When my car is cold in the morning, it sounds like a diesel. Only at light throttle between 2k and 3k RPM. If I give it a little more throttle, it smoothes out. It only does this when it's cold.

Any ideas on what this might be and how to fix it?

Thanks.

 

knock sensor, or chain tensioner or some other sensor

 

KS is relatively new.

Tensioner may be an issue.

No codes for other sensors.

 

mine sounds more deep and rumbly in the moring. i thought it was b/c it was cold and grumpy

 

Same hear but only until it starts warming a little

 

I guess same over here now, just started. It doesn't grone but it kicks back a little just when it's called. I had all my fluids replaced so I guess it's normall. Also it only does it when I sit still

 

Mine does it too. No idea what it is. Mine is a raw sounding noise between 2500-3000 but smoothes out above that and when the car is completely warm.

-R

 

Mine too, but it does it sometimes when the car is warm too.

But my exhuast is friggin loud with the y-pipe.

 

Hmm how's your oil pressure?

 

The light doesnt come on...other than that I have no idea.

 

This is just a wild guess but if you have low oil pressures when you first start the car, you might get some noises from the chain tensioners or maybe some main bearing noise from the crank? Could be a host of things really.

 

i have same prob but it lasts 2 sec RIGHT WHEN I START. it has happened a few times only in COLD weather

 

No, my noise (or roughness) occurs when driving, not at startup. When I accelerate lightly I get the diesel-like noises from 2000 - 3000 RPM. More throttle or more RPM makes it go away.

 

what kind oil and filter do u use?

 

Bosch & Castrol GTX 10w30

 

Well off hand, it sounds like piston slap. Never heard anyone else having it though.

 

have the same problem , i pin-pinted the source to EGR valve or EGR back pressure transduces valve
it is an exhaust leak for sure.
once the metal gets worm and expands - noise goes away.

Nick

 

it may be time to replace ur timing chain tensioner
these MIGHT help
http://forums.maxima.org/showthread....t=timing+chain
http://www.rpmrons.com/nissantiming.html

 

Cold oil usually produces higher pressure because it's thicker. The diesel type of noise could be coming from your combustion being very rich. Try a complete intake cleaning process, I'm talking taking the runners off and all. There are a few products that claim to be able to clean your intake without dissasembly, I think 3M or Champion makes a system. Sea Foam might be another one. Another thing to consider is your ECTS. It's a cheap sensor and might be off enough be effect your cold A/F ratio. You might be running to rich when your engine is cold.

 

ECTS is new...

I may tackle the intake cleaning one of these weekends coming up.