low rev/idle performance issue

[mathew lisett]

so generally when the car has started from cold its "normally" laggy, its certainly not smooth and normally goes straight to 1400revs for idle and then may take 1 minute to come down to 800revs. but even when this is happening and even if the car goes straight to 800 in random moments, the whole time the idle is lumpy and if you press the throttle it struggles to give some revs and only gets smoother when it gets to around 2.3k.

it also has an issue when you slow down to a junction and you need to get off again, you need to rev the engine a little so that it "wakes up" so to speak for the performance to pull it forward, but again it only happens at low revs.

when its higher revs, it pulls away.

after seeing another forum post on another audi forum, im starting to think its to do with the fuel pressure pump?

 

[SDHA4SLine]

What engine, I'm assuming a dirty diesel like me?

With this sort of thing I'd always start with the same things, vcds scan if possible then remove egr and check it's not caked up with crud.

Sorry it's a stock answer but vcds really is the best starting point

Regards
Steve

 

[mathew lisett]

2.0 tfsi se

petrol

whats vcd's and egr? sound slike a case of std's lol

 

[SDHA4SLine]

Vcds is the best (I believe) diagnostic equipment for vag cars. Egr " exhaust gas recirculation"

Many members on here have vcds and will help you out with a scan using it for beer tokens

 

[SDHA4SLine]

Forum members with vcds can be found here

http://www.audi-sport.net/xf/forums/vcds-formerly-vag-com-forum.27/

 

[dodsie75]

Start with the easy stuff. When were the plugs last changed?

 

[mathew lisett]

the sparks were installed in the last month, the coils were installed about 2 weeks later.

 

[mathew lisett]

so since for some reason the "your content" is only bringing up posts and not threads that ive created, im going to update this thread.

sent the car to audi and they found that its currently an injector or injector wiring issue .

as i type they wont check the crankcase breather hose/pipe or the pcv until the injector issue is sorted . and same goes for testing the clutch, but i have asked if its possible to do the test without sorting out the injector.

one good thing is that the compression test came back as good.

 

[SemiT]

My 2.0TFSI can be a little sluggish with revs at times. Even giving it normal revs it seems to bog down on normal acceleration from zero (not launching it like a loon). However, mine seems far worse when cold and before the coolant temperature is up to 90 degrees. Once there it's far better. Thermostat and housing was replaced in 2014 by the previous owner but I'll be replacing the coolant temp sensor this weekend.

Another strange symptom - when clutch is in I can blip the throttle and the revs barely rise at all. Even with a decent stab it'll often barely raise the revs at all.

I have full VCDS and have found no reason for this behaviour. It's been dynoed at MRC and they didn't mention anything untoward.

Interestingly I was logging in-tank fuel pump duty and according to the Rosstech site mine is working in the "getting tired, time to replace" percentile.

I have replaced both main PCV valve and the "rear" (on ours left-side) PCV tube (the revised part with one-way valve), plugs, N80, HPFP follower etc but never really solved it. It's manageable and rarely bothers me now.

 

[DrEvil]

My 2.0TFSI can be a little sluggish with revs at times. Even giving it normal revs it seems to bog down on normal acceleration from zero (not launching it like a loon). However, mine seems far worse when cold and before the coolant temperature is up to 90 degrees. Once there it's far better. Thermostat and housing was replaced in 2014 by the previous owner but I'll be replacing the coolant temp sensor this weekend.

Another strange symptom - when clutch is in I can blip the throttle and the revs barely rise at all. Even with a decent stab it'll often barely raise the revs at all.

I have full VCDS and have found no reason for this behaviour. It's been dynoed at MRC and they didn't mention anything untoward.

Interestingly I was logging in-tank fuel pump duty and according to the Rosstech site mine is working in the "getting tired, time to replace" percentile.

I have replaced both main PCV valve and the "rear" (on ours left-side) PCV tube (the revised part with one-way valve), plugs, N80, HPFP follower etc but never really solved it. It's manageable and rarely bothers me now.

What is your fuel duty cycle out of interest. Does you low pressure log well? And how low does it go on Wot?