Coils a problem?

[Guest]

I have been driving my ladies BH 2000 B4 for a while and have just bought a '95 GT SW BG5. I think they share the same problem. This is different to the power hole where the primary turbo switches to the other (newby here, soz is this what the regulars call the VOD?).

Both of these cars quite often fall in to this 'null power' mode. It's symptoms are the typical Subaru engine sound seems to be not normal (is off beat for want of a better term), and it's dead flat in power.

To resolve it means backing off the gas a little and waiting for the engine to kind of get 'on beat' again (takes anywhere from 2-6secs). I know that's a pretty piss poor explanation, but if you have experienced it, you will know what I mean.

Could this be failing coils, and if so how do you know which one?

[Durty-Sanchez]

What exactly do you mean by 'null power' .. ? Is there still enough power to provide propulsion (i.e. it goes, but not very fast), or is it a complete loss of engine power?

My first guess would be that you could be changing gears too close to the VOD change over points. There is the noticable power drop during the change, but if you change up a gear after it's just completed chances are your exhaust gas flow will drop (lower revs), but it'll be trying to spin both turbos still. The result is it bogs down for a few seconds before realising that it doesn't have the power to spin both, then powers back to life again after closing off the secondary.

AFM going bung is usually shuddering/complete loss of power. You'll feel it if you're moving along and it feels like all of a sudden you don't have an engine.

Coils.. you might notice some missfiring/shuddering while driving, but the real effect of coils is during acceleration. When you put your foot down there might be nothing for a second, then you're away. You might also get some severe shuddering/missfiring with bad coils.

Crap timing.. this gives you the feeling of poor throttle response when you put the power on. Over time the ECU's severely retard the timing at low load/rpm, giving you not a lot of power when you plant it. Resetting the ECU (battery off overnight on older models) will help with this.

[log1call]

Certainly doesn't sound like coils.

I'd suspect the ignition timing is retarding.

EAsy way to test it is to find someone that can connect the car to a laptop or get a dealer to connect it to a scanner.

[Guest]

By null power I meant the engine feels as though it's not doing anything at all. No power... In fact the more you put your boot up it to clear the problem the longer the problem will sustain, you have to back off the gas and place the pedal as if it were 1/2 load and she comes right.

I am certain it's not the VOD changing close around it etc. Can be at any load, or any RPM (extreme high RPM is not so much of a prob if at all). It kind of feels like the twin turbo limbo thing but i'm sure it's not that either. We just went overseas a while ago so the battery was off for 1 month... I think this would have cleared the ECU Still the problem was there when we got back.

I have just heard that when your coils start breaking down (common Subaru prob apparently) this was one of the symptoms. Definitely no shuddering going on in the B4, and the BG (mine) only suffers from shuddering from the clutch area.

One more possible symptom, in fact pretty damn sure is semi to abrupt load bring it on bad. Light load cruising like you probably should is fine.

PS. B4 is a tiptronic and mine is a manual.

[log1call]

Make sure you are using high octane or put some octane booster in as an experiment.

You could also get someone to put a timing light on and check the ignition timing is correct. The timing shouldn't be off unless a cam belt has slipped and then you would have bad idle and other symptoms though.

It sounds to me like knock sensor is telling the ecu to retard the timing.

[Guest]

Yea, I might just chuck the light on it to be sure.

I think it is right but never hurts to check.

I like the knock sensor idea too. Ta.

[log1call]

Some people reckon to shift the knock sensor to the bellhousing.

That could be worth a try to see if it makes a difference, but if it did cure the problem I'd get a new one and put it back in the original position.

People like to modify their cars and change several things then find the car isn't going as it's meant to and they can't figure out where to start because there is so much not operating as it's meant to be. Guess what.... the experts don't know where to start then either and it is a nightmare to diagnose even supposedly simple problems.

[Guest vf20/21bg5]

 gadget said:

By null power I meant the engine feels as though it's not doing anything at all. No power... In fact the more you put your boot up it to clear the problem the longer the problem will sustain, you have to back off the gas and place the pedal as if it were 1/2 load and she comes right.

I am certain it's not the VOD changing close around it etc. Can be at any load, or any RPM (extreme high RPM is not so much of a prob if at all). It kind of feels like the twin turbo limbo thing but i'm sure it's not that either. We just went overseas a while ago so the battery was off for 1 month... I think this would have cleared the ECU Still the problem was there when we got back.

I have just heard that when your coils start breaking down (common Subaru prob apparently) this was one of the symptoms. Definitely no shuddering going on in the B4, and the BG (mine) only suffers from shuddering from the clutch area.

One more possible symptom, in fact pretty damn sure is semi to abrupt load bring it on bad. Light load cruising like you probably should is fine.

PS. B4 is a tiptronic and mine is a manual.

yeah i sort of have the same problem in my gt too...if ive got my foot to the floor wen the secondary kicks in its a smooth powerfull transition with no power loss but if im anywer from 1/4 to 3/4 throttle as soon as the secondary kicks in i die(no power)and it takes for ever to wind both up as from that point both turbos are sharing the exhaust gases to run thm.... then i take foot off and let the primary take over and start again and your away again untill the certain rev range that the bloody secondary kicks in again lol...ive actually learnt to feather the throttle and get max power out of the primary turbo b4 changing gears(same in auto)and thats far better thn letting that bloody secondary turbo kick in wen you dont want too much power......it seems to me that with these twin turbo's its either foot to the floor or dont let the secondary kick in for the most power lol...and i do alot of driving as my gt is also my work vehicle....i know what your trying to say m8 and it sux but thats why most turn to single turbo conversion as its just str8 out raw pover from the get-go...i will be in a year

[ReubenH]

Just a little more on vod. If you change gear anywhere near vod, you get caught in it, and have no boost. You can climb through 1000 rpm easy and not have any boost. An example situation would be revving up to 4500rpm, change gear, and you'd be no boost till you're past 4300 ish again (in other words, no boost till you're back to where secondary really kicks in). I recommend getting a boost gauge so that you may see what's going on.

vf20/21bg5, you need a sequential controller. You can select when you want vod to occur with one, and push it back. I pushed it back to 4600 rpm, that was all i needed to stay on primary all day, and when going through vod, secondary almost instantly kicked in.

[Guest vf20/21bg5]

 ReubenH said:

Just a little more on vod. If you change gear anywhere near vod, you get caught in it, and have no boost. You can climb through 1000 rpm easy and not have any boost. An example situation would be revving up to 4500rpm, change gear, and you'd be no boost till you're past 4300 ish again (in other words, no boost till you're back to where secondary really kicks in). I recommend getting a boost gauge so that you may see what's going on.

vf20/21bg5, you need a sequential controller. You can select when you want vod to occur with one, and push it back. I pushed it back to 4600 rpm, that was all i needed to stay on primary all day, and when going through vod, secondary almost instantly kicked in.

...oh true,can you point me in the right direction of one? and how much?...yeah staying on primary all day sounds good to me as it feels way better in the way of power then both of them working at same time......that is unless my foot is on floor and i dont want to drive like that all the time

[ReubenH]

PM'd so that we don't stay off topic too much.

[Guest boostin]

I say its VOD and both cars have leaking ECVs.

[Guest vf20/21bg5]

 boostin said:

I say its VOD and both cars have leaking ECVs.

will a hand held test vacume pump pick up the leak in the ecv?

...and how are they best adjusted?trial and error?start stop adjust,start stop adjust and so on untill you got it kicking in when you want it to?...or ant it that easy?

...and pls what does vod stand for(duh to me for not knowing)

[Guest boostin]

 vf20/21bg5']

[quote name='boostin said:

I say its VOD and both cars have leaking ECVs.

/quote]will a hand held test vacume pump pick up the leak in the ecv?

...and how are they best adjusted?trial and error?start stop adjust,start stop adjust and so on untill you got it kicking in when you want it to?...or ant it that easy?

No. The easiest way I've found is to whip the intercooler out and unplug the AFM. Start the engine and feel for air coming out of the turbos. Give it a bit of a rev too. There should be some from the primary but none from the secondary. Any air from the secondary indicates exhaust leaking through the ECV and driving the turbine.

And the engine won't run with the AFM plugged in and cooler out.

[Guest boostin]

VOD = Valley Of Death, ie, pulling out to pass a cattle truck and booting it, hit VOD and find logging truck coming the other way.

[Guest vf20/21bg5]

 boostin']

[quote name='boostin said:

I say its VOD and both cars have leaking ECVs.

/quote]will a hand held test vacume pump pick up the leak in the ecv?

...and how are they best adjusted?trial and error?start stop adjust,start stop adjust and so on untill you got it kicking in when you want it to?...or ant it that easy?

No. The easiest way I've found is to whip the intercooler out and unplug the AFM. Start the engine and feel for air coming out of the turbos. Give it a bit of a rev too. There should be some from the primary but none from the secondary. Any air from the secondary indicates exhaust leaking through the ECV and driving the turbine.

And the engine won't run with the AFM plugged in and cooler out.

cool thanx...and wer shld the ecv be adjusted too?...as tight as poss or backed off a little?...have played around a little with it but afraid to do too much

[Guest vf20/21bg5]

ps...i have got a boost gauge on the primary and secondary turbo's and do think its a must for twin turbo's......thy tell you exactly wen the secondary is about to kick in so you can button off if you want to stay in primary....and its cool watching them rise together wen you have your foot to the floor too.....at first i had just the secondary boost gauge hooked up for a while but as soon as i hooked the primary up as well it all made sence and was able to picture in my head what all those valves and flaps wer doing and how.!

[Guest boostin]

Its separate from the actuator arm and rod. The linkage wears inside the exhaust and the little valve flap doesn't seat properly any more. Seen it so many times now.

Its hard to describe without showing you exactly what I mean.

[webup]

Same problem on my late BH GTB.

Most of the time fine.

Occasionally go to accelerate and car feels like it has a 50cc motorbike engine in there.

It makes a different engine sound like a muffled bogged down noise and if I back off the gas for a second it usually comes right.

Its only a recent thing and is definitely not VOD as it used to be perfectly smooth for 6 months previously.

Subaru specialists have run the laptop code checker.

Replaced cam angle sensor

Tried new AFM

New plugs

Still does it...

[Guest]

Sweet. So now there are a few of us experiencing the same thing, suddenly I don't feel that nuts

 

The linkage wears inside the exhaust and the little valve flap doesn't seat properly any more. Seen it so many times now.

Boostin. Is there any chance you will be seeing this again soon and have the ability to show us by way of a photographic display with arrows for dummies on them? I understand this may just not be practical for you but I have to ask.

It really does sound like this could be the cause, and obviously so many of us suffer from this problem. The VOD you can drive around, but this is soo random it really bites. Is this something we can attack ourselves and repair? ???

[mattapo]

I found that backing the change over flap in the exhaust off helped the recovery time reduce greatly.

Its on the drivers side and liiks like a large waste gate acuator. there is an adjustment on the rod, use a couple of 10 mill spanners and wind it so it makes it a bit longer

[Guest boostin]

 mattapo said:

I found that backing the change over flap in the exhaust off helped the recovery time reduce greatly.

Its on the drivers side and liiks like a large waste gate acuator. there is an adjustment on the rod, use a couple of 10 mill spanners and wind it so it makes it a bit longer

That will work for a little while, but the arm is wearing and will keep wearing. Lengthening the actuator rod will prevent the valve fully opening too.

[Guest boostin]

 gadget said:

Sweet. So now there are a few of us experiencing the same thing, suddenly I don't feel that nuts

 

The linkage wears inside the exhaust and the little valve flap doesn't seat properly any more. Seen it so many times now.

Boostin. Is there any chance you will be seeing this again soon and have the ability to show us by way of a photographic display with arrows for dummies on them? I understand this may just not be practical for you but I have to ask.

It really does sound like this could be the cause, and obviously so many of us suffer from this problem. The VOD you can drive around, but this is soo random it really bites. Is this something we can attack ourselves and repair? ???

Not really a home job. If you want a brand new one you need to buy a new secondary turbo. That's the only way you can get it.

Yeah next time I do one I'll snap some pics. Might be tomorrow, might be next Xmas though.....

[Guest vf20/21bg5]

 boostin']

[quote name='gadget said:

Sweet. So now there are a few of us experiencing the same thing, suddenly I don't feel that nuts

quote]

The linkage wears inside the exhaust and the little valve flap doesn't seat properly any more. Seen it so many times now.

Boostin. Is there any chance you will be seeing this again soon and have the ability to show us by way of a photographic display with arrows for dummies on them? I understand this may just not be practical for you but I have to ask.

It really does sound like this could be the cause, and obviously so many of us suffer from this problem. The VOD you can drive around, but this is soo random it really bites. Is this something we can attack ourselves and repair? ???

Not really a home job. If you want a brand new one you need to buy a new secondary turbo. That's the only way you can get it.

Yeah next time I do one I'll snap some pics. Might be tomorrow, might be next Xmas though.....

..

.....bugger i just upgraded my gt turbo's to gtb turbo's a good 5 months ago now but the actuator and valve was not with it and i remember wen the turbo was off looking directly at the ECV and and having a bit of a fiddle with it while it was disconnected from the actuator and to be honest at that time i never had my head properly around the fact of its importance and wot it had to do properly......but i do think wot ReubenH had said earlia in this thread about a sequential controller makes alot of sence for some of you out thr who may try replacing the ECV to no avail it may be a last resort to help you out of the Vally Of Death ............as for me im just going to put up with it for another 9 mnths untill ive finished building my new engine(twisted,link,semi monster tune) and since im addicted to this site thrs no doubt ill thread the whole build starting from a bare closed deck block.

[mattapo]

Well my sequential controller is for sale