[s-cars] Drastic Power Loss-So far No Joy

[Manuel Sanchez]

Chris, didn't see any obstruction in that WGFV to Wastegate line. We  
pulled it and swapped components from another UrS and had the same  
cut-off result.

We also tested the wastegate diaphragm with a vacuum pump, and it  
held the pressure.

We are also planning on seeing what the fuel pump is doing at the  
time of cut-off as Stott and DJ have suggested.

Taka, after further investigation I've discovered that only the  
resistance/continuity was checked on my WGFV. I have a new stock WGFV  
on special order. Haven't tried just disconnecting the WGFV and  
plugging the line on a test drive yet either.

Thanks again to all of you for the suggestions and experiences. If  
you have anymore, please send them my way.

Regards,

-Manny




On Sep 21, 2007, at 9:24 PM, chris chambers wrote:

> This may be out in left field BUT...
>
> I have heard of some "tuners" putting a ball bearing in the line
> from the WGFV to the Waste gate. IF this is the case OR there is some
> other obstruction in the line it can lead to overboost.
>
>
> right?
>
> HTH
> Chris
>
>
> --- Manuel Sanchez <manuelsanchez at starpower.net> wrote:
>
>> S-heads,
>>
>> Still hunting for whatever is causing my drastic cut off of power
>> near peak boost. This happens with my MRC RS2 software in my ECU as
>> well as with a bone stock ECU. So with my RS2 ECU I hit the wall at
>> about 26-27 psi, when the Stock ECU is installed (with the stock
>> injectors) I hit the wall at about 13-14 psi.
>>
>> Many of you have suggested I'm experiencing an Over Boost situation
>> and have given me some avenues to pursue, here's what's been done
>> today:
>>
>> 1. My RS2 WGFV
>> Checked with a multimeter, and it's within spec
>>
>> 2. Other used, Stock OEM N75 WGFV
>> Checked with multi-meter, within spec
>> Installed in my car, test drive results in the drastic cut off in
>> power (nuts)
>>
>> 3. Inspect Wastegate Diaphram
>> No tears are apparent. Will test vacuum on this tomorrow hopefully.
>>
>> 4. Turbo Outlet hose and Wastegate hose (that small diameter crinkled
>>
>> and ultra expensive bugger).
>> Swapped these hoses, as well as this other stock N75 WGFV into my
>> car, same boat anchor results
>>
>>
>> Some people have suggested the altitude sensor, hopefully I can check
>>
>> that soon.
>>
>> What's puzzling, is that I think many of these electronic items would
>>
>> throw a code if they were malfunctioning, no? Previously the only
>> codes I had been receiving were :
>>
>> 00537 – Oxygen Sensor Control
>> Maximum Control Level Exceeded
>>
>> Condition:
>> Fuel Tank Low resulting in fuel system pressure less than 3.3 bar (48
>>
>> psi) [Note tank was ¾ full as indicated on fuel gauge]
>> Ignition System Failure
>>
>> Symptom:
>> CO before 3 way catalytic converter less than 0.5% (Hmmm, what could
>>
>> this mean???)
>> Fuel Consumption high
>>
>> Repair:
>> Fill Fuel Tank (tank had plenty of gas, and fuel gauge reads
>> accurately)
>>
>> 00537 – Oxygen Sensor Control
>> Minimum Control Limit Exceeded
>>
>> Condition:
>> Engine Intake Air Leak after Mass Air Flow Sensor-G-70
>> Leak in Exhaust System in front of 3 way catalytic converter
>> Heated Oxygen Sensor (HO2S)-G39-malfunctioning
>> Fuel System Pressure greater than 4 bar (58 psi) [This is
>> interesting, seems like I will throw this code all the time if I set
>>
>> the Fuel Pressure to 4 Bar/58 psi, which is what I believe I’ve been
>>
>> told is the Fuel Pressure for RS2’d cars. True?]
>>
>> Symptom:
>> Rich Exhaust
>> Spark Plug Fouling
>> CO before 3 way catalytic converter greater than 3%
>>
>> Repair:
>> Repair Leak
>> Check HO2S-G39
>> Check Fuel System Pressure
>> 00561-Mixture Adjustment
>> Adaptation Limit (mul) exceeded
>> Condition:
>> Fuel System Pressure too low
>> Spark Plugs, ignition coil, ignition coil power output stage
>> malfunctioning
>> Symptom:
>> Reduced Fuel Economy (no kidding)
>> Sooty Exhaust (yeah, in spades)
>> Repair:
>> Fill Fuel Tank
>> Repair Leakage
>> Check Fuel System
>> Check Fuel System Pressure
>> Check G70 (Mass Air Flow Sensor) [We cleaned the OEM MAF with MAF
>> Cleaner, and we also installed a brand new RS2 MAF-we still had the
>> drastic engine cut-off]
>>
>>
>> Lately  we've been thinking that whatever the fault is, it's
>> something mechanical as opposed to electrical (that would throw a
>> code).
>>
>>
>> Some people have suggested  a few things that we haven't had time to
>>
>> try yet:
>>
>> Altitude sensor
>>
>> Check the wiring between the MAF and ECU with an ohmmeter
>>
>> Throttle Position Sensor - the ECU allows boost only when the
>> throttle position sensor is above a certain value. So you could check
>>
>> the sensor
>>
>> Light on the fuel pump to see if it's getting cut off when the Cut in
>>
>> Power occurs (I'm not exactly sure how to rig this up actually),
>>
>> Hopefully I can check these soon.
>>
>>
>> Any other ideas are greatly appreciated.
>>
>>
>> Thanks.
>>
>> -Manny
>> 95 UrS6 (still kickin my arse)
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>>
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