Author Topic: Throttle lag  (Read 970 times)

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Offline Hotspur

  • Posts: 4
Throttle lag
« on: April 21, 2019, 03:31:49 pm »
2004 A3 2.0 FSI
The throttle can be a little jerky
But of more concern is the, at times, serious lag in pickup/acceleration
"Pumping" the pedal will then bring immediate response
Of late, has had fuel pump replaced, and coils and plugs too
Crank sensor just done, Scan reveals "no codes/issues"
I have seen "manifold pressure sensor" mentioned on another Forum, re another model
Any ideas please
« Last Edit: April 23, 2019, 07:37:39 am by Hotspur »

Offline Hotspur

  • Posts: 4
Re: Throttle lag
« Reply #1 on: May 24, 2019, 08:14:54 pm »
Wow

A Month has gone by and no ideas

 ???

Offline McDoof

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Re: Throttle lag
« Reply #2 on: May 27, 2019, 10:52:09 am »
AFAIK these are DWB, so could be something to do with the pedal side sensor.
Could be dirty/faulty MAF
Could be a dirty air filter
Could be a sticky throttle body
Could be excess carbon build up
NZ New MK5 GTI - Tuned by HSP Tuning

Offline Hotspur

  • Posts: 4
Re: Throttle lag
« Reply #3 on: June 06, 2019, 08:31:16 pm »
Thanks for your thoughts

Sorry, what is DWB and MAF

Air Filter has been changed. It's been scanned twice. ("It's fine")

The "pedal side sensor" - You mean that area at the base of the pedal itself ?

Is the excess carbon a contributor/related issue to the sticky throttle body ?

Thanks again

Offline McDoof

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Re: Throttle lag
« Reply #4 on: June 07, 2019, 02:22:32 pm »
Thanks for your thoughts

Sorry, what is DWB and MAF

Air Filter has been changed. It's been scanned twice. ("It's fine")

The "pedal side sensor" - You mean that area at the base of the pedal itself ?

Is the excess carbon a contributor/related issue to the sticky throttle body ?

Thanks again

DWB = Drive by Wire. which means that there is no physical connection from the accelerator pedal to the throttle body
MAF = Mass Air Flow sensor. This a sensor that sits in line with your intake pipe. Normally between the air filter and the throttle body. It measures the amount of air going into the engine. If it gets dirty or damaged, the readings are out and the fuel and timing adjustments that are made by the ECU are thrown out.

The pedal side sensor is just the electronic box attached to the accelerator pedal that senses your throttle position. Part of the DBW system

A sticky throttle body and carbon build up are possibly symptoms of the same cause, but not the same thing.
EGR (Exhaust Gas Recirculation) pumps unburnt fuel back into the intake of the engine. Along with this is will also deposit carbon and some oily sludge into your intake.
This can sit around the valve stems and harden like rock. This can affect air flow into the cylinder. It can also blow back into the throttle body under some circumstances causing that to get sticky or just not flow as well as it should.
 
NZ New MK5 GTI - Tuned by HSP Tuning

Offline Hotspur

  • Posts: 4
Re: Throttle lag
« Reply #5 on: June 08, 2019, 02:03:47 pm »
Thanks for that detailed reply

I'll get those issues checked