Audi BLB running issues

[HSD85]

Hi I'm new to this forum, I am a technician but this one I'm stuck with and wonder if anyone can shed some light on this one.

Audi A4 2.0 tdi 2005 BLB.

Purchased this car hoping to repair it and keep for the family. Takes 20 seconds or so to start then its noisey like top end sound and it won't rev at all.

Things i have checked so far with vcds (new to vcds and learning) and only has glow plugs faults, live data shows pedal signals are working when pressed . Oil pressure at 4 bar at idle. Removed egr and throttle in case any restrictions. Front end off and timing Is correct with timing tools.

Carried out relative compression test seem to be consistant and cam an crank with picoscope but req known good wave form also I am getting signals from sensors.

Revs with abit of easy start, I know these suffer from oil pump failure so I didn't might fitting a engine if needed but my 1st task is to get it to rev up to hear the engine higher up the revs.

Can the pedal response be disabled with vcds I wonder if previous owner has done that somehow with vcds to hide the fact it needs a engine.

Any help would be appreciated
Thanks
Harry.

[stevieturbo]

If there is such a major problem.....there should be fault codes. If there are no fault codes using proper diagnostic software....then you need to ask why ?

You seem to suggest you bought this as a bad runner, presumably at reduced cost ? Is there nothing to identify the previous owner to get some history for the car, or a previous garage that may have worked at it ?

[HSD85]

Hi thankyou for your response

I purchased this car from a audi specalist around 4 years ago, yes at a reduced cost back then but still paid just over 3k and values for these were around 5 to 6k. The car is black with black leather,manuel sline. He just said he needed more time to diagnose it but the owner can't afford it and the owner sold him the car towards paying for the bill so far.

So I been messing with it on an off with no rush to fix it as I bought it as a project, family and work has had me busy.

About 2 years ago I did speak to a previous owner as I found his number on a receipt when I rang him he just said he was driving on the motorway and lost power.
6 months before that he had another engine fitted due to oil pump issues so that's y he sold it to the garage as he has spent too much on it.

The only codes there is are glow plugs, and cooling fans as the front end is hanging to access timing
I have left it running for 10 mins running rough, won't accelerate and no new codes it's a strange one. Maybe ecu is shot I might get it checked not sure yet if thats the issue.
Turbo looks fairly new. But what will stop it from revving i wonder.

Thanks
Harry.

[eliot]

Got the exact same engine and year - Only thing I can add is that mine has had glow plug fault codes for many years with no apparent ill effects.

[HSD85]

Yes I didn't think glow plugs would cause a no rev issue, I have removed rocker cover and nothing apparent, checked and adjusted rocker arms for each injector and still the same.

Thanks

[geeks]

Has it been Mapped?
Have you checked the DPF?
Turbos can go and give similar symptoms without always chucking up fault codes
Any sensor that has been disabled i would re-enable to find out what codes that is hiding.
Could be a wiring issue

[HSD85]

Not sure if it has been mapped, and not checked dpf, even if dpf was blocked it hasn't made a difference even when I removed egr and the exhaust gasses venting from the pipe that runs from the exhaust.

It only had glow plugs faults when I bought it and the additional cooling fan fault is because I've removed the front end forward.

Checked torque value via vcds reads 2 degrees which is minimal adjustment required even so this would not cause it not to rev at all there is literally no response from the pedal again love data shows it reading.

Thanks

[geeks]

HSD85 said:

Not sure if it has been mapped, and not checked dpf, even if dpf was blocked it hasn't made a difference even when I removed egr and the exhaust gasses venting from the pipe that runs from the exhaust.

It only had glow plugs faults when I bought it and the additional cooling fan fault is because I've removed the front end forward.

Checked torque value via vcds reads 2 degrees which is minimal adjustment required even so this would not cause it not to rev at all there is literally no response from the pedal again love data shows it reading.

Thanks

Could still be the DPF
Could still be the turbo
Could still be a stty homebrew remap
Could also be the MAF, does the symptom change with it disconnected?
Could be many things still. I would be ditching the data and the reader though, either you dont know how to follow it or it isnt showing you anything useful for the fault!

[HSD85]

The turbo does spin freely not seized,
Egr venting exhaust gasses eleminates if the dpf is blocked by not creating back pressure if any in the exhaust system.
Maf unplugged makes no difference.
I've used bosch diag but then also purchased vagcom hoping it would give me more of a direction but still in the same boat.

Yes I am familiar with live data and how to read fault codes, however I have been a mechanic for 22 years since I left school, as with any profession I'm still learning everyday, still keen as ever hence y I haven't cut my losses and scrapped the car.

Thanks.

[geeks]

Oh something else came to mind, is it a 170? they had a recall a number of years ago for injectors, however as you have a replacement engine in there difficult to find out if it has been done. So injectors well worth checking those!

[HSD85]

140hp, and I have no replacement engine yet.

[stevieturbo]

HSD85 said:

Hi thankyou for your response

I purchased this car from a audi specalist around 4 years ago, yes at a reduced cost back then but still paid just over 3k and values for these were around 5 to 6k. The car is black with black leather,manuel sline. He just said he needed more time to diagnose it but the owner can't afford it and the owner sold him the car towards paying for the bill so far.

So I been messing with it on an off with no rush to fix it as I bought it as a project, family and work has had me busy.

About 2 years ago I did speak to a previous owner as I found his number on a receipt when I rang him he just said he was driving on the motorway and lost power.
6 months before that he had another engine fitted due to oil pump issues so that's y he sold it to the garage as he has spent too much on it.

The only codes there is are glow plugs, and cooling fans as the front end is hanging to access timing
I have left it running for 10 mins running rough, won't accelerate and no new codes it's a strange one. Maybe ecu is shot I might get it checked not sure yet if thats the issue.
Turbo looks fairly new. But what will stop it from revving i wonder.

Thanks
Harry.

ECU fault is possible...but very rare.

Dodgy ecu remap...very possible. But the symptoms and history dont suggest that ? A reputable remap lace should be able to tell though.

Rough running, presumably there is some smoke ? Do you know which cylinder is not firing correctly, or is it more than one ?
Injector wiring inside the rocker covers on those can give trouble ?

Check that and/or also have injectors checked out ?

Assuming all sensor data does seem normal.

[eliot]

these dont have dpf as far as i'm aware.

[HSD85]

Yes maybe worth getting the ecu checked I do know some chap who might me able to have a look if it's mapped correctly. Think it will be far cheaper than getting injectors checked.

I did inspect injector wiring for injectors in the rocker it seemed good also I would expect to see injector faults for open circuit etc... but then again if ecu is the fault maybe not.

Not sure which cylinders not firing and I do get some smoke but not excessive.
Vcds on measuring blocks reads 0 and not altering so can't see if one cylinder requires more fuel then the other.

I will remove injectors tommoro and carry out a compression test with a mechanical gauge also cylinder leakage test and will update on here.

Thanks..

[GreenV8S]

HSD85 said:

Not sure which cylinders not firing

If you can provoke a persistent misfire you can see which cylinder is affected by checking the header temperatures - ideally with a thermometer, but if you're stuck a plastic cable tie held against the header will give you a very crude indication.

[eliot]

Not sure if he's still on here, but there was a guy called tametechnician who's in the audi section who knows these things well. (i followed his tip for checking the engine was good before buying the car many years ago - essentially drive it foot to the floor in 4th or 6th from about 30 and make sure it pulls - if not it should put a code up)

[stevieturbo]

very odd that if it is as bad as you say, the ecu isnt reporting misfires and which cylinders it thinks.

[HSD85]

Yes very strange why there is no other fault codes. I'm not 100% convinced with what I was told about the car when I bought it, I seem to wonder if this engine fitted into this car after the 1st ones oil pump failed that it's never run and had this issue and then sold to me, whereas the owner before last said he was driving it then packed up whilst driving, maybe wrong ecu,wiring etc...

In the mean time I have drained off some diesel in a cup and it seems to be clear of engine oil and not contaminated with petrol. I might get ecu checked next step.

After reading some old forum I read somewhere that if the smooth running is at 0 which mine is, that the car may have been mapped, and now failed. this to me seems like a good idea to look into further. I will get hold of this chap I know to see if it is mapped if so to wipe the ecu and back to factory if possible.

If u can look out for a update sometime soon I hope I will tell you my findings.
So far thanks to everyone for your responses much appreciated...

Thanks
Harry.

[stevieturbo]

It's very possible the car never really ran at all after the engine swap....probably because they fked something up during the swap...including the possibility of the wrong engine for the car/ecu etc

There are just so many variations of engines used in the vehicles it can be hard to know if it is correct.

[HSD85]

Suppose I will know more after ecu has been checked, if I can get hold of a dealer schematic for the ecu I can start checking correct pin locations not a straight forward job but enjoy this kind of work I can't let it beat me...!