GR86 Jerky acceleration when cold?

[midlife_sportscar]

Initially I found the 86 needed much more concentration & finesse to drive smoothly than the Fiesta I had previously.
Over time (getting on for 3000 miles now) I have definitely gotten more used to it and it is much less of an issue.
During cold start however it is noticeably 'lurchy' and I always try to let that initial phase complete before I drive off, otherwise going over a speed cushion, for example, is really difficult to deal with if you want to avoid kangarooing down the road.

 

[Conscript]

This is a bit anecdotal, but maybe worth sharing. When I had my GT86 I don't remember initially having much of a problem with a jerky throttle. A little sensitive sometimes, but nothing worth mentioning.

After about 4 years, I had it modified - new exhaust manifold/cat, and remapped with an Ecutek tune at Abbey Motorsport. Great upgrade, got rid of the torque dip, but I then started suffering with an issue very much like what I have inthe GR86, but worse - most of the time alright, but occasional, a bit of kangarooing. Most noticeable at part throttle and slower speeds. Quite often I'd slow down as turning into a junction, drop into second, and as I was accelerating again, I'd feel jerkiness as if my foot was shaking, even though it was dead steady on the pedal. This was with the clutch full engage too, so definitely all throttle.

I went back to Abbey, thinking perhaps it was just the remap that needed fine tuning, but they could find no issue with the fuelling, the throttle mapping, nothing. All seemed to be good, but Mark came out with me in the car and he noticed it too. I ended up leaving the car with them for a week or so while they did some data logging, and the only thing they could find was that there was a bit of a voltage spike coming from the throttle pedal (afterall, it's just a potentiometer). They ended up swapping the throttle pedal from their development car into mine and hey presto....the issue went away.

Now I'd already driven the car for 4 years with the original pedal, but we surmised that perhaps it was only after the remap, when the car was given a boost in torque, that it came to be something I could feel. Anyway, the point of all this rambling is that perhaps the issue is the same with the GR - perhaps it's just a case of the throttle pedal not being the most rigorously engineered thing in the world, and now that the GR is develops more power than it's predecessor, any issue with a less than perfect throttle input voltage gets exacerbated and felt as a jerkiness in acceleration sometimes, even with a steady and controlled right-foot. It might also explain why some people never have an issue - perhaps they are simply lucky enough to have been given a car where the pedal wasn't manufactured on a Friday afternoon

Just some food for thought, because as I say, the symptoms I feel are very much like what I had with the GT after it was modified, but not as bad.

 

[GRistopher]

I dont mind having a sensitive throttle and a bit of kangarooing as a result of my bad inputs. When I first commented on this thread 6 or 7 months ago after first getting the car, that's what I put it down to. However I'm not a fan of a car doing this to me while I'm supposed to be in control of it

For me, driving the car when it's started to warm up is fine. The problem is with the wierd stuff that goes on during the cold start. This is mainly during the initial blaring horrible 20 or so seconds, but there is definitely a staged cold start when throttle inputs don't correlate with the output. It isn't just 20 seconds of blaring nonsense then it runs as normal.

I can be maintaining a certain throttle position while pulling away, just for the revs to drop as a result of some wierd cold start stuff and the car lurches around as a result. There also seems to he a disconnect between throttle position/engine Revs in neutral and the torque applied as the clutch is then engaged during the cold start. It's just F%@king in annoying in a car that's designed to be fun.

It'll by no means make me sell the car. I love it too much to let a minute or so of odd behaviour when it's cold spoil things. I also know this is the work if the vehicle design department that gives us lane departure and collision warnings. Not the people who thought, "lets make a fun car." It's another one of those "new car things" designed to bypass legislation that make me hate the world and want to rant on the Internet.

 

[FRAJ]

The problem is with the wierd stuff that goes on during the cold start. This is mainly during the initial blaring horrible 20 or so seconds, but there is definitely a staged cold start when throttle inputs don't correlate with the output.

Agreed, trundling along in 1st after startup and really gently increasing the pedal it doesn't accelerate but after a few seconds it cuts power and the kangaroo starts. The aggressive pedal map just makes it worse. However, if your just quick on to the clutch pedal then it's ok, and soon clears up.

 

[sim61]

This is a bit anecdotal, but maybe worth sharing. When I had my GT86 I don't remember initially having much of a problem with a jerky throttle. A little sensitive sometimes, but nothing worth mentioning.

After about 4 years, I had it modified - new exhaust manifold/cat, and remapped with an Ecutek tune at Abbey Motorsport. Great upgrade, got rid of the torque dip, but I then started suffering with an issue very much like what I have inthe GR86, but worse - most of the time alright, but occasional, a bit of kangarooing. Most noticeable at part throttle and slower speeds. Quite often I'd slow down as turning into a junction, drop into second, and as I was accelerating again, I'd feel jerkiness as if my foot was shaking, even though it was dead steady on the pedal. This was with the clutch full engage too, so definitely all throttle.

I went back to Abbey, thinking perhaps it was just the remap that needed fine tuning, but they could find no issue with the fuelling, the throttle mapping, nothing. All seemed to be good, but Mark came out with me in the car and he noticed it too. I ended up leaving the car with them for a week or so while they did some data logging, and the only thing they could find was that there was a bit of a voltage spike coming from the throttle pedal (afterall, it's just a potentiometer). They ended up swapping the throttle pedal from their development car into mine and hey presto....the issue went away.

Now I'd already driven the car for 4 years with the original pedal, but we surmised that perhaps it was only after the remap, when the car was given a boost in torque, that it came to be something I could feel. Anyway, the point of all this rambling is that perhaps the issue is the same with the GR - perhaps it's just a case of the throttle pedal not being the most rigorously engineered thing in the world, and now that the GR is develops more power than it's predecessor, any issue with a less than perfect throttle input voltage gets exacerbated and felt as a jerkiness in acceleration sometimes, even with a steady and controlled right-foot. It might also explain why some people never have an issue - perhaps they are simply lucky enough to have been given a car where the pedal wasn't manufactured on a Friday afternoon

Just some food for thought, because as I say, the symptoms I feel are very much like what I had with the GT after it was modified, but not as bad.

This made me recall, probably incorrectly, that there is some sort of throttle pedal reset procedure.

I seem to have "ignition on, five full presses of the accelerator pedal" in my head. Could be complete rubbish though..

Can anyone confirm?

 

[sbc_uk]

I really don't get any of this. Not at all. I leave my drive with the little blue 'cold engine' symbol still on sometimes, but I don't get any of the extremes you guys are referring to......

 

[Conscript]

This made me recall, probably incorrectly, that there is some sort of throttle pedal reset procedure.

I seem to have "ignition on, five full presses of the accelerator pedal" in my head. Could be complete rubbish though..

Can anyone confirm?

Yes, that still works and I've done that. That's more about sorting the calibration of the pedal though, it gets rid of the dead spot at the top of the pedal travel, but doesn't stop the jerkiness you get every so often.

I really don't get any of this. Not at all. I leave my drive with the little blue 'cold engine' symbol still on sometimes, but I don't get any of the extremes you guys are referring to......

It's not all that extreme (for me anyway), nor all that frequent, but noticeable when it happens. And I've had it with a fully warm car too. So perhaps we are all just conflating our own foibles. But there is definitely something a little tricky with the throttle. Someone on here even sold the car and moved to an MX5 as they couldn't live with it.

I guess it doesn't help that the pedal has obviously been mapped to be very 'top heavy'....only the first 50% (or so) of travel does anything. I think I would prefer it if you there was a more linear relationship between pedal and throttle opening, but I guess they do it to give you the illusion that the car is faster.

 

[Noel McC]

Mine seems grand cold…. But i do get a bouncing-lurching-pogoing kangaroo effect even warmed up when getting back onto the throttle after downshifts / applying throttle etc to make a decent move on. It is annoying, think drive train and stiff suspension/chassis amplify it.

 

[Triggaaar]

I do wonder if some of our cars are afflicted with this issue more than others.

I'm totally happy with mine and this jerky throttle thing has not been a concern for me.

Same. I just have a problem with mine.

 

[AdamST205]

I am 5k miles in now and whilst 1st to 2nd can be a bit jerky, once warmed up and on it no real issue. I have even got my heel n toe nice and smooth.

Is it as good as something with a cable throttle from 20 years ago? No but then nothing really is.

 

[SJR202]

I really don't get any of this. Not at all. I leave my drive with the little blue 'cold engine' symbol still on sometimes, but I don't get any of the extremes you guys are referring to......

Is your car a second batch 2024 car or one of the first off the boat 2022/2023 models out of interest?

 

[GRistopher]

are you one of the second wave of 2023/2024 cars?

Mines a 73, so the 2nd batch.

I've definitely made the problem worse with having an aftermarket exhaust. If its early or late in the day, and I don't want to sit on my driveway with the cold start blaring away, I tend to start up and immediately roll off my downhill driveway. I don't have to touch the accelerator at all until I get to the T-junction at the end of my road and it does all sorts of weird stuff during this time.
By the time I go to pull away from the T-junction at the end of my street, I'm still at the mercy of an engine that does whatever it wants. Given the engine is still cold and I'm trying to be as gentle as possible until I get some heat into it, this is when the jerky power delivery presents itself pretty much 100% of the time.

It seems that it's something ill have to live with for now if I don't want to annoy the neighbours with the cold start, unless I put the stock exhaust back on - which isn't happening.

 

[sbc_uk]

Is your car a second batch 2024 car or one of the first off the boat 2022/2023 models out of interest?

Mine is a 73 plate delivered October 2023

 

[ZN8]

This may be of interest to people in this thread but at some point earlier this year the latest version of the GR86, known as the 'Type C' has revised throttle mapping due to the number of complaints of the throttle response.

Unfortunately I don't know if this can be amended on our cars which are Type A and Type B, simply because Toyota GB know very little about the GR86 and have no interest in it.

Info sourced from Japan and some dodgy translations:

The GR86 has a different driving taste due to changes in the electronic throttle output characteristics​

The software changes are available for all models. The first is a change in the electronic throttle output characteristics. The GR86's throttle control is a characteristic that "intentionally" emphasizes the feeling of acceleration, but because of this, it ...... evaluated that it is difficult to control the accelerator. Therefore, while taking advantage of the conventional characteristics, the C-type has been retuned in a more "linear" direction with acceleration G connections.

The other is the optimization of VSC control. In the conventional model, the control allowed a certain amount of behavior change even when the VSC was turned on, but in the C type, the control was changed to a safer / more secure direction (= intervention at an earlier timing).

This makes the function as a VSC clearer because people who changing behavior (= sliding driving) select the VSC OFF/TRACK mode. However, the suspension and EPS settings have not changed from the previous model, so the GR86's crisp handling characteristics remain unchanged In other words, this change has been adjusted in the direction of "slightly" adulthood from the characteristics that I felt a little yancha in everyday life.

 

[Itcaptainslow]

Interesting info. I might approach my local dealership and ask if this is something that can be applied.

 

[ZN8]

Interesting info. I might approach my local dealership and ask if this is something that can be applied.

I wouldn't bother, as mentioned dealerships know nothing about the GR86, bear in mind between the whole UK dealership network their sold about 1500 of them. Half of them can't navigate the software to open both doors, or even get oil filters in stock. Best of approaching TGB and get ignored for 3 months

 

[Hachi-roku]

This may be of interest to people in this thread but at some point earlier this year the latest version of the GR86, known as the 'Type C' has revised throttle mapping due to the number of complaints of the throttle response.

Unfortunately I don't know if this can be amended on our cars which are Type A and Type B, simply because Toyota GB know very little about the GR86 and have no interest in it.

Info sourced from Japan and some dodgy translations:

Seems to add weight to my comment earlier in the thread with YouTube clip with Mr 86 himself driving the very latest model year revision of the car.

Hopefully it is just a software flash that can be resolved at some point by someone even if it’s outside of the dealer network. I don’t think I’ve found its quirks as invasive as some but it would be nice if there’s a better throttle map nonetheless!

 

[Conscript]

This may be of interest to people in this thread but at some point earlier this year the latest version of the GR86, known as the 'Type C' has revised throttle mapping due to the number of complaints of the throttle response.

Unfortunately I don't know if this can be amended on our cars which are Type A and Type B, simply because Toyota GB know very little about the GR86 and have no interest in it.

Info sourced from Japan and some dodgy translations:

Interesting. Sounds like it could potentially be an easy update, if it wasn't for Toyota dealers getting in the way.

I wonder if this will be something we have to work out ourselves, like those people with the GT86 who managed to get the better VSC module from the facelift retrofitted to the earlier cars.

 

[ZN8]

I'm using Google translate to see if any of the Japanese owners are able to have it updated on their cars, nothing concrete at the moment. I personally don't have an issue with it, mine was the clutch but I still think it would be good to see if it can be sorted.

I have figured out that the Type A B C is to do with model year.

 

[jb1750]

From the translation above, it looks like the Type C update includes a recalibration for ‘safer’ implementation of the VSC.
Would this make the Type C spec a suitable update for a safety recall??
I would quite fancy that more linear throttle map… though in fairness I think I’ve developed a ridiculously sensitive right foot over the last year- able to flex in 1/10th millimetre increments in order to make smooth and modest progress