NM35 VQ25DET Camshaft Rattle Post Senor Replacement

[stealth01]

NM35 VQ25DET Camshaft Rattle Post Senor Replacement

Hi All

Just replaced the 2 camshaft position sensors on my old mans NM35 Stage (VQ25DET) and now the car is getting a rattle at circa 2000RPM from what appears to be the camshafts. I have read that this can be caused by using oil that is too thin, or the spring return within the variable cam timing assembly failing.

Prior to going down the path of the variable cam timing assembly, we will be trying an oil change but was also curious if maybe the replacement of the camshaft sensors requires a camshaft re-learn procedure and is there anyway to do this without a Consult 3?

Any assistance is greatly appreciated.

 

[m35stagea]

What sort of rattle? You will get a loud click sound at around 2300ish rpm thats when the intake cam advances from 0-30* its quite pronounced sound and cant miss it. 

What oil are you using? 10-40

 

[stealth01]

It's more a clunking sound than a rattle to be honest and happens randomly above circa 2000RPM. Car is running 10-40. From what I can recall, this has only come about post replacement of the sensors.

Engine performance still feels strong and there is no loss of performance from what I can gather.

[m35stagea]

If its a single clunk its going to be the cam advance. 

If its a repeated clunk clunk then its going to be the mechanism.

 

I have changed my intake timing to advance earlier so i hear it when i put my foot down basically from idle it is quite loud and would sound like something is wrong id you didnt know what it was.

[stealth01]

I am assuming the mechanism replacement isn't a fun job

[stealth01]

Just a quick update. I replaced the oil and for the first quick little drive the clunk didn't happen. Once the car warmed up, the clunk came back.

 

I then disconnected the passenger side blue cam plug and the clunk disappeared.

 

I am assuming that with the VCT not active (both blue cam plugs disconnected) there is no issue running the car ad there is just less power as the cams haven't been advanced. Thoughts?

 

Is the cam mechanism removal an engine out type job? 

Edited June 27, 2017 by stealth01

[m35stagea]

Its fine and normal. If its the noise Im talking about,

 

The cams dont seem to advance initially when cold (i have found from my logs showing 0 degree across the whole rev range when first starting up).

I can try and record mine for you it sounds like a clunk almost like slack in a centrebearing noise.

 

When you disconnect the solenoid you are not activating the advance.  thats why it goes away. 

Edited July 2, 2017 by m35stagea

[stealth01]

The sound is something new and one that we haven't heard before. Doesn't sound like it would occur in normal operation given the nature of the loud clunks.

Has anyone tried the replacement of the VCT Cam and is it an engine out type job or is there enough room in the front of the engine to remove this when taking off the front engine cover?

[m35stagea]

Yes because you said you replaced the sensors. Perhaps the cam advance wasnt working before?

 

Am I talking to myself here?