pulling power loss on boost
26 October 2009, 05:36 PM
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pulling power loss on boost
hi, i had my car in the bodyshop because some **** rear-ended it, only bumper damage so no big deal...
anyway, when the car came back and i got it on a straight i noticed that it doesnt have the same pull as before on boost - it has lost some power.
the turbo still spools up as normal but when the turbo kicks in, it isnt as savage as before and it runs out of puff much quicker. it has lost high end acceleration.
initially (around 3000rpm) when the turbo kicks in it still pulls pretty well, it just doesnt keep accelerating quickly.
what i noticed was that when the turbo now kicks in, its a silent pull - before it would make a loud rapid scooting noise as if it was spraying air or extra fuel into the engine (dont know how it works, not good with cars) and this kept the strong pull going.
its almost definitely the loss of this scooting noise that has resulted in the power loss. it is very noticeable by its absence.
it would keep making a scooting noise and maintain strong acceleration well above 60mph. that is gone now, the speed just gradually builds up after the initial strong pull after 3000rpm, but doesnt last. very weird boosting in silence.
does anyone have an idea to what is going on here? the bodyshop claim they never touched it, at first i thought they had messed about with it - it was fine when it went away.
one idea was because my battery is very weak and i warned them about it. it runs flat within just 3 days of no use.. someone on another forum suggested maybe the mapping was lost if the battery was disconnected/flat for a period of time (which it probably was - as it was away for 2 weeks) but someone else debunked that idea, saying the ECU wouldnt lose a remap if the battery was disconnected.
it has had this done...
BRD/TEK3 custom engine mapping
3-port boost solenoid valve
the previous owner of the car is on here i will try and find him, he may have some insight at least.
cheers.
anyway, when the car came back and i got it on a straight i noticed that it doesnt have the same pull as before on boost - it has lost some power.
the turbo still spools up as normal but when the turbo kicks in, it isnt as savage as before and it runs out of puff much quicker. it has lost high end acceleration.
initially (around 3000rpm) when the turbo kicks in it still pulls pretty well, it just doesnt keep accelerating quickly.
what i noticed was that when the turbo now kicks in, its a silent pull - before it would make a loud rapid scooting noise as if it was spraying air or extra fuel into the engine (dont know how it works, not good with cars) and this kept the strong pull going.
its almost definitely the loss of this scooting noise that has resulted in the power loss. it is very noticeable by its absence.
it would keep making a scooting noise and maintain strong acceleration well above 60mph. that is gone now, the speed just gradually builds up after the initial strong pull after 3000rpm, but doesnt last. very weird boosting in silence.
does anyone have an idea to what is going on here? the bodyshop claim they never touched it, at first i thought they had messed about with it - it was fine when it went away.
one idea was because my battery is very weak and i warned them about it. it runs flat within just 3 days of no use.. someone on another forum suggested maybe the mapping was lost if the battery was disconnected/flat for a period of time (which it probably was - as it was away for 2 weeks) but someone else debunked that idea, saying the ECU wouldnt lose a remap if the battery was disconnected.
it has had this done...
BRD/TEK3 custom engine mapping
3-port boost solenoid valve
the previous owner of the car is on here i will try and find him, he may have some insight at least.
cheers.
Last edited by alanspec_c; 26 October 2009 at 05:38 PM.
26 October 2009, 08:10 PM
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Hi fella. My car previously ...
Sorry to hear that you got rear ended, driving a bit quicker might help!
The noise that you mention that you're not getting now will be the RCM induction kit. Can't understand why it wouldn't be working but if it isn't you'd certainly lose power. BTW the car used to pull hugely up to the rev limit when I had it ie 8000rpm ...
I'll post a link to the General Section to see if others can help.
Cheers, TX.
PS
Car is a 54 plate Spec C with following mods - RCM induction kit, RCM decat exhaust, 3 port boost solenoid, Walbro fuel pump, uprated actuator, Bob Rawle remap.
Sorry to hear that you got rear ended, driving a bit quicker might help!
The noise that you mention that you're not getting now will be the RCM induction kit. Can't understand why it wouldn't be working but if it isn't you'd certainly lose power. BTW the car used to pull hugely up to the rev limit when I had it ie 8000rpm ...
I'll post a link to the General Section to see if others can help.
Cheers, TX.
PS
Car is a 54 plate Spec C with following mods - RCM induction kit, RCM decat exhaust, 3 port boost solenoid, Walbro fuel pump, uprated actuator, Bob Rawle remap.
Last edited by Terminator X; 26 October 2009 at 10:54 PM.
26 October 2009, 08:45 PM
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If it’s not a huge difference have the garage (or you) put 95 Ron fuel in?
The ECU will retard the ignition/reduce the boost if crap fuel is used.
Leaving the battery off for a time will not wipe the remap but it may reset the ECU settings (especially if crap fuel is in it)
somebody else may confirm this or correct me if it doesn’t.
The ECU will retard the ignition/reduce the boost if crap fuel is used.
Leaving the battery off for a time will not wipe the remap but it may reset the ECU settings (especially if crap fuel is in it)
somebody else may confirm this or correct me if it doesn’t.
26 October 2009, 10:40 PM
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does it not have to re-learn some of the boost,ignition,and timing values when battery has gone flat just like doing a reset?but i think power is only lost by about 15% ish,and its not long till its upto scratch,about a week i think depending how much you drive it.i would check if they put fuel in at garrage too.may be cheap crap if they have.
27 October 2009, 02:01 AM
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If its had a bad tank of fuel in there the ecu multiplier may have knocked itself down a fair bit to compensate, also was the exhaust hit when you were rear ended? that may have damaged the system and caused some issues with gas flow, but best taking her to a dealer (or speciallist) who has knowledge of the jdm twin scroll cars and see what they say.
Tony
Tony
27 October 2009, 02:48 AM
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27 October 2009, 09:42 AM
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If it has a stainless system on it would need a big wack to bend it enough to reduce the flow and would be obvious looking underneath it wouldnt sit right at the back.
Have the garage driven it around then toped it back up so you don’t know but with crap fuel
did you check the mileage when you dropped it off?
27 October 2009, 11:27 AM
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pretty sure it was fine after the rear-ending and before the garage got it.
didnt note the mileage unfortunately. will know better next time. i thought they may have been out in it and topped it up with the wrong fuel, so i filled the rest of the tank back up to try and dilute the rest of the fuel. no difference so far. would i need to use up all the fuel in the tank before it changes? (if that is the problem)
i will ring the garage tonight and ask.
seems fine off boost. just as responsive...
thanks for the replys.
didnt note the mileage unfortunately. will know better next time. i thought they may have been out in it and topped it up with the wrong fuel, so i filled the rest of the tank back up to try and dilute the rest of the fuel. no difference so far. would i need to use up all the fuel in the tank before it changes? (if that is the problem)
i will ring the garage tonight and ask.
seems fine off boost. just as responsive...
thanks for the replys.
Last edited by alanspec_c; 27 October 2009 at 11:32 AM.
27 October 2009, 12:11 PM
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As I understand it (I am no expert just starting to learn about ECUs 
)
The ECU will need to relearn the settings again (IAM)
I think it can take a couple of tanks to do this especially if the IAM has gone very low due to the bad fuel.
Might be worth resetting the ECU again now you have good fuel in some mappers set the default IAM a bit higher than default so you should notice a difference. Drive it around of boost a while before opening her up let the ECU adjust a little.
Again if somebody can confirm this to make sure I am right
) The ECU will need to relearn the settings again (IAM)
I think it can take a couple of tanks to do this especially if the IAM has gone very low due to the bad fuel.
Might be worth resetting the ECU again now you have good fuel in some mappers set the default IAM a bit higher than default so you should notice a difference. Drive it around of boost a while before opening her up let the ECU adjust a little.
Again if somebody can confirm this to make sure I am right
27 October 2009, 02:55 PM
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the turbo still kicks in when it should. and its still pretty strong, just it doesnt keep on pulling, it tails off after a short while.
the lack of the scooting noise in some gears and very muted in others (where before it was prominent in all gears) is what i think is causing the loss in continuous pulling.
its like that scooting device what ever it is, keeps the power going after the initial surge. what is this scooting noise? (or what was it) that is the problem i feel.
the lack of the scooting noise in some gears and very muted in others (where before it was prominent in all gears) is what i think is causing the loss in continuous pulling.
its like that scooting device what ever it is, keeps the power going after the initial surge. what is this scooting noise? (or what was it) that is the problem i feel.
Last edited by alanspec_c; 27 October 2009 at 02:58 PM.
27 October 2009, 05:20 PM
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if everything is ok there, i will burn as much fuel as i can before refueling then i will disconnect with battery for ?10 mins to try and reset it, see if that makes a difference.
if not i will need to take it to a garage. someone has recommended me a good one performance place nearby.
it is just suspect it comes back from the bodyshop like that. they must have been thrashing it or they put in the wrong fuel. doubt they will admit to it though. i'll be noting the mileage next time and letting them know... bad thing is its going back in 6 weeks as they are importing a back bumper from japan.
Last edited by alanspec_c; 27 October 2009 at 05:22 PM.
27 October 2009, 05:43 PM
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I would reset the ECU now if you have filled it up. Pull the battery then press the brake a few times.
Reconnect and take the car out keeping off boost. Find a straight bit of road in 3rd gear (doesn’t have to be 3rd but for speed sake probably best) you need to keep it on boost for at least 5 seconds you will have to hold it back on the brakes.
After that you should feel the difference if that what it was If it’s no different that’s not the problem.
Next time write the mileage down and put a piece of paper on the dash with it on then they will know you have recorded it
Reconnect and take the car out keeping off boost. Find a straight bit of road in 3rd gear (doesn’t have to be 3rd but for speed sake probably best) you need to keep it on boost for at least 5 seconds you will have to hold it back on the brakes.
After that you should feel the difference if that what it was
If it’s no different that’s not the problem.Next time write the mileage down and put a piece of paper on the dash with it on then they will know you have recorded it
27 October 2009, 10:32 PM
#18
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Hi all, this sounds as though the turbo is not holding good boost at the higher end of the rpm range. It really needs a boost gauge fitting to check whats happening there, temporary would do.
The noise described is not induction related or generated as such but can be heard though the filter, the induction simply allows air into the intake, it doesn't do "work" as such and from a rear end impact is not likely to have been harmed, its what I term a passive item. You were hearing "surge" which is the turbo running at the edge of its compressor map particularly up to about 4500 rpm when it sort of would clean up somewhat. the fact that its not now there leads me to suspect a boost response or restriction possibility, if the exhaust had been hit end on has it damaged any internal parts so adding a restriction ?
Another possibility is that if the garage has put 95 ron in it in which case the ecu will be well unhappy (as would the engine), it will react and pull ignition big time.
Its almost as if there is now a leak somewhere in the intercooler inlet manifold area but if the garage had no need to touch it why would there be.
If fuel related it will take at least three full tanks of V Power (or whatever) to get rid of the 95 ron, resetting the ecu will do nothing and could hurt things if there is poor fuel involved, leave alone, run the three tanks full then on the fourth you can try that. As far as learning is concerned there is no need for all the described ritual, if a Jecs ecu was involved then yes but not Hitachi, the ecu starts to learn imediately, however it will learn back far quicker than it learns forward. It also, given time, learns to anticipate boost response for throttle setting as well.
It really needs a bit of a diagnostic session if it doesn't sort itself out.
best regards
bob
The noise described is not induction related or generated as such but can be heard though the filter, the induction simply allows air into the intake, it doesn't do "work" as such and from a rear end impact is not likely to have been harmed, its what I term a passive item. You were hearing "surge" which is the turbo running at the edge of its compressor map particularly up to about 4500 rpm when it sort of would clean up somewhat. the fact that its not now there leads me to suspect a boost response or restriction possibility, if the exhaust had been hit end on has it damaged any internal parts so adding a restriction ?
Another possibility is that if the garage has put 95 ron in it in which case the ecu will be well unhappy (as would the engine), it will react and pull ignition big time.
Its almost as if there is now a leak somewhere in the intercooler inlet manifold area but if the garage had no need to touch it why would there be.
If fuel related it will take at least three full tanks of V Power (or whatever) to get rid of the 95 ron, resetting the ecu will do nothing and could hurt things if there is poor fuel involved, leave alone, run the three tanks full then on the fourth you can try that. As far as learning is concerned there is no need for all the described ritual, if a Jecs ecu was involved then yes but not Hitachi, the ecu starts to learn imediately, however it will learn back far quicker than it learns forward. It also, given time, learns to anticipate boost response for throttle setting as well.
It really needs a bit of a diagnostic session if it doesn't sort itself out.
best regards
bob
27 October 2009, 11:14 PM
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did the exhaust get hit during the shunt, does it have a cat, if the cat has been damaged it can restrict the exhaust, and loss of power is a symptom of a partly blocked exhaust.
27 October 2009, 11:26 PM
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^^ No cat as decat exhaust!
Thanks for post Bob Listen to Bob as he mapped the car & probably knows what he's talking about
TX.
Thanks for post Bob
Listen to Bob as he mapped the car & probably knows what he's talking about TX.
Last edited by Terminator X; 27 October 2009 at 11:30 PM.
28 October 2009, 05:24 PM
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^ no idea what that is...
thanks for the advice and help people. will just need to monitor it and reset it after 3 tanks-full like bob said.
enjoying the car regardless, the best thing about it isnt the straight line speed, its just good for overtaking people like they are standing still (its still rapid anyway) the best thing about the car is the handling. grips to the road like glue on the twisties. very satisfying!!
will update if theres a change... and cheers for the car Tx. its a beast.
thanks for the advice and help people. will just need to monitor it and reset it after 3 tanks-full like bob said.
enjoying the car regardless, the best thing about it isnt the straight line speed, its just good for overtaking people like they are standing still (its still rapid anyway) the best thing about the car is the handling. grips to the road like glue on the twisties. very satisfying!!
will update if theres a change... and cheers for the car Tx. its a beast.
28 October 2009, 10:07 PM
#24
Ecu Specialist
The neutral switch is a possible if it was playing up on idle as well and/or general boost instability. But its not just appears to have lost some ground.
bob
bob
29 October 2009, 11:25 AM
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overtook someone today and pull in 3rd was quite pathetic to what it was. much more gradual and smooth. but heres the thing, i have an entire half tank of extra fuel than what i usually would have by now compared to my normal journey. same amount of miles, much more fuel left... does this tell us anything?
also i hardly ever use the boost during the week too (dont get the chance with traffic) so its not like its saving fuel from the weak boost... but it doesnt feel less powerful off boost??
also i hardly ever use the boost during the week too (dont get the chance with traffic) so its not like its saving fuel from the weak boost... but it doesnt feel less powerful off boost??
Last edited by alanspec_c; 29 October 2009 at 11:27 AM.
30 October 2009, 11:22 AM
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