BC5 RS Legacy Low power EDIT FIXED

[THUNDA]

 

Brand New Coil

New HT Leads

New Plugs

 

Fixed it, old plugs looked ok but were old as F***

coil was second hand from a GC8 so replaced the whole lot

 

Sorted

 

 

 

===================================

 

 

 

Riiiiight so this problem has been doing my head in

Need some outside perspectives

Problem was only barely noticable when I got the car and has gradually got worse

 

So, the situation - Car runs well, no fault codes, no hesitation or mis-firing

 

Driving along, at 0, 1/4 or 1/2  throttle the car performs well pickup is good even when the turbo isnt spooling

 

as soon as you go past 3/4 throttle to Open throttle, you can feel the car loose power, slightest hesistation, like when a coil is failing and 1 of the cylinders is cutting in and out, but not as noticeable

 

It is very noticable because if you back off on the throttle after having foot to floor, the car with pick up power again and perform strongly

 

At any throttle the car with make boost and hold it strong at 9psi with no spikes or creeps, however at full throttle, there is a noticeable lack of power compared to if I boosted with only 1/2 throttle

 

=========================================================

 

This weekend I installed a new fuel filter, which made no difference, original filter wasnt very old either

I also installed the factory Cold air intake box with a new filter (fitted the same AFM so its running as it was technically)

 

Had a look under the fuel pump cover to view hoses and wiring, all seems ok like it has never been touched

 

Checked for loose wiring / unplugged wires in engine bay

 

========================================================

 

Suspicions:

 

Fuel pump looks to be the original, and with 265,000kms I wouldnt blame it if it started to fail (am thinking of trying the fuel pump wiring mod)

 

checked the H/T leads were secure and noticed on 1 of the coils on 1 outlet had a small amount of white build up where the H/T lead goes in, where as the others are completely clean

(running V1 Coil set up)

 

Somewhere under the car in the middle, roughly above the driveshaft there is what sounds like a vacuum leak, ive been under the car multiple times and have not been able to find the source, this has been like that since I bought the car and does not seem to have gotten worse

 

Last owner installed yellow injectors and td05 turbo however I am unaware if the ecu was changed to suit, so could be injectors over fueling and coil packs have been under high load causing them to slowly break down

There are no physical signs that the car is running rich, engine doesnt smoke at all and never smells like petrol

 

Rocker cover gaskets are slightly leaking on both banks

 

TPS looks like its been adjusted many times by an amateur (screws completely rounded) so no idea if this is in the right position, car does idle fine despite this

 

 

==============================================

 

 

Any help appreciated!

 

 

 

Edited December 14, 2016 by THUNDA

[THUNDA]

ECU is a W6, thinking thats the standard ecu? z4 ran the td05 and yellows iirc

wasnt even bolted into the bracket

 

 

This small grey plug is plugged into nothing and cant find anything for it to go into, under the intake manifold behind the ps res

 

 

2 Yellow wires cut off going to nothing, am thinking it may have been the wires for the old water to air intercooler ?

 

[slystiguy]

Best get back to stock grey injectors to figure out if that's the issue, unless you have access to a wideband sensor? Check to see if ecu has a chip in the corner of the board. 

 

Apart from that I assume you've checked the coils for cracks? You can test the resistance on them to see if one is stuffed.. How do the plugs look? 

 

First pic plug looks like your p/s pump sensor? And non stock pump fitted?

Other one can't really see... Could be o2 but hopefully yours would still be in the stock position on the exhaust manifold  

[THUNDA]

11 minutes ago, slystiguy said:

Best get back to stock grey injectors to figure out if that's the issue, unless you have access to a wideband sensor? Check to see if ecu has a chip in the corner of the board. 

 

Apart from that I assume you've checked the coils for cracks? You can test the resistance on them to see if one is stuffed.. How do the plugs look? 

 

First pic plug looks like your p/s pump sensor? And non stock pump fitted?

Other one can't really see... Could be o2 but hopefully yours would still be in the stock position on the exhaust manifold  

 

Ecu does have a chip, speedlab or something crap, its switchable so I just leave it turned off, car backfires while decelerating with chip on.

 

Yup i gave the coil a visual inspection, seems fine however not ruling out failing coil just yet

 

Will have to pick up a new multimeter and give them a proper check

 

I only checked 1 spark plug which looked sweet, not oily, not crispy white just a tad carbonish

 

Nice yeah I thought that grey plug would be something like that, the res on top of the pump doesnt quite fit properly, leaks a bit which is on my to do list also

 

the last pic of the 2 yellow wires are located under the topmount intercooler, so thinking they would have been like a temp sensor which ran the original water pump

 

02 sensor is sweet and working well, cleaned it up when i installed the external wastey

 

was leaning more towards fuel pump / fuel pump wiring issue but now im also thinking coil / dead ht lead / plugs

[THUNDA]

51 minutes ago, THUNDA said:

ECU W6 - 1993 WRX RA – TDO5- 11.47PSI (0.8BAR) -FUELCUT 14.5PSI (1BAR) - 240PS (237BHP)

 

ok so to confirm the ecu is suitable for the mods

 

wonder why when I switch the chip on the car runs so crapily? sure its more aggressive but it pops n farts, doesnt sound right, maybe with the chip switch on the fuel map richens up a bit and the failing coils cant handle it, which makes sense as when the chips switched off the coils run sweet untill you floor it, sounds like a "cant keep up" worn coil issue even more now

 

 

[THUNDA]

/?Actually looking further into it it said 380cc injectors... those are greys yeah?

 

so the 93 wrx ra had greys? interesting

 

edit : getting conflicting information, 93 wrx ra had yellows (info from 3 sources)

Edited December 3, 2016 by THUNDA

[slystiguy]

Swap back to grey injectors and ditch the speedlabs chip. Sadly every single one of this ecu I've heard about has popped the engine shortly after install, unsure if just because weak engine or random contributing factors? Or it could be a bad tune/match. I've used it and stuffed an engine from it but I was deliberately seeing how far the stock engine would go lol (the guy I sold it too also blew his engine). Keep the chip for a later date or send it back to him and get a 6k/7k ecu tune put on it... or send it to me so I can play with it. 

 

 

I'd say the injectors and speedlab chip will be the cause of your issues. 

If you do want to keep running it I'd suggest you get a wideband/knock indicator before going further.

 

 

[SpeedySub]

Look for a z4 ecu if running stock grey injectors and td05. that's what I have and runs well. from memory .9 bar dropping to .8bar

[THUNDA]

Car currently has yellows so its got the right ecu in there, 

 

fuel pump wiring mod is done and FP is running at 100% car is still fading, so guess its gonna be onto the ignition system next weekend 

 

am thinking its a failing coil, if it is then hopefully there is a suitable MSD coil similar to the current wrx twin pack  bang bang bang bang

3 hours ago, slystiguy said:

Swap back to grey injectors and ditch the speedlabs chip. Sadly every single one of this ecu I've heard about has popped the engine shortly after install, unsure if just because weak engine or random contributing factors? Or it could be a bad tune/match. I've used it and stuffed an engine from it but I was deliberately seeing how far the stock engine would go lol (the guy I sold it too also blew his engine). Keep the chip for a later date or send it back to him and get a 6k/7k ecu tune put on it... or send it to me so I can play with it. 

 

 

I'd say the injectors and speedlab chip will be the cause of your issues. 

If you do want to keep running it I'd suggest you get a wideband/knock indicator before going further.

 

 

 

 

Fully understand where your comming from but when i got the car it ran pretty well (id say 90% power compared to my other BC5s)

and the problem has gradually got worse over a few months time - which to me indicates a physical deterioration

 

 

if it was computer related wouldnt it have been constant?

[THUNDA]

 

the computer in the car is from a 93 RA wrx which ran yellows 

 

so with the chip turned off the computer is still expecting to run yellows

[slystiguy]

93 wrx ra runs grey, I repeat for the 3rd time go back to grey injectors. Ignore what you've read on the net. Yellows didn't arrive in cars until 1997ish

 

Well let me know when the engine pops lol... Hopefully I'm wrong...

[Guest]

17 minutes ago, slystiguy said:

93 wrx ra runs grey, I repeat for the 3rd time go back to grey injectors. Ignore what you've read on the net. Yellows didn't arrive in cars until 1997ish

 

Well let me know when the engine pops lol... Hopefully I'm wrong...

 

If V3 sti was where it all started its 1996.

[THUNDA]

4 minutes ago, slystiguy said:

93 wrx ra runs grey, I repeat for the 3rd time go back to grey injectors. Ignore what you've read on the net. Yellows didn't arrive in cars until 1997ish

 

Well let me know when the engine pops lol... Hopefully I'm wrong...

 

Quote=  W6 ECU code = 380cc injectors, 240ps TD05H turbo

 

Ah, looks like a case of google research gone wrong on my behalf

 

Just had a deeper search and found that you sir are correct!

 

 

[slystiguy]

Worth mentioning speedlabs does do a yellow injector tune. So maybe think about getting a wideband/see if someone will lend you one/take it to dyno

[BC5RA]

Fuel pump upgrade should be mandatory when raising boost in these cars.

 

Yellow injectors were featured when the EJ20 went to the under intake manifold and only in the STIs. Besides that anomaly WRX which I can't remember the specs of - came with a VF roller bearing Turbo.

 

Pull the coils out of the heads for a proper inspection, call Speedlab with details about the chip to rule it out as suitable for 440cc injectors or not - I'll go on record saying that it won't be, they are an upgrade for RS/GT and early WRX with 380cc injectors. Faster to do this than have it checked for AFRs.

 

Swap out the afm with a known working unit, and look into the conotion of the Turbo.

 

Re: Plug - the one in behind your retro fitted power sterring pump, will have been the speed sensor plug that would have been on your original PS pump most likely, the wires I'm not sure about, the only electrical stuff on the intercooler in that location were on the silver WAIC, which was a level sensor.

 

Edited December 5, 2016 by BC5RA

[SpeedySub]

38 minutes ago, BC5RA said:

the only electrical stuff on the intercooler in that location were on the silver WAIC, which was a level sensor.

I have a spare Silver WAIC, will check for any wires when I get home tonight

[BC5RA]

12 minutes ago, SpeedySub said:

I have a spare Silver WAIC, will check for any wires when I get home tonight

 

Top right hand corner. These were blanked off on the Prodrive rally cars, see below.

 

Edited December 4, 2016 by BC5RA

[THUNDA]

1 hour ago, BC5RA said:

Fuel pump uograde should be mandatory when raising boost in these cars.

 

Yellow injectors were featured when the EJ20 went to the under intake manifold and only in the STIs. Besides that anomaly WRX which I can't remember the specs of - came with a VF roller bearing Turbo.

 

Pull the coils out of the heads for a proper inspection, call Speedlab with details about the chip to rule it out as suitable for 440cc injectors or not - I'll go on record saying that it won't be, they are an upgrade for RS/GT and early WRX with 380cc injectors. Faster to do this than have it checked for AFRs.

 

Swap out the afm with a known working unit, and look into the conotion of the Turbo.

 

Re: Plug - the one in behind your retro fitted power sterring pump, will have been the speed sensor plug that would have been on your original PS pump most likely, the wires I'm not sure about, the only electrical stuff on the intercooler in that location were on the silver WAIC, which was a level sensor.

 

 

Roger that

 

Boost is at 9/10psi which is standard I believe . I don't run a boost controller so psi is regulated by the new wastegate

 

do you mean just the fuel pump wiring or the pump itself also? 

I'm quite keen on putting the usual walbro pump in before a head towards tuning it professionally.

 

the coils are from a later model wrx looks like v3 so the coils arnt in the heads. They are I top of manifold and visually the look fine however I'm yet to do a resistance check .

 

i have 3 green sticker afms which all perform the same. Spent nearly the whole weekend eliminating / testing factors to try to find the source

 

physically turbo functions well, no shaft play and turbo makes and holds boost easily. Will have a check around the x manifold and up pipe as I did fiddle with that area when doing the wastegate , maybe a leak

 

Next steps I'm thinking will be confirming Ecu ability to run which injectors/ going back to grey injectors and checking the ignition circuit 

 

will have to to wait till next weekend . I don't get much free time at all during the week 

[SpeedySub]

50 minutes ago, THUNDA said:

 

Boost is at 9/10psi which is standard I believe . I don't run a boost controller so psi is regulated by the new wastegate

According to the interweb the stock boost for a W6 is 11.47psi. So looks like its not reaching full boost.

Im a bit confused when yous say you are not running a boost controller. Do you mean you're not running after market but still running factory controller or you have disconnected it totally.

Also why were you adjusting the wastegate?

 

W6 - 1993 WRX RA – TDO5- 11.47PSI (0.8BAR) -FUELCUT 14.5PSI (1BAR) - 240PS (237BHP)

[BC5RA]

9 psi is wastegate pressure for a TD05, you won't get lower than that. Expect 12 to 13psi.

 

Yeah Walbro. Piss easy job and nice and cheap too.

 

Curious about your coil setup.. Individual coils or wasted spark modification, could you post a pic @THUNDA?

 

Edited December 4, 2016 by BC5RA

[THUNDA]

5 hours ago, SpeedySub said:

According to the interweb the stock boost for a W6 is 11.47psi. So looks like its not reaching full boost.

Im a bit confused when yous say you are not running a boost controller. Do you mean you're not running after market but still running factory controller or you have disconnected it totally.

Also why were you adjusting the wastegate?

 

W6 - 1993 WRX RA – TDO5- 11.47PSI (0.8BAR) -FUELCUT 14.5PSI (1BAR) - 240PS (237BHP)

 

 

Nope, no boost controller at all, boost controller leaks vac to obtain different pressure from the wastegate actuator 

 

I dont use the factory wastegate either, installed a 38mm Tial  (mounted under the car straight off the exhaust manifold) and it performs extremely well

no boost spikes at all, not even half a psi, no boost creep in the slightest

 

Yup ive seen stock boost is 11.47psi which it would be if I had the factory ebc hooked up the computer could and did make it that before I upgraded a wastegate

No need for the factory ebc at all once you run an aftermarket wastegate, you can turn it up by fitting an aftermarket ebc/mbc but im happy with a nice low 9/10psi at the moment because I dont want it to blow up before ive had a chance to fix all the stupid hack job mods its had in the past

 

 

 

 

[THUNDA]

4 hours ago, BC5RA said:

9 psi is wastegate pressure for a TD05, you won't get lower than that. Expect 12 to 13psi.

 

Yeah Walbro. Piss easy job and nice and cheap too.

 

Curious about your coil setup.. Individual coils or wasted spark modification, could you post a pic @THUNDA?

 

 

 

I dont use factory wastegate

 

Have a tial with a 9 or 10psi spring, very happy with its performance over the factory wastegate. i say 9 or 10 psi as I dont often look at the gauge and not very closely while driving, but whereever the needle on the gauge goes its always the same

 

Yo what walbro fuel pump exactly? what model number did you use?

 

Wasted spark on the coils from what looks like a V3, 2 double ended coils on top of manifold

only 1 bolt to mounting it on though, would like make a plate to fit it properly in future

 

Just to confirm I do still have the factory MAP and EGR hooked up to the factory vacuum line, just factory ebc is unused

[BC5RA]

Ah i see, I went with external mounted Bosch coils.

 

Walbro GSS342 is the one you want. Tip - reuse your fuel pump filter sock, located at the bottom of the pump assembly - Not the supplied sock.

 

Reason being is that the Walbro sock mounts horizontally and the stock one at 45 degrees, If you used the Walbro one, you may (probably) get fuel surge when riding near empty on the corners.

 

Also - each to there own, but I'd ditch the angled WRX cooler, its not an upgrade from the stock WAIC, probably too much of a fuss to go back, just thought i would mention it.

 

[THUNDA]

18 minutes ago, BC5RA said:

Ah i see, I went with external mounted Bosch coils.

 

Walbro GSS342 is the one you want. Tip - reuse your fuel pump filter sock, located at the bottom of the pump assembly - Not the supplied sock.

 

Reason being is that the Walbro sock mounts horizontally and the stock one at 45 degrees, If you used the Walbro one, you may (probably) get fuel surge when riding near empty on the corners.

 

Also - each to there own, but I'd ditch the angled WRX cooler, its not an upgrade from the stock WAIC, probably too much of a fuss to go back, just thought i would mention it.

 

 

 

Sweet have locked that walbro pump into the list of to dos (there really is a list and its loooong haha)

 

Im all over the factory WAIC. they rule imo. When i got the car it had the V1 IC on it already, and factory water pipes and pump have been removed

 

Which is why I tried to "upgrade" to a V6 sti IC.

Did a bit of research AFTER buying my V6 Sti intercooler, turns out nearly all top mount intercoolers perform very similarly, almost no gain from the V1 IC to the V6

 

and also they dont fit on the ol BC's - good lesson though now I always check my S*** first haha

 

Still got the bloody v6 ic couldnt sell it for 1/3 of what I paid for it >_<

[BC5RA]

13 minutes ago, THUNDA said:

 

 

Sweet have locked that walbro pump into the list of to dos (there really is a list and its loooong haha)

 

Im all over the factory WAIC. they rule imo. When i got the car it had the V1 IC on it already, and factory water pipes and pump have been removed

 

Which is why I tried to "upgrade" to a V6 sti IC.

Did a bit of research AFTER buying my V6 Sti intercooler, turns out nearly all top mount intercoolers perform very similarly, almost no gain from the V1 IC to the V6

 

and also they dont fit on the ol BC's - good lesson though now I always check my S*** first haha

 

Still got the bloody v6 ic couldnt sell it for 1/3 of what I paid for it >_<

 

Ah bugger.

 

Yeah Autospeed did a bunch of flow testing etc and found that only the Larger GD STI coolers were worth swapping to, but then you would have to run a giant bonnet scoop and ruin those nice smooth BC/BF lines.