Knock Sensor Replacement

tylka · Post by **tylka** » 07 Jun 2005, 05:26

MY car is giving me codes that the front Knock sensor is bad. My question is will I have to take the manifold off to get to it, or can I replace the sensors without going through all that trouble? Thank you.

White850Turbo · Post by **White850Turbo** » 07 Jun 2005, 05:49

You have to take the manifold off. It's not that hard to do. I even wrote a guide to removal of the manifold if you're interested.

tylka · Post by **tylka** » 08 Jun 2005, 16:21

If you don't mind, let me know how to take the manifold off. Haven't done it on the 850 yet. Thanks.

Post by **hernhaw** » 08 May 2007, 00:24

White850Turbo wrote:You have to take the manifold off. It's not that hard to do. I even wrote a guide to removal of the manifold if you're interested.

Hi Sean:
Where can I find your guide for the removal of the manifold? I have a 1-4-3 code on my recently purchased '94 850 Turbo & would like to attempt doing it myself or actually, having someone more knowledgable help me.
Thx!

Post by **MadeInJapan** » 08 May 2007, 17:48

I had posted a diagram on here some time ago on how to remove the intake manifold but couldn't find it. I'm hoping this will help.

Post by **pfeener** » 08 May 2007, 18:47

If you're going to take off the intake manifold, you might want to consider rebuilding the PCV system at the same time. FCP sells a kit with all the parts.

Post by **MadeInJapan** » 08 May 2007, 20:12

You are completely correct, don't consider it...DO IT....the pcv system clogging is responsible for (in my opinion) over 90% of all engine trouble in these cars.

ccgaudette · Post by **ccgaudette** » 10 May 2007, 13:40

What MIJ said -- only more-so.

In an older 850/s70, in the process of taking the intake manifold off you are likely to break the PCV hose. The PCV hose gets brittle with time and heat. Once the hose is broken the engine will not run right.

I did not, nor would I ever, take the intake manifold off my car without a new PCV kit and intake manifold gasket already at hand.

JFO · Post by **JFO** » 10 May 2007, 19:37

I just completed changing the PCV system with the kit from FCP. The pictures in this link will show you how to do the knock sensor and while there, you can do the PCV which is visible in the pics. You don't need to disconnect the fuel lines at the rear of the engine as shown on page2. It took me about 3 hours or less I think.

http://volvospeed.com/Repair/knock_sensor.pdf

Jim

ccgaudette · Post by **ccgaudette** » 10 May 2007, 21:55

JFO wrote:I just completed changing the PCV system with the kit from FCP. The pictures in this link will show you how to do the knock sensor and while there, you can do the PCV which is visible in the pics. You don't need to disconnect the fuel lines at the rear of the engine as shown on page2. It took me about 3 hours or less I think.

http://volvospeed.com/Repair/knock_sensor.pdf

Jim

Very well done JFO!

Definitely should have steam cleaned my engine bay first. The squeamish will not want to look at the few pictures I rounded-up!

http://web.mac.com/cjgaudette/iWeb/Roof ... ifold.html