The Project Pad

One of the remaining items keeping me from a test drive is the brake master cylinder. It’s been on the car with the lines bled for a while, but it had a slow leak. I feared it was on the piston on this brand new MC, because I paid about $90 for it a couple years ago, but the only one’s available now are over $300 now. After bench bleeding it and letting it sit in my vice for a few days, I was able to confirm the source of a leak was at the rubber seals for the reservoir. So, I swapped the old ones on and it's been dry ever since. Let's hope it stays that way.





Was able to get some of the dash back together last weekend too.




And received this in the mail from Issam. I’m fearful my DIY drill/tap job on the stock extension is going to leak since there is very little sealing area on one side of the gasket.




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Happy to report the coupe appears to have working brakes and clutch. Got the master cylinder back on and it appears to be leak free. Also bled the system and was able to move the car at least a couple inches in the lift, to check for clutch engagement.

Put some Audi content on the shop wall too.





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Weekend recap…

Saturday was a big upgrade day for the coupe…installed a keyless entry with a switchblade key. lol

https://youtube.com/shorts/NGOkOJdJzYE

Also pulled it out of the shop for a little vitamin D and quickly realized the alignment was really bad. It looks like I turned the wheel to pose for a picture, but the driver’s side wheel was perfectly straight.






Using crude front and rear measurements on the front tires told me there was a 3-3/16” difference. Adjusted the the tie rods and ended up within 1/16”. Should be good enough until I can get it to an alignment shop.

Since getting it back in the shop, it’s struggling to stay running. Pulled these with my VCDS.

00523 - Intake Air Sensor G42 - Open or Short to Positive
00513 - Engine Speed Sensor G28 - No Signal

I thought I recall that the 00513 code is one of that will pop up when the engine dies, but could be wrong. Any ideas on the 00523? Are there tests for the G42?


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jbrentd wrote:
I thought I recall that the 00513 code is one of that will pop up when the engine dies, but could be wrong. Any ideas on the 00523? Are there tests for the G42?

From searching "G42" in the quattroworld UrS FAQ, located here:

https://forums.quattroworld.com/s4s6/msgs/15184.phtml

I found:

https://forums.quattroworld.com/s4s6/msgs/20996.phtml

Hope this helps. Lots of info there.

Berserker wrote:

jbrentd wrote:
I thought I recall that the 00513 code is one of that will pop up when the engine dies, but could be wrong. Any ideas on the 00523? Are there tests for the G42?

From searching "G42" in the quattroworld UrS FAQ, located here:

https://forums.quattroworld.com/s4s6/msgs/15184.phtml

I found:

https://forums.quattroworld.com/s4s6/msgs/20996.phtml

Hope this helps. Lots of info there.

Thanks for the reply! I was able to find the PIN numbers for the IAT sensor on the ECU plug. Didn’t see any continuity. So, inspected the connection and found this. I think I have it soldered back. The code went away, but car is still struggling to run/idle.




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Sounds like you fixed the idle sensor issue

I had a similar issue with the g28 that cause a horrible idle and affect on driving - a few things

1. If you’re careful you can remove it off the flywheel housing - it may just have metal attached to the magnetic end - clean it and check it out. You know this but remember It’s really easy to strip those Allen bolts or break that bracket.
2. You can test it without removing - check continuity of pin 1+2 to ~1000 ohm and 1+3 Infinite (open)
https://www.audiworld.com/forums/audi-o ... o-2802889/
3. In my case it wasn’t any of those but rather the g28 sensor resting directly on ignition wires and worn out insulation on the wire - definitely worth checking IMO

It is tough to find an OEM replacement and when you do it is either in the same condition or worse in my experience - I ended up finding an aftermarket replacement with a ‘g4’ part number as they are interchangeable. I ended up buying something just like this to troubleshoot which is how I found the issue - heck for 16$ it is good to have a spare especially if it is the G4 in the future. (Tip) if the car ever doesn’t start from a g4 no crank you could technically swap the g28 and drive the car home (albeit poorly)

https://www.ebay.com/itm/254483604240

Congrats on the moving and driving way to go car looks awesome

themagellan wrote:Sounds like you fixed the idle sensor issue

I had a similar issue with the g28 that cause a horrible idle and affect on driving - a few things

1. If you’re careful you can remove it off the flywheel housing - it may just have metal attached to the magnetic end - clean it and check it out. You know this but remember It’s really easy to strip those Allen bolts or break that bracket.
2. You can test it without removing - check continuity of pin 1+2 to ~1000 ohm and 1+3 Infinite (open)
https://www.audiworld.com/forums/audi-o ... o-2802889/
3. In my case it wasn’t any of those but rather the g28 sensor resting directly on ignition wires and worn out insulation on the wire - definitely worth checking IMO

It is tough to find an OEM replacement and when you do it is either in the same condition or worse in my experience - I ended up finding an aftermarket replacement with a ‘g4’ part number as they are interchangeable. I ended up buying something just like this to troubleshoot which is how I found the issue - heck for 16$ it is good to have a spare especially if it is the G4 in the future. (Tip) if the car ever doesn’t start from a g4 no crank you could technically swap the g28 and drive the car home (albeit poorly)

https://www.ebay.com/itm/254483604240

Congrats on the moving and driving way to go car looks awesome

Thank you! It feels good to have it running, albeit badly at the moment. And thanks for the info! I'll check to see if I have any issues like that with my G28. And a few other things to check, like the ISV, fuel filter, and fuel pump.

Cool, that G28 code should go away if the engine is running. For what it’s worth only once I replaced my actual ISV did the car ever idle correctly never threw a code would just chug around 800 rpm - well worth a new Bosch unit