stubborn rieger / engine problems (update #2)

[sfenton@amazon.com (Fenton, Shannon)]

Sounds like o2 sensor to me as well. Have you tried disconnected the
sensor completely and checking DPR? With the sensor plugged in can you
bump the mix with the fuel plate screw and get a change in DPR current?
Have you done the fuel plate position sensor check? You could have
something wacky with that sensor.

Potter will sell you a mustang bosch O2 sensor. That is, if you can get
ahold of him and feel like waiting for it.

Shannon=20

-----Original Message-----
From: Allyn [mailto:amalventano1@comcast.net]=20
Sent: Sunday, April 28, 2002 3:48 PM
To: scirocco list
Subject: Re: stubborn rieger / engine problems (update #2)


did some more testing:
(following tests done at the cis-e box connector)
- throttle body wot and closed switches: good (~1 ohm closed)
- coolant temp sensor: good (abt 1.4k when cold, was abt 200 ohms when
hot)
- air flow plate potentiometer: found intermittent contact along its
range, particularly in the 2k ohm range (full range is 1k to 5k).
Disassembled and cleaned potentiometer. Reassembled and retested, good
movement through range. Went for drive: problems still exist.
- dpr current: with engine warm and ignition on i get 10 ma (expected).
shorting the o2 sensor 'green wire' (heater) to ground results in a
steady rise to 20 ma over a 20 sec period (expected). start engine,
check meter, steady at 10 ma (expected for post start). Over 1 minute
period dpr current drops stradily to 0.0 ma and stays there (it should
begin fluctuating in closed loop, not go to 0 and stay there, this is a
problem). Rev engine and snap throttle closed: current snaps to -50 ma
and back to 0 when returns to idle (expected, but should be returning to
fluctuating current, not 0).
- check o2 sensor resistance: 6 ohms. o2 sensor voltage: 0 volts with
engine running (what should i see here on a good o2 sensor?).

** what equivalent o2 sensor can i get that will replace a 3 wire on our
cars? i heard something about a mustang one or something a while back...
***

Thanks in advance,
Al

Allyn Malventano, ETC(SS), USN
87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7) 87 Jetta
8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original clutch,
driveshafts, wheels :)


----- Original Message -----
From: "Allyn" <amalventano1@comcast.net>
To: "scirocco list" <scirocco-l@scirocco.org>
Sent: Sunday, April 28, 2002 4:20 PM
Subject: stubborn rieger / engine problems


> My string of good luck has ended.
> Problem: (noticed increased random missing when hot at idle over past=20
> few weeks). Car ran fine,
then
> sputtered under acceleration (as if one cylinder wasnt firing). During

> this minute it only missed under load (revs freely when not loaded, no

> misses). After ~1 minute the sputtering went away but there was a=20
> noticable (not major) loss of power under load. The loss of power
doesnt seem to be
from
> any one cylinder. Car is still drivable. Revs freely as it ever did=20
> with no misses. The next time
i
> drove it, i had the same power loss, but noticed a sputtering that=20
> occurs only when coming off the throttle (under load). No sputtering=20
> occurs under acceleration, only the slight power loss. Engine coasts=20
> down cleanly when off of pedal (no sputtering). The sputter only=20
> occurs under partial throttle and especially when coming off of full=20
> throttle. Still no stuttering while free reving.
>
> What was done so far:
> Change plugs: no effect (old plugs were clean, all 4 looked identical,

> no sign of plugs being cause). Remove/inspect plug wires: (neuspeed=20
> wires), all wires had consistent resistance, even with wires wet.
> Swapped coil with another one: no effect, same exact symptoms.
> Checked ignition timing: Dead on, no adjustment necessary.
> Checked cam timing: dead on.
> *at this point i let the engine idle up to temperature and noted no
missing at all, i can only
> assume the missing problem was corrected and is not related to the
sputtering problem*
>
> Please let me know any opinions/thoughts. My hunch is possibly=20
> something fuel related or perhaps something funky with the coil=20
> driver.
>
> Allyn Malventano, ETC(SS), USN
> 87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
> 86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7) 87=20
> Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original=20
> clutch, driveshafts, wheels :)
>
>
> _______________________________________________
> Scirocco-l mailing list
> Scirocco-l@scirocco.org=20
> http://neubayern.net/mailman/listinfo/scirocco-l


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