Turbo problems
Discussion
Hi All,
After some advice on my car. Its an 04 A3 2.0TDI (BKD Engine) 110k miles.
Last week the turbo went, it had gone into limp mode a couple of times the week before (overboost), along with making a siren noise and being a bit smokey, and on Monday just gone it went in a cloud of smoke. So had turbo replaced at a garage, with a recon unit from eurocarparts. New oil feed pipe fitted, Cat washed out, intercooler drained of the oil that had been blown through into it (after garage had fitted turbo they started the car and it wouldn't rev, so they discovered intercooler full of oil). Garage test drove it and I collected it this morning. It was noticeably not as quick as before the turbo going, the only way i can describe it is sluggish, it feels like it doesn't want to climb through the rev range.
This evening, dropping the girlfriend off for her works party, joining the motorway and limp mode again, I wasn't even booting it, just accelerating to get up to 70. So I stop and turn it off and on again and drop her off, then on the way back, at a roundabout the car sort of bogged down for a second and then loosened up. Great i thought, maybe just burning a bit of oil out the exhaust or intake, and then for a few miles it drove just as it should, perfectly. Then limp mode again on a dual carriageway when pulling out to overtake, and now it is back to being sluggish.
So, any ideas?
I know first thing is scanning for codes to see what the car thinks is going on, but I can't do this until tomorrow, and then I will ring the garage on Monday, but they shut from Christmas Eve until the new year, so don't know what they will be able to do in a day.
Apologies for the essay, but I wanted to include as much detail as possible.
Thanks in advance,
Smithy
After some advice on my car. Its an 04 A3 2.0TDI (BKD Engine) 110k miles.
Last week the turbo went, it had gone into limp mode a couple of times the week before (overboost), along with making a siren noise and being a bit smokey, and on Monday just gone it went in a cloud of smoke. So had turbo replaced at a garage, with a recon unit from eurocarparts. New oil feed pipe fitted, Cat washed out, intercooler drained of the oil that had been blown through into it (after garage had fitted turbo they started the car and it wouldn't rev, so they discovered intercooler full of oil). Garage test drove it and I collected it this morning. It was noticeably not as quick as before the turbo going, the only way i can describe it is sluggish, it feels like it doesn't want to climb through the rev range.
This evening, dropping the girlfriend off for her works party, joining the motorway and limp mode again, I wasn't even booting it, just accelerating to get up to 70. So I stop and turn it off and on again and drop her off, then on the way back, at a roundabout the car sort of bogged down for a second and then loosened up. Great i thought, maybe just burning a bit of oil out the exhaust or intake, and then for a few miles it drove just as it should, perfectly. Then limp mode again on a dual carriageway when pulling out to overtake, and now it is back to being sluggish.
So, any ideas?
I know first thing is scanning for codes to see what the car thinks is going on, but I can't do this until tomorrow, and then I will ring the garage on Monday, but they shut from Christmas Eve until the new year, so don't know what they will be able to do in a day.
Apologies for the essay, but I wanted to include as much detail as possible.
Thanks in advance,
Smithy
Get yourself an OBD2 plug in to monitor what it's doing. There are a lot of devices around which will interface with your phone through bluetooth etc.
The main one I'd be looking for is boost pressure (which is absolute, subtract 14.7psi to get gauge pressure). I use a scangauge which is connected the whole time.
Expect 20 something psi at full load.
The main one I'd be looking for is boost pressure (which is absolute, subtract 14.7psi to get gauge pressure). I use a scangauge which is connected the whole time.
Expect 20 something psi at full load.
Ah the Garrett VNT. I know a lot about the assembly of them, but feck all about the problems in service. (well until 2000, I was a manufacturing engineer, and responsible for buying the assembly lines in the UK, that were moved to Europe.
Is the actuator, able to fully open (and close) the vanes ? (Split pipe or air leak might be enough).
How do you know the actuator is calibrated (that is that the adjustment is set correctly) - does it come preset ?
Is the actuator, able to fully open (and close) the vanes ? (Split pipe or air leak might be enough).
How do you know the actuator is calibrated (that is that the adjustment is set correctly) - does it come preset ?
Thanks for all the replies so far. I'm just about to go and collect my obd2 scanner from a mate I let borrow it.
As for the actuator, I was assuming it would come preset from the people who did the recon?
This is the part http://www.eurocarparts.com/ecp/c/Audi_A3_2.0_2004...
As for the actuator, I was assuming it would come preset from the people who did the recon?
This is the part http://www.eurocarparts.com/ecp/c/Audi_A3_2.0_2004...
Scanned the car and got P0299 underboost condition.
obd2 logger is showing no more than 8psi boost (with a correction value of 0, there was the option for +/- 14.7psi.).
I also looked at intake manifold pressure vs boost and they correlated, so does this mean less likely to be a leak?
I'm leaning towards vacuum problem?
Any further thoughts appreciated!
obd2 logger is showing no more than 8psi boost (with a correction value of 0, there was the option for +/- 14.7psi.).
I also looked at intake manifold pressure vs boost and they correlated, so does this mean less likely to be a leak?
I'm leaning towards vacuum problem?
Any further thoughts appreciated!
Crafty_ said:
Could it be the actuator pre-load isn't set up so its allowing the wastegate to be opened ?
ch427's suggestion of oil gunking up solenoids is worthy of a look too.
It might be worth getting hold of a mittyvac so you can check for proper solenoid/actuator operation and the like.
The V in the GT1749V stands for Variable Nozzle, which will not have a waste gate. ch427's suggestion of oil gunking up solenoids is worthy of a look too.
It might be worth getting hold of a mittyvac so you can check for proper solenoid/actuator operation and the like.
It will have an actuator but this will operate a series of vanes sitting around the turbine wheel. The basic concept is that the vanes close, when the engine is at low engine speed but high throttle opening, thus forcing the waste gases to travel faster through the smaller gaps, thus causing the turbine wheel to spin faster, which means the compressor wheel spins faster at the other end of the shaft, which means more boost (ie more oxygen) which means less lag. As the engine speed increases the vanes open and the turbine wheel is slightly oversize for the engine, which means that it doesn't need a waste gate. IIRC there is a bit of closed loop with most cars, so a bit of inaccuracy in the actuator setting will just mean that it takes a bit longer to get where you want it, but if it's a long way out then it will never get there.
SmithyAG said:
The turbo is integral with the exhaust manifold, so they only fit that engine (and 1 more).
The recon turbo is a Garrett GT1749V, which matches the original.
The recon turbo is a Garrett GT1749V, which matches the original.
Well as I said, the intake filled with oil when the turbo went, as the cooler needed emptying. If the MAP sensor has been affected, could it make it read too low, hence the car thinks its underboosting and not providing the fuel to match, making it sluggish?
Average mpg is down too, but I'm assuming thats to be expected with a boost problem.
Can a MAP sensor be cleaned with contact cleaner or similar? I was intending to have a look earlier once the codes were scanned but got stuck for over an hour in traffic due to a crash and a closed road, so i've not had the chance.
Average mpg is down too, but I'm assuming thats to be expected with a boost problem.
Can a MAP sensor be cleaned with contact cleaner or similar? I was intending to have a look earlier once the codes were scanned but got stuck for over an hour in traffic due to a crash and a closed road, so i've not had the chance.
Crafty_ said:
It might be worth getting hold of a mittyvac so you can check for proper solenoid/actuator operation and the like.
I've got a mitivac, however the turbo is a pain to get at, as its between the head and the bulkhead, so can't be seen from above without removing the air intake, and from below you can't see the actuator rod move as it's on top of the turbo! So best way will be with a mirror or similar and some bendy arms! Will see what the garage says tomorrow, but if they can't help (only open for the day then shut for xmas), I guess i could connect the vac line to the mitivac to see what vacuum it is pulling? However it won't request full boost in neutral will it?
ch427 said:
someone who knows a bit more will be along soon but i believe the boost pressure should read about 14 psi less than a map sensor (atmospheric pressure)
It does, at idle boost reads 0psi and inlet manifold pressure reads 14 (+/-0.5)When driving they both rise accordingly, up until 8 at boost and 22 at inlet and then no further.
When it dumped all the oil into the cooler and intake, i'm wondering if it could have fouled the MAP sensor. Although I would have expected it to have killed it as opposed to making it read low?
You seem to have a good idea what you are doing, far more than I can offer but ignoring the turbo problem you have had, the description of the problem sounds exactly the same as I had from a faulty throttle position sensor (same engine). Although that would also have thrown up codes.
Mine went at Christmas time aswell never a good time though.
Good luck
Mine went at Christmas time aswell never a good time though.
Good luck
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