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Surge issue under WOT fixed.

1067 Views 1 Reply 2 Participants Last post by  billymade
One thing that was driving me nuts about my Turbo S was a "surge" or pulse when accelerating, usually after driving the car for a while and it was warm. No check engine light and no stored codes, just an annoying surge around 3,000+ RPMS.

After reading some other's experience with this type of issue I started with the easy stuff, fuel filter, MAF cleaning.. no luck, still surged. I tested the diverter valve with a vac gauge and it was working properly.

So I gambled and bought a new N249 valve from ECS hoping that would be the issue. Nope still had the surge.

At this point I figured it was either the boost sensor (which is a pain to get to on a turbo s- pretty much remove the bumper to get to it.) or the n75 valve, which is a 5 minute job since it's on top.

Bought a new n75 from amazon (Fowler VW) for about half the price of the local dealership. Put it in and problem solved!! Soooo much smoother and the car accelerates perfectly now.

So I have a spare N249 valve now, but happy I did not have to remove the front of my car to get to that boost sensor!
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Same, here... was driving around with a worn out DV and N75: car is totally different, with the boost levels and system working correctly! :) Also, check all the "check valves"; some of mine, were corroded and falling apart.


Another thing I did; which I recommend you do, check all the hoses on top of the valve cover that connect to all these boost related components. I went ahead and bought a bunch of small "pex" clamps/fittings; which are similar, if not the same as oetiker automotive crimp style clamps and clamped ALL of the connections to everything. Some of the connections were loose and I replaced allot of the plastic "t's" with brass fittings, that are part of the same pex system, at your typical hardware store or home improvement center (you can also, use these to replace coolant hose "t's" that break so easily). The mess of hoses on top of the valve cover; is all one assembly, which was over $100, so as a interim solution (all silicone hoses would be nice).... I just sealed all the possible leaks. All new valves; sealing all the hoses and checking everything, really made the boost system come to life! :D

Get some PEX clamps, fittings and fix all those possible leaks!
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