VR6 pinking

[NickVR6 0]

My VR pinks when up to full temp. Never before 3k but if its hot it pinks badly between 3-4 usually, with a nice big hisitation, puff of smoke and horrid cat smell. Usually about 3500, then maybe again at just over 4k.

 

Its fine when its showing 80-95 on the oil temp, but once its up to normal 108-112 cruising temp it does it all the time. Sitting in traffic makes it far worse when you blast away again. Its not so bad with the bmc but still does it with or without the cold air feed to varying degrees.

 

I have changed:

 

Plug Leads

Plugs

Lots of cooling stuff which is all now where it should be

 

This really worries me and i drive around it now as i dont want to burn out the top of a piston. What should i do next??

 

Im thinking of venting the bonnet or wing to let some cooler air in!!!!

 

PS: Lamda thingy is original 1994 with 121k on the books, and mine has never had any sensors done either. But vag com shows nout ?? ??

[dr_mat 0]

Either you have a sneaky VSR (and an unsuitable engine map), or you've got one or more faulty knock detectors I'd say.

[NickVR6 0]

What sensors are these then? Same as cam position ones or crank speed thingy? Sorry, any chance of a list of these sensor things?

 

I did get the ecu reset drove it a mile in traffic and stopped it for the whole day. Reading other threads that may have confussed it i guess?

 

Def something wrong though (and i allways use optimax)

[dr_mat 0]

The ECU wouldn't have got "confused" by the incomplete reset procedure, it just wouldn't have made it to fully adapted state, and it will take much much longer to do so. I would have expected it to be the other way around though, tbh. Not that I know, but always assumed it would run slightly richer with default settings and then lean off over time as it adapts.

Now that you've started the ECU reset procedure, you should do it properly, as you've blown away the previously adapted settings.

Meanwhile, the knock sensors are a fair bit cheaper than the crank pos sens. They're just little microphones screwed into the block which the ECU uses to "listen" for pinking or detonation. If they're working and your engine is otherwise healthy you shouldn't really ever hear any pinking. The ECU will have already picked up the tiniest amount and backed off the ignition timing before you ever hear it.

[NickVR6 0]

Do you think on my car with my mileage they are likely to be toast then Dr?

 

are we talking £20 each ? If so its worth doing anyways i surpose as atempt no 1 to cure it? I assumed it was the ecu kicking in to stop the pinking though, as it only ever does it for a split seond then picks up again with no pinking??

 

I have had cars that will pinking continually if you labour them in a hi gear, its not prolonged like that though?

[NickVR6 0]

and why are you not a MOD by now!?

[Kevin Bacon 5]

Pinking for a split second is normal.... the knock sensors need to 'hear' it first before the ECU can pull the timing back. Your sensors are fine.

 

It's summer, and you're probably being lead footed with the BMC on.... you're worrying about nothing mate.

 

I think you need to invest in VAG-COM.

[NickVR6 0]

Kev, where can i get vag com and how much for it with a leed?

 

I bought an old P2 laptop the other day just because it had a dvd player and had bearly been used, asum that would do the trick though?

 

its a big enough hesitation to spoil the performance. im talking 1-2 seconds rather than a split second and enough to blow a load of smoke out when it does it!

[NickVR6 0]

whens its really bad it will do it 3 or 4 times between 3.5k and 5k!

[StormVR6 0]

You can get a "home-kit" VAG-COM lead from ebay for £20-£30, plugs into your serial port and the other end has a OBD socket for your car, free VAG-COM software can be got from the internet.

[NickVR6 0]

bonus ! thats me in then, i thought we were talking £100 +

 

presume a search will turn up some useage instructions.

[Kevin Bacon 5]

Blue smoke or grey? Gray is excess fuel and blue is oil....

 

http://www.vag-com.co.uk or http://www.ross-tech.com for your lead mate....software is free to registered lead owners. You need the Hex-com one.

 

It'll pay for itself many times over in saved VW visits....

[NickVR6 0]

GREY definately. and when its not pinking ie when its at 90 degrees on the oil it revs right round without a hint of any smoke at all. its allways just after it pinks

[NickVR6 0]

presume its over compensating after it goes lean then!? if not im confused!

[StormVR6 0]

VAG-COM 409.1 (which is the one I use) is very easy to use, it doesn't give you all the extras (like Kev's!) but it is fine for basic use and will show faults and allow you to "rest" them and show you engine logs.

 

Perfect for me as I wouldn't understand anymore info! :lol:

[NickVR6 0]

Sounds like my version alright !

[StormVR6 0]

This is the one I've got, make sure your OBD socket is the 16 pin and not the 2+2.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 48979&rd=1

[dr_mat 0]

If it's temperature dependant you may have a temp sensor problem. VAG-COM will reveal all ...

[Roger Blassberg 0]

VAG-COM will reveal all

 

er.... maybe not. It will tell you if there is a continuity fault with the knock sensors (ie broken wires or such-like) but I don't believe that it will detect such things as incorrect through-bolt torque.

 

Nick, I went through this about a year ago. It turned out to be a cracked knock sensor. Your are probably aware that there are 2 of these, one on the front bank of cylinders and one on the back. The front one is difficult to get at. There is a bolt through each one, holding it to the block. This must be tightened to precisely 15lb.ft. - too loose and it won't hear the detonation, too tight and it will break. The contact surface must be scrupulously clean.

 

They are not cheap - the pair cost about £125.

 

I still get some pinking, even on 97 RON petrol, but the sensors do what they are supposed to - sense it and pull back the timing.

 

I have heard it said that a faulty cam position sensor can interfere with the operation of the knock sensors; does anyone have an opinion on that?? Does the engine run with a faulty CPS and is it reported by VAG-COM/1551??

 

Best wishes

 

RB

[dr_mat 0]

If the cam position sensor is actually being ignored by the ECU, it will run with fully retarded timing, so pinking should not be an issue. (The ECU has, iirc, 11 degrees of knock-sensor controlled timing that it can adjust.)

 

Of course, VAG-COM won't report poorly responding knock sensors, but as you say it will report open/short circuits on those sensors. The same goes for a temp sensor. If its value is not changing, the ECU is unlikely to flag it as faulty, but clearly it IS faulty if it has a fixed output.

 

The only times I've had pinking on my VR has been since fitting the Schrick manifold, but as said above, it pinks once, maybe twice, then the ignition timing gets retarded and it's ok again.

[NickVR6 0]

thanks guys, food for thought and i've just ordered my cable.

 

Every time i ask why Dr_Mat is'nt a mod nobody replies, i presume there is some mysterious reason then!??

 

Do i need to shut up now then!?

[dr_mat 0]

Two reasons: they don't like me, and I don't like them .. ;)

 

Just joking. I'm not really interested in being a mod, but am happy to regurgitate what knowledge I have that can be helpful for people.

[Kevin Bacon 5]

LOL.....do you fancy Dr Mat or something Nick?? :lol:

 

I'm sure if the great Dr applied for the position, his application would be duly considered.....and then swiftly rejected :mrgreen:

[dr_mat 0]

See this is the other problem.. I don't apply for positions, they are offered to me, and the great Hayward is unlikely to offer me a used mars bar .. ;)

[Henny 0]

dr_mat, depends what it's been used for... :|