Nissan VQ35 V6 clunking sound

[tubbedz]

HI guys, I'm fairly new to this board, but I really need all the help from expert Nissan owners/mechanics with my problem. I originally posted a similar topic on Murano.org but there was not much Engine experts to help me out.

My wife's 2003 Murano recently started to make this clanking/rattling sound under load at about 1200 rpm - 1400 rpm. Others suggested it was the fuel injection dampers(regulators) but that was not it. The sound is a louder clanking. Also, it is not the CVT as I can pinpoint that the sound is coming from the front valve cover. Besides this clanking, the car is mechanically sound....no oil consumption, no smoky exhaust, no nothing...except this clunking under load. The Murano even accellerates smoothly when I nail it from a stop. It runs on 92 octane, new plugs, new filters and Royal Purple Synthetic oil. It only makes this clunking sound under light load at 1200rpm - 1400rpm.

This is how I started to troubleshoot. Had the wife start the car with the Parking Brake engaged. Then in Park, with the left foot on the brake pedal had her slowly depress the Gas pedal with her right foot until the revs were at 1500rpm. In Park, with no load on the engine the VQ35 V6 revved beautifully, no clanking, no rattling, just a smooth roar. Next, I had the wife engage the transmission into Drive. While in Drive, I had her slowly raise the revs to 1500rpm. In gear and under load, the VQ35 V6 started to clank at 1200rpm and got louder as the revs went up to 1500rpm. I listened to where the clanking was coming from and it eminated from inside the front valve cover. The cover closest to the radiator. Has anyone who worked on these V6 engines know what's going on???? What's happening under load in gear??? Please Help???? Nissan mechanics????

My mind started racing to find a cure!!! Is the valvetrain lash adjustable??? Could a rocker or valve be loose??? Could the chain tensioner or guide be broken??? Did a lifter collapse??? Did the overhead cam flatten a lobe???

Has anyone run into this issue??? Please help???

This weekend I will remove the front valve cover, hoping not to find any carnage.....I'm soooo sad.....

[9095240SXDUCK]

One issue they have is the a/c idler pulley bracket cracks. It can cause a buzzing/clanking noise on accel and it is close to the B2 valve cover. Best way to check is by taking the belt off and look at the bracket.

[tubbedz]

Thank you 9095240SXDUCK

I will look into that this weekend. Wish me luck, I hope it's something minor.

Anyone else have this issue????

[Timmbo]

Welcome to the Murano Forum! I will see if any of our techs have any other ideas, sit tight.

[tubbedz]

Update.....

I went to see my friend, who is a Mechanic at Honda and we hooked a scanner to my Murano. Apparently, the noise is pinging or spark knock. In Park, while revving, the timing advanced smoothly from 17'degrees and up. In Drive, while revving, the timing was eratic and flashed up real quick to 43'degrees. This was too much advance too fast, creating the pinging or spark knock. My friend suggested to check on the Nov 17, 2003 recall that replaced the cam and crank sensor and the variable timing control sensor. Also he suggessted that I have the ECU reflashed.

I have an appointment next week at the Nissan Dealer to take care of these issues. Hopefully they will not give me any hassles.

[tubbedz]

Finally got the wife's Murano back from the dealer and paid $300 for nothing. The dealer had the "engine mechanic" diagnose the Murano. He verified the engine pinging noise. He checked for intake leaks-none. He attempted to"relearn" the idle but failed. So he reprogrammed the ECM with new software and then "relearned" the idle. Engine pinging still there. Nissan mechanic found a dent in the oil pan. He said the ping was from lack of oil because the pan was dented......BULL. If it's not the pan, he suggested a new replacement engine. Why????? So I took the Murano home and replaced the pan. Engine oil pickup was not bent or crushed. With the pan off, I looked at the crank, rods, and bearings....it was spotless, no sludge, no oil burning or oil stains. The bottom of the oil pan was also clean...no sludge, no shavings....just spotless. Called the dealer today and left a message for the mechanic on what he advises to do next. In the meantime.........anyone have any ideas??? No codes or warning lightsNo pinging in Park or NeutralNo pinging at high speed or nailing it from a dead stopPings only at part-throttle load approx 2000rpm 92 Octane Chevron unleadedRoyal Purple synthetic oil 10w-40wNo oil consumption issuesNo blue smoke out of the exhaustWIX oil filterNGK platinum plugsMAF cleanedThrottle body cleanedFRAM air filter

[MrSlug]

Stupid question but are you getting a MIL light? Pinging can also come from too much air flow in the motor and not enough fuel causing pre detonation. I would check the fuel filter (in case it is plugged); the fuel pump (in case it is not sending enough fuel under load) and the MAF (Mass Air Flow Sensor).

If the MAF is screwed up, it can send incorrect Air/Fuel ratio information to the CPU which can cause a lean condition. I am very surprised (well not really) that the tech did not check the MAF.

You can also clean the throttle body as well, but I doubt that is your problem.

[tubbedz]

Stupid question but are you getting a MIL light? Pinging can also come from too much air flow in the motor and not enough fuel causing pre detonation. I would check the fuel filter (in case it is plugged); the fuel pump (in case it is not sending enough fuel under load) and the MAF (Mass Air Flow Sensor).

If the MAF is screwed up, it can send incorrect Air/Fuel ratio information to the CPU which can cause a lean condition. I am very surprised (well not really) that the tech did not check the MAF.

You can also clean the throttle body as well, but I doubt that is your problem.

MrSlug

Thanks for your input!!!

I'm getting no MIL light....nothing

The fuel filter is integrated into the fuel pump....how to test??? I would have to buy the whole pump for $500(Bosch #67994)http://www.rockauto.com/catalo...77875

I cleaned the MAF, but the tech didn't check it because there were no codes.

I also cleaned the throttle body.

Man.......this is really killing me!!

[MrSlug]

No problem. I rebuild motorcycle engines quite a bit, and have holed a few pistons do to pre detention.

I would hold off replacing the fuel pump as a first resort. It could very well be the MAF. The MAF is in line with your intake before the throttle body. There should be a wireharnes that is connected to it. Just look at the intake past the intake box (where the filter is) and see where a wiring harness connects to it.

You can have them checked, because I doubt you have the meter that is needed. Can you take it back down to your buddy at Honda and have him check it out?

This is where I would start.

If the fuel pump is in the fuel tank, that can be a harry job if it needs replacing.

[ddv2005]

I have absolutely same problem (pings only at part-throttle load approx 2000rpm) on Murano 2007. But it happened only on hot engine. Today i got car from Nissan Service and they can't do anything because no repair available. Nissan Service confirm that car have pinging noise but it is normal for Murano because .... other clients have same problem and no repair available from Nissan . They check all sensors, clean injectors but nothing find ("no problem found at this time")

Dmitry

[tubbedz]

Done...Fixed!!!!A special thanks goes out to my local "stealership" who said nothing was wrong because there was no codes......awesome troubleshooting Nissan!!! I guess that's why their called "technicians" and not "mechanics".

Anyway, I removed my upper and lower pelnum collectors so that I could change all my spark plugs. Not just three, all six of them. I'm a thorough mechanic and took tons of pictures if you want to see the procedure. I was careful not to remove or unplug the throttle body so that I would not have to "relearn" anything on the ECU...same goes for the battery. What I found was that the rear cylinder closest to the brake master cylinder was not firing. The coil had white powder deposits on the valve cover from arcing and was doused in oil. When I pulled the coil out it was soaked in oil. The spark plug was also sitting in a "lake" of oil. What appeared to have happeded was that the valve cover did not have a good seal around the spark plug port which caused oil inside the valve cover to overflow and fill the spark plug port. When I pulled this plug it was blackish-brown, as if it was trying to fire and soaked in oil. The five other plugs were perfect and burning beautiful, but I replaced all six to be sure. As for the valve cover, I got a new rubber gasket and put a thin layer of silicone around the spark plug port so that oil would not seep into the port/coil again.

I also tested the resistence(ohms) on the oil soaked coil and it was good, but on the next oil change I will replace it. Per the 2003 Murano Field Service Manual, it explains how to check the coil wiring from the ECUwithout a Consult2. So, I checked this also and the wiring was perfect. Since I was deep into the Murano and I have the FSM, I tested every single sensor that dealt with ignition timing and camshaft/crankshaft timing. All was perfect. I also changed the PCV valve because it was "sticky" and only made of cheap plastic.

I also flushed the coolant and refilled with premixed 50/50 long life coolant and a bottle of Redline "Water Wetter"and tested the temp sensor. Perfect.

With the plenum collectors off I could see directly in the cylinder head and the backside of the intake valves. They were clean as a whistle!!! No deposits, no oil, no nothing....super squeaky clean. I took pictures if you want to see. A week before this tear down, I went through two bottles of "Redline SI-1 Fuel System Cleaner". I did this because the Nissan technician said I have a lot ot deposits......whatever Nissan technician.

All is running well now and the wife is happy. The next project is to install a custom sound system and a build a hidden fiberglass subwoofer enclosure. I'll take pictures again. So far on the wife's car, I've installed color matched 4-sensor reverse sensors, Yellow ion fog lamps, and added an alarm "shock sensor" to her factory "horn alarm". I have pictures of all of these installs if you folks want a "write-up", please let me know.

I'm a hardcore, backyard, shadetree mechanic and enjoy modifying/racing cars. I could take the Nissan technician to "school" as I have built and raced everything from 2-stroke motorcycles to BMW M50 engines. I'm from the old school and can mechanically find my way around any engine. If my wife decides to keep her Murano I will eventually purchase a "Consult2" and screw the Nissan technician.

See my current toy.....http://www.cardomain.com/ride/1864005

love......tubbedz

[MrSlug]

Glad to hear it was a relatively easy fix. Think of Air Fuel and Spark to make the motor go is always the best way to trouble shoot.

As for the reply saying then engine is pinging while hot, again it is predetonation. As the engine warms, the fuel mixture gets hotter and can pre ignite before the cylinder has reached the top if its stroke.

You can try higher grade octane, but that is not really a fix.

Just think Air Fuel and Spark (timing).

[9095240SXDUCK]

Stupid question but are you getting a MIL light? Pinging can also come from too much air flow in the motor and not enough fuel causing pre detonation. I would check the fuel filter (in case it is plugged); the fuel pump (in case it is not sending enough fuel under load) and the MAF (Mass Air Flow Sensor).

If the MAF is screwed up, it can send incorrect Air/Fuel ratio information to the CPU which can cause a lean condition. I am very surprised (well not really) that the tech did not check the MAF.

You can also clean the throttle body as well, but I doubt that is your problem.

On a Side note! ANYONE WITH DRIVE BY WIRE NISSANS!!!!! ALL VQ35, VQ40, QR25, VK56, Anything with a drive by wire. DO NOT CLEAN THE THROTTLE BODY!!!!!!!!!!!!!!!!! That is the worst thing you could ever do! you be out 400 for a throttle body+ a ECM relearn! Even if you clean it with a dry rag! soon as you move the plate it mess up the memory of the throttle body, even with a dry rag 99.9% of the time you need a Idle Air Volume Learn! SO CLEANING A DRIVE BY WIRE THROTTLE BODY IS A BIG NO NO!

Tubbedz glad to hear you fix it sorry I had not have a chance to come by on NICO for this long, and you got very lucky on the cleaning, just be carefull! Also The Oiling is very common on the RWD VQ35s (G35,350Z,M35.....), I have never seen it on FWD VQs Yet! Also Keep a Ear out on Timming Chain Wine, because I have done many of them already on FWD VQ35s!

Modified by 9095240SXDUCK at 4:48 PM 2/26/2009
Modified by 9095240SXDUCK at 4:49 PM 2/26/2009