What can cause hesitation on acceleration?

an2rey

A2OC Donor
Guys, I would appreciate your thought on the following. I have a Stealth map on my car, 100.6bhp.
Recently, an oil service and MOT have been carried out by the main dealer, all good. Although, after collecting the car it just felt so different, very dull, felt like somebody was holding me back when trying to accelerate. Before service, when I put my foot down the revs were easily reaching the red zone in 3-4-5 gears and car was accelerating much quicker, I was able to feel that extra power cruising in 5th gear, whether now, it feels like a pre-mapped car. In 1st gear when taking off it feels like I am towing a caravan. Just wondering, whether the dealer could have removed or disabled the map somehow?, I am not sure whether it is possible though. Or what else can cause such hesitation? Thank you!
 

an2rey

A2OC Donor
Dan, Thanks for the prompt reply as always.
How can it be traced and where the obvious places to look for a leak? If it is a boost leak, why it is happened immediately after the service?
 

Skipton01

Well-Known Member
It may have appeared after the service because something has been disturbed - it's very normal for boost leaks to appear after cambelt services especially, as to change the cambelt, the engine is raised off its mount a little - this often pulls the little vacuum pipes apart.

Check around the drivers side of the engine bay for the little black pipes. See if there's any splits and in particular, my money is on a solid plastic green pipe having slipped out of a black rubber pipe at the left rear of the engine.

Cheers,

Mike
 

an2rey

A2OC Donor
It may have appeared after the service because something has been disturbed - it's very normal for boost leaks to appear after cambelt services especially, as to change the cambelt, the engine is raised off its mount a little - this often pulls the little vacuum pipes apart.

Check around the drivers side of the engine bay for the little black pipes. See if there's any splits and in particular, my money is on a solid plastic green pipe having slipped out of a black rubber pipe at the left rear of the engine.


Mike

Thank you, Mike! I would have to investigate and hope that it can be easily rectified. You are probably right, to pin point to the boost leak, as on heavy acceleration I have a humming noise coming from the engine, that I never heard before.
Cheers,
 
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dan_b

A2OC Donor
I had a boost leak develop after a cambelt change - turned out the mechanic had disturbed/ split/ disconnected the little vacuum lines down the back of the engine that control the turbo wastegate actuator.

Humming noise could also be pressurised air escaping from a split in the intercooler at the bottom - that's another common failure route. A quick visual inspection will tell you - look for any signs of oil splat at the bottom of the intercooler - it should be nice and clean.
 

an2rey

A2OC Donor
Well, my visual inspection did not bring any results. Checked all visible pipes and connectors, all seems fine. There only one plastic pipe attached to an L shaped nozzle, leading back from top of the engine, which had signs of grease or diesel, but it always been like that. Do I have to look for the vacuum lines from under the car or they can be seen from the top of the engine?
Intercooler looks dry, no signs of oil or any leaks.
The car is reaching 40-50 m/h with a great difficulty, steering is very heavy, almost like power steering is off, it simply dangerous to drive as it's not easy to keep up with the traffic flow. I have done 100 miles trip in this condition yesterday, it just crazy.
 

Skipton01

Well-Known Member
The prime suspect pipes live down the back of the engine on the drivers side - if you follow the rubber vacuum pipes from the manifold block, you'll come across 2 that dip down the back. Further down, there's a plastic pipe that fits inside the rubber pipe and it's this that normally slips out or gets cracked.

Cheers,

Mike
 

an2rey

A2OC Donor
photo(1).JPG photo(2).JPG

Thanks Mike, that is where I have a greasy looking pipe running down.
 
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Skipton01

Well-Known Member
That's just a breather and will always have some oil seepage. The pipes you're tracking down are the thin black rubber ones behind that breather and drop straight down behind the engine to the turbo area.
 

dan_b

A2OC Donor
Slightly concerned that you're saying the power steering has stopped working too since the work. Who did the work for you?
 

an2rey

A2OC Donor
Slightly concerned that you're saying the power steering has stopped working too since the work. Who did the work for you?
The power steering is working, it just feels a lot heavier than usual. Could that be due to a loss of power?
I had interim service and MOT carried out by Worthing Audi at the same time as my OSS replacement. I am not pointing at them, but it all started immediately after I collected the car.
I will do some more investigation in the evening and hopefully will be able to trace the issue.
 

dan_b

A2OC Donor
Check your powersteering fluid level - it's the green bottle beneath the offside headlamp - easiest way is to take the headlamp cluster out!
 
Surely your first port of call should be Worthing Audi. The car should have come back better than it went in after being serviced. Contact them and tell them so they can arrange for you to go to a local dealer FOC. I had a similar prob when my 80 tdi had its first mot in 97, Audi said that it had blown the turbo, tuned out to be a air metre wrecked by the 'new' mot. Audi refused to pay as it was 2 weeks out of warrenty, but the dealership paid half. Just as well I didnt let them replace the turbo. They did admit it was their fault, a bit like yours. I lost confidence in Audi and swapped to a Merc, even worse. Best of luck Colin
 

an2rey

A2OC Donor
Had a good look at all vacuum lines as suggested, all seem to be fine, no cracks or leaks. Examined thoroughly an intercooler, all dry, no leaks. Started the engine and listened to it, immediately could hear a strange humming noise coming from the driver's side of the engine. Well, of course, it could not be easier...., the pipe right in front of me was dislodged from its place, not sure how it's called and what does it do, it is pointed on the pictures. I have connected the pipe securely, went for a drive and it looks like the car is back to normal, although, I still have a slight suspicion that something else is playing on, time will show. Could that pipe cause so much power loss..? Greatly appreciate all your advice and comments as usual!

photo(4).JPG photo(3).JPG
 
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the grim reeper

A2OC Donor
I would say yes as the part of the pipe with the cable connection is your MAF meter and it will not get the correct reading so has just gone hey wire if you know what i mean lol

Phil
 

Leopard680

A2OC Donor
Glad I found this thread! Same problem with Alison. Her clutch master cylinder was replaced. The engine needed to be dropped. This caused one of the three very small diameter vacuum hoses to part from another thing. Tomorrow Alison will return to the garage who will reunite said pipe to wherever it should go. There are two small diameter black pipes and one green one. It is one of the black pipes that has come adrift.

Thankyou very much!

:D
 
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