View Full Version : What have they done to my performance?
matthew_hall_20
05-10-2002, 22:55
Hi guys,
Just had my Leon (110) serviced after 20,000 miles. Problem is, the dealer has done something to my car!!
Before the service I was happy with the performance and power my car had, now it seems to lack power and just performs a lot differently.
There just doesn't seem to be any low down torque any more, no grunt or go in the engine. Could they have adjusted something to do this? If not, what else?
Cheers.
-Matt
mark sheerin
05-10-2002, 23:00
Difficult ..which service was it?
If it was an oil service then its difficult to imagine what they could have done....
...however if its diesel and it had a cambelt change service then its feasible that they haven't got the timing right on your new cambelt.
matthew_hall_20
05-10-2002, 23:04
That's the weired thing. It was just an oil change service, I don't know what else they could have played with.
Could they have adjusted something to maybe clean up the emissions or something? This wasn't done at my 10,000 oil service though.
The car is definately behaving differently though, it's not as if I even drove another car while mine was being serviced - so it's not just wishfull thinking ;-)
-Matt
mark sheerin
05-10-2002, 23:11
How much fuel did you leave the car with?
If you didn't leave much in then they could have blocked an injector with crap from the bottom of the fuel tank or airlocked an injector.
Do you notice any unusual (for a diesel) smoke from the exhaust?
matthew_hall_20
05-10-2002, 23:16
Nope, enough fuel in the tank. Was well above 1/4 of a tank.
No more smokey than normal. I haven't had time to test mpg properlly yet, but seems about normal.
I was averaging about 53mpg before - but I had oodles of torque and power. I just had to blip the throttle in any gear and the pawer was there - the car would accelerate.
Now I have to really depress the accelerator almost fully, and the power seems to come on a lot slower, it take a time to think about accelerating.
Seems like the turbo isn't kicking in, but I think it is - I can at leat hear it anyway.
Really confused.
-Matt
Matt,
This is a shot in the dark but they may have messed up your MAF sensor if they changed/cleaned your air filter with the engine running. The MAF is very sensitive and if dirtied even by tiny microscopic air-borne particles it will be affected.
Disconnect the connecting wire clip from the MAF and see if performance improves, this will be the proof.
The MAF wires are connected to the air intake pipe "behind" the air filter.
:cheers:
matthew_hall_20
05-10-2002, 23:19
Sorry to sound really stupid, but what is a MAF sensor?
What does it do, and if I disconnect it. how will this prove this is my problem?
Are they expensive?
Thanks for your help
-Matt
MAF sends message to ECU telling how much air to allow into engine.
If MAF is faulty it will send wrong message to ECU, disconnecting will give back 80%/90% performance (if MAF is faulty).
They are expensive...£200+ :eek: but covered by warranty.
:cheers:
mark sheerin
05-10-2002, 23:30
MAF sensor detects the airflow on the inlet side of the engine (from filter to inlet manifold) so that the fuel/air mixture for efficient combustion can be calculated.
look for a wire going to the plastic hose just after the air filter and before the injectors.
matthew_hall_20
05-10-2002, 23:32
Ok, cheers guys.
Will try disconnecting it tomorrow. If I find out the MAF sesor is at fault, how can I go back to the dealer and say it is their fault?
If it isn't the MAF sensor, what else could it be?
Thanks again.
-Matt
matthew_hall_20
06-10-2002, 19:03
Ok. I disconnected the MAF sensor today, went for a drive. The car did seem even more underpowerred than before (As expected really).
Re-connected the MAF sensor plug. Performance was a bit better, but no better than yesterday.
So, to cut a long story short, it doesn't seem to be the MAF sensor that's at fault.
What else could it be?
-Matt
Originally posted by matthew_hall_20
Ok. I disconnected the MAF sensor today, went for a drive. The car did seem even more underpowerred than before (As expected really)
Edited.
Yep, this is to be expected, but if the MAF is playing-up, performance improves by disconnecting it.
:cheers:
matthew_hall_20
07-10-2002, 12:41
Sorry, Brian. I din't mean to offend.
What I meant was, by disconnecting something that should be there, the performance dropped, so we can assume the MAf sensor is working - or at least partly working from this yes?
No, please don't feel like that. I'm greatful for any help/advice people give me here. I could have worded my message better.
Sorry.
Sorry Matthew, apologies for my reply.
I mis-read your reply (plus was a bit oikey having had only 12 hours sleep in the last 4 days)
Can't think of anything else they would touch during a 20K service which would affect performance. :dunno:
Apols again.
:cheers:
matthew_hall_20
07-10-2002, 20:28
That's OK. Thanks Brian.
Just a few quick questions:
1) Vag-com interface: Is this under the ashtray in the central console in the Leon? I noticed a purple plug there, the black cover was missing after my service. Why would the dealer be connecting anything to my car via this port for a regular oil change service?
ii) So you think they should they have changed my airfilter at 20k miles?
iii) Whereabouts in the engine bay is the diesel pump located?
Cheers again.
-Matt
Even when its a regular Oil change service, they will still plug in the 5051 VAG Computer to do general diagnostic readings reset fault codes etc.
It maybe this is where they've done something, but i cant think what they could of done, its sophisticated system, and only they would know what they've done.
The diagnostic computer is pretty much linked into everything, even your car stereo speakers are linked into it.