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Guys quick question. I have a half tank of older fuel left in the car. As per previous post i have cooling fans coming on when ignition at position 1. Coolant sensor at bulkhead replaced but issues remain with the fans running to full speed. On last start the car ran very rough.

Before trying to turn the car over for a restart i would like to freshen up the fuel to rule that issue out. Plugs replaced in advance. What is the best approach.

1. Top up with 99 Ron petrol.

or

2. Syphon the petrol from the tank?

If option 2 is the best are there any pitfalls other than a mouth full of petrol?.

Appreciate your input.

Steve

I wouldn’t siphon it. Not even sure it’s possible with modern(ish) cars and anti-siphon mechanisms.

I personally would just drive it normally unless there’s a chance the fuel is contaminated. Sometimes the fuel
In mine is months old if it’s been hibernating.

Ben would you fill the car with fresh. The car was idling so rough i would not want to drive it as it was. I initially presumed it was related to the fans as had no issues prior to this but now wonder if totally unrelated. She has been hibernating for over a year but always started fine every fortnight until recently so i wondered if it could have degraded. Thanks Steve

Oh I see. You sure the rough running isn’t due to something else? I wouldn’t want to run the engine if it wasn’t running sweet.

I cannot be confident to be honest. I have never had any issues with the car but she does not cover many miles. Over the last year I started to notice the cooling fans coming on early and hunting up and down. Then recently noted coming on at full when ignition at pos 1. When I then started the car it ran rough like not on all 8. I suspected the fans could be the source of the issue possibly draining the battery. Replaced the battery, fans came on but initially car ticked over fine before then running rough. I have done the coolant sensor and plugs.... But as yet only had the balls to put the key beyond position 1 as fans came on. I was thinking freshening the fuel could be a good idea before any attempt at starting.

I think the fuel is the least of your worries.
Probably adding confusion to the situation and distracting you from the real issues.
Do you have any form of diagnostics for your car, Vag Com or other. If not your going to be changing sensors that might not be the issue.

Regarding the rough idle I would check that your inlet plenum/mafs is seated properly in the 2 seals at the back. You've just had it all apart, I'd look there first.

I cant remember if you have changed the seals or not? Some one on here found a great aftermarket source for replacement seals

Putting fresh fuel in won't do any harm and Shell VPower does last pretty well. Mine wasn't used much at all either. They tolerate it for a bit then get the arse after a few years of it I think.

There's so many reasons it might not be running right. I think you'd have to go through everything from the basics. Could be something daft like the airbox has been knocked and isn't on or any other connector has got knocked.

Is the emissions warning light coming on when it's rough? Is the SAI still connected for example? Could be one of so many things or several things being slightly off and it's just generally sulking.

Felix2566 wrote: ↑

Wed Jan 29, 2025 9:04 am

I think the fuel is the least of your worries.
Probably adding confusion to the situation and distracting you from the real issues.
Do you have any form of diagnostics for your car, Vag Com or other. If not your going to be changing sensors that might not be the issue.

Regarding the rough idle I would check that your inlet plenum/mafs is seated properly in the 2 seals at the back. You've just had it all apart, I'd look there first.

I cant remember if you have changed the seals or not? Some one on here found a great aftermarket source for replacement seals

This. You'll need a Vagcom to resolve this properly.

I'm with Ben and the others on this, don't confuse the issue, they are separate issues.
Mine was the same when it had been sat for about a year. Like SRichards mentions, they do seem to sulk if not driven regularly and the gremlins creep in.
I'd put Vagcom on it to establish why it runs poor. It's the best option really.

Hi All to confirm the rough idle was before I had the Airbox off. I decided to change the coolant sensor as part of my fan issue and thought the fans could be pulling the battery voltage low giving some gremlins with tick over. I did the plugs as i was in there anyway.

In some ways that was quite enjoyable doing the plugs and sensor as I have had a lot of cars that i have worked on quite happily but have been pretty scared of doing anything on the RS myself.

I will get some Super unleaded and fill the tank from half to full and see if any change on the tick over.

Heading down purchase of Vagcom. I have been avoiding this as shitting it at the thought of getting the software and then understanding what the Feck i am doing with it.

Are there any issues with the latest software and connection to the C5?

Really appreciate the advice and support as frustration levels are ramping up.

Steve

It’s pretty straightforward. We’ll help you use it.

Thanks Ben will get it ordered.

Hi all update. Let the forum support begin.

I have ordered the following
Ross-Tech VCDS HEX-V2 USB Package (3 VIN) it cost £233 including DPD delivery. No idea if this is good or not!!

I did this through Gendan website as was not sure I could trust anything on EBay.

Hopefully will receive over the weekend.

Nice. Gendan are legit.

Hi all, Back again. VCDS arrived from Gendan. Seem a really professional company as dispatched really quickly.

I have down loaded the software and have connected it to the car. First Question, I could not connect with CAN-BUS, I had to Input 4B from the chassis number and then it appeared to connect is this right?

I have run an auto scan and attach it below.

Please guys can you help me out with advice based on this info. I thank you all very much in advance.

Saturday,01,February,2025,14:51:49:20920
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 24.7.1.0 (x64) HEX-V2 CB: 0.4643.5
Data version: 20240919 DS356.3
www.Ross-Tech.com


VIN: WUAZZZ4B54N901020 License Plate: E13SMD
Mileage: 42086 Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 4B (4B - Audi A6/S6/RS6/allroad C5 (1998 > 2005))
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
75 76 77

VIN: WUAZZZ4B54N901020
-------------------------------------------------------------------------------
Address 01: Engine Labels: 077-907-558-BCY.lbl
Part No: 4D1 907 558
Component: 4.2l V8/5VT G 0002
Coding: 0010752
Shop #: WSC 66565 257 00032
VCID: 6B8418848F90EBD29A9-5160
VINID: 9E546AAAA11214478900100200826CDC3A

1 Fault Found:
16501 - Engine Coolant Temp. Sensor (G62)
P0117 - 001 - Signal too Low
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01L-927-156.lbl
Part No: 4B0 927 156 FB
Component: AG5 01L 4.2l5VT RdW 1315
Coding: 00001
Shop #: WSC 02195
VCID: 6C861B988F9EECEA933-516C

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 4B0-614-517.lbl
Part No: 4B0 614 517 AD
Component: ESP 5.7 RS 6 2310
Coding: 06697
Shop #: WSC 02195
VCID: 639470A46240A392229-516C

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 4B0-820-043-MY2.lbl
Part No: 4B0 820 043 AR
Component: A6-Klimavollautomat 0208
Coding: 00001
Shop #: WSC 00189
VCID: 6A8A1D80855AF2DAE1F-258E

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 4B0-959-655-AI84.lbl
Part No: 4B0 959 655 AA
Component: Airbag 8.4EP 1002
Coding: 0000606
Shop #: WSC 02195 785 00200
VCID: 6FBC0C94BB8817F2B61-5160

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 4B0-920-xxx-17.lbl
Part No: 4B0 920 983 B
Component: KOMBI+WEGFAHRS. VDO D14
Coding: 01484
Shop #: WSC 37301
VCID: 270C24B456F80FB23E1-5160
WUAZZZ4B54N901020 AUZ7Z0C2485385

1 Fault Found:
01304 - Radio
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels:. 4B0-962-258.clb
Part No: 4B0 962 258 N
Component: Zentralverrieg.,DWA D38
Coding: 06859
Shop #: WSC 02195
VCID: 3436C3F8971E742A8B3-4F12

3 Faults Found:
01368 - Alarm triggered by Luggage Compartment Switch
35-00 - -
01561 - Rear left door
61-10 - Won't De-Safe - Intermittent
01134 - Alarm Horn (H12)
77-00 - Internal Supply Voltage

-------------------------------------------------------------------------------
Address 37: Navigation Labels: 4B0-035-192-RNSD-37.lbl
Part No: 4B0 035 192 K
Component: RNS 4.2 H06 BNO 0140
VCID: 25102EBC2CC41DA20CD-4B02

No fault code found.

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 4B0-951-178.lbl
Part No: 4B0 951 178 A
Component: Innenraumueberw. D04
Coding: 00102
Shop #: WSC 02195
VCID: 261229B051C216BA057-514A

No fault code found.

-------------------------------------------------------------------------------
Address 55: Headlight Range Labels: 4Z7-907-357.lbl
Part No: 4Z7 907 357
Component: dynamische LWR D09
Coding: 00050
Shop #: WSC 00182
VCID: 04565338873E04AA7B3-4B3A

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 4B0-035-192-RNSD-56.lbl
Part No: 4B0 035 192 K
Component: Radio BNO 0001
Coding: 00017
Shop #: WSC 00189
VCID: 25102EBC2CC41DA20CD-4B02

No fault code found.

-------------------------------------------------------------------------------
Address 57: TV Tuner Labels: 4D0-919-146.clb
Part No: 4D0 919 146 B
Component: TV Tuner H10~1206
Coding: 0000010
Shop #: WSC 00182 210 83141
VCID: 280E27885ED600CA37B-5160

No fault code found.

-------------------------------------------------------------------------------
Address 65: Tire Pressure Labels: 4D0-907-273.lbl
Part No: 4D0 907 273 C
Component: Reifendruckueberw. D310
Coding: 22350
Shop #: WSC 02195
VCID: 270C24B456C80FB23E1-5160

No fault code found.

-------------------------------------------------------------------------------
Address 76: Park Assist Labels: 8E0-919-283-8E2.lbl
Part No: 8E0 919 283
Component: Parkingsyst. A6 RDW D09
Coding: 01156
Shop #: WSC 02195
VCID: 6D80169CB4B4E5E284D-5160

No fault code found.

End----(Elapsed Time: 04:52, VBatt start/end: 12.6V/11.3V. VIgn 11.1V)-----