Replacing knock sensors?

[audipmpn]

SO I am getting a service light on my Manual 2001.5 S4 Avant saying that my signal is too low for one of my knock sensors. I found one cheap and ordered one but I have heard to loosen them and re torque them to 20 f/lb of tq first.

Since my light came on my boost went from spiking at 18lb to spiking at 13...maybe even 12lb.

I also have no other CELs

Car is stage 2 with custom tune.

Anyone have experience with this or experience changing them? I have an idea where they both are but would appreciate any help/suggestions.

Thanks!

[b6Hate4]

I had re-torqued mine when I got a CEL and it did the trick.

[audipmpn]

I had re-torqued mine when I got a CEL and it did the trick.

Are they hard to get to? I know there is one on each side of the block but couldn't really see them with a quick glance.

[JDM EJ1 95]

I have 2 newer sensors if you need any

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[Monty23]

Are they hard to get to? I know there is one on each side of the block but couldn't really see them with a quick glance.

They are under the intake manifold

[blmlozz]

Are they hard to get to? I know there is one on each side of the block but couldn't really see them with a quick glance.

I/M removal is required, they're directly in the center of the block, there's no way to get to them otherwise.

As mentioned, you may try to retorque rather than replace, but whether you want to dis assemble the top end twice to save $50 is up to you, and if there's surface corrosion, I would also sand that down. They need good contact with the block to 'detect' the knock.

http://www.ecstuning.com/Audi-B5_S4-.../Knock_Sensor/

[01audia4]

Would an AUX pump leak cause me to throw a code like this if it has disrupted the clean contact on the block?

16711 - Knock Sensor 1 (G61): Signal too Low

P0327 - 35-00 -

Wondering if I should get a new sensor or try to clean the surface area. Have to do my AUX pump anyway.

EDIT: Code doesn't throw a CEL, just comes up when I scan VIA Vag-com

[ilyafil]

There's probably corrosion on the sensor to block contact area. Clean it up and re-torque. Should be good to go. Knock sensors rarely go bad.

[audipmpn]

Anyone know if a DIY anywhere to do them with proper walk through and torque specs? I am fairly new to the 2.7 motor.

[Monty23]

Have you checked the knock sensor wiring connectors?

[audipmpn]

Have you checked the knock sensor wiring connectors?

I looked at one quick this morning and it looked good but am not sure where the second connector is. The Brown one I found was on the passenger side.

I forgot to mention the PO changed them both out very recently.

[ilyafil]

There should be a troubleshooting procedure in the Bentley manual for this. You can download it for free. I suspect the PO installed the sensors incorrectly.

[01audia4]

There's probably corrosion on the sensor to block contact area. Clean it up and re-torque. Should be good to go. Knock sensors rarely go bad.

Alright, I'll give it a go. Hopefully it fixes my issue and I won't need to pull my IM off twice. Won't be the end of the world if I end up having to though.

I figure since it says signal too low, maybe it doesn't have a good connection with the block. If I can pick one up from the dealer for under $50 i'll just replace it.

[Monty23]

The dealer will charge you oem list (MSRP is $77 from GAP) +markup. I was in need of a head gasket and MSRP is $88 and the local audi stealership wanted $110.

[audipmpn]

There should be a troubleshooting procedure in the Bentley manual for this. You can download it for free. I suspect the PO installed the sensors incorrectly.

Where can I download it for free?

[ilyafil]

Where can I download it for free?

Right here: http://bit.ly/1eFt5IV

[Monty23]

my 5 year old son asked me the other day, "why do you guys say google? why, why? what is google?"

I laughed

Then I said "google is the answer to all your questions!"

[audipmpn]

Right here: http://bit.ly/1eFt5IV

Sorry, I did that...but at work so since it said porn in it my work blocked it and I thought it was a non working link. MY BAD lol

[01audia4]

The dealer will charge you oem list (MSRP is $77 from GAP) +markup. I was in need of a head gasket and MSRP is $88 and the local audi stealership wanted $110.

Yup just found that out. I'm gonna try to clean it first see what happens and re torque it. Worst comes to worse I do it again in the spring when it's nice out.

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