Rev MS3 in MSM bogging under boost
#1
Rev MS3 in MSM bogging under boost
I have a Rev MS3 in my MSM, and it was tuned by a shop last summer. It has been behaving very well with one exception. When I shift under full throttle/boost, the engine will bog down as soon as I grab the next gear and floor it. It will recover after about 2-3 seconds and drive fine after that. I can mitigate this by slowly rolling onto the throttle after shifting into the next gear.
I have been poking around the software but cannot figure out where to start on diagnosing this.
Can someone help point me in the right direction on where to start?
I have been poking around the software but cannot figure out where to start on diagnosing this.
Can someone help point me in the right direction on where to start?
#7
Retired Mech Design Engr
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EDIT... it's all about timing.
#8
mkturbo.com
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LPT: If you are taking a log you can hit spacebar in TS and it will make a mark in the log at that point. It is very helpful to do that so you know where to look in the log for the problem.
#10
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From what I see, your AFR spikes at max (20 AFR) when you get back on the throttle, and not until the AFR goes back down to 14.0 does the RPM start rising again. It's also running very lean in general. Plot your AFR and AFR Target, and you'll notice that the AFR is above the Target curve, and there are also a lot of lean spikes while you are at full throttle.
The after-shift stumble I would put at acceleration enrichment, I'm not sure about the full-throttle lean spikes.
https://www.diyautotune.com/support/...el-enrichment/
The after-shift stumble I would put at acceleration enrichment, I'm not sure about the full-throttle lean spikes.
https://www.diyautotune.com/support/...el-enrichment/
#12
aceduce802: Thanks for the feedback. I am wondering if there is something going on with my wideband 02. When they tuner had the car for a few weeks last summer, he said that the wide band was very noisy and recommended I keep an eye on it. He rewired the ground on it and even replaced the sensor, but said he still saw noise in the signal. I'll start reading up on AE, thanks for the link.
mmmjesse: I don't think so, I'm not driving aggressively when it does this, just full throttle, switch gears, full throttle. I'm not speed shifting or riding the clutch between shifts.
mmmjesse: I don't think so, I'm not driving aggressively when it does this, just full throttle, switch gears, full throttle. I'm not speed shifting or riding the clutch between shifts.
#13
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That's certainly a possibility as well, the TPS threshold is set to 10%, I would set it to more like 60-70%. It looks like there is a period where the throttle is being applied but launch control is still active.
Edit: in response to above, you are not using flat-foot shift, but flat-foot shift is activating. Since your threshold is at 10% throttle, if there's a time where your clutch is pressed (the switch immediately engages when pushing the clutch) and the throttle is over 10%, then you won't make any power. If you raise the threshold, you will likely never have a situation when the TPS will be above 60% while the clutch switch is activated, unless you're flat shifting of course.
Edit: in response to above, you are not using flat-foot shift, but flat-foot shift is activating. Since your threshold is at 10% throttle, if there's a time where your clutch is pressed (the switch immediately engages when pushing the clutch) and the throttle is over 10%, then you won't make any power. If you raise the threshold, you will likely never have a situation when the TPS will be above 60% while the clutch switch is activated, unless you're flat shifting of course.
#14
That's certainly a possibility as well, the TPS threshold is set to 10%, I would set it to more like 60-70%. It looks like there is a period where the throttle is being applied but launch control is still active.
Edit: in response to above, you are not using flat-foot shift, but flat-foot shift is activating. Since your threshold is at 10% throttle, if there's a time where your clutch is pressed (the switch immediately engages when pushing the clutch) and the throttle is over 10%, then you won't make any power. If you raise the threshold, you will likely never have a situation when the TPS will be above 60% while the clutch switch is activated, unless you're flat shifting of course.
Edit: in response to above, you are not using flat-foot shift, but flat-foot shift is activating. Since your threshold is at 10% throttle, if there's a time where your clutch is pressed (the switch immediately engages when pushing the clutch) and the throttle is over 10%, then you won't make any power. If you raise the threshold, you will likely never have a situation when the TPS will be above 60% while the clutch switch is activated, unless you're flat shifting of course.
#15
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There is no downside to raising the threshold. If you are flat-foot shifting, you are never lifting, aka TPS is 100% and your threshold could technically be 99%. If you are using launch control, you are also likely at 100% TPS, the only reason you want a threshold is in case you can't get to 100% TPS before the target launch RPM.
If you really will never use flat-foot shifting or launch control, then just turn it off in the settings. But, every now and then a nice flat foot shift getting on the highway feels great haha.
If you really will never use flat-foot shifting or launch control, then just turn it off in the settings. But, every now and then a nice flat foot shift getting on the highway feels great haha.
#16
Now this is interesting. I thought you both were referring to a driving technique, not a setting in TS related to flat-foot shift. What is the downside to raising the threshold? I can't think of a time when I would ever want to flat foot shift, but maybe I'm missing something.
#18
You're also very lean throughout the whole pull. Worryingly so. You need to do some VEAL tuning for sure.
Check out this screenshot - you're at 5800 RPM, 173KPA (~10psi). But it's running 15.8 AFR (4.1 AFR error, looks like the AFR target for this area is 11.7). This is because your VE fuel map isn't tuned.
Your duty cycle is also 117%? Meaning the ECU is commanding 17% more fuel than it thinks the injectors can provide. You may want to double check your REQ_FUEL settings (though Rev is pretty good about getting this right) and make sure it matches whatever injectors you have (stock?).
Check out this screenshot - you're at 5800 RPM, 173KPA (~10psi). But it's running 15.8 AFR (4.1 AFR error, looks like the AFR target for this area is 11.7). This is because your VE fuel map isn't tuned.
Your duty cycle is also 117%? Meaning the ECU is commanding 17% more fuel than it thinks the injectors can provide. You may want to double check your REQ_FUEL settings (though Rev is pretty good about getting this right) and make sure it matches whatever injectors you have (stock?).
#19
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The ugly AFR spike, that occur even when accelerating gently and not yet out of fuel are troublesome to me. Misfire, bogus readings?
Another important issue is that you are running out of fuel. Old code (it would seem) used to use some strange method of calculating Inj Duty Cycle. Modern MS3 code does so correctly and when you see DC above 100%, the MS is calling for more fuel than your injectors can flow (if you are going lean, which you are). Your injectors are too small or your fuel pump too weak, or your FPR bad, or your fuel filter is clogged. You can keep increasing the VE in the upper cells, but I don't think you will improve the AFR.
Thirdly, you are not using any form or AE on throttle press, or MAP increase. I don't know anything about Time-Based AE. I would suggest ACCEL PUMP (And EAE, but that gets complicated).
On a side note, why the 90% decel fuel cut?
Your Knock Sensor settings make no sense at all. Reverant's Basemap Knock settings that came on mine (I think they are his) make much more sense, and work.
#20
Thanks again for all the help.
Update: I replaced the wideband as a first step. I found that the LC-1 was not installed cleanly. It was not getting power or ground through the ECU and there were several poor quality splices in the wiring. I replaced it with a new AEM wideband (that's what my tuner prefers) and soldered it directly to the ECU power and ground. I haven't been able to get any logs yet because it's raining outside, but the initial readings under boost are in the 10.5 - 11 afr range. That's not in the higher gears though, so I still need to get good logs in a gear other than 1-2-3. I also upped the TPS threshold to 75% and didn't experience any throttle cuts, but I haven't been able to really test it since it's raining outside. I'll get some logs when the weather cooperates and report back.
Update: I replaced the wideband as a first step. I found that the LC-1 was not installed cleanly. It was not getting power or ground through the ECU and there were several poor quality splices in the wiring. I replaced it with a new AEM wideband (that's what my tuner prefers) and soldered it directly to the ECU power and ground. I haven't been able to get any logs yet because it's raining outside, but the initial readings under boost are in the 10.5 - 11 afr range. That's not in the higher gears though, so I still need to get good logs in a gear other than 1-2-3. I also upped the TPS threshold to 75% and didn't experience any throttle cuts, but I haven't been able to really test it since it's raining outside. I'll get some logs when the weather cooperates and report back.