Yea, I know, there's a million threads on hesitation... but my problem seems to be slightly different from what I've been reading:

Shortly after fully releasing the clutch after a gear change at WOT, the engine will "bobble" (hesitate) once or twice for a second before continuing to accelerate.

For example, if you mash the throttle to the floor in first, everything is fine up to redline... shift into second, release the clutch, floor it again...

... and it'll accelerate fine for 1/2 second, then hesitate for an instant, accelerate for for 1/4 second, hesitate again for an instant, then accelerate fine up to redline.

This happens consistently since I've had the car, whether TC/DSC is on or fully off (long switch press), or engine is warm or cold.

I've had the M-flash since day two of ownership (about 4,000 miles now).

I sometimes think the clutch is slipping, but it does fully catch for a second before it hesitates. Doesn't seem right it would catch, then slip, then catch? My foot is entirely off the clutch when it hesitataes.

I've wondered about the coils, but this only happens at lower RPMS, as I start a new gear, and never at high RPMS.

It ONLY happens at Wide Open Throttle. Running up the gears at even 9/10 throttle is fine.

Any ideas? It's going in for an oil change soon, and I'll be sure to have them check into it, as it's easy to reproduce.

If you look at some of MazdaManiac's G-Tech graphs, you can see something very similar to that even with the long switch press. It seems like that some semblance of TCS/DSC is still on even after the long press, which could cause what you are feeling.

Is this only shifting into 2nd, or up-shifting into any gear at WOT? Seems like it would do that in 1st gear also, if the computer was worried about traction.

If you look at some of MazdaManiac's G-Tech graphs, you can see something very similar to that even with the long switch press. It seems like that some semblance of TCS/DSC is still on even after the long press, which could cause what you are feeling.

He describes it perfectly when he says:

Upon reapplication of throttle after engaging the next gear, the power will "bobble" twice in a period of 1 to 2 tenths of a second before resuming normal acceleration.

But where it happens to him at part throttle, it ONLY happen to me at WOT. I'm looking for said graph now...

The TC would certainly explain it, but I haven't read of anyone else experiencing it with the TC turned off. I believe in that thread everyone who turned TC off also eliminated the bog.


Is this only shifting into 2nd, or up-shifting into any gear at WOT? Seems like it would do that in 1st gear also, if the computer was worried about traction

I'm not so sure it happens in first, as I rarely stomp on it from a standstill... I usually end up feeding in throttle through first, hitting WOT 1/2-way through, then shifting into 2nd.

Definately happens when going 1-2 and 2-3 though.

http://www.rx8club.com/showthread.php?s=&threadid=17220

Here is the graph, and the accompanying thread.

What is WOT?

http://www.rx8club.com/showthread.php?s=&threadid=17220

Here is the graph, and the accompanying thread.

Thank you! Yup, that's exactly what it feels like.

What I don't understand then is: why isn't everyone on the forum complaining about it? It's a nasty hesitation... you certainly don't need a datalog to know it happened.

I'm mostly trying to figure out if it's a normal quirk of all RX-8s... or something broken on just my car.

I'm beginning to learn towards a) normal quirk, but I surprised it's not a more common complaint.

What is WOT?

(W)ide (O)pen (T)hrottle :)

Worn clutch a possibility?

(W)ide (O)pen (T)hrottle :)
Thanks! :)

Worn clutch a possibility?

I've wondered that, but it DOES grip just fine immediately after the shift... it's only a 1/2 second later that it suddenly bobbles, then continues normally.

It's difficult to imagine it being worn at 4,000 miles. I'm sure everyone who destroys their clutch says this, but I really do know how to shift, lol. I never do hard launches... and in fact have never done a clutch dump, etc. The car only had 12 miles on it when I purchased it, so I can't imagine test drivers scorched it.

But it is one possibility that I'm worried about, which is why I'm trying to determine if it's a common problem or not.

I don't think it would be clutch related - because after it is engaged, if there was a problem, the engine would rev higher, not bobble.

Maybe a knock sensor is detecting a non-existent pre-detonation (maybe through a resonance), and momentarily retarding the timing? I didn't look at the graphs, maybe that would be captured...

Let me ask this another way:

Do any of you NOT experience this "bobble" almost immediately after shifting into 2nd (after near redlining in 1st) and going to wide open throttle?

I experience what feels like a surge, if I am running thru the gears at WOT and shifting at slightly less than redline. It feels as the torque momentarily dips and then comes on strong. The engine seems to be firing correctly; it's just that there's a dip of power delivery for a moment and then the rate of acceleration increases back to it's previous level. I notice this when I'm running thru the 7500 - 8500rpm range. If I run all the way up to 9k I don't think it occurrs. This may just be a function of the motor's normal torque curve and possibly a side effect of some aspect of the S-DAIS. Any thoughts, people?

Yes, I get the same thing...I mostly notice it in the 2-3-4 shifts at significant % of throttle. I don't normally drive WOT, nor to redline... but when I'm "gettin on it" up to 7500-8000 rpm, I get the hesitation. My theory is that its something to do with the injection/intake system..when you let off the gas for the shift and then stomp on it, you're probably catching the system(s) reseting from high rpm to low(er) rpm settings and it has to re-open the paths it was shutting down.

Yes, I get the same thing...I mostly notice it in the 2-3-4 shifts at significant % of throttle. I don't normally drive WOT, nor to redline... but when I'm "gettin on it" up to 7500-8000 rpm, I get the hesitation. My theory is that its something to do with the injection/intake system..when you let off the gas for the shift and then stomp on it, you're probably catching the system(s) reseting from high rpm to low(er) rpm settings and it has to re-open the paths it was shutting down.
This is similar to what I was thinking.. If you get up there in revs, and then shift, it's possible that you'll drop enough revs to close the tertiary intakes and the slight bobble would be them dropping to closed and then re-openning.

This sounds somewhat similar to the famed 3k hesitation on 3rd gen RX-7's, with the obvious differences being that they occured only at 3k rpms, and not at WOT. Normally it was worse when the car was cold.

Anyway, this doesn't sound good. In fact, this would annoy me quite a bit. I certainly didnt notice this on my two lenghty test drives, and there was plenty of WOT driving.

Mine does it when I run WOT to the redline, shift hard and get that wheelspin "chirp" from the back end - and then I get the blinking skid light and the DSC/TCS puts the wet blanket on the fun for a second or so, and then away we go.

Shutting off the TCS/DSC stops that cold - get a serious "screech" on the 1-2 shift, and the car will jiggle sideways a bit unless pointed perfectly straight! YEE HA!

I think you're feeling the traction/stability control exerting it's morals on your driving.

SC

10-4 to your post, Ajax.

I've been WOT'ng it for a whole year once a day thru third gear and the hesitation has been always present until I decided to unable the traction control. Without it the problem completely dissappeared. Remember you need to disable it every time you start your car...

Ups, I meant disable

I've been WOT'ng it for a whole year once a day thru third gear and the hesitation has been always present until I decided to unable the traction control. Without it the problem completely dissappeared. Remember you need to disable it every time you start your car...

Yuppers, I disabled it (long press) and it made no difference - it still "bobbles." But the MazdaManiac thread talks about it happening with TC on or off, so I guess I'm not alone.

I rarely do WOT runs, but I just wanna be sure nothing is actually wrong with my car. If anyone else CAN do WOT, redlined shifts from 1-2 and 2-3 without a hesitation right after releasing the clutch and going WOT again, then I have to assume something is wrong with mine. But I don't hear anyone saying they can... yet.

I rarely do WOT runs, but I just wanna be sure nothing is actually wrong with my car. If anyone else CAN do WOT, redlined shifts from 1-2 and 2-3 without a hesitation right after releasing the clutch and going WOT again, then I have to assume something is wrong with mine. But I don't hear anyone saying they can... yet.

I would think that if every RX-8 had this problem, we would see many more threads on this issue, wouldn't we?

Also, I think that there would be many more people responding to this thread saying "me too" if everyone had this problem.

I don't think that running WOT is a particularly rare occurance, especially for people on this board! :)

Again, I don't even own an RX-8 yet, so these are just my observations from monitoring this forum. Also, I never noticed the hesitation on my two test drives (plenty of WOT runs). FWIW.

Ok. I have experienced this and have been checking into it further (excuse to make more WOT redline shifts).

I found that the hesitation is easily removed by applying the throttle a little earlier than I normally would. If I apply the throttle the way I would in any other car I get the hesitation (even with DSC and TCS off - long press). I have not been getting any hesitation with the early throttle (DSC and TCS on and off) and can easily recreate it by allowing the tach to dip a little lower.

Just thought I'd share.

I would think that if every RX-8 had this problem, we would see many more threads on this issue, wouldn't we?

Also, I think that there would be many more people responding to this thread saying "me too" if everyone had this problem.

I don't think that running WOT is a particularly rare occurance, especially for people on this board! :)

Again, I don't even own an RX-8 yet, so these are just my observations from monitoring this forum. Also, I never noticed the hesitation on my two test drives (plenty of WOT runs). FWIW.

Yes, mine does this as well.
Sometimes between the 2-3shift or the 3-4shift I can see the traction control light flash.
I'll try it with the traction control off (long press) and see what happens.

I have not been getting any hesitation with the early throttle (DSC and TCS on and off) and can easily recreate it by allowing the tach to dip a little lower..

So you're saying I don't shift fast enough, huh? Is that it? I don't know how to shift? lol...

OK, I'll try it... I DO tend to baby it a bit when shifting. No more Mr. Nice Guy ;)

So you're saying I don't shift fast enough, huh? Is that it? I don't know how to shift? lol...

Yes. That's exactly what I'm saying. (j/k)

I've just been getting back on the throttle slightly earlier and have noticed that it eliminates the lag. I'd noticed that when I was leisurely running the tach up and shifting slowly the lag was much more apparent, but I remembered times when the lag was not present (with DSC TCS both on and off) when I was really getting on it. So I started playing around with it over the weekend and found that lag could be eliminated without regard to DSC TCS. I've had many runs at WOT with no lag and the DSC TCS still on, it does indeed indicate traction loss with 2nd and 3rd gears (not 4th though) initially but does not cause the lag. My guess is something to do with the intake structure (as was mentioned here somewhere) and letting the RPMs hit one of the lower configurations.

Yes. That's exactly what I'm saying. (j/k)

I've just been getting back on the throttle slightly earlier and have noticed that it eliminates the lag. I'd noticed that when I was leisurely running the tach up and shifting slowly the lag was much more apparent, but I remembered times when the lag was not present (with DSC TCS both on and off) when I was really getting on it. So I started playing around with it over the weekend and found that lag could be eliminated without regard to DSC TCS. I've had many runs at WOT with no lag and the DSC TCS still on, it does indeed indicate traction loss with 2nd and 3rd gears (not 4th though) initially but does not cause the lag. My guess is something to do with the intake structure (as was mentioned here somewhere) and letting the RPMs hit one of the lower configurations.

Man, I love this board. I noticed this issue just recently as well. I leased the car, so as much I enjoy winding it up, I am trying to be easy on the trans. I made what I thought was a very methodical and accurate gear change while getting on the highway last week and was very disapointed by the percieved hesitaion. I was mostly disapointed because I was aproaching redline and felt sure power should have been there. I was obviously out of the gas too long and needed a quicker shift.

I've been meaning to post to this thread for the last couple days, but haven't got to it until now.

I recently went on my third test drive of an RX-8 with this thread clearly in my mind. I was definitely going to be doing some WOT runs and shifts at the buzzer, specifically looking for any "hesitation" in the motor.

I did four seperate WOT runs, and never once noticed any hesitation in the motor at all. Nothing but very smooth power across the entire rpm range, shifting from 1st through 3rd gears.

FWIW

Happened to me on WOTs. I decided to try a double-clutch with out letting out the throttle at all and there was no issue. If you really want to bust ass and not lead the throttle then keep it to the floor the whole time (trying not to hit the fuel cutoff).

Fredinlou - here is the thread.

What EXACTLY do you mean by hitting the throttle earlier? Meaning before I usually release the clutch, hit the throttle after the gear change?

If the car is hesitating after you shift simply apply the the throttle a little earlier than you normally do. Lead the throttle. Someone else suggested simply poping the clutch (do not release the gas) but I shift at 9k so if I tried that I'd bounce off the spark limiter.

So I mean hit it earlier (.1 seconds...it isn't much) than you are hitting it. I can't really quantify it since I don't really think about what my left foot is doing.

I noticed an obvious example of the hesitation just last night. (it seems I just don't get the opportunity to stomp on it very often, so it hadn't been obvious before!) "Leading" the throttle may be a good solution, but it would be nice if the engine responded more consistently without having to adapt a new technique for each different driving circumstance.

Perhaps it will be solved in the "N" flash? (not that a newer flash is actually available...)

Jim Mederer from Racing Beat described how the extremely sophisticated PCM in the 8 changes maps according to conditions. One of those conditions was when there is a decrease in rpms. The people describing the quicker re-application of the throttle may have a point.

Jim Mederer from Racing Beat described how the extremely sophisticated PCM in the 8 changes maps according to conditions. One of those conditions was when there is a decrease in rpms. The people describing the quicker re-application of the throttle may have a point.

Mine's definately far WORSE whenever I rush the shifts and throttle. That is, if I just shift, stomp... shift, stomp... it bobbles badly as soon as I stomp on it.

But if I shift as I really should.... by squeezing the throttle back on after each shift... it's not so bad. It's still there, but you don't feel it as much. I'm guessing it's simply because when stomping on it, it goes from WOT to nothing and back (big contrast), where easing into it goes from 1/4 throttle to nothing and back.

The bobble is consistently proportional to how quickly I reapply the throttle. Stomp on it, and it stumbles badly. Ease it back to WOT over a second or so, and it's smooth.

My does this all the time. I would say it's normal. Now I have tried giving the car more rev's in between shifts into 3rd and it has helped to a degree. I spoke to my Mazda tech at the dealer and I got the answer......ah, that's pretty normal for a rotary engine!!

- Irish :cool:

It is the L and or M flash!!!
I drove the car for 9K miles and never had a problem no mater how hard or how fast I would shift. (K flash). :)
The problem showed up after I got the M flash :mad:

Everyone that has this problem needs to tell Mazda about it, so maybe it will get fixed with the next flash.

I was having a hesitation problem all the time after shifting at WOT or Part throttle (post M flash). It seemed to be electrical in origin though - I mean ignition/spark related. Subsequently, I burned a coil (blistered the casing), and replaced it, and I haven't had ANY hesitation after shifting lately. In fact my 8 LURCHES forward after shifting. It always feels torquey and responsive so that I can just cruise around at low speed calmly and confidently.

Besides a new coil, the following could also be helping my 8 to have such good driveability:
I've been using primarily Shell gas (89/91) for months now without knowing that it has triple (or more) the detergent in it than other brands which could keep the plugs clean of carbon.
I accelerate hard at least once a day (to redline) which should also clear the carbon, if any.
And believe it or not, I think my Nology hot wires is helping with the low speed torque - no flames please (just in the combustion chamber). A stronger spark, cleans plugs, burns fuel more completely - could it be true?!!!

I have also noticed it and hate. I used to have Civic si and loved perfect gear changes with good power but this is a little dissapointing. I noticed partial throttle helps but who wants that? I will try faster throttle response.

Still in love though.....

I used to have Civic si and loved perfect gear changes...

Agreed. Everything else about the 8 makes it so rewarding to drive smooth... except for this horrible lurch after hard shifts which is making me look bad, lol.

I did manage to take an informal test drive with a Mazda tech armed with a nifty computer which plotted the various sensor positions (try driving fast with a data cable between your legs!), including both throttle positions (engine and pedal?).

Bottom line: he didn't see anything unusual. They seemed to track together well, as he put it.

Nevertheless, he too felt the lurch, although it behaved better that day than most (of course).

I mentioned the coils, but he swore "that can't be it, you'd REALLY feel it during normal use."

I'm not entirely convinced, so it's probably going back for an official diagnosis some day soon.

My guess about what everyone was experiencing is the same with all cars to a degree and seeing that RenKat didn't experience this until after he had the "L" flash kinda confirms my thought.
HeelnToe, are you shifting it hard without blipping your rpms and expecting a smooth shift? I would experience the same thing in my M3 if I didn't blip the throttle right. As soon as the clutch re-engages and the rpms have dropped there is going to be a hesitation unless you have given it enough gas to compensate. You are on the right track and it will only be a matter of time before you have this mastered but it is the same with any car. As soon as the clutch engages there is drag on the drivetrain. That will cause a slowing effect and immediately effect the rpms. Try it in a controled area where you can safely watch the tach. You'll see what I mean when there is an immediate drop to your rpms when the clutch engages again. Giving a little extra gas earlier helps absorb this phenomenon. Let us know how your experiment works out.

umm.......
Haven't really noticed, but.......

I did race a Z once and I thought I missed 4th gear, it startled me so much I hit the clutch and slowed down.

Road and Track said this when they tested the car. The text went something like "maximum acceleration requires revving to redline or even just past it to keep the car in the meat of its torque curve." What I've found is that you need to be at or just over redline so when you upshift your revs are high enough to stay up in the tertiary (last stage) of the intake system. This is where the maximum torque of the engine resides. You have to stay in that rpm range to get the most acceleration out of the car.

What is ironic is that if you fall under the necessary revs to keep the car in its tertiary intake stage, you feel a huge surge of torque when the revs get high enough to re-open the tertiary intake. Unfortunately, you've also had that momentary hesitation... ultimately slowing your acceleration. If you keep the revs up high you don't feel the torque swell even though you're accelerating faster.

^ That's the most logical explaination Ive heard yet regarding this issue. That being said, I have yet to experience this "hesitation" myself.

At the track, I noticed this hesitation consistently (always had DSC on), even remarked to my instructor about this. Running conditions on the track: were 3rd gear and 4th gear ONLY so on turns followed by any straight

.... WOT in 3rd, redline, shift to 4th, WOT, 1/2 sec OK, then **BOBBLE**, then go!... 100 something, brake, downshift to 3rd, slow, WOT in 3rd, shift, 1/2 sec OK, **BOBBLE**, then go... etc.

I did this maybe 50 times (and shifting obviously AFAP :D ) in a day, same 1/2 sec delay, same bobble, just like clockwork. Wish it wouldn't bobble, but what to do, that seems to be how it works, at least with the DCS on. So it must be built in (M-flash, BTW)

Again,I don't think the hesitation is DSC - I don't have it on my Base 8, so I can't be experiencing DSC stepping in.

There is already a flash at the dealers for what they call " Injector trip in stumble @ WOT"

This seemed to fix a few cars.

They are working on a flash to address the others.

My two cents (well, penn'orth for me ;) )

I know what you mean exactly, HeelnToe.

So first, forget the actual shift technique...

I find there is definitely a sweet spot when shifting up, and if you leave it late enough you gain a serious advantage in the next ratio because it won't bobble at all. The sweet spot -feels- like it's higher than it "ought to be" (By which I mean looking at rear-wheel torque curves cross for different gears.)

IOW, educate yourself to stay in gear until "beeeeeeeeeeeeeeeeeeeeeeep" rather than just "beeeeeep". :D For 1-2 I now stay in until 9499.99999 rpm, although timing that is a bit of an art. Luckily the limiter is quite gentle so it's not disasterous if you "miss."

Now shifting...

I think the problem is -something- in the management is having trouble disambiguating "I am coming off the throttle" and "I am coming off the throttle BRIEFLY for the sake of my cones".

I think the something is the mapping, because like you say, the problem is still there (although less so) with DSC off.

I have a vague feeling (and I couldn't say exactly why or provide any evidence, but...) that there is a lag between asking for WOT and the drive-by-wire actually doing it. Kinda feels like a cable system would if there was a little slack in the cable. This explains the comments about getting back on the gas early, ie when your left foot is still below bite (or you think it is, anyway.)

When you do get the bobble it's almost like the hestitation you see with a troublesome MAF or lambda, so that says to me it's something in the management isn't quite right.

I've seen one of those battle videos with an RX8 and the driver there was making real off-stamp-snick-stamp gearshifts and believed it was the right thing to do in this car. He might be right because I think the drive-by-wire smooths out a stamp on the throttle anyway. (Come to think of it there must be a limit to how fast the servos move, and I bet it's slower than a human right foot moving a cable would be.)

By the way, fitting the Typhoon helped - didn't eliminate it totally, but definitely helped. Some of that is because the car definitely has more puff than it did over 8500.

It also helps to time your upshifts absolutely correctly - even a slight slip from having revs too high seems to incur a big penalty, much bigger than in anything else I've driven.

Hmm, and M3s are drive-by-wire too... perhaps that explains the similarity.

Anyone come up with a solution to this?

I was out at Gingerman last weekend and noticed the same thing. When running at WOT in 3rd gear, then shifting around 9k RPM to 4th gear and going back immediately to WOT, there is a noticable lack of power for the first few 10th's of a second.

These shifts were done as quickly as possible with RPM matching. It's not a tire-slip problem (DSC is off), and not a clutch slip problem (it didn't sound or feel right for this). It felt a lot like the engine was hesitating, like the computer was trying to figure out what page it should be looking at for engine control.

I was actually quite happy with this car on the track until this point (well, that and when I almost ran out of gas on the back stretch -- who knew the engine would start to stumble with a 1/4 tank indicated under hard cornering?).

Anyone come up with a solution to this?

2.5 years into ownership, and mine STILL does it. Latest flashes and everything up to date and working perfectly otherwise.

Resetting that eccentric shaft sensor thingie (turn key to on, tap brake pedal around 20 times very fast until oil gauge sweeps over and back) SEEMED to fix it once or twice (I have no idea why it would though). But not anymore.

I just live with it, and intentionally hesitate a bit now when releasing the clutch. It's annoying though, just KNOWING it's there... anticipating it to stumble.

I've turned off the TC/DSC (hold switch in until warning light pops on), and it still happens. BUT...

There's a certain railroad crossing I bump over on my way home from work. I generally stay on the throttle when I bound over the tracks, and I've found that it confuses the TC apparently... as it momentarily cuts the power for a second until the road smooths out again. And this feels *exactly* like the WOT bobble.

I'm not saying the TC is the cause of the WOT problem, but it's definately not the clutch... it's the engine cutting power for whatever annoying reason.

I have the exact same thing with mine... even with TC off... :banghead:

I bought the car in Mar04. I drove the car for 9500 miles and did not have this problem.
After having the flash updated from K to L or M this problem appeared. When I took the car in for the flash I drove a specific route to the dealer a specific way (WOT, part throttle, ect) so I would have a reference to compare the new flash. 1/2 hour later after the new flash I went back the same way and discovered this problem. I firmly believe the new flash is the cause, it has to be something with the mapping or timing.

My guess then would be the timing. It could have been an early attempt to fix the heat and lack of oil issue. Now we are getting more oil to lubricate the apex seals. Anyone notice this with the latest flash? I haven't really noticed it.

Just an idea of course.... ;)

When running at WOT in 3rd gear, then shifting around 9k RPM to 4th gear and going back immediately to WOT, there is a noticable lack of power for the first few 10th's of a second.


Through some "on-ramp testing" over the last week, this occurs from 2nd gear into 3rd gear as well. However, it is most noticable when shifting at 8k RPM. Going to 9k lessens the effect quite a bit.