WOT Issue & Fault Codes

Steve · 03-08-21, 06:46 PM

I currently have an issue where the car is loosing power under hard acceleration or wide open throttle. It tends to be in the early gears i.e. 1st and 2nd when trying to launch the car.

If the progression of the throttle is fairly steady then boost and reasonable acceleration will be achieved. Last week I changed the coil packs to see if this would remedy the issue as they have been on the car for a few years but this has made no difference. All boost pipes seem tight and there don't appear to be any air leaks.

This evening I pulled the codes and got the following which I can't find the answers to all of them.

65535 The ECU is modified with TSW Tuning Chips so I have discounted this one.
65282 ?
00002 ?
00255 ?

The engine is RS2 code ADU.

Suggestions welcome.

tractor Dave · 03-08-21, 07:57 PM

Have you done a proper boost leak test?
Other causes could be
Maf
Maf pins
Fuel pump unable to meet demand
Knock sensors
N75
Check all the little vac pipes if they haven't been changed, especially the one to the ecu and N75.

Isimmo · 03-08-21, 09:05 PM

I know this is semantics, but is it ‘losing power’ or not gaining as much power as expected? E.g. lethargic? If it’s the latter check (and I mean properly check) the small vacuum hoses from the head to the dump valve and around N75. Also check N75 is working. Our S2 was down on power for literally years and I was convinced it couldn’t be the hoses because they looked fine. After a rebuilt turbo, various ECU, complete new Roose boost pipe setup, new plugs, coil packs and gawd knows what else it still was shite. Tried an 034 1.9 bar spring and turbosmart controller…. Slightly better, but no cigar. Finally, I just went mad one weekend and stripped out all the tiny vacuum lines out the back of the head and replaced with new. Most were like something out of an Indiana Jones movie and turned to dust. The smoking gun was the dump valve pipe had split under the tiny wire clamp right next to the valve.

Once replaced, I then had proper boost again and had to reverse engineer all the ‘hopeful’ engineering of uprated wastegate spring, wound down screw, turbosmart valve etc. Predictably, detuned it too far and have slowly worked back up to full boost.

Worth plumbing in a boost gauge if only temporary, it’s invaluable to tell what is going on.
Oh, and not blowing the thing up….

mikes2 · 03-08-21, 09:08 PM

None of those are valid codes on a standard RS2 ecu.

It may well be the chips are the problem.

Is it just a chip or has anything else been changed ? I'd be looking to get a standard ecu in there and go from there.

Isimmo · 03-08-21, 09:11 PM

Quote:

Originally Posted by mikes2

None of those are valid codes on a standard RS2 ecu

Interesting. Because I have an MTM ECU (All ABY/AAN) here that can’t be interrogated. The Nothelle one can and I think the Homefry in the Rally car can too.

I wonder if the spurious codes are similar to MTM’s attempt to prevent chipset copying.

mikes2 · 03-08-21, 09:16 PM

A decent chip retains all factory diags and codes.

Anything that's throwing a checksum error, should set alarm bells.

Steve · 04-08-21, 04:51 PM

Interesting points and none that I deep down hadn't thought of, but was looking for some reassurance/inspiration. Here's where I am with this:

1. The vacuum lines have been on there forever. I have around 5 meters of new pipe so let's just call it over due maintenance and change the lot.
2. Occasionally I get rust in the pre pump fuel filter, so I have to take it off and clean it out. The pump which is a BOSCH 044 doesn't make a constant buzzing noise, but it's up and down all the time like it is working too hard. Perhaps this is because it is a 39 year old tank and it's is sucking petrol through the blocked filter inside? Time to go for an alloy tank or at least get this one opened up for investigation.
3. I'll get the boost gauge on and see what I am getting.
4. The chips are from a reliable source, so I'll hold off for the moment.
5. N75 valve, I'll get the engine to do the self diagnostics. Worst case I can swap over for a know good one.
6. Knock sensors, now there's a thought but I've never had one go down on me before so that is way down the list.

I appreciate the replies gents, I really do!

tractor Dave · 04-08-21, 05:48 PM

How is your pump fitted? Is the basket still there?

Steve · 04-08-21, 07:40 PM

Quote:

Originally Posted by tractor Dave

How is your pump fitted? Is the basket still there?

It's external to the tank. The ADU is fitted in a shortened UR WR.

tractor Dave · 04-08-21, 07:47 PM

Quote:

Originally Posted by Steve

It's external to the tank. The ADU is fitted in a shortened UR WR.

Could be muck in the tank then. It should do it wot in all gears mind. My S2 had a similar issue, cutting turbo, did it in all gears. It was my fuel pump unable to keep up with demamd. If you engine is starved of fuel, ecu will pick up she is running lean and cut boost to protect engine.

03-08-21, 09:05 PM	#3
Isimmo Super Moderator Classic Audi Club Member Join Date: Jul 2007 Location: Sissix-by-the-sea Posts: 15,218	I know this is semantics, but is it ‘losing power’ or not gaining as much power as expected? E.g. lethargic? If it’s the latter check (and I mean properly check) the small vacuum hoses from the head to the dump valve and around N75. Also check N75 is working. Our S2 was down on power for literally years and I was convinced it couldn’t be the hoses because they looked fine. After a rebuilt turbo, various ECU, complete new Roose boost pipe setup, new plugs, coil packs and gawd knows what else it still was shite. Tried an 034 1.9 bar spring and turbosmart controller…. Slightly better, but no cigar. Finally, I just went mad one weekend and stripped out all the tiny vacuum lines out the back of the head and replaced with new. Most were like something out of an Indiana Jones movie and turned to dust. The smoking gun was the dump valve pipe had split under the tiny wire clamp right next to the valve. Once replaced, I then had proper boost again and had to reverse engineer all the ‘hopeful’ engineering of uprated wastegate spring, wound down screw, turbosmart valve etc. Predictably, detuned it too far and have slowly worked back up to full boost. Worth plumbing in a boost gauge if only temporary, it’s invaluable to tell what is going on. Oh, and not blowing the thing up…. __________________ 1985 WR quattro, 1985 20vT RallyRep, 1993 MTM ABY S2 Avant. 2010 S3 Sportback. Last edited by Isimmo; 03-08-21 at 09:09 PM.

03-08-21, 09:08 PM	#4
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	None of those are valid codes on a standard RS2 ecu. It may well be the chips are the problem. Is it just a chip or has anything else been changed ? I'd be looking to get a standard ecu in there and go from there. __________________ 1991 90 quattro 20v sport 1991 90 quattro Last edited by mikes2; 03-08-21 at 09:10 PM.

03-08-21, 09:16 PM	#6
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	A decent chip retains all factory diags and codes. Anything that's throwing a checksum error, should set alarm bells. __________________ 1991 90 quattro 20v sport 1991 90 quattro

03-08-21, 07:57 PM	#2
tractor Dave Senior Member Classic Audi Club Member Join Date: Apr 2018 Location: Wales Posts: 1,157	Have you done a proper boost leak test? Other causes could be Maf Maf pins Fuel pump unable to meet demand Knock sensors N75 Check all the little vac pipes if they haven't been changed, especially the one to the ecu and N75.

04-08-21, 04:51 PM	#7
Steve Grown up member Join Date: Nov 2007 Posts: 355	Interesting points and none that I deep down hadn't thought of, but was looking for some reassurance/inspiration. Here's where I am with this: 1. The vacuum lines have been on there forever. I have around 5 meters of new pipe so let's just call it over due maintenance and change the lot. 2. Occasionally I get rust in the pre pump fuel filter, so I have to take it off and clean it out. The pump which is a BOSCH 044 doesn't make a constant buzzing noise, but it's up and down all the time like it is working too hard. Perhaps this is because it is a 39 year old tank and it's is sucking petrol through the blocked filter inside? Time to go for an alloy tank or at least get this one opened up for investigation. 3. I'll get the boost gauge on and see what I am getting. 4. The chips are from a reliable source, so I'll hold off for the moment. 5. N75 valve, I'll get the engine to do the self diagnostics. Worst case I can swap over for a know good one. 6. Knock sensors, now there's a thought but I've never had one go down on me before so that is way down the list. I appreciate the replies gents, I really do!

04-08-21, 05:48 PM	#8
tractor Dave Senior Member Classic Audi Club Member Join Date: Apr 2018 Location: Wales Posts: 1,157	How is your pump fitted? Is the basket still there?