follow ft86club on our blog, twitter or facebook.
FT86CLUB
Ft86Club
86SPEED
Register Garage Members List Calendar Search Today's Posts Mark Forums Read

Go Back   Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB > Technical Topics > Forced Induction

Forced Induction Turbo, Supercharger, Methanol, Nitrous


User Tag List

Reply
 
Thread Tools Search this Thread
Old 08-10-2018, 12:08 PM   #1
Gt86Force
Member
 
Join Date: Aug 2018
Drives: GT86 Supercharged
Location: Europe
Posts: 19
Thanks: 1
Thanked 9 Times in 6 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Engine bogging in WOT after gear change

Hi to all,
I have a problem and I don't know how to proceed...
I have a 2015 86, 45k miles, HKS supercharged by 4k miles. Since last week the car was working fine without any problems, I use it as a daily with 1 track day a month (full day or a full weekend).
Recently I have a strange issue, after changing gear near the rev limit in wot the engine stops climbing the rpms for a second and if I keep my foot down eventually the rpms start increasing again.
This happend to me like 4 times, it's not persistent.

My engine modifications are:
-Hks supercharger
-Hks oil cooler
-Hks spark plugs
-Avo 3 bar MAP sensor
-Hks EL headers with cat (GT Spec)
-Milltek overpipe 2,5"
-Custom front pipe 2,5" no cat
-Custom catback 2,5"
-Greddy oil pan baffle
-Ecutek Tune

Stock injectors and fuel pump. I think the problem is mechanic because since last week the car was running fine, the only thing that has changed is the external temperature (like 35įC) No CEL or whatsoever.

Here is the log of a 3rd gear pull
https://datazap.me/u/gt86forcenew/lo...?log=0&data=15

Here is the log of the problem, 2nd to rev limiter, change to 3rd gear, back in wot, rpms stops climbing, i keep my foot down for a couple of seconds until the car starts pushing again and after that I stop accelerating.
https://datazap.me/u/gt86forcenew/lo...?log=0&data=15

My tuner unfortunately it's not available until the end of the month and I want to have other ideas about what the problem might be.

Sorry for the english, It's not my first language.
Gt86Force is offline   Reply With Quote
The Following User Says Thank You to Gt86Force For This Useful Post:
Irace86.2.0 (08-10-2018)
Old 08-10-2018, 03:19 PM   #2
Irace86.2.0
Senior Member
 
Join Date: Mar 2017
Drives: Q5 + BRZ + M796
Location: Santa Rosa, Ca
Posts: 1,946
Thanks: 1,225
Thanked 862 Times in 577 Posts
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Seems like your AFR is off; you are leaning out. Rpms are climbing just not as aggressively, right?

Your AFR is like 16-17 initially before it drops to your target.

https://datazap.me/u/gt86forcenew/lo...7&zoom=129-181
__________________
Irace86.2.0 is offline   Reply With Quote
Old 08-10-2018, 04:12 PM   #3
Gt86Force
Member
 
Join Date: Aug 2018
Drives: GT86 Supercharged
Location: Europe
Posts: 19
Thanks: 1
Thanked 9 Times in 6 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Irace86.2.0 View Post
Seems like your AFR is off; you are leaning out. Rpms are climbing just not as aggressively, right?

Your AFR is like 16-17 initially before it drops to your target.

https://datazap.me/u/gt86forcenew/lo...7&zoom=129-181
Exactly! Any idea why or what to check?
First time happend during a track day, but only once... I've done like another 30 /40 laps that day with no issues.
I'm thinking fuel pump or injectors but it happens only after the gear change... if one of this things is broken maybe the problem should be in a specific rpm range.
Gt86Force is offline   Reply With Quote
Old 08-10-2018, 04:33 PM   #4
Irace86.2.0
Senior Member
 
Join Date: Mar 2017
Drives: Q5 + BRZ + M796
Location: Santa Rosa, Ca
Posts: 1,946
Thanks: 1,225
Thanked 862 Times in 577 Posts
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by Gt86Force View Post
Exactly! Any idea why or what to check?
First time happend during a track day, but only once... I've done like another 30 /40 laps that day with no issues.
I would be concerned because that is pretty lean, right? If it is intermittent then it is hard to say. For the record, Iím learning how to read these so real novice, so donít take what I say as Bible.

This seems to show that you are WOT but actual trottle position was reduced to 15%. A safety net maybe:

https://datazap.me/u/gt86forcenew/lo...6-210&mark=113

Here the fuel rail pressure seems to drop:

https://datazap.me/u/gt86forcenew/lo...2-239&mark=152

Fuel pump is going? Fuel starvation during aggressive shifts with a low fuel tank? I really donít know.
__________________
Irace86.2.0 is offline   Reply With Quote
Old 08-10-2018, 04:56 PM   #5
Anderzz
Senior Member
 
Anderzz's Avatar
 
Join Date: Jun 2016
Drives: 2013 Subaru BRZ Premium
Location: Maine
Posts: 228
Thanks: 95
Thanked 73 Times in 59 Posts
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Garage
Buy some MAF cleaner, clean your MAF, ensure your MAF is sealing correctly, and then give her a go.

Both of the last 2 major issues I've been directly related to with difference FI kits both traced back to the AFR's going mad off of MAF seal/cleanliness issues.
__________________
Anderzz is offline   Reply With Quote
Old 08-10-2018, 06:58 PM   #6
steve99
Senior Member
 
steve99's Avatar
 
Join Date: Dec 2013
Drives: FT86
Location: Australia
Posts: 7,346
Thanks: 955
Thanked 4,579 Times in 2,724 Posts
Mentioned: 508 Post(s)
Tagged: 2 Thread(s)
Is your tune speed density ??


Can you log manifold pressure a lot of aftermarket map sensors go bad


Do you have blow off valve if so check its operation carefully. And for leaks or damafed or loose hoses. Have you clamped all the hoses under intake manifold ?
steve99 is offline   Reply With Quote
Old 08-10-2018, 07:05 PM   #7
Irace86.2.0
Senior Member
 
Join Date: Mar 2017
Drives: Q5 + BRZ + M796
Location: Santa Rosa, Ca
Posts: 1,946
Thanks: 1,225
Thanked 862 Times in 577 Posts
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by steve99 View Post
Is your tune speed density ??


Can you log manifold pressure a lot of aftermarket map sensors go bad


Do you have blow off valve if so check its operation carefully. And for leaks or damafed or loose hoses. Have you clamped all the hoses under intake manifold ?
He did log MAP, right?

https://datazap.me/u/gt86forcenew/lo...34&zoom=95-212

What do you think about my comments? Was there a drop in fuel rail pressure because of a mechanical problem or was that by design/tune or a safety net?
__________________
Irace86.2.0 is offline   Reply With Quote
Old 08-10-2018, 10:26 PM   #8
steve99
Senior Member
 
steve99's Avatar
 
Join Date: Dec 2013
Drives: FT86
Location: Australia
Posts: 7,346
Thanks: 955
Thanked 4,579 Times in 2,724 Posts
Mentioned: 508 Post(s)
Tagged: 2 Thread(s)
Quote:
Originally Posted by Irace86.2.0 View Post
He did log MAP, right?

https://datazap.me/u/gt86forcenew/lo...34&zoom=95-212

What do you think about my comments? Was there a drop in fuel rail pressure because of a mechanical problem or was that by design/tune or a safety net?



Haha yeah he did log map, too late at night.


Its looks ok


Something weird going on with fueling though the di fuel pressure changes with injector opening time and rpm.



He should probably lookat checking low pressure fuel pump, although low fuel pressure usually effects top end more


Check the di computer is grounded and any intake or exhaust leaks usuall suspects
steve99 is offline   Reply With Quote
Old 08-11-2018, 08:37 AM   #9
Gt86Force
Member
 
Join Date: Aug 2018
Drives: GT86 Supercharged
Location: Europe
Posts: 19
Thanks: 1
Thanked 9 Times in 6 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Thanks for the replies!

Just a couple of questions, I'm dumb and not very mechanically inclined

@steve99
Yes the car is tuned in a hybrid speed density using MAF on low rpms, or at least that is what my tuner told me.

Low pressure pump is the one in the tank right? By top end do you mean? My problem seems to be at the top end, over 5,5k rpms. By more do you mean that the problem should be more accentuated?

I need to check for exhaust leaks in the headers right? The rest of the exhaust system should not interfere or not?

By DI computer do you mean the injector "ECU" correct? I have to check if everything is connected or?
I don't have the knowledge/tools to disassemble and bench test the computer. If it's a cpu problem my only option is to replace it, but i want to keep it as my last option...

@Irace86.2.0
Yeah i am a little concearned because as you say, it seems really lean. I'm also trying to understand how this things work..


A faulty DI Injector can cause this problems? I have a friend who just changed one because the seal broke, but his car had a CEL and was making popping sounds.


First thing i'll check for leaks and clean the MAF to see if anything changes, but usually i'm not that lucky.
Gt86Force is offline   Reply With Quote
The Following User Says Thank You to Gt86Force For This Useful Post:
Irace86.2.0 (08-11-2018)
Old 08-11-2018, 08:52 PM   #10
steve99
Senior Member
 
steve99's Avatar
 
Join Date: Dec 2013
Drives: FT86
Location: Australia
Posts: 7,346
Thanks: 955
Thanked 4,579 Times in 2,724 Posts
Mentioned: 508 Post(s)
Tagged: 2 Thread(s)
Yes di computer is injector ecu under bonnett


Yes check for any exhaust leaks before or near o2 sensors once you get say meter past o2 is not going to effect readings.


Check for intake leaks or leaks due bov not sealing correctly


Check map sensor reads 1 bar ie same as atmospheric with ignition on but motor off.


When engine running you usually see something like 0.3-0.4 bar at idle if its more than that its likely got some form of leak



Its difficult to diagnose hybrid speed density as we dont know what the parameter setup is ie where changover occurrs from maf to sd or any other custom tables in use it might be triggering some weird boost related cutout but if its run before for a fait period ok on this tune ist very likely hardware fault
steve99 is offline   Reply With Quote
Old 08-12-2018, 02:52 AM   #11
jflogerzi
Senior Member
 
jflogerzi's Avatar
 
Join Date: May 2012
Drives: 2013 Series 10 6MT FR-S
Location: Moreno Valley, CA
Posts: 3,250
Thanks: 1,086
Thanked 971 Times in 754 Posts
Mentioned: 60 Post(s)
Tagged: 0 Thread(s)
Garage
I would get your log to your tuner. As @steve99 said the hybrid MAF/SD tunes require more fine tuning.
__________________
2013 Series 10 FRS #553
Tomei UEL with Stock FP and MXP SP CB
Upgraded Brake Pads Stock Rotors with Motul 600 Fluid
Koing Hypergram 17x8 ET40 FS Indy Hawks 225/45/17
Sprintek 210 IC + FF + Tuned by Mike @ Xero Limit
jflogerzi is offline   Reply With Quote
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Engine bogging / stumble / hesitation / jerking during accelaration ard 2.5k - 3k RPM mo420 Issues | Warranty | Recalls / TSB 24 07-29-2017 07:35 PM
Engine rattling sound like bogging the engine when not. stockysnail Engine, Exhaust, Transmission 6 09-15-2016 12:57 PM
Change gear ratio? Afdad120108 Engine, Exhaust, Transmission 61 08-17-2016 10:44 AM
Engine bogging down FRiSson Issues | Warranty | Recalls / TSB 6 08-14-2015 08:07 PM
Gear Ratio Change Lunatic Wheels | Tires | Spacers | Hub -- Sponsored by The Tire Rack 34 06-26-2014 10:20 PM


All times are GMT -4. The time now is 04:52 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Garage vBulletin Plugins by Drive Thru Online, Inc.