BH5 Twin Turbo legacy diagnosis

[Fast Eddie]

Hi All, thought I would try this forum out to bounce some ideas off and maybe get some new ideas. Diagnosis on a BH5 twin turbo legacy, it has 2 main issues at the moment.

1st from cold start it really struggles, crank crank crank, it may catch and run on 1 or 2 cyls for a revolution or two then die, more cranking, a cough or two, more cranking, probably on the 3rd or 4th try it will catch and run on two or 3 cyls then slowly the 4th kicks in and then it settles into its warmup idle - about 1200rpm.

Once warm however the idles hunts a little bit - first it settles to about 820rpm and is fairly steady then drops to 740/750rpm and starts to hunt a bit ranging from 700-760rpm and by the time the coolant has warmed to the 70/80 degree mark the idle really doesnt feel right and hunts from 650rpm-720ish rpm. It hasn\'t stalled yet but you get the feeling its not far off.. boost gauge/ (vacuum at idle) needle flickers a wee bit at idle. if you bring and hold the rpm at say 1500rpm then vacuum gauge is steady and rpm is steady.

Won\'t list all the things I\'ve checked so far - just throw ideas out to me and if I havent had a go yet then I\'ll go have a go.

2nd problem is boost - what is the psi that the first turbo should hit and at what rpm? and the secondary turbo? whats the psi that should hit and at what rpm?

This vehicle has a massive \'VOD\' between the turbos and the second turbo is a bit hit and miss, I\'v had some clean pulls all the way to 7,500rpm where both turbos seem to hit near 0.5 mpa but I\'m not sure I trust the boost gauge fitted.. 0.5mpa would be about 57psi?? doesnt pull like its getting 57psi haha

also finally after a few drives it started only doing the first turbo and at about 5,000 where the first turbo dies off and second feels like it should kick in, it just starts misfiring and hesitating big time - won\'t boost up and won\'t rev out. I 2 lovely codes of 66 (twin turbo system) 2 identical numbers but slightly different wording in the code..

Anyway.. those or the issues.. I\'m working through things slowly 1 by 1 but its a daunting task with a vehicle that should prob be sent to the scrap heap! someone has fitted another loom.. a loom which has many redundant plugs hanging around going no where.. lots of none stock looking earths that have not been done very well.. knock sensor has been cut and soldered to the loom for some unknown reason - all I can think is that this loom is not for this legacy at all.. joy!

[lachlan]

where abouts in the country are ya ?

between vac leaks and god knows what wiring i dont see this going very far via the net

[Marky]

The loom sounds pretty suspect (are you sure its not just redundant plugs which are meant to be there? Theres a few) but the symptoms are a lot like what a dud air flow meter can do to these

Its a very very common fault in this model and only normally fixable by replacement

Stock boost is about 10psi on primary and 14ish on both - I domt know the conversion to mpa sorry

Code 66 can be brought on by other faults, its a very vauge "theres a problem" code if that makes sense, low boost or misfiring can trip it

[Fast Eddie]

 lachlan said:

where abouts in the country are ya ?

between vac leaks and god knows what wiring i dont see this going very far via the net

yea probably true.. will see if I can find a maf/af sensor to borrow to try. It\'s going to be a bit of work

[Fast Eddie]

 Marky said:

The loom sounds pretty suspect (are you sure its not just redundant plugs which are meant to be there? Theres a few) but the symptoms are a lot like what a dud air flow meter can do to these

Its a very very common fault in this model and only normally fixable by replacement

Stock boost is about 10psi on primary and 14ish on both - I domt know the conversion to mpa sorry

Code 66 can be brought on by other faults, its a very vauge "theres a problem" code if that makes sense, low boost or misfiring can trip it

Loom does not look like other bg/bh twin turbo GT\'s that are untouched and I know it is a replacement but from where I don\'t know. The redundant plugs were left to touch the exhaust manifolds or just hanging down, a few plug connections are modified like knock sensor just cut and soldered to loom, other plugs just disassembled and siliconed into mating plug, general loom routing is poor.. can\'t see subaru doing that.

can try air flow meter with a spare.. the loom is bound to cause problems eventually if it isn\'t already. the twin turbo system seems to have a fault unless the maf is only causing a misfire at 5,000rpm when second turbo feels like it should be kicking in.

plus the code 66

I\'ll play around with it a bit

[log1call]

With poor start-up, and the vacuum gauge flickering at idle... you really need to get a compression check, leak down test, engine tune and all the standard things like small hoses checked first... It could be that the motor is poked...

[Fast Eddie]

 log1call said:

With poor start-up, and the vacuum gauge flickering at idle... you really need to get a compression check, leak down test, engine tune and all the standard things like small hoses checked first... It could be that the motor is poked...

yea did compression test first and a general checkover of all vacuum lines, air hoses, intercooler etc.. charged up battery, tried known good coils and air flow meter. slowly getting through it.

compression was OK.. 150psi on all 4.. seems a little low, think last quad cam turbo boxer I did was about 175psi? but at the end of the day they were all even. Leak down test was rather basic, got a home-made fitting from an old spark plug and air hose piece. Blew some compressed air in each cyl, couldn\'t hear or feel anything from intake, exhaust or other cylinders.

Working my way through the black box, solenoids and vacuum lines for the twin turbos now. It runs smoothly at part throttle, if you floor it, it\'s pretty gutless and not much boost, at 4,500 it just mis fires.. or you can go to redline at part throttle so its only when its trying to boost with the 2nd turbo charger. The cold start and idle seems to be much better now after cleaning some of the vacuum lines and 1 of the solenoids in the black box. So will keep playing around.

[Rosssub]

Pull your Secondary Relief Valve off and try to blow through it, should be completely sealed. You might have a tear/hole in the diaphragm maybe? Acting as a Vac leak at idle, then a massive boost leak as the Secondary kicks in??? Worth a shot:

[kamineko]

what a mission. I might be free on sunday to have a look at the loom for you. dodgy earthing is a hell of a thing

nick

[Fast Eddie]

 Rosssub said:

Pull your Secondary Relief Valve off and try to blow through it, should be completely sealed. You might have a tear/hole in the diaphragm maybe? Acting as a Vac leak at idle, then a massive boost leak as the Secondary kicks in??? Worth a shot:

Cool, checked secondary bov and it opens with x amount of vacuum and is sealed shut unless open. Checked primary bov on intercooler too. Also ok. Must figure out how to run it through valve check - subaru select monitor keeps returning "out of check condition" even though i have test leads connected and engine warm/idling normal. During test drive vehicle seems low on primary boost but yet to find a boost or vac leak. Wastegate seems ok as in can move it and doesnt stick, havent put any pressure to wg to see when it opens.

[Rosssub]

Connecting the Green and Black Diagnostic Plugs under dash, then turning Ignition on. Puts Car into D-Mode (diagnostic mode), for testing Solenoid operation etc. If it does nothing you may have a broken Wire? Or it\'s the messy Loom thing?

With Boost Gauge flickering at Idle, maybe Mechanical issues. Valve Seats/Seals/Intake Manifold Gasket Leaks. Plus your compression is low... :-\ But can also be from Vac Leaks/Boost Leaks, which could also cause all of your issues...

Block your Intake at the AFM with a Baked bean can or something that fits well and seals. Then pump 14psi into your Vac/Mani/TMIC. Any Air Leaks will be very obvious.

Also spray Ether/Engine Starter Fluid around your Intake Manifold Gaskets/TB/Pipe Joins. Any leaks, the fluid gets sucked in and the Idle will change drastically.

Code 66 - Boost issues. Clean out your Primary Boost Solenoid and BBOD:

http://www.uklegacy.com/forums/index.php/topic/11043-code-66-and-boost-issueshow-to-clean-them-out/

Primary Boost Solenoid is hiding inside the F/L Guard, right beside battery. Can also gunk up and not open or not close, causing issues on Primary and Secondary.

[Fast Eddie]

 Rosssub said:

Connecting the Green and Black Diagnostic Plugs under dash, then turning Ignition on. Puts Car into D-Mode (diagnostic mode), for testing Solenoid operation etc. If it does nothing you may have a broken Wire? Or it\'s the messy Loom thing?

With Boost Gauge flickering at Idle, maybe Mechanical issues. Valve Seats/Seals/Intake Manifold Gasket Leaks. Plus your compression is low... :-\ But can also be from Vac Leaks/Boost Leaks, which could also cause all of your issues...

Block your Intake at the AFM with a Baked bean can or something that fits well and seals. Then pump 14psi into your Vac/Mani/TMIC. Any Air Leaks will be very obvious.

Also spray Ether/Engine Starter Fluid around your Intake Manifold Gaskets/TB/Pipe Joins. Any leaks, the fluid gets sucked in and the Idle will change drastically.

Code 66 - Boost issues. Clean out your Primary Boost Solenoid and BBOD:

http://www.uklegacy.com/forums/index.php/topic/11043-code-66-and-boost-issueshow-to-clean-them-out/

Primary Boost Solenoid is hiding inside the F/L Guard, right beside battery. Can also gunk up and not open or not close, causing issues on Primary and Secondary.

Cheers for all that, will run through it in the next day or two. Yea comp is a bit low but subaru allow down to 140psi before its an issue provided no more than 10% diff between best and worst cyls. Yea had connected the test prongs and with select monitor tried to run through valve check but returned out of check cond. so may be a wiring issue in there too. Have tried the ether trick but havent tried the can over intake yet, cheers. Will report back. I also have the genuine subaru service manuals here and have spent a few hours on the code 66 procedure - stumped due to the select monitor not being able to do valve check but so far everything else been ok as far as solenoid box vac lines etc go. Yet to check surge/serge tank and hose tho

[Rosssub]

Instead of using D-Mode to clean/check Solenoids etc. I wired an External 12V from Battery and removed all Solenoids, tested Solenoids one by one. Cleaning, then reinstalling as I went to avoid Hose mix ups.

Make sure Hose 5 goes to Top of ECV Actuator and Hose 6 goes to the Bottom of ECV Actuator. These mixed up could cause issues.

Also check Hoses 21 & 22 at the Differential Pressure Sensor (on firewall). Sensor should be numbered both sides for the corresponding Hose. A mix up here will cause issues too.

Edit: Both of these issues could cause a CEL 66.

[Fast Eddie]

End diagnosis was damaged/worn primary turbocharger. Specifically the wastegate itself. Mechanical wear. Hard to find replacement parts so most likely try find used turbo at wreckers/ebay etc. Subaru don\'t sell parts anymore to repair/replace the wastegate with new OE parts

The loom on this vehicle is someone elses problem - apparently loom fitted by local dunedin shop. Wont name names but very suprised at how poorly it was done by "professionals" ie the loom resting on the secondary turbo literally.. No attempt to even route it like factory, wires hanging everywhere engine bay and in cabin.

[Marky]

Turbo won\'t be a major to replace (is it just the wastegate itself and thats it? or the turbo core)

Weird it gave the symptoms it has but the code 66 thing does also come from over or under-boost so makes sense... just not the first thing I\'d check since it did make boost

Chances are the wastegate from any TT legacy will work just fine, will prob be a $5 thing to do

Weird about the loom that\'s for sure, why would a suby even need to be re-done at all given they\'re interchangable so much

[Fast Eddie]

Wastegate itself. seems unable to hold or regulate psi now, just about 0-4/5psi all the time under 4,000 and the cel when secondary should phase in, when I first got the job it may have been a bit better as over the testing period it got less and less boost on primary. Anyway its gone back to its owner now and he can swap turbo or whatever he wants to do.

[Rosssub]

 Fast Eddie said:

Wastegate itself. seems unable to hold or regulate psi now, just about 0-4/5psi all the time under 4,000 and the cel when secondary should phase in, when I first got the job it may have been a bit better as over the testing period it got less and less boost on primary. Anyway its gone back to its owner now and he can swap turbo or whatever he wants to do.

Not a blocked Cat?

Put some Vacuum, or 10psi into the Waste Gate Actuator and see if it holds. Might have a hole in the Diaphragm?

Or unclip the Actuator Rod and see if the Gate moves freely.

[Fast Eddie]

Car\'s actually gone back to its owner and a whole used primary sourced as easy/lazy fix. I believe I put something like 72kpa (whatever the manual said) vac on the wastegate and and it held that (from memory) but there was a mechanical slopiness/play in the wastegate and its little pushrod and in the wastegate itself. Just went ahead and assumed it was shagged. Having fun with that bg5 now in other post and think friends bd5 rs is on its way to my shed soonish

[Fast Eddie]

Was wondering about the blocked cat on the bg5 actually but 10psi on primary exhaust sounds free/unobstructed. Blocked the tip for whatever it tells ya. No obvious leaks, can feel decent back pressure