I've learnt recently that 'kind of' doesn't cut it on these cars. Pop it all back together and pressure test the whole system. Well worth doing. I thought mine was leak free as I'd changed most parts but found 5 small leaks and one of call a 'medium' leak. Until it's proved to be leak free is not look elsewhere.
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i agree about that.
What do I have to block off? throttle body or let the IM take the pressure?
And intake boot at MAF?Comment
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Disconnect CCV to maf hose, and bung the maf hose, pressure test from the maf hose through the whole intake including manifold.Current-2004 Impreza PPP wagon
Sold-92 3B coupe-RS2+, 996s, konis, rear torsen, forged rods........
Sold ABY-stockComment
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CCV is PCV (breather pressure control) valve, right?
Then why do I want to disconnect it? is there a particular reason breather is not tested? So you mean that I have to bung the hose @ huge maf connection (bottle works great here) then bung the disconected line to pcv, and apply pressure to MAF boot, where PCV line was?Comment
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BecUse it will just blow out of the fitter etc. That bit isn't really supposed to have pressure in it. I did it up to 1 bar through the MAF hose then made one to go on the front of the turbo for higher pressure as I think the MAF hose would pop at more than a bar. Lol. Then use soapy water to find bubbles. Lol. It's not a high tech job really. Just time consuming as for mine I removed the trays and the front bumper.Comment
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oh, ok, I see what you mean now. So block off breather pipe and give some pressure to the turbocharger directly, but what about blow off valve? Isn't it supposed to leak pressure back to intake boot when the pressure is higher before TB than after it?
I thought you meant that I need to blow to the intake boot anyway in the previous post.Comment
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If your dump valve leaks with this test it's shot.Comment
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In the test I did straight into the turbo leaves the diverter valve connected. Once you've tested the MAF hose I prefered the direct turbo way of doing it but that's just me.Comment
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Lol. Yeh there is that too!!Comment
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nein, my DV was checked many times, I have taken it out, and it was just fine. flipped it around to wrong orientation, no change, flipped it back.
So, prj, what lambda or afr values I expect at WOT with semi stock 3b?
Can a n75 valve get tired after 24 years of usage?
And yeah I guess if there is a boost leak the mixture should be more rich than normal, and if there is not enough fuel, then the opposite will be sen on wideband, right?Comment
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Ok, as I already hijacked the thread, so I will just continue doing it without any feeling of guilt I guess? ;-]
Boost drop videos:
Video with normal WOT acceleration:
Video with wot + LFB to keep rpms constant to prove that that is not the turbo that is getting weak at specific rpms:
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Seems like boost leak to me. Assuming 3B mixture at WOT is much like ABY then expect sideband O2 readings in mid 12 range. If you see AFR dipping much below that it (i.e. too rich) it would correlate with a boost leak (as MAF measure more air than was actually consumed).Paul Nugent
Webmaster http://S2central.net
Administrator http://S2forum.com
1994 S2 Coupe ABY - aka Project Lazarus
2001 A6 allroad 2.5TDi - family tank
2003 S4 Avant 4.2 V8 - daily burble
Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)
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So it should be approx 0,85 lambda.. Lets see what I can find outComment
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Software is **** probably. If the RPM's are constant and it's doing this, it means it's overboosting and ECU is cutting all boost.
3B has a 200kpa MAP. Unless that's been changed it can't even see more than 1 bar boost. Not that changing it with random chips is a good idea.Comment
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no no - it started doing this out of the blue. Was okay before. I tried it with other good known ECU from ben swann with 3 bar sensor. It boosts to 1,6bar and then drops in the same manner 0,1bar /secComment
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