Since your trim values start off at zero, I am guessing you reset them by clearing the engine DTC? It takes a few miles of driving for meaningful trim values to develop.
You sure about the boost? It should be asking for up to 1800 (stock) when you're asking for power.
109 successful flashes? Bonkers. Someone used your car to develop a map or it was owned by a tinkerer.
Hunting idle when AC on
Re: Hunting idle when AC on
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Hunting idle when AC on
Yes I zero'd them before I started the log, good to know. I have done two more log's.
One just normal run and other with WOT.
One just normal run and other with WOT.
- Attachments
-
- LOG-01-032-002-001.xls
- (306.5 KiB) Downloaded 75 times
-
- LOG-01-002-115-120-boost.xls
- (142.5 KiB) Downloaded 74 times
Re: Hunting idle when AC on
Only once does your car ask for full boost in those logs (assuming it's stock) and it doesn't achieve it.
Your MAF readings are low, assuming you were WOT at 6000 rpm when full boost was requested.
I think you need to do some more WOT logs. Maybe in turbo mode. Maybe in advanced mode so that you can log things like accelerator pedal position and throttle angle.
Maybe you've got a vac leak *and* a boost leak that is balancing out your trim. Suppose it could happen, but I admit, it doesn't sound likely...
Boost circuit pressure test would eliminate that.
Your MAF readings are low, assuming you were WOT at 6000 rpm when full boost was requested.
I think you need to do some more WOT logs. Maybe in turbo mode. Maybe in advanced mode so that you can log things like accelerator pedal position and throttle angle.
Maybe you've got a vac leak *and* a boost leak that is balancing out your trim. Suppose it could happen, but I admit, it doesn't sound likely...
Boost circuit pressure test would eliminate that.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Hunting idle when AC on
you got to do some WOT logs in 2nd and 3rd gear, by what you just posted i could say that your MAf's have either <beep> the bed or you're getting a lot of un-metered air, those readings below 3.64 while idling are totally off...i've recently had issues with my MAF seals and did many logs trying to pinpoint the culprit of my erratic idling which wouldn't always occur and it turned out that the MAf's seals were toasted, once replaced my reading on both banks are similar and steady at 3.64 and at full WOT they go a bit over 364, which is about the norm for a stock map.
If your' fuel trims were either too rich or lean they'd throw and error code...
If your' fuel trims were either too rich or lean they'd throw and error code...
2004 RS6 by ABT, madly in love with it, RNS-E, ST coilovers, new TC, 19x9x29 RS4 B7 wheels, non-resonated Milltek w/blk tips, TBC....SOLD - but never to be forgotten!
2004 RS6 ebony schwarz, SE exhaust, 19'' rims - SOLD
'09 RS6 C6 - the great white - now, this means business!
2004 RS6 ebony schwarz, SE exhaust, 19'' rims - SOLD
'09 RS6 C6 - the great white - now, this means business!
Re: Hunting idle when AC on
Looked at your logs. I'm fairly certain you have a knock issue occurring, where the ECU is reducing boost. Load at 4000 to 6000 rpm is barely above 110, where a standard car, running well, should be around 140 here.
It would help to get some serious datalogging on the go here, but that means moving beyond VCDS which would involve a fair bit of effort and probably £40 or so in some new cables for you. You would be logging around 50 params from the engine ECU at 5 samples a second though, including things like knock activity, requested boost, throttle plate angle vs throttle position, lambda voltage, injector on time etc etc... as well as various error states the ECU may be seeing. I would also be keen to pull the map off the car and investigate that - 119 flashes is quite a lot.
I'm happy to assist if you need it.
It would help to get some serious datalogging on the go here, but that means moving beyond VCDS which would involve a fair bit of effort and probably £40 or so in some new cables for you. You would be logging around 50 params from the engine ECU at 5 samples a second though, including things like knock activity, requested boost, throttle plate angle vs throttle position, lambda voltage, injector on time etc etc... as well as various error states the ECU may be seeing. I would also be keen to pull the map off the car and investigate that - 119 flashes is quite a lot.
I'm happy to assist if you need it.
Recycling dinosaurs for fun
Re: Hunting idle when AC on
ps, the ECU has a function specifically for dealing with the aircon at idle. Could well be a problem with the AC to ECU comms or perhaps with 119 flashes, there are some problems with the current ECU calibration....
Recycling dinosaurs for fun
Re: Hunting idle when AC on
Do you think it might be worth getting the stock ecu software flashed onto it to rule out any settings that might have been messed with?
I hope this gets resolved soon
I hope this gets resolved soon
2003 C5 RS6 Avant Daytona Grey
Re: Hunting idle when AC on
Just had a quick read of the history, and if the Milltek was originally without cat's, there's bound to be someone's tune in the ECU else there would be the MIL light on. Although I have seen that taped over before on these cars, believe it or not!
Rather than put new software on straight away, I think it would be valuable to get the current map off the ECU and have a look at the current state. It's very possible that the torque reserves that control the AC clutch at engine idle are not working as intended, caused by things like tuners scaling the MAF values to get around the need for mapping the gearbox (for example). I also find it suspicious that the engine appears to be in knock at reduced boost in the logs I've seen so far.
Something is not quite right here and my best pointing finger is making a poke at the ECU.
Rather than put new software on straight away, I think it would be valuable to get the current map off the ECU and have a look at the current state. It's very possible that the torque reserves that control the AC clutch at engine idle are not working as intended, caused by things like tuners scaling the MAF values to get around the need for mapping the gearbox (for example). I also find it suspicious that the engine appears to be in knock at reduced boost in the logs I've seen so far.
Something is not quite right here and my best pointing finger is making a poke at the ECU.
Recycling dinosaurs for fun
Re: Hunting idle when AC on
So I have fixed non working AC fan and also replaced low valued MAF and MAF seals, but problem still exists.
I have figured out how problems starts:
I start AC with 1 stick and there is no rpm fluctuation. I can move up to 4 sticks and then rpm's start moving. Also at this time I can see in measured blocks that engine load raises from 25% to 27% and this is the range where rpm fluctuation starts.
My idle rpm't with gear in D is 700rpm's what I think is too low. I tried to change this under channel 1 where original value was 128, but nothing changed when I went higher by 1 or 2 or 3.
I did notice that engine mounts are turned off in ECU and when doing test then one of them did not click, visually they look good. I wonder if they can influence ac system.
Sweegie I'm sending you PM to know about cables what I need to download this tune and how I can send it to you.
Next week I will do vacuum pressure test also just in case.
There is no fault codes in ECU and car drives otherwise nice. I'm not with heavy foot so not 100% sure how fast it should be.
I have figured out how problems starts:
I start AC with 1 stick and there is no rpm fluctuation. I can move up to 4 sticks and then rpm's start moving. Also at this time I can see in measured blocks that engine load raises from 25% to 27% and this is the range where rpm fluctuation starts.
My idle rpm't with gear in D is 700rpm's what I think is too low. I tried to change this under channel 1 where original value was 128, but nothing changed when I went higher by 1 or 2 or 3.
I did notice that engine mounts are turned off in ECU and when doing test then one of them did not click, visually they look good. I wonder if they can influence ac system.
Sweegie I'm sending you PM to know about cables what I need to download this tune and how I can send it to you.
Next week I will do vacuum pressure test also just in case.
There is no fault codes in ECU and car drives otherwise nice. I'm not with heavy foot so not 100% sure how fast it should be.
Re: Hunting idle when AC on
I'd do definately as sweegie suggests in his post above - he really knows his stuff. Especially note his comments about logging, load & knock.
It "can" be a bit of a faff to get the tune off the ecu the first time - depending on the tune that is on it being locked or not, but if you pull the tune off (you only have to do that once) it's relatively straightforward to reset with a benchmark again and then push the current one back on once you've tweaked/validated/corrected it.
It "can" be a bit of a faff to get the tune off the ecu the first time - depending on the tune that is on it being locked or not, but if you pull the tune off (you only have to do that once) it's relatively straightforward to reset with a benchmark again and then push the current one back on once you've tweaked/validated/corrected it.
"not a professional engineer, mechanic and mechanist"
Re: Hunting idle when AC on
Problem solved with Sweegie's help. Tune was bad.
Thank you all.
Thank you all.
Re: Hunting idle when AC on
I'm due you an email Tom - will be in touch tonight
Recycling dinosaurs for fun
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