GR Yaris Inconsistent Boost

YobboYaris

YobboYaris

Devoted member
Joined
Feb 8, 2022
Messages
53
Reaction score
148
Location
Winsford, Cheshire
Hi, I don't know if anyone has had anything similar to this but my GRY doesn't have consistent boost.

In first and second gear the boost fluctuates either giving me full boost or limiting itself to around 14PSI for the whole rev range. It's really noticeable as the car seems to "drop off" with power as you climb the revs. I know there's a dip in the torque curve at the top end with the GRY but I would of thought it wouldn't limit itself all the way through the range?
Third gear seems to be fine and when above 5K it boosts normally. What I've found is If I hold the car in third gear and then drop down to second the car gives me full boost.

Is anybody having similar issues to this? Should I take it into Toyota to have it sorted out?

My bolt on mods are a MST Intake and a Remus GPF-Back Exhaust.
Thanks. 😁
 
YobboYaris said:
Hi, I don't know if anyone has had anything similar to this but my GRY doesn't have consistent boost.

In first and second gear the boost fluctuates either giving me full boost or limiting itself to around 14PSI for the whole rev range. It's really noticeable as the car seems to "drop off" with power as you climb the revs. I know there's a dip in the torque curve at the top end with the GRY but I would of thought it wouldn't limit itself all the way through the range?
Third gear seems to be fine and when above 5K it boosts normally. What I've found is If I hold the car in third gear and then drop down to second the car gives me full boost.

Is anybody having similar issues to this? Should I take it into Toyota to have it sorted out?

My bolt on mods are a MST Intake and a Remus GPF-Back Exhaust.
Thanks. 😁
Click to expand...
Yes a lot of people have this including myself. There's been discussion about it here https://www.gr-yaris.co.uk/forum/threads/reduced-engine-power.1619/ (discussion starts around the 2nd page) and Facebook groups. Some have tried replacing various valves on the car with no change. At this point I personally believe it's built into the software and unless Toyota acknowledge it abnormal and release an update it will remain this way. Would love to be proven wrong and shown that this is in fact a hardware fault but it's not looking that way. For reference my car is stock.
 
Last edited:
Benj said:
Yes a lot of people have this including myself. There's been discussion about it here https://www.gr-yaris.co.uk/forum/threads/reduced-engine-power.1619/ (discussion starts around the 2nd page) and Facebook groups. Some have tried replacing various valves on the car with no change. At this point I personally believe it's built into the software and unless Toyota acknowledge it abnormal and release an update it will remain this way. Would love to be proven wrong and shown that this is in fact a hardware fault but it's not looking that way.
Click to expand...
I was just reading into this after doing some digging. It's annoying but I'm pretty thankful It's not just me! I was gonna remap my car in the near future but this has put me off as I don't know what the car will do with more boost pressure. Unless with the map, it overrides the old buggy software and will work normally? I have no idea. 😅
 
YobboYaris said:
I was just reading into this after doing some digging. It's annoying but I'm pretty thankful It's not just me! I was gonna remap my car in the near future but this has put me off as I don't know what the car will do with more boost pressure. Unless with the map, it overrides the old buggy software and will work normally? I have no idea. 😅
Click to expand...
It's possible that flashing will provide some kind of workaround for it but at this point in ownership I don't wanna risk it.
 
There must be a way to log and see if the ecu is actually requesting lower boost(and why) at that time or if it just doesn't build boost for some reason. But I guess nobody has done that, or complained to Toyota because there seems to be no answers. Mapping would definitely help if the problem is not in the hardware and if they actually have full control over the ecu. I hope Toyota fixes this, it's not normal to feel major inconsistencies in power delivery when you're just occasionally accelerating on the street. It's normal to loose power when the engine protection protocols kick in, but not like this IMO. I don't have my car yet, this concerns me a little bit. Are there people who don't have this issue?
 
Mine does too, and with a lot of breeding mods it's super noticiable.

The remap will cure it 100% since they have control over everything, if it does not, return to the tuner and complain to get it fixed.

I'll do the remap on one or two months after the replacement of the valvetrain springs and camshafts, so I'll let you know if it will cure the thing, but if it does not, I'll complain to the tuner until it's cured :p
 
amarce said:
I'll do the remap on one or two months after the replacement of the valvetrain springs and camshafts, so I'll let you know if it will cure the thing, but if it does not, I'll complain to the tuner until it's cured :p
Click to expand...
Not sure running camshafts on stock ECU is a good idea... Unless they are very close to OE spec...
I hope you have a good tuner that remembers who you are after you pay him otherwise can become expensive ;)
 
Last edited:
Mine did it early in ownership but doesn’t do it now. However I am questioning myself if the car was actually in its warm up phase still.

It definitely happens in 2nd the most

The Yaris isn’t torque limited (by boost) in any gear. Often cars with one driven axle are, to prevent excessive wheel spin or axle stress. Yaris doesn’t really have that issue.
 
Mintmansam said:
The Yaris isn’t torque limited (by boost) in any gear. Often cars with one driven axle are, to prevent excessive wheel spin or axle stress. Yaris doesn’t really have that issue.
Click to expand...
As the engine gets heat soaked, it will request more boost but because of the lower density of hot air turbo spool takes longer time also. So combined it means boost isn't built as fast as the revs raise esp. in lower gears, giving the impression of power loss and elastic band sensation on the throttle.

Which isn't the same obviously as actual boost cuts either due to ECU requesting less boost as protection (e.g. faulty boost sensor) or because requested boost cannot be met (e.g. malfunction in the electronic/pneumatic waste gate control).

A suggestion is for those with issues is to log the engine for rpm, boost request, actual boost, IAT, CACT, timing, throttle valve position at the least. Waste gate duty cycle isn't available afaik...
 
Last edited:
Onehp said:
As the engine gets heat soaked, it will request more boost but because of the lower density of hot air turbo spool takes longer time also. So combined it means boost isn't built as fast as the revs raise esp. in lower gears, giving the impression of power loss and elastic band sensation on the throttle.

Which isn't the same obviously as actual boost cuts either due to ECU requesting less boost as protection (e.g. faulty boost sensor) or because requested boost cannot be met (e.g. malfunction in the electronic/pneumatic waste gate control).

A suggestion is for those with issues is to log the engine for rpm, boost request, actual boost, IAT, CACT, timing, throttle valve position at the least. Waste gate duty cycle isn't available afaik...
Click to expand...
Yes, I forget the expression for boost at fixed rpm, ie if you hold at 2,000rpm for a long time you can make more boost than if you were travelling through from 1800-2500rpm quickly. Boost saturation or something? I think it’s why at high speed in a high gear I’m impressed with the torque.

however in this instance the lack of boost (for whatever reason) is so noticeable that rpm increase in 2nd is slower than 3rd. When I’ve felt it. It’s exactly as per the boost of the engine during the warming up phase. Very very flat. As in noticeable, changing to 3rd from 2nd would give a faster rate of acceleration noticeably.

It seems to have resolved its self now but a strange experience
 
Onehp said:
A suggestion is for those with issues is to log the engine for rpm, boost request, actual boost, IAT, CACT, timing, throttle valve position at the least. Waste gate duty cycle isn't available afaik...
Click to expand...
How do you log this information?
 
Benj said:
How do you log this information?
Click to expand...
DIY without a Toyota technician in the car, I use a bluetooth OBD2 dongle (mine is a 'premium' OBDlink MX+) and a phone app called Torque. If buying the dongle new, find reviews that get high read frequency (>5Hz) from modern Toyotas. Other apps probably exist too but no experience with them.
Log file can then be exported and uploaded to datazap.me for analysis and sharing.
 
Onehp said:
DIY without a Toyota technician in the car, I use a bluetooth OBD2 dongle (mine is a 'premium' OBDlink MX+) and a phone app called Torque. If buying the dongle new, find reviews that get high read frequency (>5Hz) from modern Toyotas. Other apps probably exist too but no experience with them.
Log file can then be exported and uploaded to datazap.me for analysis and sharing.
Click to expand...
Thanks for the info. I just had a look into Techstream but the only options are a yearly subscription of around $1200 USD or a likely malware filled download from some random website. 😂

Do you know whether the Torque app is able to show the same parameters as Techstream?
 
Benj said:
Do you know whether the Torque app is able to show the same parameters as Techstream?
Click to expand...
No Torque is just genereric showing limited non-manufacturer specific PIDs, but enough for general performance logging. On plus side, can be used on most cars... You could get away with 20-200£ depending on the quality of the dongle and if you get the paid Torque app.
 
Onehp said:
A suggestion is for those with issues is to log the engine for rpm, boost request, actual boost
Click to expand...
Just thought about it then. Would Torque be able to log boost requested and actual boost as I'm guessing these will be most important in diagnosing inconsistent boost?
 
Last edited:
Benj said:
Just thought about it then. Would Torque be able to log boost requested and actual boost as I'm guessing these will be most important in diagnosing inconsistent boost?
Click to expand...
If my memory doesn't fail me completely it can log requested boost also, but please let someone else confirm, I don't have the possibility to check anytime soon.
 
Onehp said:
If my memory doesn't fail me completely it can log requested boost also, but please let someone else confirm, I don't have the possibility to check anytime soon.
Click to expand...
I'll get an obd bluetooth adapter and start doing some digging myself. Thanks for your help (y)
 
You must log in or register to reply here.
Back
Top