Audi 2.0 A4 tdi brd engine code ,,, injectors blocked????
Discussion
Hi new here guys after some technical help please. Audi a4 2.0 tdi 2007 brd engine code. Runs ticks over perfect. But wouldn't pull skin off rice pudding. Vcds engine fault 1 code just exhaust temp probe in turbo. This obviously doesn't give lack of power. Has anyone had similar fault. Is it fuel related as turbo , egr, mass air etc etc all working fine with vcds values. Measuring blocks on injectors does show odd readings but not sure what they should be. The only way it can get driven with some normality is if map sensor is unplugged but then I believe it just runs in basic settings. Any input would be greatly recieved. Are injectors blocked or fuel pressure an issue??? Thanks in advance
So you think the ECU seeing a faulty value from the exhaust temp sensor wont make it run the engine in a restricted performance (limp home) mode.
I dont agree, you have to rule that out first. IF you have a code reader whats the lice data from the sensor say? can you sub a resister to get it to read say 300 degress just for testing??
Failing that, you need to see my PD TDI diagnosis thread.
your problem could be one of these
Air Mass sensor faulty
Fuel pressure to low (filter, injector seals, tandem pump, cylinder head)
EGR (jammed open)
Turbo - vacuum control inop, split pipe, failed N75, leaking manifold flap actuator)
Turbo - Mechanical (damaged blades, shaft play / bearing failure
Valve timing
injectors need cleaning
DPF blocked if fitted
good luck
I dont agree, you have to rule that out first. IF you have a code reader whats the lice data from the sensor say? can you sub a resister to get it to read say 300 degress just for testing??
Failing that, you need to see my PD TDI diagnosis thread.
your problem could be one of these
Air Mass sensor faulty
Fuel pressure to low (filter, injector seals, tandem pump, cylinder head)
EGR (jammed open)
Turbo - vacuum control inop, split pipe, failed N75, leaking manifold flap actuator)
Turbo - Mechanical (damaged blades, shaft play / bearing failure
Valve timing
injectors need cleaning
DPF blocked if fitted
good luck
thanks for reply tame technician i was hoping u would after reading some of your other threads u seem a good guy.
items replaced so far
new ecu and latest software
egr valve
mass air meter
map sensor
dpf has been raped (ie cut open and emptied) b4 i got involved ( i also believe a bad remap was the cause of ecu dying)
new turbo charger
all pipe work correct
swirl flap acctuator diapragm replaced
apparently according to audi mofified injectors replaced on 2012 recall
electric pump in tank replaced
new fuel filter / air filter
the only code im getting now electrically is the exhaut temp sensor (g235) the one in the turbo charger short circuit. Ive ordered from audi today £113.00 ish
The only other thing i havent checked is tandem pump for pressure can this be checked with vcds i dont think so , unless u know different i think a bar gauge needs to be plumbed to it about 7bar i think it should run at.
The strange thing is i left it parked outside workshop all day yesterday as i was busy. without working on it as i started it to drive inside for overnight safety it revved crisp as the day it was from the showroom, i took it up road and it drove perfect with all power and boost. then 5 minutes later back to how it has been lack of throttle response and no power.
wierd eh??
Any input greatly recieved , Kind Regards steve
items replaced so far
new ecu and latest software
egr valve
mass air meter
map sensor
dpf has been raped (ie cut open and emptied) b4 i got involved ( i also believe a bad remap was the cause of ecu dying)
new turbo charger
all pipe work correct
swirl flap acctuator diapragm replaced
apparently according to audi mofified injectors replaced on 2012 recall
electric pump in tank replaced
new fuel filter / air filter
the only code im getting now electrically is the exhaut temp sensor (g235) the one in the turbo charger short circuit. Ive ordered from audi today £113.00 ish
The only other thing i havent checked is tandem pump for pressure can this be checked with vcds i dont think so , unless u know different i think a bar gauge needs to be plumbed to it about 7bar i think it should run at.
The strange thing is i left it parked outside workshop all day yesterday as i was busy. without working on it as i started it to drive inside for overnight safety it revved crisp as the day it was from the showroom, i took it up road and it drove perfect with all power and boost. then 5 minutes later back to how it has been lack of throttle response and no power.
wierd eh??
Any input greatly recieved , Kind Regards steve
Wow thats had alot of work.
The way the exhaust temp sensors tend to fail is they short to earth when they get to a certain temperature, so if you test them from cold, they may read 100 degress of somthing at idle and pass the test, but when you drive hard, or the DPF regens and the temp should be more like 400-800 degrees they fail and report back to the ECU as a short to ground or an implorsable signal. If you are driving the car hard, it needs to know the exhaust gas temp to control fueling and boost pressure, so it is very likely it would go into limp home and you would have no boost. But normally an ignition off and on again would fix this unlit the next temp the sensor goes out of spec.
In addition
The ECU might get confused if it thinks the car has a DPF and its been removed, it might try to regenerate it and go into limp mode when it doesnt regenerate. When the tries to regenerate it injects extra fuel after the main injection so it fuels the exhaust rather than the engines combustion, this increases the heat in the exhaust and burns the soot out of the DPF (known as regen) Now if the temp doesnt increase when extra injection occurs because the DPF is not there, this might be recored by the ECU as the temp sensor not working, but I think this is unlikely.
Fuel pressure doesnt usually come and go, but can do. You need a mechanical gauge to test it propperly, but if you get the car in a failed state, i.e no boost, and fit a hose clamp on the return like (blue paint + has fuel temp sensor in line) between the filter and the tandom pump, you can raise the fuel pressure artificially and if the performance returns its a low fuel pressure issue. Only do a short (3-4 mins) run with the clamp on or it will blow a hose off and you will have fuel everywhere.
The way the exhaust temp sensors tend to fail is they short to earth when they get to a certain temperature, so if you test them from cold, they may read 100 degress of somthing at idle and pass the test, but when you drive hard, or the DPF regens and the temp should be more like 400-800 degrees they fail and report back to the ECU as a short to ground or an implorsable signal. If you are driving the car hard, it needs to know the exhaust gas temp to control fueling and boost pressure, so it is very likely it would go into limp home and you would have no boost. But normally an ignition off and on again would fix this unlit the next temp the sensor goes out of spec.
In addition
The ECU might get confused if it thinks the car has a DPF and its been removed, it might try to regenerate it and go into limp mode when it doesnt regenerate. When the tries to regenerate it injects extra fuel after the main injection so it fuels the exhaust rather than the engines combustion, this increases the heat in the exhaust and burns the soot out of the DPF (known as regen) Now if the temp doesnt increase when extra injection occurs because the DPF is not there, this might be recored by the ECU as the temp sensor not working, but I think this is unlikely.
Fuel pressure doesnt usually come and go, but can do. You need a mechanical gauge to test it propperly, but if you get the car in a failed state, i.e no boost, and fit a hose clamp on the return like (blue paint + has fuel temp sensor in line) between the filter and the tandom pump, you can raise the fuel pressure artificially and if the performance returns its a low fuel pressure issue. Only do a short (3-4 mins) run with the clamp on or it will blow a hose off and you will have fuel everywhere.
couldnt find it, lots of info here though
no idea why google finds it in the manaro forum
http://www.pistonheads.com/Gassing/topic.asp?h=0&a...
http://www.hsv.org.uk/topic.asp?p=1&f=86&t...
http://www.hsv.org.uk/topic.asp?t=733947&f=86&...
no idea why google finds it in the manaro forum
http://www.pistonheads.com/Gassing/topic.asp?h=0&a...
http://www.hsv.org.uk/topic.asp?p=1&f=86&t...
http://www.hsv.org.uk/topic.asp?t=733947&f=86&...
Hi chap thanks for reply as u say alot of work has gone into this audi. I have rectified the ecu issue as b4 vcds code was p00000 corrupt software. At least now I have a working ecu. Before u could unplug any sensor on car and still showed no dtc codes. Im fitting the temp sensor in the turbo tomorrow and hopefully then will have a clear code free ecu. The thing that really puzzles me is the fact yesterday eve it ran perfect for 5 mins and again today. But then goes back gutless. The onky other code stored when it ran fine was a dpf fault because as u rightly say tge dpf is missing so once I get it running a1 I need to get the dpf element remapped out the ecu. Could I email u regarding this also.
did the exhaust gas temp sensor make any difference ?
To check if the car is in limp home you need to look at the live data when driving, specified and actual boost should be 2400mb WOT above 2000rpm.
Did clamping the fuel return make any differance?
The email attached to my PH account doesnt work and I dont give out my personal one sry.
To check if the car is in limp home you need to look at the live data when driving, specified and actual boost should be 2400mb WOT above 2000rpm.
Did clamping the fuel return make any differance?
The email attached to my PH account doesnt work and I dont give out my personal one sry.
Stevelewiswebb said:
Another though would it be possible for an electrical component ie mass or boost pressure solenoid to fail but not record a dtc ,, just thinking out the box as I am running out of ideas slowly. Kind regards Steve
Yes this is totally possible, for examply Air Mass meters never log a code when they fail. You only get an Air mass code if the EGR isnt working or if there is a boost leak. If the boost solonoid is leaking air but is electrically ok the ECU cant detect that either.But first things first, try the sensor it is failing.
The working fine for a bit and then not can be explained simply by the sensor having to reach the temp at which it fails before it causes the problem.
Hope this helps
TT
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