GR Yaris Inconsistent Boost

logged boost data today on short run just out of curiosity. occasionally ECU decides to drop boost 3-4psi. luckily its not that common but feels bit random.
98 RON and 13'C ambient.
 
Yaris146 said:
I’m guessing you think it is a stability program cutting in ?
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Not sure if it’s stability related but when I first got the car (nearly 3 years ago now!) I found some days doing the traffic light Grand Prix even little shopping cars could out run me as it bogged down even when not expecting it. Switching to expert I’ve found it just takes off consistently.
 
The traction/stability control is quite agressive I find... even going over minor lumps and bumps in the road I can feel it backing off the throttle which then lowers boost momentarily.
 
I would guess TC related would be visible as throttle pull. if throttle is not pulled, ecu is backing boost of some other way (that is unknown).
 
Michael Knight said:
I would guess TC related would be visible as throttle pull. if throttle is not pulled, ecu is backing boost of some other way (that is unknown).
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Number of ways to do it without adjusting the throttle. Ignition timing, turbo wastegate to name two.
 
Michael Knight said:
that's normal, car has hardly 1bar boost at redline in certain conditions.
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This was a perfectly cold night though and it’s super inconsistent. I’d understand if this happened every pull but the matter of the fact is it doesn’t…

If you’re stock would you be able to do a pull downshifting and share with the group?
 
nikoel said:
Good luck buh' - You will be the first

My prediction. They will keep taking your car, doing their 40km'h single runs and charging you 200 kangaroos every time you go there and then telling you how there is nothing wrong with it

Andrew from Motiv replied to my query himself and said that his has never seen an ECU that has been this inconsistent before

For the record I have not tuned for Ethanol either. The stock ECU handles my mix just fine

I would love to go the route of ECUTEK sometime, but I am in Brisbane and will be a downright lab rat, which I am not keen on

Biggest increase with Ethanol that I have observed is the down low torque - Knock Feedback value is back up to 24-26 btw
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You’re spot on with the first bit. That’s all they did, took data off ecu, charged me and said they couldn’t find anything wrong with it. My ECU never seemed to have this kind of issue before though? As I said this issue ONLY started out of nowhere about 3-4 weeks ago

What’s your mix? E30 or E50 blend?

Is that safe within the normal knock range?
 
Ecsrobin said:
You haven’t mentioned if using expert or expert+. If I was a betting man going into expert or expert+ the problem might disappear.
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Not something I’ve tried, will go out and test more in the coming nights as I have got a few 8-9 degree Celsius nights
 
Anyone know how I can post the videos? Can’t seem to find an option…


If anyone would be willing to downshift from 4th to 2nd and then WOT I’d love see see the boost gauge. @Michael Knight this was the biggest issue I’ve had as mentioned.

A normal 2nd gear pull I hit 1 bar at 3,000rpm and it held all the way to redline.

Downshifting from 4th - 2nd it appears in loosing boost, when shifting into 3rd i don’t hit boost until 6k rpm

Then sport mode shifting from 1st - 3rd, I’m not hitting boost until 6k rpm (1st gear), 6.3k rpm (2nd gear) and 5.5k rpm (3rd gear).

Downshifting is how ‘everyday’ driving would be and is where I’ve discovered the car suffers the most. So yes to anyone who’s stock (with or without intake and exhaust), please share or send any videos to me because I’d love to show Toyota.

My next plan of action is I’m going back to stock intake, mechanic has booked in a dyno run for my car, so I’ll have something to look at and compare with Toyotas data.
 
JJ.King said:
You’re spot on with the first bit. That’s all they did, took data off ecu, charged me and said they couldn’t find anything wrong with it. My ECU never seemed to have this kind of issue before though? As I said this issue ONLY started out of nowhere about 3-4 weeks ago

What’s your mix? E30 or E50 blend?

Is that safe within the normal knock range?
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I tried E20 and then E30. I would not go anywhere north of E30. The start on E30 is sus enough

So 17L of E85 and the rest is RON98

What do you mean safe within normal knock range? The whole point of E## is to push higher RON values to reduce knock probabilities. The issue stems from the fact that for me, the knock feedback value is sticky. When you fill up with this new blend, you force the ECU to re-learn the values. This is why many suspect "bad fuel", (which in fairness could be)

Funnily enough, the first time I did so, my value went from 20 to 24ish under normal driving conditions, but at WOT it has an other feedback value that is seperate from the first. It kept the same value as before (21). Took a while for the ECU to realise what it was doing. Because of the discrepancy, at partial throttle, my acceleration was miles ahead of WOT

(Also because my car is a daily I am okay with having high ethanol figures in the tank, if I were to store the car as a collectable (what a waste!) I would stay as far away from Ethanol as possible)
 
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nikoel said:
I tried E20 and then E30. I would not go anywhere north of E30. The start on E30 is sus enough

So 17L of E85 and the rest is RON98

What do you mean safe within normal knock range? The whole point of E## is to push higher RON values to reduce knock probabilities. The issue stems from the fact that for me, the knock feedback value is sticky. When you fill up with this new blend, you force the ECU to re-learn the values. This is why many suspect "bad fuel", (which in fairness could be)

Funnily enough, the first time I did so, my value went from 20 to 24ish under normal driving conditions, but at WOT it has an other feedback value that is seperate from the first. It kept the same value as before (21). Took a while for the ECU to realise what it was doing. Because of the discrepancy, at partial throttle, my acceleration was miles ahead of WOT

(Also because my car is a daily I am okay with having high ethanol figures in the tank, if I were to store the car as a collectable (what a waste!) I would stay as far away from Ethanol as possible)
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Ahh yup awesome, do you use any tools to measure out your E blend? Or do I just keep driving until the dash shows 0km range left?

I’ve confirmed with someone from Toyota that the dash lights comes on at 20-30km range (forgot which one), but when it shows 0km range the cars still able to do another 100km - apparently.

Edit: our tanks are 50L right? I usually always fill up at my last bar, which to fill up to full is anywhere from 30-35L
 
When the range is zero there are still at least 5 l left in the tank, probably 6-7 l given the nominal 50 l tank.

I leave it to the reader to determine how long they can drive for from that point ;)
 
JJ.King said:
Ahh yup awesome, do you use any tools to measure out your E blend? Or do I just keep driving until the dash shows 0km range left?

I’ve confirmed with someone from Toyota that the dash lights comes on at 20-30km range (forgot which one), but when it shows 0km range the cars still able to do another 100km - apparently.

Edit: our tanks are 50L right? I usually always fill up at my last bar, which to fill up to full is anywhere from 30-35L
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Math

As I said, my blend is less E30 - more E30ish

I used 17L of E85 and then brimmed 98. Then subsequently when i got the fuel light I put in 15L of E85 and the rest 98. Knock feedback value only changed by 0.1 telling me that my catculations are about right

Fuel Consumption went up to 11/100kms as ethanol is obv lower density fuel
 
Onehp said:
Or, the ECU programming is not capable to deal with the real world variations in how the hardware responds - that, or said harfware has too large variations. Something like that.
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This is precisely what I think the issue is and why I think changing/modifying the engine management is the only way to properly resolve it. Development of the software, which was new and unique to the GRY, hasn't sufficiently accounted for the range in variance of hardware.

It's possible replacing all the solenoids, actuators and vacuum lines could bring the hardware back into optimal range but it would be purely luck. It also wouldn't be necessary if the software had have just been further developed to better account for that range in variance.

My car only rarely does this these days but at some point further down the track will probably try EcuTek.
 
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How much would an aftermarket intercooler help with this? In my i30N it definitely made it more consistent on hotter days.
 
CerN said:
How much would an aftermarket intercooler help with this? In my i30N it definitely made it more consistent on hotter days.
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imo the inconsistency is more algorithmic than any specific piece of hardware or condition like intercooler and temperature respectively. It happens when it's cold too.
 
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