Subaru Forester Owners Forum banner
1 - 20 of 43 Posts

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #1 ·
Hi folks!

I noticed a "wavelike" acceleration after getting my car tuned! I don´t know how to describe it but it is in the 4th and 5th gear when you floor the pedal and accelerate... the car acts like - boost - no boost - boost - no boost -

maybe there is something wrong with the mapping or could it be the wastegate of my td04 (to weak?)??

any ideas?

thanks
 

·
Mad Englishman.
MY06 Forester STi 6MT
Joined
·
4,157 Posts
Get it on a rolling road and see exactly what it's doing.

It may be that the ECU is retarding the ignition due to detection of det - that can go "in waves". You would see this from an AFR plot most likely.

What type of tuning have you done...?
What is a bespoke map or a pre-programmed "flash" type...?
 

·
Don, King of the parts diagram
MY11 WRX STi Sedan 6MT
Joined
·
5,926 Posts
Have you had a 3 port boost control solenoid fitted?

If not, it could be that the 2 port setup is not holding the boost.
 

·
Registered
none none
Joined
·
8,844 Posts
Have you had a 3 port boost control solenoid fitted?

If not, it could be that the 2 port setup is not holding the boost.
Or the 2 port could even be gummed up and just sticking a bit, or even the maf or front O2 sensor. It could be a lot of things, you'll have to log to really see whats up. However the tuner should have addressed it when logging the car. Do you have a boost gauge?
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #5 ·
tuner only tuned it on a dyno...

ecu was mapped with ecuflash! I will install ecuflash/romraider on my laptop tomorrow to get some logs! i´ll logg as much as possible to hand it over to my tuner!

hardware changes:

3" turboback catless exhaust
3" aerys uppipe
TD04L Turbocharger

rear o2 sensor is disabled and front was given new last friday!

I will also copy my mapping so i can share stuff if there are any further questions!

3rd time i was at my tuner... starting to loose my trust in him...
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #6 ·
damn it... can´t log data with romraider or ecuflash because i dont have a openport 2.0 cable... seems that i have to buy one...

my tuner is 180 km away from my home so i can´t do a quick visit to get things logged every time somthing is wrong...

i try to get the map he made sent to me so i can share some parts from it... maybe this can help you guys!

i also posted in the engine tuning section to get more people and maybe other maps :)
 

·
Registered
05 2.5XTEn
Joined
·
315 Posts
Sounds like the wastegate duty is too high for the target boost in higher gears and/or the wastegate control dynamics are not setup correctly. The boost is over shooting and then the ECU is over compensating, slowly over a few seconds it should settle but can feel like you are on a roller coaster when it happens.

Problem can occur when a car is mapped on a dyno as generally the wastegate duty required to achieve a specific boost level is higher than on the road, which is one of the reasons the car should be checked on the road afterwards, preferably where high load (gear) boost control can be checked.

I mentioned the turbo dynamics because setting these correctly for a specific turbo/WG solenoid/restrictor pill is vital to getting accurate boost control on the OEM ECU.

Andrew...
 

·
Registered
99 UK S-turbo
Joined
·
8,566 Posts
Just get a boost gauge on it first, boost control is the most likely cause and that will show up easily enough.

Simon
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #9 ·
Hmm I´ll look for a boost gauge in the near future!

Hopefully i´ll get my tuned map over the weekend! Thank you guys in the meantime for your suggestions and tips!
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #10 ·
Now i have my map, which tables should i post so you guys can take a look?

For now, take a look at this please :) i do have several other maps out of the internet for comparison!

 

·
Registered
2004 Forester Sti 6 MT
Joined
·
725 Posts
Its pretty difficult to say just looking at the duty and the target boost (looks like you have a maximum boost around 1.1bar). You really need to get a boost guage as has been mentioned or log it using an openport 1.3 or 2.0 cable. As I recall there is a boost error parameter that can be logged, once the turbo starts to spool this should be near zero, if you are seeing fluctuations then, as has been noted, the turbo dynamics part of the map is desperately trying to compensate.

You could look for similar maps here:
RomRaider • View forum - Base Maps

but at the end of the day only logging will tell you what is going on (it might not even be the map, might be some air leak, fueling issue, electrical problem or anything really)
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #12 · (Edited)
Yes 1,1 bar correct! i first thougth the wastegate is not able to hold the pressure but... as you said, only logging will tell!

ok, so i´ll look for a boost gauge and/or a openport cable!

I think a cable is better because i can log more than only the boost ;)

I looked for other maps in the internet and at the forum you mentioned. I also downloaded some for comparison... there are some differences with certain tables, maybe i´ll try some changes!

I made my decition - i´ll buy a openport cable and will post the log here than! Since i am from austria it can take a while until the cable is here!
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #14 ·
Hi again!

Just received my openport 2.0 cable! I did some reading on several sites but still i am not sure which parameters i should log!

Any suggestions?

I thought of:
RPM
Boost Error
Mass Airflow (g/s)
Knock Correction Advance (IAM only)
Knock Correction Advance
A/F Sensor #1
Engine Load (calculated)

What do you guys think i should log to find the error!

Thanks
 

·
Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
Joined
·
5,242 Posts
Manifold pressure (corrected) would be worth logging.

Also it may be your BCS as mentioned by a few above causing wastegate creep... quoted from Scoobiepedia:

"Wastegate creep is a very common fault on the 2 port solenoid system, on both modded and standard cars, the most common cause is a lazy or dirty 2 port solenoid, what this does is reduce the bleed rate through the solenoid which allows the pressure in the system to build up enough for wastegate actuator to creep open, this reduces boost then the wastegate will close again then the boost will increase again and the wastegate will creep open again and so on, in this situation a simple clean of the solenoid would normally cure the fault, the symptoms of this fault are lumpy, flat and hesitant boost , on a standard car wastegate creep will feel like the the car is pulling then backing off repeatedly like a surging effect whilst you are accelerating. This issue can also be caused by a poorly setup boost controller or a weak actuator spring (I have yet to come across a weak spring but it can happen)."
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #16 ·
Ok, added to my list :D

I will log some stuff over the weekend if i have the time!

I´ll also look for the selenoid, my tuner also said the thing with the weak spring!

But first i will log and post the results here! I try to get a 3rd gear pull from 2000 to 2500 rpm till red and maybe 4th gear if i find a track to do so!
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #17 ·

·
Registered
2004 Forester Sti 6 MT
Joined
·
725 Posts
Well I'm not a pro (for that I think you need to post on the romraider forum) but a couple of observations from a very brief look.
When posting 'runs' it is expected that you have the throttle mashed to the floor i.e. 100%, you seem to have it varying below this?
You seem to have some knock correction factored in so would be interesting to log 'knock sum' and use learning view to get a view on your knock correction factors.
The more parameters you log the less resolution you get i.e. the more time between each data point so keep it around this number of parameters for a useful log i.e. not a whole load more selected at once.
I'll have another look when I have more time.
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #19 ·
When posting 'runs' it is expected that you have the throttle mashed to the floor i.e. 100%, you seem to have it varying below this?
You seem to have some knock correction factored in so would be interesting to log 'knock sum' and use learning view to get a view on your knock correction factors.
The more parameters you log the less resolution you get i.e. the more time between each data point so keep it around this number of parameters for a useful log i.e. not a whole load more selected at once.
I'll have another look when I have more time.
Hi fleetwood!

Thanks for your suggestions! I floored the pedal, or at least i thought so! I´ll check if the carpet or so was in between the pedal and the floor...

I´ll try to use learning view next time to get some values of knock orrection!

Maybe i can do some pulls today, but since it´s raining outside and the forecast said it would rain till late afternoon i´m not sure about that...

Will post logs as soon as i can run some pulls!
 

·
Registered
04 Forester XT Rinspeed manual 5 speed
Joined
·
740 Posts
Discussion Starter · #20 · (Edited)
1 - 20 of 43 Posts
Top