[s-cars] Hesitation at 3,500 rpm WOT - bad BPV?

[Nicholas]

i can't say i know much about these engines thus far as i have minimal
experience, but i just went through diagnosing a failing ignition coil
which turned out to be plural (coils). and if your spark plug failed
it might be good to step slowly up the chain and rule out your
ignition system, here's why:

i had one coil fail that was easy to detect and diagnose. after i
replaced it i was fine at lower rpms but was still having trouble
getting full power as boost was building just over 3k: where it felt
like more than one cylinder was giving up (i did not test/rev beyond
4k so i can't speak to boost/ignition coming back at higher rpms). i
got 2 coils, 1 as a backup (or so i assumed) and moved it around to
the other cylinders but it seemed almost the same no matter where i
dropped it in. not impressed with the necessary cutting of 1.8t coil
and all i've read about them failing, i decided not to get 3 more and
i replaced all five with (cheaper) 2.0t coils and now it pulls hard
and smooth to redline like it used to.

my two cents,
-nick


On Fri, May 20, 2011 at 9:53 PM, JC <jc at j2c3.com> wrote:
> Funny you mention it... I'm chasing an exactly same symptoms.  Car pulls
> like a damn train at partial throttle, main stumble is right in that 3-4k
> area under WOT.  might get a little stumble again at full WOT and high RPM
> but not as bad. Car is making a solid 1.7bar at full bore on the aftermarket
> boost gauge and for a while it was quite happy about that, no other major
> changes in the time it started acting up.
>
> MAF connection and MAF cleaned to no avail, but I just borrowed a known good
> MAF that I'll be tossing in quickly next weekend to see if that helps.  I
> started to make a deluxe boost leak tool at one point with a schrader valve
> and a pressure gauge on it but never got it completed, this might be the
> impetus...
>
>> Nathan,
>>
>> It sounds like the exact same issue I had for about a year
>> until it finally popped code 2224 and I found my answer.
>> Essentially your ECU is being tricked believing you are
>> overboosting, and wen that happens it momentarialy shuts off
>> the fuel pump.
>> I bet you either have a boost leak, defective MAF or dirty
>> MAF connections at the cable
>>
>> Read here:
>> http://www.sjmautotechnik.com/trouble_shooting/20vboost.html#oboost
>>
>> HTH
>> Chris
>>
>
>
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