Audi b4 coupe 2.0 hesitating

vag2109 · 24-09-15, 08:17 AM

Hi,
my 2.0E coupe is hesitating at idle and whilst driving,seems to be worse when engine has warmed up. Temp gauge stays just above 50 even after a 40 min, journey,is this about right? There are no obvious vacuum leaks. Can anyone give me some pointers pls?

Thanks

John. · 24-09-15, 08:57 AM

" hesitating at idle"......?? Do you mean idle is rough? It's more likely to be an air/fueling issue but worth checking distributer cap, rotor arm, HT leads and plugs. Even cleaning dirt from outside of cap can help......if insulation is gone then spark can use the dirt to get to earth.
Air/fuel filters??......how old?

Worth checking the above......could be a cheep fix?!

vag2109 · 24-09-15, 09:08 AM

Thanks John,
the car has fsh history,i bought it 6 months ago and it stood until just over a week ago. By hesitating at idle I mean,that it idles steadily but then there is a blip engine note changes for a second as does the idle speed. According to the records car was last serviced 5000 miles ago.

mikes2 · 24-09-15, 11:53 AM

temp gauge should be higher once warm - to around 87-90 degrees.

Possibly thermostat or gauge sender. No guarantee this will fix the idle misfire.

S2Andy · 24-09-15, 04:14 PM

Could it be the MFTS that's causing the problem?

vag2109 · 25-09-15, 07:13 AM

Thanks for the replies everyone. Andy what`s the MFTS?

John. · 25-09-15, 07:29 AM

Quote:

Originally Posted by vag2109

Thanks for the replies everyone. Andy what`s the MFTS?

Multi Function Temperature Sensor............I don't think your's will have the type that can cause issues on certain models?? Worth saying what engine is in your coupe, I'm assuming it's like what was fitted to Golfs of the same age, ie. not KE Jetronic ? Was it digifant or something?
That blip you describe could well be a HT misfire......does your car have the square coil with the module mounted to it?
Although it has FSH, the rotor arm could still be almost burnt out!?.......or leads corroded where they join the distributor cap or coil?

vag2109 · 25-09-15, 08:57 AM

Thanks a lot John,you certainly know your stuff .The engine is the ABK unit,not sure about the coil.Tomorrow I shall go through all the items you`ve listed and hopefully it will cure the blip

msh · 25-09-15, 09:50 AM

Quote:

Originally Posted by S2Andy

Could it be the MFTS that's causing the problem?

No, it couldn't. MFTS is for all the systems which needs engine temperature, apart from ECU, which has different sensor.

msh · 25-09-15, 09:51 AM

Quote:

Originally Posted by vag2109

Thanks a lot John,you certainly know your stuff .The engine is the ABK unit,not sure about the coil.Tomorrow I shall go through all the items you`ve listed and hopefully it will cure the blip

Sounds like mixture too lean. Temperature sensor, air mass sensor...

24-09-15, 11:53 AM	#4
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	temp gauge should be higher once warm - to around 87-90 degrees. Possibly thermostat or gauge sender. No guarantee this will fix the idle misfire. __________________ 1991 90 quattro 20v sport 1991 90 quattro

24-09-15, 04:14 PM	#5
S2Andy Grown up member Classic Audi Club Member Join Date: Jun 2014 Posts: 77	Could it be the MFTS that's causing the problem? Last edited by S2Andy; 24-09-15 at 04:17 PM.

24-09-15, 08:57 AM	#2
John. 4 ring whore! Classic Audi Club Member Join Date: Mar 2011 Location: Scottish Borders. Posts: 7,539	" hesitating at idle"......?? Do you mean idle is rough? It's more likely to be an air/fueling issue but worth checking distributer cap, rotor arm, HT leads and plugs. Even cleaning dirt from outside of cap can help......if insulation is gone then spark can use the dirt to get to earth. Air/fuel filters??......how old? Worth checking the above......could be a cheep fix?!

24-09-15, 09:08 AM	#3
vag2109 Grown up member Join Date: Feb 2012 Posts: 369	Thanks John, the car has fsh history,i bought it 6 months ago and it stood until just over a week ago. By hesitating at idle I mean,that it idles steadily but then there is a blip engine note changes for a second as does the idle speed. According to the records car was last serviced 5000 miles ago.

25-09-15, 07:13 AM	#6
vag2109 Grown up member Join Date: Feb 2012 Posts: 369	Thanks for the replies everyone. Andy what`s the MFTS?

25-09-15, 08:57 AM	#8
vag2109 Grown up member Join Date: Feb 2012 Posts: 369	Thanks a lot John,you certainly know your stuff .The engine is the ABK unit,not sure about the coil.Tomorrow I shall go through all the items you`ve listed and hopefully it will cure the blip