Car idles better with the lights on???????????

[nickeym1]

As the title suggests my car has a rough idle but runs smooth with the lights on (what the hell???) I changed the oil today and after i drove home it was dark and i sat in my drive way for a minute with the car ticking over and noticed it was running very smooth so i thought jesus the oil change has worked wonders. I then switched off the lights (while car still running) and the rough idle came back again but not as bad as it was before i changed the oil so the oil change did help. Can anyone understand why the car runs smooth when the lights are on. Very strange one for me but maby a very simple answer im hoping??

[Crasher]

Alternator issue maybe, start with a code read.

[a8 tech]

alternator loading boosts the idle via j519, this sends a request for increased idle to the engine ecu

goto address 01 login 12233

goto adaption channel 2 increase the idle speed until smooth

or channel 3 turn off egr

or do both

Channel 2: idle speed

* No login required
* The stock adaptation value should be 32768 (corresponds to 903 rpm).
* Increase or decrease this to change idle speed.

Channel 3: EGR

* To decrease the EGR rate, increase the number to the highest possible value (typically 33768).
* This will prevent/slow down the intake manifold clogging problem and reduce smoke.
* Though the MAF at idle is still within specifications (370 mg/h) do not use this adaptation on the road :-)
* Again, this EGR setting is for off-road use only !!!

[Crasher]

I didn’t think you could turn the EGR off on a PD TDI?

[a8 tech]

you can crasher, mines been off for 3 years as this value controls the pwm signal to the egr vacuum solonoid.

I set mine with vcds and mitivac till it stopped any vacuum to the egr valve but not the figure used by rosstech

I also increased the fuel to improve the acceleration

[Crasher]

Huh, never tried it because I feel it is wrong to remove emissions equipment but Ross Techs site says you can’t.

“Special adaptations: Login code 12233:
These procedures do NOT apply to the PD engines, which use a completely different type of EGR system and for which there is no known modification. !”

[nickeym1]

Alternator issue maybe, start with a code read.
Hi mate i have done a code read its only a cheapo code reader but it does not show up codes only the airbag one after i changed the battery. In the service sheets that came with the car it says the alternator was changed at 125000 and theres now 150000 miles on it

[nickeym1]

alternator loading boosts the idle via j519, this sends a request for increased idle to the engine ecu

goto address 01 login 12233

goto adaption channel 2 increase the idle speed until smooth

or channel 3 turn off egr

or do both

Channel 2: idle speed

* No login required
* The stock adaptation value should be 32768 (corresponds to 903 rpm).
* Increase or decrease this to change idle speed.

Channel 3: EGR

* To decrease the EGR rate, increase the number to the highest possible value (typically 33768).
* This will prevent/slow down the intake manifold clogging problem and reduce smoke.
* Though the MAF at idle is still within specifications (370 mg/h) do not use this adaptation on the road :-)
* Again, this EGR setting is for off-road use only !!!
Cheers for the info mate but unfortunately i have not got vag com cable yet. I would like to turn off the egr if possible because i did take it off before and gave it a good clean with carb cleaner but car still ran rough. I blocked it off again same as i had it before and it wasnt too bad again. i just blocked the pipe that goes into the diaphram on top dont know anything else needs to be blocked?? I was thinking about getting a blanking plate for the bottom of the egr maby that would cancel it out altogether??

As for the rpms do you mean just turn the rpm up till the idle improves? Would this fix the problem or just disguise it though?

[nickeym1]

Anyone else any ideas on this

[benjie]

Sorry to semi-hijack, just a quick question for a8tech - Do you know why the 130TDI quattro idles slower than the 130 TDI FWD?

[nickeym1]

Sorry to semi-hijack, just a quick question for a8tech - Do you know why the 130TDI quattro idles slower than the 130 TDI FWD?
Ill let it slide just this time :) The quattro idles slower thats interesting what is the idle rpm on the quattro the fwd is 903rpm is it. Is yours rough on idle too? Any chance you could send or post up a picture of the back of your car id love to see how the v6 exhaust tips look

[benjie]

I can't remember the idle speed off hand, I can just remember looking at the measuring blocks in vcds and thinking that mine was out of the stated range until
I spotted a note about a slightly lower range for AWD!

Here's a couple of pics, I did it the poor man's way - already had twin pipes because it's a quattro, got someone to weld a but of pipe on, then fix these over the too. Looks awful if you look 8" into the pipe, but 99% of the time, you can't see!

http://i44.photobucket.com/albums/f15/benstirling/dcaa5838.jpg

http://i44.photobucket.com/albums/f15/benstirling/e9ebbf57.jpg

[nickeym1]

I can't remember the idle speed off hand, I can just remember looking at the measuring blocks in vcds and thinking that mine was out of the stated range until
I spotted a note about a slightly lower range for AWD!

Here's a couple of pics, I did it the poor man's way - already had twin pipes because it's a quattro, got someone to weld a but of pipe on, then fix these over the too. Looks awful if you look 8" into the pipe, but 99% of the time, you can't see!

http://i44.photobucket.com/albums/f15/benstirling/dcaa5838.jpg

http://i44.photobucket.com/albums/f15/benstirling/e9ebbf57.jpg
Seems to me if i could increase my rpm a fraction it would take the rough idle out of it but as i said earlier in this thread i think thats just disguising the problem and not fixing it. But im very curious why the rpm is lower for the quattro i thought if anything it would be higher. Maby someone on here could shed some light for us.

Im in the market for a vagcom cable and was going to get the proper genuine one but they dont ship to ireland there is ones on ebay but i dont know which one to get i emailed the sellers in hong kong but they wont respond maby you would have some idea which one i could get.

As for exhausts mate i think they look really good id like to do that with mine its quattro too so has the twin exhausts. Where could i get the tips from? Did you modify the back bumber to put these on or is it a different bumber. Its a nice motor you got there man they look mean in black :biglaugh:

[a8 tech]

engine code avf a4 1.9 tdi qauattro avant

800 rpm to 950 rpm

mine is set to 900rpm



If the idle is poor at lower rpm then increase until it smooths but check valve timing as well as egr flow if you are unhappy then look at fuel pressure at the tandem pump and look at the DF SIGNAL from the alternator, this signal is used to determine alternator loading to increase or decrease engine rpm depending on demand


One other suggestion as a simple test

goto address 01 goto adaption channel 0 and save, this resets all engine learned settings.Turn the ignition off for 5 mins then restart and see if it changes the idle issue