Audi TDI Smoking on startup and bad injector readings
Discussion
Car is a 140bhp tdi audi a3 with a BKD engine
The problem bad smoke on startup (its definatly diesel smoke)
will smoke badly on cold startup and doesnt start very well
the bad smoke on cold startup will stay for a good few minutes if i leave the car on tickover but if i drive the car right away the smoke is gone in a few seconds and it doesnt smoke then unless i turn it off and start it from cold again.
when its warm it starts fine and does not smoke.
when im driving it does feel like i get the odd misfire sometimes
Vagcom says misfire on cylinder 1
I checked my injector readings and i get
cyl1 cyl2 cyl3 cyl4 measured in mg/str when cold
2.99 -3.01 2.79 -2.78
when the car is upto temp it goes to
2.82 -1.6 -0.73 0.45
from what i can gather reading online injector 1 is injecting out of spec and injector 2 is trying to compensate for it same with injector 2 and 3 when cold but when warm injector 2 and 3 are within tollerance but injector 1 and 2 are still struggeling
things iv tried
checked coolant and its not loosing any
fuel pressure is fine
changed glow plugs
changed injector loom
changed injector 1 and when the old one came out had an x on it so from that someone has already swapped them at some point cos iv been told that means they are exchange units
changed tandem pump
changed starter motor
changed the MAF
compression tested cylinders and they were fine
the car has had a full service
Does anyone have any idea what I can try next
i do have a ross tech vag com cable so can check more reading if needed
Those figures could well mean, No 1 isnt injecting enough (because its faulty)and 2 is trimmed right back to try and smooth it out. That would be my first thought looking at those figures.
But it could equally be No.2 has a poor nozzle and is masivly over injecting so the ecu is trying to trim the injection quantity right back. That would give you smoke.
With No.1 and No.3 out of spec high and 2 and 4 out of spec low, it could be simply the injectors are not seated correctly or the injector seals have failed or not fitted correcly.
If you pump a bit of fuel out of the fuel filter what colour is it, if its black the injector seals are not sealing correctly, and or an injector is not seated correctly.
You need to swap the injectors round in the head, with new injector seals fitted and see what happens to the figures really.
But none of this explains why it improves with temperature.
There is sadly a chance that the seats are worn where the injectors seal in the head, this causes a loss of fuel pressure and the random injection readings you have. Also this fault tends to change with engine temperature. Only a new head will fix this fault. But at £1200 its has to be a last resort.
But it could equally be No.2 has a poor nozzle and is masivly over injecting so the ecu is trying to trim the injection quantity right back. That would give you smoke.
With No.1 and No.3 out of spec high and 2 and 4 out of spec low, it could be simply the injectors are not seated correctly or the injector seals have failed or not fitted correcly.
If you pump a bit of fuel out of the fuel filter what colour is it, if its black the injector seals are not sealing correctly, and or an injector is not seated correctly.
You need to swap the injectors round in the head, with new injector seals fitted and see what happens to the figures really.
But none of this explains why it improves with temperature.
There is sadly a chance that the seats are worn where the injectors seal in the head, this causes a loss of fuel pressure and the random injection readings you have. Also this fault tends to change with engine temperature. Only a new head will fix this fault. But at £1200 its has to be a last resort.
thank you for your post tame technicion
i bought a spare engine today for £480 off ebay and that comes with a c code head and a set of injectors so iv got the parts if i need them now,i guess it looks like my next port of call is to buy a new set of injector seals and stretch bolts and fit those with the injectors out of the spare engine when it arrives, i hope i dont have to change the head over as thats a massive pain,
are there any tests i can do to check if the seats are gone
i bought a spare engine today for £480 off ebay and that comes with a c code head and a set of injectors so iv got the parts if i need them now,i guess it looks like my next port of call is to buy a new set of injector seals and stretch bolts and fit those with the injectors out of the spare engine when it arrives, i hope i dont have to change the head over as thats a massive pain,
are there any tests i can do to check if the seats are gone
While your changing the injectors from the doner engine, look into your head and look at the injector seats.
They should be uniform all the way arround, like a valve seat in a combustion chamber, but much smaller. If they are sort of oval or the seat is not uniform, wider in some places than others, the head is faulty.
The injecor strech bolts are 3Nm + 90 degrees then 180 degrees.
Rocker shaft strech bolts are 20nm + 90 degrees.
The bolts wont pull the injectors into possition, they must be pressed down first.
They should be uniform all the way arround, like a valve seat in a combustion chamber, but much smaller. If they are sort of oval or the seat is not uniform, wider in some places than others, the head is faulty.
The injecor strech bolts are 3Nm + 90 degrees then 180 degrees.
Rocker shaft strech bolts are 20nm + 90 degrees.
The bolts wont pull the injectors into possition, they must be pressed down first.
ok i finaly got around to changing the injecotors,used all new o rings stretch bolts etc and started it and iv still got the same problem,nightmare,lol
i took photos of the cam and injector holes,do they look ok
these are my cold start reading
12:30:39
7.4 °BTDC Injection Start (specified)
6.6°KW Injection Duration (specified)
2.5°KW Torsion Value
2.99 mg/str Injection Quantity Deviation Cyl. 1
-2.94 mg/str Injection Quantity Deviation Cyl. 2
-2.96 mg/str Injection Quantity Deviation Cyl. 3
2.82 mg/str Injection Quantity Deviation Cyl. 4
i took photos of the cam and injector holes,do they look ok
these are my cold start reading
12:30:39
7.4 °BTDC Injection Start (specified)
6.6°KW Injection Duration (specified)
2.5°KW Torsion Value
2.99 mg/str Injection Quantity Deviation Cyl. 1
-2.94 mg/str Injection Quantity Deviation Cyl. 2
-2.96 mg/str Injection Quantity Deviation Cyl. 3
2.82 mg/str Injection Quantity Deviation Cyl. 4
Edited by markmills2000uk on Thursday 2nd February 13:14
Bloody hell, thats a tricky one. Nightmare indeed.
Hard to tell from the pics but injector seats do look fine to me.
Cam looks a little worn but not anywhere near enough to cause a problem
Did you set up the injector clearance (the thing that looks like a old school tappet adjustement) 18mm nut 6mm allen in the middle.
Has it got a new, genuin fuel filter?
What injectorion trim readings do you get now.
Hard to tell from the pics but injector seats do look fine to me.
Cam looks a little worn but not anywhere near enough to cause a problem
Did you set up the injector clearance (the thing that looks like a old school tappet adjustement) 18mm nut 6mm allen in the middle.
Has it got a new, genuin fuel filter?
markmills2000uk said:
The problem bad smoke on startup (its definatly diesel smoke)
Are you sure its diesel smoke? what colour is it, whats it smell like. markmills2000uk said:
when im driving it does feel like i get the odd misfire sometimes
Is it a propper misfire, like you have lost a cylinder or just the odd splutter?What injectorion trim readings do you get now.
yeah brand new fuel filter from tps
i set up the injector clearence by tightening it up till i felt it touch the bottome then i turned it back quarter of a turn
here is a video of the smoke,it smells very diesely and iv had two other guys say its definatly diesel smoke,also im definatly not loosing any water
i wouldnt say iv lost a cylinder just the odd splutter but not too much
im wondering could the engine loom be damaged maby????
i set up the injector clearence by tightening it up till i felt it touch the bottome then i turned it back quarter of a turn
here is a video of the smoke,it smells very diesely and iv had two other guys say its definatly diesel smoke,also im definatly not loosing any water
i wouldnt say iv lost a cylinder just the odd splutter but not too much
im wondering could the engine loom be damaged maby????
OK looks like diesel smoke, if it smell like diesel then it is.
The correct seting is to back the injector off 1/2 a turn from the bottom stop when the injector is fully compressed. Turning the engine over to compresses each one as you set them up. 1/4 turn might be enough. Its to stop them bottoming out when the engine is running they have expanded a bit with heat.
It will be pretty hard to test, but at this stage what I would want to know is, does the signal to trigger the injector get from the ECU to the injector its self. So that checking all the harness from the ECU to the connector on the back of the head, and from there to the injectors. But I'm sure you would get a more in your face misfire if one of the wires was bad, and a fault code too.
What you have looks like massive overfueling (from a failed or dribbling injector) or fuel leaking into the cylinders while the engine is off then burning off the cat when it starts
If the wires are all ok, and everything else logical has been replaced, (injecors, tandem pump etc) maybe its the ECU.
Someone on here had funny injector reading and reflowed there ECU and fixed it, but I cant find the thread.
The correct seting is to back the injector off 1/2 a turn from the bottom stop when the injector is fully compressed. Turning the engine over to compresses each one as you set them up. 1/4 turn might be enough. Its to stop them bottoming out when the engine is running they have expanded a bit with heat.
It will be pretty hard to test, but at this stage what I would want to know is, does the signal to trigger the injector get from the ECU to the injector its self. So that checking all the harness from the ECU to the connector on the back of the head, and from there to the injectors. But I'm sure you would get a more in your face misfire if one of the wires was bad, and a fault code too.
What you have looks like massive overfueling (from a failed or dribbling injector) or fuel leaking into the cylinders while the engine is off then burning off the cat when it starts
If the wires are all ok, and everything else logical has been replaced, (injecors, tandem pump etc) maybe its the ECU.
Someone on here had funny injector reading and reflowed there ECU and fixed it, but I cant find the thread.
i just went out and redid the setting so they are all back half a turn now,cheers for that could have done some damage if i had gone for a drive,
i guess i now need to find out how to check if the signal is getting to the injectors ,it is very lumpy when it starts not sure if that points to anything.
i get a misfire fault code on cylinder 1 put its not very frequent,only if i boot it from cold i think.
iv changed the injectors for a set out of another engine i had here so hoping that should take the dribbling injector out of the equasion.also i can leave the car running for a bit and it clears and then if i turn the car on and off straight away it smokes again but if the car has done a long run i can leave it a couple of hours and start it and get no smokes,never smokes once its warm but my injector readings are still out of spec.
Maby it might be worth getting my ecu firmware updated (depending on cost)
cheers for your help on this problem id be lost otherwise
i guess i now need to find out how to check if the signal is getting to the injectors ,it is very lumpy when it starts not sure if that points to anything.
i get a misfire fault code on cylinder 1 put its not very frequent,only if i boot it from cold i think.
iv changed the injectors for a set out of another engine i had here so hoping that should take the dribbling injector out of the equasion.also i can leave the car running for a bit and it clears and then if i turn the car on and off straight away it smokes again but if the car has done a long run i can leave it a couple of hours and start it and get no smokes,never smokes once its warm but my injector readings are still out of spec.
Maby it might be worth getting my ecu firmware updated (depending on cost)
cheers for your help on this problem id be lost otherwise
ok i think i might have had a small breakthough,i went out just now to put some moly purge through the engine which means disconecting the fuel lines from the fuel filter and putting the flow and return from and putting them straight into a can,started the car and had no smoke so plugged in vag com and injectors were all within tollerance,
im guessing this means there is somethings up between the fuel tank and the fuel filter,im waiting for the car to go cold again and am going to try with pure diesel in a can instead of moly purge and take reading again just to be sure but im thinking maby the lift pump has something wrong with it or maby someone at some point could have put fuel lines on wrong way around?????
im guessing this means there is somethings up between the fuel tank and the fuel filter,im waiting for the car to go cold again and am going to try with pure diesel in a can instead of moly purge and take reading again just to be sure but im thinking maby the lift pump has something wrong with it or maby someone at some point could have put fuel lines on wrong way around?????
no scratch that i was getting ahead of myself,must have just been that the purge stuff doesnt smoke as much,
what i have learnt today is that since changing my injectors my mpg apears to have increase from 53mpg to 57mpg,thats good
my injector readings do seem to have improved,iv not taken readings when the car is warm yet but when its cold on tickover they were
1.93 -1.86 -0.4 0.33
technicaly that within tollerance cos tollorance is -2.8 to +2.8,
i wish i knew what i am doing cos its still smoking,lol
what i have learnt today is that since changing my injectors my mpg apears to have increase from 53mpg to 57mpg,thats good
my injector readings do seem to have improved,iv not taken readings when the car is warm yet but when its cold on tickover they were
1.93 -1.86 -0.4 0.33
technicaly that within tollerance cos tollorance is -2.8 to +2.8,
i wish i knew what i am doing cos its still smoking,lol
Edited by markmills2000uk on Thursday 9th February 20:58
Be interesting to see what they are like hot and cold.
I got to admit, really not sure whats causing this.
The fuel coming out the filter isnt black is it? (No engine oil in the fuel)
Oil level normal (not suspiciously high) (No fuel in the engine oil)
Did you try it with the EGR blanked off yet.
Look on the bright side, I live for very occasionly getting the magic 30mpg, your getting 57, with an apparant over fuel on cold start, cant be that bad.
I got to admit, really not sure whats causing this.
The fuel coming out the filter isnt black is it? (No engine oil in the fuel)
Oil level normal (not suspiciously high) (No fuel in the engine oil)
Did you try it with the EGR blanked off yet.
Look on the bright side, I live for very occasionly getting the magic 30mpg, your getting 57, with an apparant over fuel on cold start, cant be that bad.
to get that mpg i really have to cruise at 50mph on a long journey,i dont do that very often lol. Before i changed the injectors when id get 53mpg on a long granny run my fuel calculater was only ever 1 or 2 mpg out compared to briming the tank so hopefully as long as thats still accurate then i definatly have an improvement.its all a massive improvement over my someof my previous cars though,1 of which being a 6.6 litre trans am,now that had poor fuel economy,lol
im doing a journey today so il get some hot and cold readings from the injectors tonight and post them up tommoorrow,
iv checked the fuel filter and the diesel is clean as a whistle and green the same colour it comes out the pump,
0il level is fine and not high at all,last time topped it up i filled it to just below max and its still around there but il keep an eye on it cos it should go down once iv done some more miles,
iv not blanked off the egr but i did drive it for a while with the vacuum pipe unpluged and that made no difference apart from turning the engine management light on after a while.
today i also tried starting it with the ect sensor unplugged and that made no difference
im going to ring audi on monday and get it booked in to get the ecu firmware updated,from what iv read they quite often update them free when you have a service,i dont need a service but il see if they will just do the update even if i have to pay a bit,guy on another forum got told if he had a diagnostic test done for £57 quid then they will update the firmware and id be happy to do that.
pospiech is your problem the exact same as mine,what have you tried to fix it so far??
im doing a journey today so il get some hot and cold readings from the injectors tonight and post them up tommoorrow,
iv checked the fuel filter and the diesel is clean as a whistle and green the same colour it comes out the pump,
0il level is fine and not high at all,last time topped it up i filled it to just below max and its still around there but il keep an eye on it cos it should go down once iv done some more miles,
iv not blanked off the egr but i did drive it for a while with the vacuum pipe unpluged and that made no difference apart from turning the engine management light on after a while.
today i also tried starting it with the ect sensor unplugged and that made no difference
im going to ring audi on monday and get it booked in to get the ecu firmware updated,from what iv read they quite often update them free when you have a service,i dont need a service but il see if they will just do the update even if i have to pay a bit,guy on another forum got told if he had a diagnostic test done for £57 quid then they will update the firmware and id be happy to do that.
pospiech is your problem the exact same as mine,what have you tried to fix it so far??
Edited by markmills2000uk on Saturday 11th February 14:02
I havent done half as much as you only had 1 of the injectors replaced but didn't work the additives seem to work for a few days my friend is a mechanic so he's looking at other possible reasons if any work I will let you know and if you find a solution please let me know sorry I'm not much help
would it be a sticky needle in the nozzles?
i had the same problem on a AGR engine recently,tapping away when cold, but when warm it went away, sounded like a misfire, and smoked white/grey smoke!
in my case, i removed the injectors 1 by 1, took the nozzles out, removed the needles and cleaned them up with brakecleaner and a air line, then put them backtogether, and its working fine now!
i also had a problem with the needle lift sensor, what fault codes is vagcom throwing up?
i had the same problem on a AGR engine recently,tapping away when cold, but when warm it went away, sounded like a misfire, and smoked white/grey smoke!
in my case, i removed the injectors 1 by 1, took the nozzles out, removed the needles and cleaned them up with brakecleaner and a air line, then put them backtogether, and its working fine now!
i also had a problem with the needle lift sensor, what fault codes is vagcom throwing up?
sorry not updated this iv not used the car recently to get it properly warm,
my warm readings were
19:51:22
93.6°C Coolant Temperature (G62)
0.0 °BTDC Injection Start (specified)
7.1°KW Injection Duration (specified)
1.0°KW Torsion Value
245.0 mg/str Mass Air Flow (actual)
-0.28 mg/str Injection Quantity Deviation Cyl. 1
-1.13 mg/str Injection Quantity Deviation Cyl. 2
0.71 mg/str Injection Quantity Deviation Cyl. 3
0.66 mg/str Injection Quantity Deviation Cyl. 4
i dont think its a sticky injector as i have differnt injectors fitted now.
my warm readings were
19:51:22
93.6°C Coolant Temperature (G62)
0.0 °BTDC Injection Start (specified)
7.1°KW Injection Duration (specified)
1.0°KW Torsion Value
245.0 mg/str Mass Air Flow (actual)
-0.28 mg/str Injection Quantity Deviation Cyl. 1
-1.13 mg/str Injection Quantity Deviation Cyl. 2
0.71 mg/str Injection Quantity Deviation Cyl. 3
0.66 mg/str Injection Quantity Deviation Cyl. 4
i dont think its a sticky injector as i have differnt injectors fitted now.
sorry I might be missing something but why dont you just take it back to audi, even if you bought it private, crashed it and repaired it and even had your own service history this is not acceptable.
Why are people think ah well injectors went faulty we will fix ourself. this is not acceptable, if injectors are going faulty after 5 years then they were not fit for purpose int he first place, you could go to small claims court and argue this quite successfully. I have had cars that were 15 years old and I have never in my life had this think about injectors until I bought this bloody audi a8.
I am sure I have a problem and as soon as its confirmed I will go to audi and say i want this fixed asap foc. I have no cover what so ever and my car is 3 years out of warranty. why do I expect this? becuase I dont find it acceptable that these cars that cost in excess of 18-20k when new (60k in my case) and for them to go belly up 5 years later. A one off I can understand but not this. I am not letting this lay down. I will then set up a website called chocolate injectors.com and dedicate it to audi, by the time im finished with them they will wish i never bought the dam thing.
Why are people think ah well injectors went faulty we will fix ourself. this is not acceptable, if injectors are going faulty after 5 years then they were not fit for purpose int he first place, you could go to small claims court and argue this quite successfully. I have had cars that were 15 years old and I have never in my life had this think about injectors until I bought this bloody audi a8.
I am sure I have a problem and as soon as its confirmed I will go to audi and say i want this fixed asap foc. I have no cover what so ever and my car is 3 years out of warranty. why do I expect this? becuase I dont find it acceptable that these cars that cost in excess of 18-20k when new (60k in my case) and for them to go belly up 5 years later. A one off I can understand but not this. I am not letting this lay down. I will then set up a website called chocolate injectors.com and dedicate it to audi, by the time im finished with them they will wish i never bought the dam thing.
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