Changing the Knock Sensor - VR6

[TomB 0]

I know the rear one's supposed to be a doddle, but I thought I'd ask from the horse's mouth, just how much of a sod is the front one to do?

Some of the posts in the search suggest taking the front end off the car is the best way to get at it. Is is possible to do with everything (bar the oil cooler) in situ though?

Also, can some kind person point me in the direction of the cam position sensor, as apparently that's gone as well...

Cheers,

Tom

[TomB 0]

Just an update, ever since getting back from the garage, it's been running worse than it was before. I know one of the knock sensors is gone and needs replacing, but now while still popping on the overrun at about 1250rpm, it now stutters & spits when pulling of from junctions in first, or under anything but the most gentle of throttle applications.

The misfire wasn't there before, and I'm thinking might be sooted plugs (I'll check ASAP) but it doesn't do it when cold, only when warmed up, so I'm thinking it must be sensor related. I'm putting the popping of unburnt fuel down to another vacuum leak, which brings this rambling post to some sort of point. Can anyone tell me what this PTFE tape wrapped device hissing like a cobra under my bonnet is?:

2.8l 24v Climatronic system.pdfDSC00019 [800x600].JPG[/attachment:17c016st]

 

DSC00020 [800x600].JPG[/attachment:17c016st]

 

It's obviously leaking and needs either re-binding as a bodge or replacing, but can anyone tell me what it is any how expensive it might be please?

 

Any other comments or suggestions on the cause of the misfire gratefully received....

 

Thanks,

 

Tom

[bruny 0]

Its the idle pot damper valve Tom, it cracks which allows excess air in to the mix. It will be down on power and running weak. I think its only £20 ish from memory. I didnt have spluttering etc, just lack of power, so it may not be the only problem you've got :shrug:

[TomB 0]

Thanks for that, most helpful! It's been bodged in the past by the looks of it so it's time to splash out on a new part... It's certainly down on power, but has been for a while (another bust hose and possibly a cam position sensor as well), so I can't tell the difference :)

I'll see if I can find the part online to get an idea of the price...

 

Cheers,

Tom

[bruny 0]

Etka part no. 021 133 429A @ £22.55. Be more than that now I expect with the weak pound :wave:

[TomB 0]

:notworthy:

You're a scholar & a gent sir, I shall call Continental/JCT6000 tomorrow!

 

Thanks again,

Tom

[TomB 0]

Just an update for anyone else who might need the part, it's about £23 including VAT & CCGB discount. Very helpful guy in the parts department who really likes the older VWs as well. I was most impressed!

 

Cheers,

Tom

[TomB 0]

Just a further question/favour for anyone with a VR6 please. The new damper valve has a main 'in' and 'out' (about 10mm connections) but also a much smaller pipe which is blanked off, but still has a hose to attach to.

The old one also seemed to be blanked off about 7mm down the pipe where it joined the main body of the valve, but I couldn't say for sure.

 

Can anyone confirm that this third pipe should be blanked off? If so, can they explain (just to satisfy my curiosity) what the purpose of having a hose connected to it is!

 

Cheers,

Tom

[Kevin Bacon 5]

Front Knock sensor - It's a b1tch! From memory it's above the oil filter housing, behind the plastic water transfer pipe. I found it easier removing both of these items because the knock sensor needs a very specific torque setting (Roger Blassberg's your man for that) and I couldn't get any tools onto it at all unless the filter housing and crack pipe were removed.

 

Cam sensor - Under the plastic cable tidy that sits above the coilpack. It's just to the right of the pack.

 

New ISV damper - Look at your pictures and the answer is there. The "blanked off" bit is merely a support :)

[TomB 0]

Much obliged Kev, thanks for that. I assumed that it was a sod to do, however, it's unlikely that the knock sensor is the cause of the misfire, so it can wait for now... Good to eliminate the possibility of having an incorrectly blanked off part causing the popping on the overrun. Let the hunt continue...

I think the cam position sensor forms part of the distributor on the dizzy models, so that's one down!

 

Cheers,

Tom

[bruny 0]

Oh dear, still having problems, dont you just love the Corrado. If you still think its an air leak check the underside of the main air feed pipe from the air filter to the manifold, oil seems to collect at the junction of the smaller pipe from the camshaft cover which causes perishing and cracking. It may not be the problem but easy to check for illimination :shrug:

I am assuming you have checked the obvious, plugs/ leads etc !

[TomB 0]

Yup, it's just had a new set of plugs and leads (and a dizzy too)! I changed the air intake elbow after I bust the original one at the track day :oops: however that's a good tip as to where to check it. I shall have a look prior to giving it an Italian tune up with a bottle of injector cleaner tomorrow.... :D

 

Cheers,

Tom

[Roger Blassberg 0]

Well, to be quoted as an expert by the Great Pianowire is praise indeed ! You must have a long memory Kev, it's a while since I went through the agony of changing the front knock sensor.

 

From memory the correct torque is 15 pounds feet, 20.4 Newton metres. Undertight and it won't hear the knocking soon enough, overtight and it will be damaged.

 

Best wishes

 

RB

[Kevin Bacon 5]

LOL! I remember your knock sensor exploits very well for some reason, probably because it was a job I tackled myself recently and I was racking my brains trying to remember the torque setting you mentioned!!

[TomB 0]

Thanks again gents, that's really helpful. When I get the chance to do it, I shall use those settings. Time to get it off the road for a months to do all those little jobs methinks....

 

Cheers,

Tom