1.4 Petrol idle / running issues.

A

A2Andrew

Member
Hi folks,

I hope someone can point me in the right direction with this, my 2001 1.4 petrol (AUZ?) has a rather low idle of around 450-500 and it does hunt ever so slightly, and in low revs if I don't give it a bit of gas (about 1200-1300) it will stall when pulling away at lights etc.

In overrun after lifting off the gas it is often jerky and I'm finding it a bit of a nause to drive. Anything over 1000rpm and out of 1st + 2nd gear it's ok.

I have noticed a whiff of petrol every now and again.

I've just had it plugged in on VCDS lite and got the following. I cleared the codes each time, shut the car off, then started it up again and scanned again to check for repeat offenders. Note the time stamps to see what I did. The lambda sensor code came up but didn't come back, but I'm thinking this might be the culprit?

If anyone can advise it'd be much appreciated.



5 Faults Found:

16786 - EGR System: Excessive Flow

P0402 - 35-00 - -

17604 - Shareware Version. To Decode all DTCs

P1196 - 35-00 - Please Register/Activate

17591 - Shareware Version. To Decode all DTCs

P1183 - 35-10 - Please Register/Activate - Intermittent

17972 - Throttle Actuator (J338): Under-Voltage during Basic Setting

P1564 - 35-10 - - - Intermittent

17586 - Shareware Version. To Decode all DTCs

P1178 - 35-10 - Please Register/Activate - Intermittent

---------------------------------------------------------------------------

Thursday, 24 May 2018, 18:57:55.

2 Faults Found:

17604 - Oxygen (Lambda) Sensor Heater Circuit: B1 S1: Electrical Malfunction

P1196 - 35-00 - -

17591 - Shareware Version. To Decode all DTCs

P1183 - 35-00 -

---------------------------------------------------------------------------

Thursday, 24 May 2018, 19:03:38.

1 Fault Found:

16555 - Fuel Trim; Bank 1: System Too Lean

P0171 - 35-00 - -

---------------------------------------------------------------------------

Thursday, 24 May 2018, 19:08:12.

1 Fault Found:

16555 - Fuel Trim; Bank 1: System Too Lean

P0171 - 35-00 - -

---------------------------------------------------------------------------



 
Hi - to be honest you may have a combination of faults there and most petrol 1.4 models have them as they approach 100,000 Miles . I would start with a clean of the throttle body followed by the egr valve as both are probably pretty dirty and cause bad running and stalling issues . The pre cat lambda sensor is also a common failure as the miles increase and the engine management light will illuminate intermittently but car will run fine in my experience for a long time
Cheers Dave
 
Hi Dave, thanks for the reply. I'll have a go at cleaning them both tomorrow, are they fairly straightforward? Apologies I'm not familiar with these engines. Would these fault codes explain the low idle too?
 
Hi - depends on your experience to be honest - I changed my egr valve and dropped a small gasket and bolt and took me hours . You need new gaskets for both before starting and will have to perform a basic settings reset afterwards for throttle body so not that easy without the correct equipment but cleaned mine in situ with cleaning fluid but not generally recommended
Dave
 
Ok, I'd say confidently that I'm good with spanners, and I have VCDS Lite on my laptop so I'll be all set in that sense - assuming I can do the TB reset with the Lite version? I'll have a hunt through the how-to section for an EGR removal guide, found the TB removal guide already.
 
Bit of an update, changed the pre-cat lambda sensor, there are now no fault codes at all - but the idle was still a bit lumpy and on the low side at 400-450.
A tank full of v-power seems to have made it run smoother.
I did a readiness test on vcds and i’m getting all passes apart from evaporative emissions which is failing and I’m wondering if this could be related, so, any ideas?
 
Do throttle body clean as Dave said already. Look at my 'General Servicing' thread on how to do this on the 1.4 petrol.
 
Thanks for the help so far guys.

I carried out the throttle body clean today, got rid of a lot of sludgy black stuff and oil.
Replaced gaskets with new genuine audi, did TB adaptation with VCDS and it was still the same, idling low (400-450) and occasionally bogging down and hunting.
Did the TB adaptation again just to be sure and still the same.

No fault codes stored.
No vac leaks apparent.
O2 sensor already changed.
TB clean done.

Any further ideas?
 
I didn’t clean the egr valve as I wasn’t sure if it needed new gaskets, although it had crossed my mind to do it
 
You must log in or register to reply here.
Back
Top