ktomass

The car (MY92 Legacy with GBE MBC) is stone dead until 3500rpm then it's starting to fly. Also throttle pedal is like an on/off switch. You press the pedal for about 1/3 and until 3500rpm nothing, then flies like pedal was pushed to the metal. Boost is set at 1bar. I'm not too sure if this is the way to go. Also the car doesn't seem to be any faster.

Could anyone know what can be done to make the car smoother, besides going back to standard setup?

Thanks for your replies!

Kristijan

[Edited by ktomass - 10/1/2003 10:53:56 PM]

ktomass

...not even sure that it is MBC I don't like!? What else could be wrong if the car judders very slightly when accelerating? The feeling is like the car is holding back (it seems to me as if the ECU would retard timing? Is it possible?).

How could I say that throttle position sensor is not working as it should? What are tipical symptoms? Also is there any other sensor which can cause this trouble (knock or throttle position sensor)?

Is it possible that one of this sensors is not working as it should and I don't get CEL?

Would also like to know where can I find these two? I now know where they are located.

Reg. K.

[Edited by ktomass - 10/2/2003 9:09:39 PM]

[Edited by ktomass - 10/2/2003 9:45:55 PM]

[Edited by ktomass - 10/2/2003 9:47:22 PM]

Turbo_Steve

Doesn't sound right to me at all.
Would suggest maybe Throttle position sensor is poorly?

Turbo_Steve

Or it might be your coil packs on the way out....mine went a bit like that...was awful performance off boost and okay once the car got going!

Check your plugs / coilpacks!

ktomass

COils checked, everything OK with them (also changed sparplugs while in garage).

As for throttle position sensor how can we check if it's not working as it should? CEL is not there so diagnostic computer doesn't show anything.

We also reset the ECU and it seems a bit better but just a bit, almost not noticable.

Car is running on RON98.

In the morning I also found that the car when driven normally (highway about 130kp/h) and then boot it there seems to be hesitation and it doesn't pull the way as it should. If I lift the throttle by 1/3 after couple of seconds it's starting to do the job.

Really puzzled with this...

Thanks,

Kristijan

Gridlock Mikey

MBC = Manual Boost Controller?

If so, the Dawes used to exhibit these symptoms on some cars and as a result the bleed hole was increased from 0.5 mm up to anything upto 1.5-2mm. It still allowed the thing to work, it just smoothed the effect out slightly. Mine used to be very on/off drilled the hole out a bit and hey presto.

If however MBC does not stand for manual boost controller in this instance, I'll get me coat

Mikey

nom

The throttle thing - WOT apparently having less power than slightly under WOT - is usually due to the heavy overfuelling the ECU does when it notices you're flooring it - makes WOT slower that 80% throttle
That bit's fairly normal, I think
Then it's getting the various holes the right size

ktomass

Thanks for your replies!

About which hole size are we talking about on manual boost controler? I can only see one, and thatone is about 1mm. Is that the one? How can drilling bigger hole help to reduce on/off feeling?

ECU is overfuelling!? With 0,2 bar over standard boost? How can this happen? Before; when the car worked as it should it was quite quick; now performance is virtually the same with higher boost and before it wasn't overfuelling; on WOT the car flied without hesitation; exept when boost solenoid was blocking.

Thanks again for your effort!

Kristijan

The_Judge

How did you fit the MBC? Did you use the existing pipework, or did you unplug the existing pipework, remove the T-piece from the pipe to the boost solenoid, block it with a screw, and use new pipe?

ktomass

We mount it between turbo niple and wastegate, then blocked remaining hoses and left standard boost solenoid conected to the ECU, so CEL doesn't light and in this way we still have fuel cut if anything goes wrong.

Reg,
K.

The_Judge

Sounds like it's fitted OK. I fitted mine a couple of days ago (the Mk2), and other than finding appropriate 8mm bore pipe, haven't had a single problem. Is your turbo OK? Are you saying it's not spooling up until 3,500rpm? Or is it spooling as normal, but the power simply isn't there?

nom

It could easily be overfuelling - the additional 0.2bar might have moved it into an 'overboost' part of the map; normally this situation would occur only occasionaly and by accident, so the ECU overfuels for safety (and you wouldn't notice as you'd be out of the overboost situation very quickly). Now you're set up to stay in the overboost part of the map, hence everything is very rich.
Although I may be very wrong here but that would be my 'best guess' going on typical Subaru 'tuning' technique.

ktomass

Thanks guys for your effort!

Turbo spools up fine from 2800rpm, but the car seems to be quite flat until 3500rpm, then I get a big kick in the a$$. Not very pleasant to drive! Before we mounted Mk2 GBE controller the car was very progresive and with basically same overall performance.

The difference though is that now i don't have to press throttle pedal to the metal that something happens, I can just press the throttle by 1/3 and wait for 3500 rpm and off we go. But as I said by pressing full throttle the car doesn't pull as it has before.

Thanks,

K.

Hanslow

Kristijan, re the bleed hole.....

If you have a Dawes Device (or similar) take a read of the following thread http://www.scoobynet.co.uk/bbs/threa...threadid=61862

Sounds like you might have similar issues to Lars (towards the bottom of the post).

For more (and I mean LOTS more) info on MBCs and in particular the Dawes, have a read of the links on here http://www.scoobynet.co.uk/bbs/threa...threadid=77143

The bleed hole on the Dawes Device can be seen on this picture on the elbow joint


Hopefully, that might be of some use to you

ktomass

Thanks!

Bleed hole is 1mm wide and as for the car has bigger turbo then TD04 i presume it is good enough as it is (for now).

I'm more concerned about that slight judder from the engine (also when just on 0,6 bar at 2400 rpm the car just doesn't pull (as it would be tied to a rope from the back); the boost is there but no performance!).

Reg,

K.

ktomass

Just performed ECU reset (the thing with green and black connectors) and the car ran perfectly for a while. After 10km of moderate driving the same thing as before!

So when ECU was reset, after that car was running sweet; nice pick up without hesitation. I also found out that black connectors were pluged together. Is this OK? I put them apart after reset as it says so in "how to perform ECU reset" on MRT site.

Many thanks for your help,

K.

Edited to say that there were no fault codes stored in the ECU.

[Edited by ktomass - 10/3/2003 3:10:52 PM]

[Edited by ktomass - 10/3/2003 4:24:43 PM]

ktomass

In the evening engine ran very smooth and there was no knocking from valve lifters and the car started to fly as it should. Boost controller could not be such a bad idea after all; quicker boost build up and better throttle response. Not much quicker overall but more fun!

Is it possible that knock sensor is sensing knocking from valve lifters and thus ECU is retarding ignition?

K.