It is good to be alive...:0

[MaxRS6]

After a ECU fuse blows just prior mid apex on a 80 mph sweeper and all power is gone...to make it through the turn and onto the infield safely- it is a good day! I decided to take Crazy out on Motorsport Ranch Cresson this weekend. First time at this track and it is a beaut! It does not have the long straight at TWS. However; it has a lot of fun turns and plenty of safe run off areas.

During the 4th and last session of the day- all had been running great. The weather is fantastic in the mid 80 with a nice breeze. I'm in mid stride and "pooooof", all goes dead. Power steering gone and the power I was putting down to hit the apex unexpectedly gone- Let me say- when this happens, it can get fun...;0 Got around the curve taking all the track out area I could find (and a little)...then was able to peeter "off track". When the tow truck shows up- I'm just glad I had remembered to put the tow ring. It made me at least look like I knew something when the the tow driver asked, and I pointed to it and said we are good to go. Hooked up and towed back to paddock. After a few minutes of a few friendly techs helping out (fuel pump possibly, fuse possibly, etc, etc)- the ECU blown fuse was found.

Well- Gotta go get Crazy ready for tomorrow's adventures...

Vids to follow

[4everRS]

Damn Randy. What poor timing for something so random. Can't wait for the vids.

[SteveKen]

What the hell would cause an ECU fuse to blow?

I guess anything shorted on the engine harness could cause it?

Keep us posted and glad you handled it safely.

[MaxRS6]

^Probably poor driving stressing the 'ol thing...;0

I may have added a bit of dramatic flair to the tale...It wasn't really all that bad and it could have happened at a much worse situation. I don't know what caused it and car has run fine this evening under a bit of "testing". Another day of fun approaches- and we are running the opposite direction tomorrow. Hopefully- the car will behave.

[marklar182]

You guys run the 1.7 or 3.1? MSR is a great track! Never had my RS6 out there but did do the 1.7 in my old A4.

[MaxRS6]

^We ran the 1.7. The ECU fuse decided to keep blowing so no track love today. The guys at Texas Track Works took it off with them and I am catching a Southwest Bird home (currently sitting at gate).

The track was a lot of fun and I will certainly be back to tackle it again another day. I am going to keep my eye out for a 3.1 event as that configuration looks like a ton of fun. The turns and elevations are setup great and provide a lot of "opportunities" to see what one is made of (dangling and my English teach would be p&sssed!)...;0

We were also informed at this event that we will have priority dibs on a Track event at Circuit of America. My trigger finger will be twitching and I hope to make it to that event in March/13. Now- That would be toooooo muuuuuuchhhhh fuuuuuunnnnnn..

[lswing]

I had that full engine shutdown going 90 on the freeway, still had power steering though, so not nearly as sketchy! Glad you kept it together...

So chasing some other short that is making the fuse blow now?

[MaxRS6]

The tech started looking at the car today and it started right up without blowing the fuse. Vag com returned the following:

17865 - Exhaust Gas Temp Sensor 2 (G236)
P1457 - 001 - Open or Short to Plus
17861 - Exhaust Gas Temp Sensor 1 (G235)
P1453 - 001 - Open or Short to Plus
17473 - Fuel Pressure Regulation
P1065 - 008 - Regulation Discrepancy - Intermittent
16825 - EVAP Emission Control Sys
P0441 - 002 - Incorrect Flow - Intermittent
17640 - Fuel Injector for Cylinder 8 (N86)
P1232 - 002 - Short to Ground - Intermittent
17633 - Fuel Injector for Cylinder 1 (N30)
P1225 - 002 - Short to Ground - Intermittent
17636 - Fuel Injector for Cylinder 4 (N33)
P1228 - 002 - Short to Ground - Intermittent
17637 - Fuel Injector for Cylinder 5 (N83)
P1229 - 002 - Short to Ground - Intermittent
17635 - Fuel Injector for Cylinder 3 (N32)
P1227 - 002 - Short to Ground - Intermittent
17638 - Fuel Injector for Cylinder 6 (N84)
P1230 - 002 - Short to Ground - Intermittent
18010 - Power Supply Terminal 30
P1602 - 002 - Voltage too Low - Intermittent
17634 - Fuel Injector for Cylinder 2 (N31)
P1226 - 002 - Short to Ground - Intermittent
17639 - Fuel Injector for Cylinder 7 (N85)
P1231 - 002 - Short to Ground - Intermittent

[ttboost]

I would be looking for a loose ground wire or a loose power wire up where the power comes in (passenger side, under the cowl)

[4everRS]

Ditto to Mike. I would put money on ground cable. Also check to wiring harness for the said codes. I think they are bundled together. Something could have gotten pinched with all the engine removal/reinstallations you've had.

[MaxRS6]

^Thanks Mike & Kyle- I'll provide the input to the tech.

[MaxRS6]

The ECU fuse continued to blow at the shop each time they turned the key to on.

The techs pulled wiring diagrams and stated the wiring was fairly straight forward. The wire under the cowl looked good. They pulled engine covers, traced the power lines to all the fuel injectors. He said the wires were loose- However; he did not find any frayed wiring. They said some of the coverings on "ground" wires were somewhat crumbling but not in bad shape. They did some relatively minor cleanup of the wiring, tightened fuel rails, made sure coil packs were tight, replaced a fuel relay- put it back together and it started normally. They have run it around for the past couple of days without issue. Thus; I'm headed to Dallas to pick it up and give it a shot. Not a definitive resolution but at this point- it is "test and see".

The entire wiring harness was replaced a couple of years ago so it is in pretty good shape.

I had already signed up for an upcoming Barber Motorsport weekend (Nov 3 & 4). Sooooooo- we'll soon see if the tow truck has to come get Crazy off the track again.

[ttboost]

Congrats...but I don't like problems that fix themselves....

[MaxRS6]

Congrats...but I don't like problems that fix themselves....

^+2- That is exactly what the tech and I said to each other while blank staring the engine- I suspect this issue isn't yet buried...;0

I flew to Ft. Worth, Tx yesterday- drove the car back to Little Rock (approx 6 hours). It ran without issue. It is Crazy- I think the top speed I hit at Cresson was around 105. Jeez- I do that rather routinely without any issue. Thus; it was certainly surprising as I sat "off-track" with a dead horse.

I plan on doing a little "stress" testing this weekend.

[ttboost]

Good Luck. Glad you made it home. Don't take this the wrong way, but I hope you find something wrong...

[Elevens]

+1 on that ttboost. I am a Troubleshooter myself and there's nothing worse than Intermittent problems or problems that mysteriously vanish. You never know when they might reoccur. You can only hope the few things the Tech did, resolved the situation. Good luck...............

[G2]

Glad it's been okay so far. I always go after power and ground sources, as they are critical. Starting at the battery, might even want to do an oscilloscope test on the alternator to ensure it's not trying to pump AC voltage into the DC system. If a component resistance is too low the current demand rises, even to the point of shorting out (hint: ohm test all injectors, when engine is cold vs hot). Unlikely all the injectors would go bad at once; codes can set as an after effect.

I wonder if the extra current needed by the injectors at WOT for periods of time causes the injector drivers to surpass a conservative fuse rating? Or might be exacerbated by wiring connections/injector terminals that could be slightly deteriorated? Easy enough to plug in a fuse load tester for that circuit to "dyno" the current draw.

I've seen injector drivers go bad, but usually causes other drivability issues. Using cheap import fuses is something I avoid. Dielectric grease never hurts (both for the fuses and harness connectors). I've installed slightly higher amperage fuses for headlights or rad. fans, w/o issues, but on sensitive electronics would not.

This is kind of all encompassing, but maybe something here might help.

[MaxRS6]

^Thanks for the input Gary. I will discuss your comments with my local indy tech as he is taking a look at it Monday.

[kevin]

With all the injector dtc's and fuel press. reg. dtc, I'd try a 4D0-951-253 fuel pump relay. For $50 it's cheap enough.

[MaxRS6]

^Thanks Kevin and that is a good thought- TTW did install a new fuel pump relay during the process. As you say- they thought this might be the culprit and was cheap enough. This is one of the very few last remaining parts that I have not replaced life to date. Well- that and the Emergency kit....;0

As a side note: The shop did replace my OEM battery with an Interstate battery a few weeks ago. A wire by the alternator was causing the red battery light to blink. Thus; the wiring was repaired and the new battery installed. I will request they double check this wiring while they inspect.

I don't want to be tow truck bait again....LOL

[kevin]

Copied from IATN.

Very long and not an RS6 but may offer some new ideas.



2001 Audi A6 Quattro 2.7L No Start, Cuts out


By: Bernard
Milano (http://members.iatn.net/profile/34618POF.aspx)Jan 3, 2012 3:21:05 PM14 Replies (http://www.rs6.com/#reply_anchor)

This problem just started to appear one day, now it
seems to be getting worse, bottom line is fuse #32 continues to blow. It happens
frequently, especially when you go up a hill or under a load, it will not happen
unless the car is moving. When the fuse blows, the car cuts off, it will not
restart unless a new fuse is installed, then it starts right up. The car runs
fine otherwise. This will also not happen on the highway with a steady speed, or
when the gas pedal is not pushed far, as soon as you push down on the pedal like
to go up a hill, fuse blows. The fuse is labeled ECU in the car, and engine
timing in Alldata, 20amp. I would appreciate any guidance of where to begin
finding out why this fuse continues to blow, (possible short?). Thanks for all
help. Bernie.

<!-- S -->Bernard Milano
Owner/Technician
Ardsley
Motors (http://www.iatn.net/dir/page/i/m/34618/t/b/index.aspx)
Ardsley, New York, USA






Summary posted on Jan 31, 2012 4:43:41 PM


The problem started to appear less and less, the customer decided not to
pursue a fix at this time. I feel we would have found the problem, but we need
more time. Thanks for all the help. Bernie.









Checked for codes and none were
found.











http://www.rs6.com/images/techmail_viewer/minus-grey.gif 14 Replies
Received (Hide Replies)





Reply 1 of 14



Paul from West Virginia

Jan 3, 2012 4:16:24 PM


You've either got a shorted sensor or the wiring to one of them..could be any
of the 5volt sensors. Can you get it to pop the fuse. It probably isn't storing
a code because the ECM fuse is popping, which makes it a PITA to chase the
problem down. I'd recommend hooking up your scan tool and taking it for a
spin...have the live data open and recording. As soon as the fuse pops, look at
which sensor had a dramatic change...voltage spike or drop.




Reply 2 of 14



Alex from South Dakota

Jan 3, 2012 4:46:29 PM


The fuse #32 is for Cruise Control Switch & Fuel Injectors according to
Ondemand. Have you checked if cruise control working or have you scanned for DTC
in Engine & Instrument Cluster modules? Also check injectors & wiring
harness to them making sure its not shorted out anywhere. The fuse #32 get power
from ignition switch and provides power to injectors via black blue wire from
fuse. The other black wire from #32 goes to fuse #7 and Ignition switch and
Vacuum Pump relay (on automatic).

BTW what kind scanner you are using to
diagnose VW/Audi?




Reply 3 of 14



Koorosh from Maryland

Jan 3, 2012 8:00:06 PM


try to use vw tool see if you get any U code, it may be a shorted ecm or
shorted sensor or wiring.




Reply 4 of 14



Justin from California

Jan 3, 2012 9:31:46 PM


one of the things that I have done to brake problems like this down is to get
the wiring diagram out and install inline fuses where the circuit branches. This
can narrow down the components that are causing the fuse to blow. Good
luck.




Reply 5 of 14



Gordon from Ontario

Jan 4, 2012 3:36:41 AM


First thing you know its blowing the fuse whats on the circuit and how much
might just be bad grd and its spiking on and off,you know one thing you can
create it under a load check all your grds.first look for bad motor mounts or
just the harness being pulled or rubbed on.




Reply 6 of 14



Greg from New York

Jan 4, 2012 4:54:32 AM


Is the motor allowed to move around on its mounts chaffing the harness
somewhere?




Reply 7 of 14



Kim from Illinois

Jan 4, 2012 5:05:38 AM


I would ckeck the gas pedal wiring to the ecu and throttle body there has to
be a short in the throttle body, gas pedal, or wiring. My bet would be on the
throttle body since the car is drive by wire.




Reply 8 of 14



Greg from Washington

Jan 4, 2012 5:36:45 AM


Bernard we have seen several Audis with engine harness issues- try moving the
harness around while the engine is running to see if you can duplicate the
issue. Greg and crew




Reply 9 of 14



Mark (Jake) from California

Jan 4, 2012 5:45:01 AM


Everybody is overlooking the most likely cause, the wires going to the O2
Heaters. I suggest you inspect the O2 Sensor harnesses where they are anywhere
near the exhaust. If one has been replaced, look there first. Also where the
harnesses clip to the top of the transmission could be an issue. On that same
branch the Exhaust Temperature Sensors are also powered by that fuse. They are
the little boxsbolted to the back of the intake manifold on the
right.

The next most likely area for a short would be on the firewall.
There are posts that special securing straps should be attached to. If someone
didn't get everything back together after working on it, they can chafe the
harness. Look at the O2 harnesses in perticular.

The LDP pump in the
left, rear fender is also on the same fuse If it's been in any kind of a
collision, I suppose it could be there or in the wiring.

Also the relay
for the secondary air injection pump and the injectors are on the fuse, but they
are not as likely.

If you don't "get lucky" and find it you may have to
get creative and trace the wire (green/yellow) starting at the fuse and work
your way "downstream" eliminating or substituting branch sections till you find
it.




Reply 10 of 14



Dan from Ontario

Jan 4, 2012 5:55:14 AM


Bernard..a short in the ECU should be consistent all the time, not just when
u press harder on the accelerator pedal..Since this is drive by wire system, Id
take a very close look at the accelerator position sensors and ohms check/scope
them as well as the throttle body's tps and driver motor..it sounds like 1 of
them is shorting out when pressed past a certain point




Reply 11 of 14



Jeff from Florida

Jan 4, 2012 10:10:46 AM


Hi Bernard, I'm inclined to go with Jake from CA's theory of something in an
engine harness chafing. With 101k miles, I'd also check the condition of all of
the motor and trans mounts, especially the front mount below the radiator. Just
a theory but under load, going up a hill, etc. there's enough movement on the
engine and trans assembly to contact the harness on a part of the body and cause
that problem. I know we're all curious as to what you find. Good
luck!




Reply 12 of 14



Seth from New York

Jan 4, 2012 5:14:42 PM


After reading the replies I agree with Jake and Jeff, the o2s especially
would be where I would look, the harnesses are really long and they are clipped
everywhere up around the exhaust and the coolant pipe in the rear of engine
where they go up to the holders so check all the way down the line in those
areas.




Reply 13 of 14



Thomas from Virginia

Jan 5, 2012 10:21:53 PM


i don't know if u have access to a wiring diagram but the circuit on fuse #32
supplies power to the injectors a black with blue wire. i didn't see any thing
else on that circuit so it may possibly be shorting to ground or u have faulty
injectors.




Reply 14 of 14



Esteban from Dominican Republic

Jan 10, 2012 3:13:02 AM


I use to have a similar problen one day, it was the battery was loose, and
the terminal POSITIVE it was touching the hood. tell me if this was helpfull to
you. CHARLIE ESTEBAN HERRERA from D.R.

[kevin]

After reading a little more on IATN, I'm trending towards the o2 heater(s) and or wiring to said. Good luck!

[MaxRS6]

^Thanks again for all the info

[MaxRS6]

Well- The speed limiter still works (running the car in stock mode)...;0 Ran the car for about 25 minutes relatively agressively. Multiple runs from around 30 up to 160 (the limiter kicked in), hard braking, some shoving the car around side to side and- nada- nothing- blank- zero issues. I tested for around 20 - 25 minutes. I had "Snowman" in front scouting for bears to avoid bars...;0

It is headed to the indy shop tomorrow for some mo inspection and preparation for next weekend's Barber adventure. I'll give a heads up to the track steward to make sure the tow vehicle is available when they see the silver Audi with Ark tags pull out of the paddock..;0