Home Technical Discussions Volkswagen Jetta, Golf, GTI: 1999-2005, R32: 2004 (A4)

Volkswagen Jetta, Golf, GTI: 1999-2005, R32: 2004 (A4) What could be messing the idle?


Permlink Replies: 2 - Pages: 1
Last Post: Apr 26, 2014 1:28 PM Last Post By: tcovenant2000
alfitovw

Posts: 136
Registered: 01/24/04
What could be messing the idle?
Posted: May 27, 2013 10:46 PM
  Click to reply to this thread Reply
Hi,this is a 2001 Jetta gls, 2L gas with 5 speed manual transmission (engine code AZ...... Something), car was parked for unknown period of time when I got it, and have no maintenance history at all, any ways, the fact is that it always start at first try and idle stays up and steady while engine is warming up for like 20 seconds or so, then when idle is supposed to slow down and stay steady it gets all messed up and engine almost die if you don't give some gas, also MIL is on and there are two codes, p135 and p1473. I've already change spark plugs a wires, new coolant sensor, new fuel pressure regulator and swap a good and clean TB, MAF sensor and checked for vacuum leaks. I already ordered a new upstream O2 sensor to replace the bad one, hopefully it will fix the idle. What do you guys think?

I pretty much know everything about A1's and A2's, but I'm totally lost with A4's. Help plz.

Thanks in advance.

Alfonso .
plasmid

Posts: 1
Registered: 04/25/14
Re: What could be messing the idle?
Posted: Apr 25, 2014 5:59 PM   in response to: alfitovw in response to: alfitovw
  Click to reply to this thread Reply
I had a similar fault with a Subaru which was traced to the rheostat on the throttle setting which sent a message to the computer advising of the position of the throttle. If this device is worn/damaged/dirty it might (repeat might) be a/the source of your problem.
tcovenant2000

Posts: 1,767
Registered: 12/09/03
Re: What could be messing the idle?
Posted: Apr 26, 2014 1:28 PM   in response to: alfitovw in response to: alfitovw
  Click to reply to this thread Reply
Keep it simple:

The O2 sensor is ignored on cold start/run for a couple of minutes until it warms up. Then the ECU tried to use its signal to control fuel. If the O2 fails, it is almost certainly saying "TOO LEAN!" to the ECU can causing overriching.
An easy test: Disconnect the O2 sensor and let it idle. If the idle is better then you've found your problem. It would be good to research the MIL's as well.

Thomas

Point your RSS reader here for a feed of the latest messages in all forums

Popular Discussions:
No popular dicussions.