UrS4boy

Honking like a goose = broken OE BPV. Here is some info to read:

CLICK HERE

dacul09

i've removed the bypass valve and check it out applying about 5 bars with a compressor+tire gauge inflate device..it leaks air when under pressure , an i made sure it's just the valve no other hoses leaks, actually i could hear it on on of the valve outputs...as far i understand the turbo can put up to 16 bars...so if it leaks as 5 for sure won't work better at higher pressure..
i found this valve on ebay and i was wandering if it may be a good replacement or not ?

http://cgi.ebay.com/ebaymotors/Bosch...item23111296b8

UrS4boy

You need to do some more reading on the definition of a "BAR". It is about 14.5 psi. The stock turbo can put out a maximum of about 24 psi so under 2 bar. No where near 5 Bar that you tested. I have *no* idea why you would think the turbo can put out 16 BAR. Yikes.

My recommendation for a BPV is the "710N" or Bosch equivalent (as per the post I pointed you to).

BTW, you should be focussing on your ignition issues, not the Bypass Valve. That is a minor issue.

dacul09

oops, you are wright sorry, it's a bad habit form backhome in Europe were bar is more used than psi , but yes the nr's i was writing were psi ...

i'll try to see if i can find some S4/6 enthusiasts in Toronto with a similar car and if they are willing to spend an afternoon interchanging some electrical parts , or see if i can find a reliable shop around that will not empty my pocket and be able to provide an accurate diagnose...
i've owned about 6 Subarus by now, the old turbo Legacy, SVX , Impreza, and still have a Forester too, and never had such a hard time finding the issue..

dacul09

k, here are some more updates..
i've checked the wastegate membrane for leaks and...found out the pin that operates it was really warned out on one side which prevents it to move freely up and down... i've rotate it so the warned side faces the upper side an it feels a little better than before..
so , looks like i need a new wastegate ..the question is what else should i've replace it with, as i found it very hard to get the OEM part .
should i replace the whole turbo ? a list with some replacement parts will be much appreciated too.
thank you

UrS4boy

The wastegate is a completely separate part from the turbo. Nobody really has any problems with the OE wastegate mechanics and very rarely with the diaphragm. I think you need to look elsewhere for the solution to your problem (whatever it was). IF you need a diaphragm, dealer only, PN 035145797B.

dacul09

well , i'm sorry i haven't took a picture of that center pin that guides the diaphragm up and down to show how bad it is, not mentioning it was getting stoked mid range or on the upper position , if that looks like normal way of working for that part then i'll keep digging ..

the car has 300.000 kms.. and looks like still has all the original engine components form the day 1 when was build, i also did a compression test and all cylinders came up almost evenly - i know the car was very well maintained by the previous owner and the last thing i want to do is to spend my money by replacing things i shouldn't have to do....

all spark plugs are also even "smoked" and they are showing the proper color for the right mixture , that should eliminate my spark plug issues ...even the injectors... so..for me looks more like a vacuum leak/malfunction than anything else by now... if i floor the gas pedal and shift at 5000 rpm the car flies , 1st gear to the 5th...

SCL

I'm pretty sure the knock sensors are the same... and as you mentioned just colored so you know which one goes where. Take a blue sharpie and color it in. ;-)

As for the hesitation, skipping, idling problem... I've had mine for 10 years and I think I've run into just about every engine ignition-type failure.

Here is my opinion after reading your thread. I think there are three possiblilities that you needt to narrow down.
1. Ignition
2. fuel
3. air intake

I have had air leaks quite a few times, especially after scraping a few driveways, which will loosen (or can crack) the turbo-to-intercooler tube that goes across under the radiator. When I had a big enough leak, the engine would run OK if cruising, but would skip and hesitiate and not deliver power if I leaned on the throttle. But it would idle fine because it took some turbo pressure to make it leak. You should probably check it, but I'd look at items 1&2 first.

The objective is to figure out if the engine is missing on one cylinder or if it's running rough on all cylinders. If rough on all, then i'd go back to the air leak. Scroll down to the Air Leak part.

To figure out which cylinder and which component is failing, you just have pull each injector connector and see if the engine runs worse or the same -- then swap a few components around to see which component is failing. To do this...run the car at idle, or whatever it takes to cause the engine to run rough, and one at a time pull each of the fuel injector connectors. (I had to do this with an Automatic Audi, and had to put it in gear with the parking brake on to make it run rough enough for a test). You can just squeeze the connector clip against the connector to release it. If you pull the connector from a good cylinder, the engine will run worse. If you pull it from the already bad cylinder, the engine will run the same. Once you know which one is bad, swap out the ignition components to see which component the problem follows. If pulling any of the injector connectors cause the engine to run worse, then we are back to an air leak or some other intake problem... so skip the next part and go down to the air-leak section.

If one cylinder is not firing, swap the components around and repeat the above test to see which one is the problem.
- coils
- (2) POS transistor packs (passenger side, near the firewall)
- spark plugs

There are two POS (power output stage) packs...one of them does three cylinders, and the other does two -- which means there is a spare circuit in there if you find that one of them is bad. I had a bad POS a few years ago, and rewired the connector by moving the pins and made use of the spare -- I think that is documented somewhere on this site. They are mounted upside down relative to each other....so you may have to unscrew them from the mount to swap the connectors for testing. I remember this was a huge PITA because the back side has little tiny nuts that are difficult to reach.

After you swap the POS's, do the fuel injector connector test again, and see if the same cylinder is bad. If it's a different one, then you've found the culprit.

If not the POS, try swapping the bad cylinder's coil with a good one, and see if the problem follows the coil or stays with the cylinder. If not the coil, try the plug or plug boot-connector. If not, try the fuel injector.

Fuel injector -- first pull the fuel pump fuse and run the engine until it quits. The injectors just snap into the intake and will all pull out if you unbolt the fuel rail and pull up on it.

AIR LEAK -- To find air leaks you just need to pressurize the intake system after the turbo with a few psi of air. 3 or 4 psi is all you need. First take off the hose that connects to the bottom of the turbo. Measure the inside diameter, and go to home depot and find a PVC pipe and end cap that will fit inside. Drill a hole in the top and press in an ordinary tire valve. Now clamp it in, and add some pressure. I was able to do it with a 12 volt tire pump... it's a little noisy so I wrapped it in a few towels so that I could listen for air leaks. Last time I did this I found three different leaks.

I hope that's enough to go on... ;-)

UrS4boy

IF the problem turns out to be a POS issue for cylinder 4 or 5, you can swap pins to use the otherwise un-used "6th" position in that POS using this POS pin-swapping write-up

dacul09

thanks for all recent reply , my schedule at work got crazy at didn't had to much time to play with... maybe it's a non sens , but i've got another wastegate and hopefully this one will work better than mine as i've mentioned before on a previous post the center pin that guides the diaphragm is really rough on one side and that prevents it to move up and down smoothly, it even gets stocked some times midway
i have inspected all turbo pipes already and found no cracks / holes...
next to do will be to play with the injectors then....