recently started having a really bizarre intermittent boost issue with my 2024 45th AE 6Spd MT Supra.
Engine Mods:
Catless Downpipe
SARD Titanium Exhaust
Eventuri Intake
Femto Unlock w/MHD Stg 2+ 93 Octane OTS Map
93 Octane only. Have never run ethanol in this.
Mileage: ~1050
I unlocked my ECU at around 650 miles. First few hundred miles were great with no hiccups or weirdness. On my 2nd drive out this season I passed 1k miles. It was a spirited drive for about 30 minutes with no issues. Parked the car and had coffee with friends for a few hours. When leaving, I let the car idle for a few of minutes, drove normal for about 2 miles. On my first WOT pull, the car was noticeably slower but I am also driving on backroads so I can't be WOT for very long intervals. Did a few more WOT pulls on the way home where I could and every time the engine felt noticeably down on power. Got to one of my favorite roads where I where I can attack for a good 40 seconds straight or so. About 2/3rds up the road while exiting a corner in 3rd gear and applying throttle, the engine woke up and was boosting back to normal. This is when I realized something was wrong. It was boosting normal and healthy again for a few minutes. Again not doing full gear pulls but just jumping on throttle where I could (so it wasn't sustained load or heat soaking). Shortly after it went back to boosting low again and then bounced back into normal boost without any indicators why.
Yesterday (high 60's F' ambient), I went out and reflashed the MHD Map and made sure Map Switching was disabled thinking that maybe some how it was changing the map back and forth while driving. Went for another drive, filled up with Mobile 93 octane (tank was low) just after reaching operating temp and going WOT I had low boost again immediately. I brought the car home, plugged it in to a tender, updated MHD, reflashed the car, and reset all of the learning values. While in there before flashing, I also checked for codes and shadow codes, which there were none. Went out for another road test right after and the car was back to normal for about 15 minutes of on and off spirited driving. After a couple minutes of cool down and gentle cruise, getting back on the gas and the car was back to low boost. I did a few data logs during all of this and can see that when this is happening, the car is targeting and only boosting 8 psi. I was able to do a log in 2nd to 4th and actually catch the change happening in realtime after going WOT in 2nd. You can see 100% throttle and the car boost up to 19 psi and while still at 100% throttle the ECU target 8 psi and drop boost to there, holding it to the end of 2nd gear and also through 3rd gear. I also felt this change while driving as it was an abrupt hiccup. Attached are 2 MHD logs, one with this issue happening and another during the 15 minutes of driving spiritedly while it was boosting normal. It was relatively cool ambient temps, all engine temps were normal i.e. not heat soaking or hitting into any values where I believe any safety parameters would engage. I still do not have any error codes anywhere or any indicators as to what the hell is going on and why the ECU would intermittently reduce boost to 8 psi. I don't believe this is a boost leak because of it being intermittent. I've also never touched the charge pipes or anything else on the car.
Other areas I've since checked based on researching other's getting a somewhat similar issues was the height leveling sensor in the rear (which mine is in tact and not broken) as well as the vband clamp of the downpipe to confim it is not making contact with the wastegate actuator (which mine isn't).
Other thoughts: possibly a failing height leveling sensor in the rear causing limp mode or a failing boost solenoid but again there are no errors or codes.
I really am not sure where to go from here so any input is greatly appreciated! Thank you so much in advance!
I recently started having a really bizarre intermittent boost issue with my 2024 45th AE 6Spd MT Supra.
Engine Mods:
Catless Downpipe
SARD Titanium Exhaust
Eventuri Intake
Femto Unlock w/MHD Stg 2+ 93 Octane OTS Map
93 Octane only. Have never run ethanol in this.
Mileage: ~1050
I unlocked my ECU at around 650 miles. First few hundred miles were great with no hiccups or weirdness. On my 2nd drive out this season I passed 1k miles. It was a spirited drive for about 30 minutes with no issues. Parked the car and had coffee with friends for a few hours. When leaving, I let the car idle for a few of minutes, drove normal for about 2 miles. On my first WOT pull, the car was noticeably slower but I am also driving on backroads so I can't be WOT for very long intervals. Did a few more WOT pulls on the way home where I could and every time the engine felt noticeably down on power. Got to one of my favorite roads where I where I can attack for a good 40 seconds straight or so. About 2/3rds up the road while exiting a corner in 3rd gear and applying throttle, the engine woke up and was boosting back to normal. This is when I realized something was wrong. It was boosting normal and healthy again for a few minutes. Again not doing full gear pulls but just jumping on throttle where I could (so it wasn't sustained load or heat soaking). Shortly after it went back to boosting low again and then bounced back into normal boost without any indicators why.
Yesterday (high 60's F' ambient), I went out and reflashed the MHD Map and made sure Map Switching was disabled thinking that maybe some how it was changing the map back and forth while driving. Went for another drive, filled up with Mobile 93 octane (tank was low) just after reaching operating temp and going WOT I had low boost again immediately. I brought the car home, plugged it in to a tender, updated MHD, reflashed the car, and reset all of the learning values. While in there before flashing, I also checked for codes and shadow codes, which there were none. Went out for another road test right after and the car was back to normal for about 15 minutes of on and off spirited driving. After a couple minutes of cool down and gentle cruise, getting back on the gas and the car was back to low boost. I did a few data logs during all of this and can see that when this is happening, the car is targeting and only boosting 8 psi. I was able to do a log in 2nd to 4th and actually catch the change happening in realtime after going WOT in 2nd. You can see 100% throttle and the car boost up to 19 psi and while still at 100% throttle the ECU target 8 psi and drop boost to there, holding it to the end of 2nd gear and also through 3rd gear. I also felt this change while driving as it was an abrupt hiccup. Attached are 2 MHD logs, one with this issue happening and another during the 15 minutes of driving spiritedly while it was boosting normal. It was relatively cool ambient temps, all engine temps were normal i.e. not heat soaking or hitting into any values where I believe any safety parameters would engage. I still do not have any error codes anywhere or any indicators as to what the hell is going on and why the ECU would intermittently reduce boost to 8 psi. I don't believe this is a boost leak because of it being intermittent. I've also never touched the charge pipes or anything else on the car.
Other areas I've since checked based on researching other's getting a somewhat similar issues was the height leveling sensor in the rear (which mine is in tact and not broken) as well as the vband clamp of the downpipe to confim it is not making contact with the wastegate actuator (which mine isn't).
Other thoughts: possibly a failing height leveling sensor in the rear causing limp mode or a failing boost solenoid but again there are no errors or codes.
I really am not sure where to go from here so any input is greatly appreciated! Thank you so much in advance!
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