A3 1.8T ECU issues

[Richrich14]

My engine dies intermittently when i pull up to T-junctions, basically when i put the clutch down and brake at the same time.

Somtimes when i'm idling the revs drop and pick up to idle speed again. This occurs exactly every 4 secounds from around 850rpm to 600rpm and back again. Anybody had this before and know what to do to stop my going grey!

I have changed the MAF twice! and the crack shaft sensor but to no avail. I'm going to change the spark plugs as i have done 65,000 miles on them. I have downloaded the fault codes but they all refer to different sensors each time I download and nothing is recurring.

I would appreciate your expert opinions.
Thanks

 

[herb]

A fixed vac leak helped mine but to completely fix the issue a throttle body clean and realighnment worked for me so there are 2 things you could try

 

[Richrich14]

Thanks Herb, where was you Vac leak and how may i go about aligning my throttle body?

Cheers

 

[herb]

the most common ones are your dv (is yours a standard 1?), the y shaped breather pipe is a very common

then the rest of the pcv system

i found 3 splits in these! if your pcv valve has lots of creamy gunk in it. it would be worth considering fitting a catch tank.
link here for a guide on how to fit 1 + better pics of the pcv system
http://uk-mkivs.net/forums/t/269734.aspx

then for the tb clean you will need a new gasket, carb cleaner/wd40. the tb reset depends if yours is a cable or dbw??? if its cable the reset isnt needed, but if its dbw the reset will have to be done via vagcom.

 

[Richrich14]

Thanks for the pics, i shall have a look this week when i get some time and check for any leaking pipes. I have a standard dump valve. I guess this is locted behind the engine near the turbo.

For the throttle body... its a Fly by wire not cable. I have recently purchased a VAGCOM OBD II. Which function do i use in the software to relaign the TBody?

Thanks

 

[pgarner]

TBA alignment
http://www.ross-tech.com/vag-com/cars/throttlebody.html

as for burst pipes.
the one herb has shown is the most common
the DV is easily tested, not the nicest way but works , remove the DV and blow hard. if air leaks out the other large pipe - the one that goes into the intake - then its goosed. if you decide on a VAG replacement rather than an uprated one then go for the one for the TT as these apparently have a stronger rubber diaphragm

other ones remove the small engine cover and start checking around the PCV system under there.

any of these in a major way should show to a fault code 17705.


and welcome to the site

 

[herb]

Thanks for the pics, i shall have a look this week when i get some time and check for any leaking pipes. I have a standard dump valve. I guess this is locted behind the engine near the turbo.

For the throttle body... its a Fly by wire not cable. I have recently purchased a VAGCOM OBD II. Which function do i use in the software to relaign the TBody?

Thanks

no problem mate:bigsmile:
not quite down as far as the turbo. once the engine cover is of you will see it

i cant really help with the vagcom i dont have it. i have a fault code reader that allows me to do a tb reset.
this is 1 for pg

and by magic there he is:amuse:

 

[pgarner]

Ta Daaa.

cant find a pic. if you look at your engine cover you will see where the intake pipe goes, top right as looking in.

remove the cover and look at the intake pipe where the cover was slightly higher and you should see this

thats the diverter valve. before removing however get some jubilee clips as the VAG ones are one use

 

[Richrich14]

Hi,

Did a bit of tinkering today. Found 2 splits in my PCV system to no suprise after reading your replies. I did a temporary fix with some tape. now i need to source some OEM pipes or convert using the handy guide herb posted. Thanks for the info, no idea how long they had been there! My DV is fine by the way. I didn't get round to cleaning the throttle body, good job as a realised i need to register my VAG-COM as the free license doesn't cover realignment. I have cleared my fault codes and went for a test drive. Ideling has improved so far and no stalls. Time will tell.

After a long jounrney last night form Manchester i noticed my water wastn't getting up to temp at all. Does anybody agree this is a new Thermostat required? Water is circulating.

Cheers

 

[pgarner]

sounds like the thermostat isnt closing.

keep and eye on it for a few days to see if you see it climbing up and falling away.

might be worth checking out instruments on vagcom think its 17 and see if you can get another reading of the coolant. it could be the temp sender is goosed. ether way your looking at around £20.

the thermostat is a ballache to do

 

[Richrich14]

Cheers pgarner.

The temp rises to 90 only in traffic then falls once on the move.

I get under "instruments" on my VAG COM, the fault:

code 01039 - coolant temperature sensor (G2)
30-10 open or short to B+ - intermitent.

Does this narrow it down to the temp sendor needs replacing?

 

[pgarner]

looks like it, normally it doesnt even show a code.

if you go for a new one it should be a green topped one you get.


just checked ross techs page and got this

http://wiki.ross-tech.com/wiki/index.php/01039

01039
Contents [hide]
1 01039 - Engine Coolant Temperature Sensor (G2)
1.1 Possible Symptoms
1.2 Possible Causes
1.3 Possible Solutions
1.4 Special Notes
01039 - Engine Coolant Temperature Sensor (G2)

Possible Symptoms
Difficulties with starting a cold engine.
Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
RPM at idle is irregular.
With all engine temperatures seldom idle rpm will vary between 900 - 1000 rpm.
With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
Bad acceleration during warming up.
Diesel: an indication is extreme long time burning time of the glow indication light.
Possible Causes
Wiring and/or connections faulty
Engine Coolant Temperature Sensor (G2) faulty
Possible Solutions
Check wiring and connections
Check / Replace Engine Coolant Temperature Sensor (G2)
Special Notes
In MY 1995-2002 (?) in Europe at VW-cars the G2/G62 had the bad reputation of breaking down often. The default G2/G62 is black and all replacements are green.
Category: Fault Codes
Categories
Main Page
Fault Codes
Diagnostic Procedures
Control Module Maps
Meta
Log in

might explain your poor idle as well then. 10 min job to replace and not much coolant will be needed. you might even get away with not using any

 

[Richrich14]

Wow, amazing bit of info, how such a simple temp sensor can effect so much. Thanks alot and i will let you know how i get on. I can feel my hair growing back already.

Regards
Rich

 

[pgarner]

they are another pain of the vag engines, along with water pumps and coil packs.

 

[Richrich14]

hi, i changed the temp sensors and now the irratic idleing has gone. I did find two splits in the pipes as expected, small bodge for now with some electrical tape has sorted out the running issues.

Cheers for all your help

Rich

 

[turbonutter69]

Glad it's sorted mate. Good stuff.