2003 Maxima - Pinging Under Light Load

[Gugs]

Hello Everyone,

This is my very first post here at Nicoclub. I recently acquired a 2003 Maxima from my dad with 241k "mostly highway" miles. Initially, he wanted me to go through the car and sell it for him... but as I was spending time on it, the car grew on me, so I bought it. The engine had a misfire, radiator and cam covers were leaking, and the car was FILTHY because my dad quit giving the car any attention after purchasing his new 4runner.

I replaced a coil pack to fix the misfire, installed new '04 cam covers to fix the oil leak, threw in a new Koyo radiator to replace the old leaky one, and a bunch of misc hoses and such from Nissan.

The issue that I am currently trying to resolve is pinging under light load in the 1700-2000 rpm range. The pinging occurs once the engine is warmed up, and seems more prominent when the ambient temps are warmer. I am running 91 octane, and the in-tank fuel filter was also replaced. The MAF was also cleaned using CRC MAF Cleaner. The resistance in the Knock Sensor (KS) was also checked and it is within specs.

One thing that I noticed was that the ignition timing does not retard at all while the engine is pinging. Is this a sign of a faulty KS?

Thanks in advance for your help.

[Towncivilian]

Try running the larger bottle of Chevron Techron fuel system cleaner for one tank of gas. It contains PEA (poly ether amines) which is proven to clean effectively without leaving behind its own deposits. I think Advance Auto Parts has a buy one, get another for $1.00 on Techron so check there first.

Why did you replace the in-tank fuel filter? That should not need to be replaced except when you're replacing the fuel pump, as it's basically a mesh strainer that very rarely clogs.

Welcome to NICO.

[Gugs]

Try running the larger bottle of Chevron Techron fuel system cleaner for one tank of gas. It contains PEA (poly ether amines) which is proven to clean effectively without leaving behind its own deposits. I think Advance Auto Parts has a buy one, get another for $1.00 on Techron so check there first.

Why did you replace the in-tank fuel filter? That should not need to be replaced except when you're replacing the fuel pump, as it's basically a mesh strainer that very rarely clogs.

Welcome to NICO.

I will definitely pick up a large bottle of Techron.

I replaced the in-tank fuel filter because I was suspecting that maybe a clogged filter was causing a lean condition. The filter was replaced about a month ago. I understand that these filters are "lifetime" units, but there's a pretty sizable paper element filter contained within the housing. I had to bust it open and I'll post pics of it as soon as I figure out how to post pics here.

[Gugs]

Can someone show this noob how to post pics? =]

[Towncivilian]

Upload pictures to www.imgur.com and it should give you proper copy & paste options to post them here after uploading.

I was not aware that the in-tank filter had a paper element. In fact, I don't recall ever taking a look at an in-tank filter, so I'm eager to see your pics.

If you haven't yet, download a copy of the factory service manual. To save a copy of the FSM, right click -> Save As on every PDF, save them into a single folder, then use fwd.pdf to navigate. It's definitely an indispensable resource.

[Gugs]

This is the "lifetime" in-tank fuel filter with related hardware. The fuel pump/strainer assembly fits in the center bore of the filter assembly:



Here's a pic of the filter assy busted open... it's bonded shut and there was no other way to open it up. Notice the large hammer and chisel. =]

[Towncivilian]

Very interesting. I'd have thought that all in-tank filters would be strainers, not paper-type filters. I would assume that on my Pathfinder, which has a user-serviceable in-line fuel filter, would have a simple mesh strainer on the fuel pump itself given that the in-line filter is a paper-type filter.

[Gugs]

So what are your thoughts on the timing not retarding while the engine is pinging?

[Gugs]

Update: In an attempt to de-carbon the intake valves/combustion chambers/pistons, I sprayed a small amount of water through a vacuum port near the power valve at idle. No reduction of the pinging at 1700-2000 rpm range.

I may try the port that is closer to the throttle body to allow the water do distribute into other areas of the manifold.

Later in the day, I poured in a bottle of Techron when I filled up with Chevron 91... hoping to see some improvement by the time this tank is near empty.

[Gugs]

Update: Tank with Techron is almost empty. Unfortunately, the engine is still pinging at the same RPM range.

[Towncivilian]

Hmm. There are no pending engine codes? Have you cleaned the throttle body (use throttle body cleaner spray only)?

[Gugs]

Hmm. There are no pending engine codes? Have you cleaned the throttle body (use throttle body cleaner spray only)?

No Check Engine Light and no "ghost codes" per the scanner. The throttle body was cleaned/re-calibrated recently as well.

[Towncivilian]

I'm afraid I'm clueless now as I've never had any first-hand experience with troubleshooting such an issue. Sorry! I hope you manage to figure it out - if you do, please share your findings with us.

[Gugs]

Next move is going to be colder plugs. We shall see.

[kevintap]

Hi Gugs, I'm wondering if you ever resolved this pinging problem. I have almost the same problem with my 03 Maxima. It pings in the 1700-2000 RPM range under light load. It also seems to be somewhat intermittent and somewhat related to heat. There are some occasional days where it runs great and other days where it pings consistently. It seems to ping more often when hot. The pinging isn't what I have typically experienced with cars pinging in the past. This seems to be worse under lighter loads and often pings worse right before the transmission shifts - which seems odd since the load on the engine typically increases right after the shift when the RPMs drop.

It's not currently showing any codes. Though it did code for a bad cam position sensor in bank 1 a few weeks ago. I replaced the bad sensor the same day and the code hasn't returned. With the intermittent nature of this I'm betting on some sensor problem, though I don't know exactly what, and I hate to just start throwing money at new sensors without having any data to support a decision. I'd guess maybe an O2 sensor, knock sensor or MAF sensor might be contributing here.

[harrya]

Hi any resolve on this issue, I have the same problem, doesn't matter what octane I run?

[NutriaforBreakfast]

When you start your car in the am, does it make noise until it warms up?
You might need a new timing chain tensioner if so.
A loose timing chain can cause a lot of wierd problems.
It solved my "transmission shifting" problem when the tensioner was replaced
I was able to get one on my 1995 for $79.00

[OceanZhu]

Can you guys confirm that this is the noise that you guys are talking about? Here my video link, doing the exact condition of 40 mph at about 1900 rpm, the car was fully warmed up and the weather was 75F. thanks awfully. Link: https://youtu.be/0TxK4MiZW84