engine knocking sounds

[johnnykeil]

I have a 2000 maxima with knocking sounds from engine. I had all 6 ingition coils replaced by Nissan and the sounds persist. I have used high octane gas-no changes!! Should I look at the MAF Sensor, the Knock sensor, O2 Sensor-I'm a bit lost as to how to proceed. This sometimes doesn't happen for a day, the it rattles on for a while.

[audtatious]

Have you popped the hood while it rattles to try and determine where the noise is coming from? Is it a lifter rattle or something like a heat shield rattle?

[johnnykeil]

Thanks for responding. It doesn't do it until traveling about 20 mph or uphill. It sounds just like bad gas, except I have used high octane gas many times.

[NutriaforBreakfast]

Sounds like your lugging the engine down going up hill

Try putting the trans in low and see if you get the samenoise going up the hill

It could be the valves or a nutria in the trunk chattering

We need more info on this problem.

[Mike G]

Sounds like a knock sensor, has your Check Engine Light come on?

--Mike

[johnnykeil]

Thanks for responses. Check engine light came on a year ago and Nissan stated it was the coils-had them replaced in 9/07. I really thought this would be the cause og the knocking sound. No check engine light since this time. I am thinking about having the spark plugs and wires checked/replaced and then if the sounds persist, have the EGR valve cleaned/replaced. I wondered about the knock sensor as well but wouldn't this be a non issue when I use high octane gas? I have some savvy in automotive understanding and know it isn't something rattling around in my trunk. Thanks for the thoughts though.

[Mike G]

Since you have no SES/CEL, I think it could be the knock sensor, seems I recall seeing they won't trip the light. If the sensor itself is bad, it will not retard any timing and knock. I would also look into cleaning off your MAF sensor before replacing it, it is an easy task. Check into the thread that refers to the 0171 code issue...

--Mike

[skassamali]

I have a similar sound coming from my '03 I35. It only happens around the 2k RPM mark, while driving down the road (not while idling).

Is this similar to what you experienced?

[NutriaforBreakfast]

Can you check the timing?

[johnnykeil]

Thanks everyone. I am going to clean my MAF tonight. I think I'll disconnect the knock sensor and take it to Autozone to have them test it. I also have finally located the EGR Valve-it sounds like a bear to get out-should I go to that length? Thanks again

[Sentientbydesign]

Unless somebody wants to contradict me on this...

Your EGR will have NO effect on your engine knocking. It's an Emission Gas Recirculation Valve.

It essentially takes un-burned fuel and reintroduces it into the engine.

[johnnykeil]

I went to clean my MAF and it looked like a cartridge-and clean. I expected ot to look different-couldn't even tell where to spray any cleaner. I also just cannot find my knock sensor-I have looked at schematics and etc... and know where it should be but nothing there! I'm a Therapist-I can poke around the human mind with confidence but I can't find this damn thing . Please ....any other advice?

[Sentientbydesign]

The MAF looked like a cartridge?

It's a black "tunnel" with a small silicone sensor and a thin wire in it.

Those need to be cleaned.

[big block]

I had a 2003 max that had "spark knock" so bad I had to play the radio loud. nissan replaced all 6 coil packs, i replaced the plugs, had the computer re-programmed or updated by nissan and none of these things fixed the problem. They insisted that it was not the knock sensor as it would most definetely set a check engine light and a code (which neither ever happened) I always ran premium fuel from day one. seems like the problem started after 75,000 miles. I gave up and traded the car in last december. now my wife's 2003 max with 68,000 miles is starting to do the same thing. knocks very bad around 2000 rpm especially after trans has shifted into 2nd or especially 3rd while driving around town. this problem NEVER occurs under load or under hard acceleration-which is when you would expect spark knock or detonation. knowing all of the things i replaced on the other 2003 max that fixed nothing-i am not sure what to do with this car-and i am not in a position to get rid of this car for at least 2 years!! Help-i hope someone out there has figured out that there is something wrong with this motor/sensors/computer/something!! the dealer is clueless on this one-deer in the headlights look is all i get.

[johnnykeil]

I had the coils replaced as well in June-no change. My maxima has not made the sound in 2 weeks. I got a new gas cap and have used only premium recently, but it has also been colder. I see you are in PA as well so perhaps the cold isn't a reason for it stopping? Have you purchased a chilton manua-it lists some possible causes. I am just unwilling to spend a sh..load of money on a hunt and am trying simple things first.

[MrChuckFL]

Anyone else have any luck clearing up this problem?

I have the exact problem with an 2001 that is driving me crazy.

The vibration only happens around the 1.5 - 2k RPM mark, while driving under light load.

It doesn't seem to happen when the engine is cold only starts after driving for a while.

Replaced IAC and MAF. Problem still there.

I read on another board that this could be fuel filter.


Modified by MrChuckFL at 6:28 AM 1/26/2008