Engine stutters after quick shifts
Engine stutters after quick shifts
I've been dealing with this problem for a while now, and it's time I make a thread about it. First, some history of the issue.
I've had my car for over 20 years. I've gone through multiple engines, transmissions, clutches, flywheels, ECUs, axles, etc. I can remember experiencing this problem 20 years ago back when the car was pretty much stock, but it became much more noticeable after installing a lightweight (JWT/Fidanza) flywheel when I converted from a 5 speed to a 6 speed two years ago. Basically, the car will stutter/studder/shudder when I quickly upshift from one gear to the next. It doesn't happen 100% of the time, but it's much more likely to occur when I'm shifting more aggressively than when I'm just cruising around. Sometimes I can get a good, clean, fast shift, but most of the time it stutters. There does seem to be some relationship between how I feather the gas as I engage the next gear, but I can't get it to behave consistently. I've played with different ways of letting off the clutch when shifting- slow/slipping, quick smooth, hard/fast, but it doesn't seem to matter.
I've owned and driven a lot of manual transmission cars over the years, and one of my other current cars has a lightweight flywheel on it. No other car has ever behaved like this, and it's driving me insane. Sometimes I think the issue is related to the clutch assembly, and sometimes I think it's a fuel/ECU issue. And just to be clear, the hesitation/stutter does NOT occur when in gear and rolling on/off the throttle, it only occurs when shifting into the next gear. I have no other reliability/driveability issues with the car.
I did some searching, and this has been documented for a long time. Most complaints come from people with lightweight flywheels, but not all.
https://maxima.org/forums/4th-genera...eleration.html
https://maxima.org/forums/all-motor/...lp-needed.html
https://maxima.org/forums/supercharg...ed-advice.html
https://maxima.org/forums/all-motor/...ear-issue.html
https://maxima.org/forums/4th-genera...-flywheel.html
And the biggest thread on the topic:
https://maxima.org/forums/4th-genera...za-read-5.html
Here are some interesting quotes from the threads:
So who else is having this problem? What have you done to eliminate potential sources of the problem? The fact that I and other people have experienced this problem with stock flywheels leads me to believe the problem is somewhat inherent to the car, but can be exacerbated by the addition of things like lightweight flywheels and crank pullies.
I've had my car for over 20 years. I've gone through multiple engines, transmissions, clutches, flywheels, ECUs, axles, etc. I can remember experiencing this problem 20 years ago back when the car was pretty much stock, but it became much more noticeable after installing a lightweight (JWT/Fidanza) flywheel when I converted from a 5 speed to a 6 speed two years ago. Basically, the car will stutter/studder/shudder when I quickly upshift from one gear to the next. It doesn't happen 100% of the time, but it's much more likely to occur when I'm shifting more aggressively than when I'm just cruising around. Sometimes I can get a good, clean, fast shift, but most of the time it stutters. There does seem to be some relationship between how I feather the gas as I engage the next gear, but I can't get it to behave consistently. I've played with different ways of letting off the clutch when shifting- slow/slipping, quick smooth, hard/fast, but it doesn't seem to matter.
I've owned and driven a lot of manual transmission cars over the years, and one of my other current cars has a lightweight flywheel on it. No other car has ever behaved like this, and it's driving me insane. Sometimes I think the issue is related to the clutch assembly, and sometimes I think it's a fuel/ECU issue. And just to be clear, the hesitation/stutter does NOT occur when in gear and rolling on/off the throttle, it only occurs when shifting into the next gear. I have no other reliability/driveability issues with the car.
I did some searching, and this has been documented for a long time. Most complaints come from people with lightweight flywheels, but not all.
https://maxima.org/forums/4th-genera...eleration.html
https://maxima.org/forums/all-motor/...lp-needed.html
https://maxima.org/forums/supercharg...ed-advice.html
https://maxima.org/forums/all-motor/...ear-issue.html
https://maxima.org/forums/4th-genera...-flywheel.html
And the biggest thread on the topic:
https://maxima.org/forums/4th-genera...za-read-5.html
Here are some interesting quotes from the threads:
Fidanza flywheel correct? My ride does something very similar, though not quite as pronounced. Last week I put the stock flywheel in, and its back to normal, I think it has something to do with the material on the ring. Do you still have the first gear stumble going on too?
Do you have a Fidanza flywheel? If you do it will cause this problem. Not sure on the a/f, but it will cause a studder under partial throttle. I have had this problem for probably 5 years. There is not a problem under WOT, but at low rpm's when you push the gas it will shudder. Another thing you can try if you are sure you have a safe tune is to bypass your knock sensor (resistor), to rule that out. I was having suddering problems when I fist did my vq35 swap and it was because I had a faulty knock sensor.
Do you have either underdrive pulley and/or lightend flywheel on your setup in addition to an aftermarket clutch?
The reason I'm bringing this up is because I used to have this issue on the tracks also. Whether 3.0 or 3.5. Replaced UDP to stock, fared a bit better. Then swapped to 5th gen AE clutch and the problem was completely gone. In my words, I'm implying a harmonic balance issue. I'm doubting that the aftermarket spinners on either side of the engine are balanced to operating spec at all. Fidanza flywheel won't be an issue, because I spoke them then, and they guaranteed a complete 3 stage balancing post machining before boxing them up for sale. Our Nissan OEMs are doubtless to my "feel".
The reason I'm bringing this up is because I used to have this issue on the tracks also. Whether 3.0 or 3.5. Replaced UDP to stock, fared a bit better. Then swapped to 5th gen AE clutch and the problem was completely gone. In my words, I'm implying a harmonic balance issue. I'm doubting that the aftermarket spinners on either side of the engine are balanced to operating spec at all. Fidanza flywheel won't be an issue, because I spoke them then, and they guaranteed a complete 3 stage balancing post machining before boxing them up for sale. Our Nissan OEMs are doubtless to my "feel".
I have had my 5th gen clutch and flywheel put in about 3 weeks ago. I Broke the clutch in for at least 500 miles if not more before i got on it. There seems to be a problem.. If I shift hard and fast it feels like the clutch is slipping. It kind of studdery. Also say im in 3rd gear i let off the gas then i floor it, it seams to do the same slipping/studdering problem. Does any one know how to fix this problem? or what is worng? It just doesnt feel like the 5th gen clutch is biting as hard as i thought it would. My old stock felt better with my stock flywheel...
Have you taken any logs, via ECU talk and have you monitored the AF via wideband?
With the ECU talk log you can watch the ignition timing, injector pulse width and MAF flow rate. The WBO2 is obvious, if it goes lean or fat then it's a tune/fuel issue. If the timing is all over the place when it happens, it could be a CPS issue - either alignment with the trigger wheel or age.
With the ECU talk log you can watch the ignition timing, injector pulse width and MAF flow rate. The WBO2 is obvious, if it goes lean or fat then it's a tune/fuel issue. If the timing is all over the place when it happens, it could be a CPS issue - either alignment with the trigger wheel or age.
Last edited by 95naSTA; Nov 23, 2023 at 08:46 PM.
Have you taken any logs, via ECU talk and have you monitored the AF via wideband?
With the ECU talk log you can watch the ignition timing, injector pulse width and MAF flow rate. The WBO2 is obvious, if it goes lean or fat then it's a tune/fuel issue. If the timing is all over the place when it happens, it could be a CPS issue - either alignment with the trigger wheel or age.
With the ECU talk log you can watch the ignition timing, injector pulse width and MAF flow rate. The WBO2 is obvious, if it goes lean or fat then it's a tune/fuel issue. If the timing is all over the place when it happens, it could be a CPS issue - either alignment with the trigger wheel or age.
Yep. I used it to dial in my closed loop tuning, looking at the fuel trims. Once I got the LTFTs dialed in, I used Emanage Ultimate logging with a WBO2 input for WOT AF tuning. It wasn't perfect but it worked.
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