Here goes 2005 a3 1.9tdi i bought car with starting issues so did vcds no codes at all but would not start very well took ages when it did start no boost at all so i did the following new injectors then no difference so then noticed timing belt was loose so fitted new timing belt and waterpump with tensioner start problem sorted starts first turn of the key but still no boost then told was turbo so put new cartrige in and still no boost the car starts runs fine but no boost and no airleak at all tried new maff map sensors no difference tried exhaust off no difference the actuator is moving when engine is on about 20mm cleaned all carbon from inside turbo vanes when turbo was off so it is all now moving free also its had a new dual mass flywheel and clutch before i bought it im now stumped i have just been told could be high pressure fuel pump or it could be ecu but dont want to guess anymore and still no codes any more suggestions i appreciate any help anyone local woud like to come and have a look i am willing to pay
a3 problems with no boost
- Thread starter brett.w
- Start date
I am not a diesel bloke but sounds to me like a waste gate problem. If its normally open but closed by vacuum then i would check the vacuum pipe to the wastegate. If it is producing pressure but its low then check for restrictions in inlet and exhaust. Interesting problem though 
thanks for your reply but already checked all pipework and the boost pipes do seem to swell up when revved like my golf with same engine only thing i can think of is something is wrong with cartrige on turbo that was installed although the pipe to actuator does open fully and when on vcds the exhaust note changed this is a new one i am guessing
Hi paddy thanks for the reply its amazing how people are willing to help others on today christmas eve i will go check the ic but im sure it ok as i think boost is getting through but not sure how much should come through you have me wondering the bottom boost pipe was off when i bought the car and i wonder if something crawled into it and built a nest but if so wouldnt it have come through the pipework also the egr had been deleted before i bought it another question how big would a hole have to be to loose all boost as if i put my tongue on all pipes from the 6 block near battery and then suck they all hold pressure against my tongue
hi sorry but another question is it possible when the turbo cartrige was installed the arm has missed the slot it goes into although i was present when they did this and did watch them check it all very through or would that stop the actuator moving as it was pressing aganst the turbo vane ring thingy
just a point, the human lungs can create about 3psi max and a turbo is running about 5 times that i think. that said 15psi is not a lot if i am correct. what would happen if you pulled the pipe of the inlet to the IC ? surely you would be able to feel if the turbo was blowing ?
i believe the turbo is blowing i am just off to quacks will check that again this afternoon what would a boost check tell me will that say turbo is fine if boost is high
If you have a tool to check error codes, then just do logs!! It is very easy to do.
Maybe you just expect too much from 77kw engine, because if there were no boost the underboost error code would show up.
Maybe you just expect too much from 77kw engine, because if there were no boost the underboost error code would show up.
hi just to clarify i have the same engine in a golf and when that boosts you can tell it has kicked in i have just thought wha could be the problem when the turbo cartrige was installed they may have not set up the arm to close the vanes properly i am going to check this on thursday so i will keep you informed thanks for all the help you guys are wonderful and a merry christmas to you all thanks
hi again just to say today i checked the boost and replaced the actuator but now i am beginning to think its more severe i took off the boost pipe both underneath at the outlet from intercooler and also later at the egr valve and and someone revved the enging and i could feel the pressure pushing my hand off the pipe so there is boost but still the engine has no power now i am totally flumoxed i have no idea where to go from here is it possible there could be something wrong with the high pressure fuel pump as its mechanical there is suction from the pipe at the back that goes to the 6 block valve on passenger side bulkhead or am i now needing to look at the ecu as the car starts and will drive just no power
to be honest i was dreading that reply but the car runs without any missing and no spluttering and ticks over sweet i will try that on saturday thanks
Paddy if i am ever near your area i will come buy you a pint Right i have some good news and another question i bought a compression tester from amazon its a good one so anyone in leeds needs to do a compression test i can help at weekends takes 30 mins and i do not have any bent valves as all the compessions were 30 bar 420 psi or around that so i decided to remove fuel pump and when i put it back i noticed i had pulled the wire from the fuel sensor and noticed it had already been repaired previous and covered with black tape then the corrugated sheathing anyway once fixed took ages to start car and when it did was no different so did a check and loads of faults came up cleared them then car actually sounds like it is nearly back to normal i have noticed since i installed some new injectors but could not programme them in as no vcds i have some smoke from exhaust and the new turbo that was put on seems to lack a little zoom i have now found out that when turbo was put on it may not have been set up correctly so the question is will taking the turbo back off and getting it set up correctly sort out the smoke from exhaust or will i have to put back in the old injectors to sort the smoke and when i put injectors in i did reset them as it says online with the allen key and spanner by tightening them down then loosen them, off i think 180 degrees cant be sure of the degrees but it was on internet somewhere the car is now accellerating better but still not as fast as it should be i am a very happy bunny though
Well done Bret Dont think i have played much of a part in this , its down to you ,mate. as for smoke i would live withit for a while and see if it clears. You did a fair few miles with it running rough so who knows how much oil and stuff is in the system and Exhaust that may need to be burnt off. there is a vcds map on here somewhere showng your nearest memeber who has the cable and can help.
Dont think i have played much of a part in this , its down to you ,mate. as for smoke i would live withit for a while and see if it clears. You did a fair few miles with it running rough so who knows how much oil and stuff is in the system and Exhaust that may need to be burnt off. there is a vcds map on here somewhere showng your nearest memeber who has the cable and can help.
i have a someone who is coming over tomorrow to sort it with vcds and see what its showing i cannot thank you enough for the encouragement you have given at the most family oriented time again thanks ill let you know how it goes tomorrow just need to set the turbo and hopefully all will be ok
Hi again had vcds done and no codes showing however the car still has little boost and you can feel it pick up slightly when you thrash it so really back to square one the vcds graphs show the car asking for boost and it is showing the turbo giving boost however the car is not setting off as you would expect and has loads of black oil in the exaust and coming out of exhaust as smoke and this was not there before the turbo was changed all vcds are showing normal so i am now wondering what else there could be wrong with it anyone know how to do a smoke test to fing a leak i could do with some help please thanks
Hi Bret
I cant really help because i have never owned a diesel in my life but If you are producing boost you have compression but the boost is not reaching the engine its either being diverted or leaking. The fact you have so much oil in the pipe would say to me the boost is pressurising the sump ? so its either coming up past the rings or more likely its being put in to the intake by some sort of re circulation system thats faulty..
I cant really help because i have never owned a diesel in my life but If you are producing boost you have compression but the boost is not reaching the engine its either being diverted or leaking. The fact you have so much oil in the pipe would say to me the boost is pressurising the sump ? so its either coming up past the rings or more likely its being put in to the intake by some sort of re circulation system thats faulty..
@brett.w , I found this site rather good at explaining the boost process , maybe a read would help elimate certain things that could maybe cause lack off . ( https://auto.howstuffworks.com/turbo1.htm )
