haylze

Hi

I have a 04 Audi a4 1.8t Quattro.
108000 miles

I've only owned my audi for about 4 months and i'm loving it however i have noticed a few things that are concerning me a little.

Recently the ESP light on the dash has been going on while driving, when i turn the engine on and off it then disappears. It has only happen on a few occasion however i'm worried that something big is about to happen.

Also, Every now and again when i'm pulling away in 1st or 2nd the power disapears, i can sink the gas down to the floor but nothing happens until i lift my foot off the gas then apply it again, any ideas what could be causing that?

I'm also finding it hard to understand that fact that my audi states it has 190 bhp. I previously had a 130bph mondeo zetec which i recond was faster of the mark than my audi. I know you do loose some power with the 4 wheel drive but still expected the a4 to be quicker off the mark.

I did have the car independantly checked when i got it and no faults were recorded.

I'm greatful for any help
Graeme

terraflata

Does the power dissapear when you shift from 1st to second? It could be a vacumm problem or DV (Diverter valve problem) causing surges in your turbo. It basically feels like the engine has a brake being applied to it? It last for about 2-5 seconds but then eventually levels itself out? And I am guessing it happens in lower RPM's (Around 2500-3200)? Also any modifications to your engine would help (Chip, Intake, DV....)

Terraflata

wanthema

Have you tried VAG.COM it ? like OBD II check it for ecodes or something.

And this car makes 170 hp since its quattro... its not made for racing unless u mod and tune it up with a BT and other stuff. Reason why your previous car feels faster because its much LIGHTER and the engine isn't made for for awd stock, also the torque converter is much smaller therefore it does apply the power you are looking at the beginning until the turbo kicks in. In addition, drivetrain loss is alot for automatic. like 20-30%, where as manual are at 10-20%

haylze

Terraflatta

Thanks for your reply

Yes it does happen when changing from 1st to 2nd and in low reves and you explanation is pretty bang on. It only happen occasionaly but it is annoying. If it is one of the problems you mentioned how much will i be looking at to resolve?. It seems lately that there's things going wrong all over the place. Noticed tonight that my brake lights are staying on when driving, hoping this is just a loose connection or something but it's another headache.

haylze

Wanthema

Thanks for your reply

I appreciate it's not made for racing but i thought it would have a little more attitude off the mark. Not a complaint more an observation. Thanks for the explanation.

No, i haven't had it checked with Vag Com for errors. I'm due to take it down on Monday as i'm having problems with the ESP light coming on occasionaly when driving so i'll get it checked then.Thanks(i take it the Audi specialist i used will use Vag.COM?)A for Audi - Audi VW Specialist Glasgow Scotland - A for Audi - Audi VW Specialist Glasgow Scotland

Thanks again
Graeme

terraflata

I am not gonna say I know what my problem was. Because I didn't. So we will troubleshoot. To me it felt like compressor surge, possibly because of a bad Diverter Valve. This is a possibility as the OE DV is made of plastic and is known to fail. A new one can run up to (but can be found for less) 170$ for a high quality one. INstalling isn't too hard, plenty of DIY's out ther on changing them.

My problem doesnt happen anymore, but I never changed my diverter valve. I know my problem stopped happening after I got my Cat welded back up (After it broke my turbo at around 6500RPM
If this WAS the problem with my car, then you can simply try and inspecting your cat for any signs of possible of future breakage.

The surge I felt also happened when I was breaking hard at a stop then trying to take off hard with my foot on the gas. It felt like an extreme lag.

I'll do a little research into this and get back at you. Everything I written is pretty much guesses and experiences. I'll get back at you.

Terraflata

terraflata

Also a quick question. Are you sure it's your brake lights or do you have your rear fogs turned on? Rear fogs are the light completely on top while the brake lights are lower down. There should be a switch on your console to turn off you fogs.

Terraflata

haylze

Hey

At the moment it happens very seldamly but i've learned through bad experiences that if you just turn a blind eye to things they don't go away.

Like you said it happens when your accelerating especially from low reves then it seems as if the power just disapears for a second until i lift my foot from the pedal and apply it again and eventhing is back to normal. I've not felt anything under braking.

No, its defenetly the brake lights, it came to my attention when i seen the window brake lights reflection when i was driving, i stopped and checked the brakes and when i was pressing teh pedal nothing was happening as the brake lights were lit already.

*read a thread about it maybe being a dirty connection,dodgy bulb but i thought that would show on the dash. The brake pedal switch was also mentioned(no sure what that is) Must read more!!

I appreaciate your efforts and help
thanks
Graeme

terraflata

The last thing I was suggesting was to turn a blind eye. Just a quick suggestion...have you checked your air filter in you intake? Mine was heavily clogged and now thinking about it, my problem stopped around the same time I changed it. 4-5 minutes to change and about 20 bucks.

Terraflata

haylze

No i haven't, i'll replace it over the weekend and see if there's any diffrence.

Thanks
Graeme