2003 maxima detonation

[big block]

I am having bad detonation around 2000 rpm after the transmission has shifted into overdrive-regardless of speed. There is no detonation under load or full throttle as you would expect. I am running 93 octane and have always run 93 since the car was new. I have not received a check engine light which I assume would come on if I had a bad knock sensor? Bad spark plugs? Bad coil packs? Any help would be appreciated.

[maxhopper]

A bad knock sensor does not trigger the check engine light on the 4th gens, butdoes store a code. You may try taking your car to somewhere like Advance Auto or Autozone, and have them check for codes.

[big block]

Had Autozone check for a code today and they found nothing. Now the question is: is their reader unable to pick up such a code or is their truly no code. Any further thoughts/ideas?

[maxhopper]

I would think that their reader should be able to read the code if it were present.

How many miles do you have? What brand of gas are you using?

[big block]

101,000 miles. 75% of the fuel I buy is from flying J truckstop. Since this has started I have bought fuel from Citgo and BP thinking I may have had bad fuel but it made no difference. I am planning on putting new plugs in this week to see if that corrects the problem- I need them anyway.

[maxhopper]

Just make sure you use NGK plugs.

You may try using Chevron on your next fill up.

[big block]

NGK plugs is what my mechanic insisted on as well. Not sure if there is a Chevron around here but I will check. Many thanks and I will let you know if the plugs fix the problem.

[MinisterofDOOM]

Shell is a good second choice to Chevron if there aren't Chevron stations around your area.I'd also suggest using Techron fuel treatment or BG 44K (which you should be able to buy at your Nissan dealership if you can't find it anywhere else).

[big block]

Well- changed plugs (finally) FYI- you must pull the plenum to remove the 3 rear plugs. My local Nissan dealer did not have the plenum gasket in stock and that took 10 days to get. They stated I am the first person that they have seen with 100,000 miles needing a tuneup on an 03' maxima.

That said- the new plugs did not cure the detonation "rattle" Now my mechanic is not sure where to go as his inside Nissan source told him there were no bulletins on 03' maximas for detonation problems or coil pak problems as with 01' and 02' Maximas.

DOES ANYONE OUT THERE HAVE ANY SUGGESTIONS AS TO WHERE TO GO FROM HERE?

Thanks-

[maxhopper]

That's something I would take directly to Nissan, in this case. It seems as if the fuel, air and spark are good; that would lead to a control issue with the ECM. Perhaps there is an ECM reprogram available that somewhat inadvertantly addresses the fuel mapping or spark timing.

[RSG]

I am having bad detonation around 2000 rpm after the transmission has shifted into overdrive-regardless of speed. There is no detonation under load or full throttle as you would expect. I am running 93 octane and have always run 93 since the car was new. I have not received a check engine light which I assume would come on if I had a bad knock sensor? Bad spark plugs? Bad coil packs? Any help would be appreciated.

Do you find the detonation happen only between 1700 - 1900 RPM and when the engine fully reached operating temperature? If so, it might not be the sound of detonation ... yes I know it sounds like it. At least on mine, it does not "detonate" at any other RPMs and will not happen within the first 10 minutes driving after a cold start. In this case, it is the sound of vibration from the engine compartment, maybe a heat shield.

To date I still have not figured out a solution. Will work on it more in the coming 1-2 weeks. Please keep us update on the situation.

[03maximase]

I am having the exact same symptoms with my '03 SE.Sounds like pinging under light throttle around 2000 RPMs when the engine is hot.Dirves me nuts.I had it to the dealer and they put it on the computer, and no codes.

Just to mention for background, I had the TSB for the timing chain sprocket done 2 years ago. I still get the cold start rattle. The TSB didn't help.I also have a accessory belt noise most of the time at idle. I had Nissan change the belts, and the belt noise went away for about a year. Now it is back.

Now this is the strange thing... If I add a large bottle of Techron to the gas, the pinging sound is much reduced, almost gone. But once I burn through that tank of gas, the noise comes back???

The pinging noise didn't bother me too much when this was my wife's car, but now that I am driving the Max full time now, it really irritates me.

It seems to me that under light load and low RPMs the ECU agressively advances the timing and leans out the A/F ratio for better mileage.

Has anyone been able to remap the Max ECU?