[s-cars] S6 starting problem - ECU fuse

[Rich Beebe]

ok, just finished one last test before dinner (also now out of 5 amp
fuses, which isn't good news). i just unplugged both POSs (lower
connection on left and upper connection on right), both white
connectors for the coils and the MAF connector (for good measure).
with everything unplugged - i blew the 5 amp fuse again.

this CAN'T be good... ECU fried?

rich

From: "James Murray (QA/EMC)" <james.murray at ericsson.com>
Date: Thu, 19 May 2005 18:35:09 -0500
To: "'Rich Beebe'" <rich at beebecomm.com>, Bill Mahoney <wmahoney at disk.com>,
"'Krasusky Paul (WQQ2PXK)'" <WQQ2PXK at ups.com>, Mark Strangways
<Strangconst at rogers.com>
Cc: audi s-cars list <s-car-list at audifans.com>
Subject: RE: [s-cars] S6 starting problem - ECU fuse



Rather than think negatively... (as in blown ECU)... let's think positive
that you have a shorted wire in the cabling due to your recent engine work?
disconnecting the POS anyway and start tracing the wires from the ECU fuse
and start testing each point...

-----Original Message-----
From: Rich Beebe [mailto:rich at beebecomm.com]
Sent: Thursday, May 19, 2005 7:30 PM
To: James Murray (QA/EMC); Bill Mahoney; 'Krasusky Paul (WQQ2PXK)'
Cc: audi s-cars list
Subject: Re: [s-cars] S6 starting problem - ECU fuse

i disconnected the battery after the 1st fuse blew when i tried to
put it in. doesn't make a difference - this thing is blowing fuses
no matter what the configuration.

rich 

> From: "James Murray (QA/EMC)" <james.murray at ericsson.com>

> Well you can try (easy to pull the connectors off the POS)... if I remember
> correctly the fuse did not blow until I tried to start the car, meaning I kept
> replacing the fuse (many times) until I pulled the POS connectors, but the
> fuse would only blow when I tried to start the car... now my memory might be
> foggy on this... but I think that's how it went. Then again I never
> disconnected the battery negative either...
> 
> /Jamu. 
> 
> -----Original Message-----
> From: Rich Beebe [mailto:rich at beebecomm.com]
> Sent: Thursday, May 19, 2005 7:18 PM
> To: James Murray (QA/EMC); Bill Mahoney; 'Krasusky Paul (WQQ2PXK)'
> Cc: audi s-cars list
> Subject: Re: [s-cars] S6 starting problem - ECU fuse
> 
> 
> actually, it's blowing the fuses without even starting the car,
> just by connecting the battery.
> 
> i wonder if it would help to disconnect the POSs and attempt the
> fuse again? i've already checked the coil wires for a short and
> the ground - all seem fine. i'm gonna need more 5 amp fuses.
> 
> i thought for sure, when i saw a blown ECU fuse, that it blew
> because of the jump-starting. now, when it blows a fuse every
> time the battery is hooked up, i can't believe it's something
> else - knowing it was running just the other day with nothing
> different. so strange.
> 
> rich 
> 
> From: "James Murray (QA/EMC)" <james.murray at ericsson.com>
> 
>> Rich, this helps...
>> 
>> I'm assuming the fuse to the ECU blows only when you try to start the car and
>> not when the ignition is off and you reconnect the negative to the battery?
>> 
>> This could be a failing POS (Power Output Stage) device... mine failed on me
>> last year out of the blue (but I later found out I had a coil that was also
>> failing, so I'm unsure if the failing coil caused the POS channel to degrade
>> and fail), anyway you could have a channel in your POS that has grounded and
>> failed... or even a coil that has failed.
>> 
>> Try this test: unplug both POS, insert new fuse, try starting the car (of
>> course it won't start but you want to see if the fuse will blow), then plug
>> in 
>> one POS (repeat test), then plug in the other (repeat test). If the fuse
>> blows 
>> with either POS connected the it's likely the POS or a coil that has
>> grounded... 
>> 
>> Here's a good way to test the POS individually:
>> http://forums.audiworld.com/a4/msgs/1594531.phtml
>> 
>> Cheers, /Jamu. 
>> 
>> -----Original Message-----
>> From: s-car-list-bounces at audifans.com
>> [mailto:s-car-list-bounces at audifans.com]
>> Sent: Thursday, May 19, 2005 4:12 PM
>> To: Bill Mahoney; 'Krasusky Paul (WQQ2PXK)'
>> Cc: audi s-cars list
>> Subject: [s-cars] S6 starting problem - ECU fuse
>> 
>> 
>> bill (and s-car list),
>> 
>> i have checked the 5 amp ECU fuse and i finally found a blown fuse,
>> which i was hoping was a good sign. i unhooked the neg. battery
>> cable, inserted a new 5 amp fuse, but once i reconnect the neg.
>> terminal, it blows the fuse immediately. i'm unaware of anything
>> i might have done to cause this situation. most of the work was
>> routine (including CV boot, tie rod end, new stromung exhaust,
>> pads, rotors, hoses...), but i also fabbed up a CAI. the MAF is
>> hooked up fine and nothing else seems problematic. any thoughts
>> on what might be blowing the 5 amp ECU fuse? honestly, i'm at
>> a lose. 
>> 
>> thanks again for any help.
>> 
>> rich 
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>> S-CAR-List at audifans.com
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>> 
> 
>