VR feeling sluggish

[fla 9]

Driving back from taking my lad go-karting decided to boot it as the road was not too busy but it didt feel like it wanted to go as though it was being strangled slightly. From 70 where it normally just wants to pick up quickly it just didnt have the beans. tried catching up with an 06 Polo again from 80ish and whilst it didnt get away from me i couldnt catch it up. Did readline it a good few times to see if it would loosen up but still no improvement. Oil temp got up to 92, water to about 80 (on the gauge) and surpsingly mpg was still 33.4 when i got home!

Did a scan at home and a Knock sensor error came up. Deleted that, ran the engine again and scanned - all clear. Did an ecu reset too (VAGCOM group 000? 001 doesnt allow you to select 'go'?) Still feels a bit 'flat' - otherwise the engine is very smooth, no issues there.Any suggestions?

[VWVW 1]

Could it be the crank position sensor ? Iam no expert...but I ve had power loss on my vr before and this part fixed it.

[buttles 0]

Cam sensor will give a power loss. I had one go slowly before it finally put it's hand up and showed failed. Crank sensor usually it won't run. If a knock sensor is giving a duff input to ECU that will also retard ignition. Also it has already thrown a code to VCDS. Hope no Eggs being sucked there!!

[VWVW 1]

Cam sensor will give a power loss. I had one go slowly before it finally put it's hand up and showed failed. Crank sensor usually it won't run. If a knock sensor is giving a duff input to ECU that will also retard ignition. Also it has already thrown a code to VCDS. Hope no Eggs being sucked there!!

 

+1 on the Cam sensor. I ve just checked on my invoice and it mentioned the Cam sensor and not the crank position sensor I posted earlier.

[Supercharged 2]

The Cam sensor (G40) will always show on vagcom... could be just a bad tank of fuel / hot weather

 

Also did you go through the basic settings procedure?

[fla 9]

Yes, typo, i meant basic settings according to RW1's method. Didnt have time to try it again today though.

[RW1 0]

I tend to agree with S/C Steve, could just be a poor tank of fuel with no DTC's. Rather than chase your tail, top up with the highest octane like Shell V Power and see how it goes. Otherwise I'd look at a new fuel filter next if it has not been changed recently. VR6 is sensitive to fuel pressure drops.

 

Basic Settings will be on Group 000 on your's Hasan. Don't bhter with the battery diconnect and inital set-up. Just get it warmed up and select B.S. on 000 as per that part of the procedure. I don't think it will solve your problem.

 

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[fla 9]

Noted, thanks. Just filled up with Tesco fuel so will ahve to run that down before getting some proper stuff... replaced the fuel filter about 1 year ago, so hopefully should be ok.

[RW1 0]

Tesco is yuk fuel. It's not started doing it since you filled up has it?

 

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[fla 9]

yes....perhaps thats the problem?

 

Edit: no it was running on Esso 95RON, which is what i normally use; not driven it much since using the Tesco fuel, but it might be even worse! If not the fuel, should i just replace the cam sensor anyway?

Edited April 26, 2011 by fla

[RW1 0]

For me thats no better....... crap fuel. And 95RON will give you a drop in power anyway. First post above gives me the impression that there is no fault code. So I cannot see how the cam sensor could trigger "limp home mode" and the poorer running you are getting. What was the fault code you saw before clearing? 00515?

 

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[fla 9]

will check the log but yes i think it was 00515. Cleared it though, ran the engine for a few minutes and then rescanned but there was no further error, perhaps it takes a while to come up again.

[Supercharged 2]

Fla - the VR needs 98Ron minimum, it's in the book and on the fuel cap!

[RW1 0]

will check the log but yes i think it was 00515. Cleared it though, ran the engine for a few minutes and then rescanned but there was no further error, perhaps it takes a while to come up again.

 

It doesn't remanifest itself like that when the sensor is on the way out. The engine has to rev to the upper limits (+4k rpm) for a short period of time so that the ECU can compare and calculate. Then 00515 will re-appear and trigger limp home mode. It could be intermittant at the moment so will take a few high rpm durations for the sensor to have a wobble again. If it does then yes change the cam position sensor, its going. Got two in the loft half shot like this. And quite a few new ones for just in case.

 

If you keep the engine rpm below 3,500 rpm, the fault won't neccessarily re-appear while the sensor is on the way out. Boot it above 4k rpm for more than about 5 seconds and 00515 will probably trigger into the fault memory. Short durations do not give the comparison between the cam & crank time to be analysed.

 

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[fla 9]

knock sensor error:

00540, knock sensor 2, (G66)

31-00 open or short to ground

 

The knock sensor is the one above the crank sensor with the cream coloured plug isnt it? I've got all the aircon pipes in there so will have to remove it from underneath. Any checks possible? How much do they cost?

Edited May 23, 2011 by fla

[Kevin Bacon 5]

Front knock sensor has a black plug, rear knock sensor has a white plug, just to confuse matters. White plug on the front is the crank sensor.

 

Have a search for Roger Blassberg's threads on knock sensors. Yours might just need retorquing. They are very sensitive to that. I've got a couple of knock sensors kicking around if you need one. They're not cheap from VW.

 

Wasn't a black 06 Polo with twin tailpipes you couldn't catch was it? Might have been me in our Polo GTI. Standard VR6s really do struggle with them, so I wouldn't feel too bad about it :D

 

And ignore Steve's post about 98RON minimum. 95 is the minimum. 98 is 'recommended'.

[fla 9]

tbh, cant remember which Polo it was, perhaps not a bad thing!

Thanks for the info, which is knock sensor 2, the one at the front or back? Will have a search for Roger's thread and see what he has done.

 

Edit: just checked in Bentley, Knock sensor 2 is the one on the FRONT of the block, above the crank sensor. Tightening torque is 20Nm (15ft.lbs)

Edited May 23, 2011 by fla
additional info

[Kevin Bacon 5]

Try removing it, clean up both surfaces and then retorque it. That is easier said than done on the front sensor though as it's a right ball ache to get to. If the fault code keeps coming back, then it will need replacing unfortunately, assuming the wiring is OK of course.

 

IIRC, Roger's problem was the ECU getting duff information from the knock sensors and it was pulling ignition advance when it shouldn't have been, which will make it feel slow. I'm sure all he did was retorque them and it fixed the problem. The sensors are listening for a very specific resonance frequency and if they're not torqued to the exact specification, they don't work properly.

[fla 9]

good info there - removed it, cleaned up boith surfaces & retorqued and seems to be ok so far. Scanned with VAGCOM over the weekend and no error codes although i'd redlined it a few times already. It does feel a lot nicer at present too.