audi a4 1.9 tdi misfire

[mattol]

hi first post for me. i recently purchased an a4 1.9 tdi 2000 reg 174000k. it's started misfiring at 1900 to 2200 rpm (more notisable in 4th and 5th gears). i've had in plugged in at my local bosch service centre it showed no fault. i've changed the fuel filter and maf also checked the vaccum system over and replaced the hose from the turbo actuator valve to the solenoid. still the same problem.
could it and injector on wiring loom for the them or ecu fault.

any ideas would be greatly appreciated...

[megger]

hi first post for me. i recently purchased an a4 1.9 tdi 2000 reg 174000k. it's started misfiring at 1900 to 2200 rpm (more notisable in 4th and 5th gears). i've had in plugged in at my local bosch service centre it showed no fault. i've changed the fuel filter and maf also checked the vaccum system over and replaced the hose from the turbo actuator valve to the solenoid. still the same problem.
could it and injector on wiring loom for the them or ecu fault.

any ideas would be greatly appreciated...

Get rid of it. Iv'e had nothing but aggro with my 1.9tdi Audi.

[Ray2]

Did you ever find out what the problem was I have a similar thisng with my Audi as follows:-
I have an Audi A6 Avant, have owned it for about 5 years, 2003 1.9tdi. SE 216000 miles.
After starting from cold it runs fine for about 2 or 3 miles then miss fires under load for a few minutes, the ESP light usually comes on then it is very uneven.

I switch off and restart, let it tick over and off I go, sometimes I have to repeat this straight away then off I go with no further problems until it starts from cold again!

Audi garage checked diagnostics costing over £200 only to say they didn't know what it was but suggested it could be the head and considertha car age and mileage was not worth replacing as it would be expensive and put additional strain the rest so causing further problems.

Injectors have been suggested along with the head as above but I thought the problem would be on going if this was the case and not just whilst warming up.
A frustrating problem. Any thoughts as to what it could be or tests I could carry out would be greatly appreciated.
Thanks
Ray

[mattol]

hello still got the problem i'm afraid i changed the injector wiring loom apparently this is a very common fault (audi dealer sells about 10 a week) which made no difference but only cost £40 so maybe try that, i have been told maybe an injector or fuel pump problem. I've had any lights come on on the dash so i think yours maybe a different problem to mine. If i solve the problem I;ll let you know goodluck!
matt

[Ray2]

hello still got the problem i'm afraid i changed the injector wiring loom apparently this is a very common fault (audi dealer sells about 10 a week) which made no difference but only cost £40 so maybe try that, i have been told maybe an injector or fuel pump problem. I've had any lights come on on the dash so i think yours maybe a different problem to mine. If i solve the problem I;ll let you know goodluck!
matt

Thanks Matt, someone also suggested to me that it may be a temperature sensor so I'll find out what there is I can change and try it. If I have any luck I'll let you know.
My problem started in Dec 2008 then went away in about March but came back in Nov 2009 but more severe. I'm hoping it will go if the weather warms again.
Cheers
Ray

[mugenengineer]

hi first post for me. i recently purchased an a4 1.9 tdi 2000 reg 174000k. it's started misfiring at 1900 to 2200 rpm (more notisable in 4th and 5th gears). i've had in plugged in at my local bosch service centre it showed no fault. i've changed the fuel filter and maf also checked the vaccum system over and replaced the hose from the turbo actuator valve to the solenoid. still the same problem.
could it and injector on wiring loom for the them or ecu fault.

any ideas would be greatly appreciated...

Hi, just found this thread and the very same issue (with identical symptoms) has started happening with my A4 B6 1.9TDI Sport (AWX) FWD. Mileage is 144k and too be fair I've had 40k trouble-free mileage since buying it, besides a replacement dual mass flywheel n clutch. Did you find out what was causing the misfire? And if so could you post it back on here please?

Any help would be grately appreciated.

[mugenengineer]

Hi, just found this thread and the very same issue (with identical symptoms) has started happening with my A4 B6 1.9TDI Sport (AWX) FWD. Mileage is 144k and too be fair I've had 40k trouble-free mileage since buying it, besides a replacement dual mass flywheel n clutch. Did you find out what was causing the misfire? And if so could you post it back on here please?

Any help would be grately appreciated.

Just noticed a couple of characteristics that may help eliminate red herrings..

• The misfire only begins to happen once the engine has warmed up. Below 50'C (ish) there is no symptoms at all - this morning the misfire began after about 10miles of mild / moderate driving on my commute. So a relationship with temperature is a definite. As the car got warmer, the symptoms intensified until the thermostat energised the diverter valve and the radiator maintained the system at normal running temp.
• When the temp is right for the problem to be present, the symptoms are only experienced under load (in gear with throttle applied), but there is a 'window'. 1% to 10% throttle misfire is mild to non-existent. 10% to 60% throttle misfire is VERY noticeable! 60% to 100% throttle misfire is non-existent.
  When not in gear, revving through 1800rpm - 2200rpm does not display any misfire at all but I have noticed that it is almost impossible to hold the revs steady within this range (say, at 2000rpm). The engine either wants to fall below this range (at 1800rpm), or ride above it (at 2200rpm). Never performed this test before the problem appeared so can't say for sure that this is related to the misfire under load, but it sure is a bit suspicious!

Please, any help from anyone would be highly appreciated!

[mattol]

hi just let you know i tried various things to try and solve the problem:
new air mass meter, air temp sensor, turbo actuator solenoid, injector wiring loom. was told probably needs new injector but which one they couldn't say as they all gave a random reading on snap on diagnostic machine,
the other possiblity was blocked vains in the turbo.

no one really knew for sure, so i decided to cut by losses and sold on ebay with missfire..
still got reasonable price for it though
sorry i couldn't be more help good luck

[mugenengineer]

hi just let you know i tried various things to try and solve the problem:
new air mass meter, air temp sensor, turbo actuator solenoid, injector wiring loom. was told probably needs new injector but which one they couldn't say as they all gave a random reading on snap on diagnostic machine,
the other possiblity was blocked vains in the turbo.

no one really knew for sure, so i decided to cut by losses and sold on ebay with missfire..
still got reasonable price for it though
sorry i couldn't be more help good luck

No worries mate, appreciate the response and at least knowing what you tried and what others are suggesting is helping.

Sorry to hear the issue remained unresolved - I plan to get to the bottom of the issue on my motor and when I do I'll post the fix back on here.

[mugenengineer]

Right then guys, replacing the injector wiring loom (or harness) successfully cured the misfire on my car

..just be careful when fitting the new one - follow the instructions / pics here: Click here

Easy peasy!