Problem with version 7 STi boost control

[JWDRPN]

My fuel pumps brand new

[hijacka]

 JWDRPN said:

My fuel pumps brand new

No one cares about your fuelpump

[hijacka]

 ben-jamminn']

[quote name='hijacka said:

Gee all this dribble and no one has thought to check the fuel pressure or simply replace the 10year old factory fuel pump

I\'ve got a new genuine AEM fuel pump coming in thats rated to 320lph@43psi its the as the areomotive pump they sell on tardme for $250 you can have for $200. problem fixed

url]http://www.trademe.co.nz/motors/car-parts-accessories/performance/fuel-systems/auction-532715789.htm[/url]

Yeah I had thought of rigging up a pressure gauge temporarily and seeing what it does when the problem occurs, I also replaced the fuel filter (which looked like it was still the original one from factory) but that hasn\'t helped. Fuel pump is worth looking into though, cheers.

Although when the fuel pump in my old version 4 packed up it didn\'t give any forewarning like this, I just couldn\'t start the car one morning haha

Diffenatley look in to replacing it..Fuel pumps can give off a variaty of symptoms when they are worn. Ask yourself if you flick the key on and off(red lights) the pump primes then it will shut down,It should hold pressure for at least 30seconds.. does it prime again if you switch the ignition on again within the 30seconds?

Does the car feel like it takes afew more cranks than it should to start?either way i\'d be more than happy to whip the 400lph walbro from mine and fit to yours to see if this helps your problem

[boon]

Something that\'s just occurred to me - if your car is a blue 2000 V7 with Tein EDFC\'s and a Prova titanium exhaust then I know the car and it\'s had a LOT of time spent trying to solve the problem, and I would like my bloody exhaust back, I kinda long-term-loaned it to my cousin and then he sold the car with it on it @_@

[ben-jamminn]

 boon said:

Something that\'s just occurred to me - if your car is a blue 2000 V7 with Tein EDFC\'s and a Prova titanium exhaust then I know the car and it\'s had a LOT of time spent trying to solve the problem, and I would like my bloody exhaust back, I kinda long-term-loaned it to my cousin and then he sold the car with it on it @_@

Not me, mine is 2001 and was completely stock when I got it. All I\'ve done is put an axle back exhaust. But that\'s disheartening to see someone put so much effort in and still didn\'t solve it..

[Pappu1]

 ben-jamminn']

[quote name='boon said:

Something that\'s just occurred to me - if your car is a blue 2000 V7 with Tein EDFC\'s and a Prova titanium exhaust then I know the car and it\'s had a LOT of time spent trying to solve the problem, and I would like my bloody exhaust back, I kinda long-term-loaned it to my cousin and then he sold the car with it on it @_@

/quote]

Not me, mine is 2001 and was completely stock when I got it. All I\'ve done is put an axle back exhaust. But that\'s disheartening to see someone put so much effort in and still didn\'t solve it..

lol

y wud u spend sooo much time and not solve it?

[boon]

Might be worth asking, remember that thing ichi ban used to mention about oil from the AVCS sensors forcing its way all the way through the loom to the ECU and causing all sorts of weird issues... could be worth checking.

[ben-jamminn]

 boon said:

Might be worth asking, remember that thing ichi ban used to mention about oil from the AVCS sensors forcing its way all the way through the loom to the ECU and causing all sorts of weird issues... could be worth checking.

Yep I\'ve checked the grey plug on the LH strut tower and there was no oil to be seen.

Chappell943 has another solenoid that I am going to try tomorrow

[ben-jamminn]

 hijacka']

[quote name='hijacka said:

Gee all this dribble and no one has thought to check the fuel pressure or simply replace the 10year old factory fuel pump

I\'ve got a new genuine AEM fuel pump coming in thats rated to 320lph@43psi its the as the areomotive pump they sell on tardme for $250 you can have for $200. problem fixed

url]http://www.trademe.co.nz/motors/car-parts-accessories/performance/fuel-systems/auction-532715789.htm[/url]

Yeah I had thought of rigging up a pressure gauge temporarily and seeing what it does when the problem occurs, I also replaced the fuel filter (which looked like it was still the original one from factory) but that hasn\'t helped. Fuel pump is worth looking into though, cheers.

Although when the fuel pump in my old version 4 packed up it didn\'t give any forewarning like this, I just couldn\'t start the car one morning haha

Diffenatley look in to replacing it..Fuel pumps can give off a variaty of symptoms when they are worn. Ask yourself if you flick the key on and off(red lights) the pump primes then it will shut down,It should hold pressure for at least 30seconds.. does it prime again if you switch the ignition on again within the 30seconds?

Does the car feel like it takes afew more cranks than it should to start?either way i\'d be more than happy to whip the 400lph walbro from mine and fit to yours to see if this helps your problem

Fitted a 2nd hand BCS courtesy of Chappell943 and boost is now behaving, like it was with the boost tap.

Still have the hesitation/miss particularly at open road speed, 120km/h, 5th & 6th gear, and less prominent yet still there at lower speed. Hoping to do some data logging next week, I want to look into the fuel pump too, Hijacka, how long does it take to swap a fuel pump? is it a major?

[boon]

Fuel pump swap is like 30 mins and most of that is removing the back seat. Unless you have to re-wire for a different plug. Not too tricky at all, just make sure you have a few paper towels/rags on hand as you\'ll inevitably have some drippage. And getting the stupid fuel level float thing to go in nicely can be a slight pain.

[ben-jamminn]

 hijacka']

[quote name='hijacka said:

Gee all this dribble and no one has thought to check the fuel pressure or simply replace the 10year old factory fuel pump

I\'ve got a new genuine AEM fuel pump coming in thats rated to 320lph@43psi its the as the areomotive pump they sell on tardme for $250 you can have for $200. problem fixed

url]http://www.trademe.co.nz/motors/car-parts-accessories/performance/fuel-systems/auction-532715789.htm[/url]

Yeah I had thought of rigging up a pressure gauge temporarily and seeing what it does when the problem occurs, I also replaced the fuel filter (which looked like it was still the original one from factory) but that hasn\'t helped. Fuel pump is worth looking into though, cheers.

Although when the fuel pump in my old version 4 packed up it didn\'t give any forewarning like this, I just couldn\'t start the car one morning haha

Diffenatley look in to replacing it..Fuel pumps can give off a variaty of symptoms when they are worn. Ask yourself if you flick the key on and off(red lights) the pump primes then it will shut down,It should hold pressure for at least 30seconds.. does it prime again if you switch the ignition on again within the 30seconds?

Does the car feel like it takes afew more cranks than it should to start?either way i\'d be more than happy to whip the 400lph walbro from mine and fit to yours to see if this helps your problem

New Walbro pump arrived today, I will fit it tomorrow afternoon.

Hopefully see some improvement, either way it\'s a good upgrade and from experience with all the other Subaru\'s I\'ve had, the stock pump shits itself eventually so it\'s future proofing!

[ben-jamminn]

Fitted the Walbro, used the OEM sock.

Went for a drive, pulled hard through all gears, stopped and turned around then I only had 0.5 bar boost (Limp mode I guess)

It\'s worth noting that fuel was low as I had run it down to do the fuel pump job.

Filled up with 98, then boost was back to normal.. Is low fuel something that can cause limp mode?

Still have the surge/hesitation at certain rpm/throttle position, so I can rule out fuel problems.

To date I have:

Replaced Air Filter

Clean MAF

Replaced Plugs

Replaced Knock Sensor

Replaced Fuel Filter

Replaced Fuel Pump

Chappell943 is gonna plug in his laptop on Monday and do some logging, he has a few ideas of what parameters to log; miscount, knock, maf readings and injectors..

He asked me to see if anyone else has any other ideas

Thanks!

[ben-jamminn]

Standard filter, no havent tried a new AFM, might be able to try swapping one from another car

[JWDRPN]

I got an afm u can try

[familyman]

 SP00N']

[quote name='boon said:

Something that\'s just occurred to me - if your car is a blue 2000 V7 with Tein EDFC\'s and a Prova titanium exhaust then I know the car and it\'s had a LOT of time spent trying to solve the problem, and I would like my bloody exhaust back, I kinda long-term-loaned it to my cousin and then he sold the car with it on it @_@

/quote]

Not me, mine is 2001 and was completely stock when I got it. All I\'ve done is put an axle back exhaust. But that\'s disheartening to see someone put so much effort in and still didn\'t solve it..

lol

y wud u spend sooo much time and not solve it?

I have a strong feeling that was my car from my sig. Reason I spent so much time looking for problem and not fixing was because that car scared the shit out of me so I hardly ever fed it any power. Was just a "practical four door family car" for when the Weasel was a toddler.

[hijacka]

Im wondering if the problem is because its got a cat in the uppipe?.. seems like your losing power around the same time as the wastegate trap opens up to control boost... now when that gate opens to control boost pressure the cat slows down to much exhaust gases at this low rpm range, at this point you would see a drop in boost just after hitting boost..(if you know what i mean).. the factory solenoid is either gate open or gate shut they aren\'t great for controlling the boost curve.. i think you should either look in to replacing the up pipe with a catless one or adding a electronic boost controller to better curve the boost pressure or both. good luck please let keep up dating thread

[ben-jamminn]

 hijacka said:

Im wondering if the problem is because its got a cat in the uppipe?.. seems like your losing power around the same time as the wastegate trap opens up to control boost... now when that gate opens to control boost pressure the cat slows down to much exhaust gases at this low rpm range, at this point you would see a drop in boost just after hitting boost..(if you know what i mean).. the factory solenoid is either gate open or gate shut they aren\'t great for controlling the boost curve.. i think you should either look in to replacing the up pipe with a catless one or adding a electronic boost controller to better curve the boost pressure or both. good luck please let keep up dating thread

Yeah I get what you mean but shouldn\'t the factory boost control be just a good as an aftermarket one, just without the adjustability?

[Stoffa]

 hijacka said:

Im wondering if the problem is because its got a cat in the uppipe?.. seems like your losing power around the same time as the wastegate trap opens up to control boost... now when that gate opens to control boost pressure the cat slows down to much exhaust gases at this low rpm range, at this point you would see a drop in boost just after hitting boost..(if you know what i mean).. the factory solenoid is either gate open or gate shut they aren\'t great for controlling the boost curve.. i think you should either look in to replacing the up pipe with a catless one or adding a electronic boost controller to better curve the boost pressure or both. good luck please let keep up dating thread

I thought only the USDM v7\'s had a cat in the uppipe? I had a set of factory v7 sti headers floating around and they definatly didnt

[ben-jamminn]

Yeah was about to say that, sti v7 don\'t have a catted up pipe

[hijacka]

 ben-jamminn said:

Yeah was about to say that, sti v7 don\'t have a catted up pipe

I yep my bad...Could have a leak in the uppipe or cross pipe and what about the rear cat could be restricting it to much or slightly blocked ?? \'\'Could be\'s\'\' is all they are over the net. diagnosis is sort of like throwing a dart blind folded lol.

Try a good electronic boost controller and see if you can curve the boost.. also check the fuel pressure with a gauge.. just because you changed the pump doesn\'t rule out the reg.

[boon]

 familyman']

[quote name='boon said:

Something that\'s just occurred to me - if your car is a blue 2000 V7 with Tein EDFC\'s and a Prova titanium exhaust then I know the car and it\'s had a LOT of time spent trying to solve the problem, and I would like my bloody exhaust back, I kinda long-term-loaned it to my cousin and then he sold the car with it on it @_@

/quote]

Not me, mine is 2001 and was completely stock when I got it. All I\'ve done is put an axle back exhaust. But that\'s disheartening to see someone put so much effort in and still didn\'t solve it..

lol

y wud u spend sooo much time and not solve it?

I have a strong feeling that was my car from my sig. Reason I spent so much time looking for problem and not fixing was because that car scared the s*** out of me so I hardly ever fed it any power. Was just a "practical four door family car" for when the Weasel was a toddler.

My cousin bought it off the guy who bought it off you I think... he spent quite a lot of money and time trying to work out the limp-mode thing, never got it sorted, ended up swapping it for a quite tidy Evo 2 RS I believe...

[Pappu1]

after the logging there wud be lots more possibile clues...

[ben-jamminn]

Blair (Chappell943) came over today and we did some logging, I\'m not 100% on the in\'s and outs of it all but Blair really knows his stuff! Turns out it was the MAF sensor (hopefully Blair see\'s this post and can give the particulars) basically faulty MAF sensor causing incorrect load readings which caused excessive ignition timing and a leaner fuel mixture, we think this was causing the ecu to cut boost on and off, causing the surge but we plugged his MAF into my car and it made a night and day difference in both how the car drove and the figures showing up on the laptop.

So now the hunt is on for a new MAF sensor!

[JWDRPN]

I got my new afm from japan parts for just under $200

(Still have my issue with it)

[Pappu1]

why not try another afm and see if it works fine....?