gummydmilo

I have a 2002 maxima and the engine knocks every summer during average acceleration.

I live in Phoenix, so and air temp of 110 if normal (and sometimes the low is 95).

Several tanks of high octane did not help. Neither did new plugs.

Could it be a bad knock sensor?

Thanks

luvlexus101

iTrader: (6)

gas*

Will

iTrader: (2)

I get the same thing in humid weather, so it's a known issue in these engines, i.e. it just happens. Probably a design flaw, but most likely there'll be no damage, but it sure is annoying and unwelcome. Some brands of gas knock less, I've found, so I'd suggest try a few brands and stick with the brand(s) that knocks the least or doesn't knock. I've found Sunoco 91 and Shell 91 knocks the most in mine.

Child_uv_KoRn

iTrader: (7)

Have you tried 1 or 2 step colder plugs?

DOHCtorJT

iTrader: (3)

I'm in Phoenix too, not having a problem. I use QT or Costco gas only. Only 10k miles on fresh OEM plugs, but prior to that I didn't notice any pinging, however when I changed the plugs, one of the plugs had slight signs of detonation.

knight_yyz

iTrader: (40)

colder plugs and a cooler t-stat might help. (350z)

321VQ35MAX

iTrader: (6)

Which plugs are good?

zhuleek

iTrader: (1)

What you are experiencing is called a spark knock, I've been having same issue even in the winter. Though I've been trying to find a solution for this with no luck, I did find a temp fix-Chevron Techron, its about ten bucks for the small one. Adding that to fuel on fill up gives u few months/few thousand miles of 90-95% knock free. Note, the first time you use it you have to give it at least 2-3 consecutive fill-ups. It also fixed my gas gauge problem (another somewhat common issue for our maxs, the gauge getting stock-thought that can be temporarily resolved by slightly tapping on the gauge cluster)

sascuderi

My 2000 I30 had awful knock from day one. I changed gas brands, put in new coils, and added a Berk intake. Knock has been gone since (8 years now). Problem is I did all those things at the same time so I'm not sure which was the actual fix.

My 1995 Maxima also had a light knock, even with 93 octane. Seems common with the VQ's.

Rochester

iTrader: (3)

You were talking about "colder" plugs a few months ago... did you do that yet, and did it address your low-end pinging?

gummydmilo

Thanks for all the posts - hope everyone had a good holiday weekend.

colder plugs - this was my first option, but then I read how they are pain to change in an 02, but the car has 80k miles so I figured maybe I would, but then I checked my mechanics bill from when he replaced the head gasket a few months ago and he also changed the plugs (unfortunately this issue wasn't on my mind at that time of year). So is it worth the time/effort/cost to change brand new plugs? I have read people change them and it doesn't fix it.

Coils - changed these on my 00 max and it was easy but not cheap and it fixed the problem. It would be another $400 for coils, and a couple extra hours for plugs - would pair this with a switch to colder plugs.

The two options above probably have the highest chance of success.

Thermostat - never thought of it, but it makes sense. The car's temp gauge runs on the cool side so not sure if I would create and negative effects.

Knock sensor - need to research this one...

MAF - I paid the mechanic to change this on my '00 (even thought it is easy to change but didn't know it was the source of the problem). Actually, that was also pinging/knock so maybe this will be an option. Not too expensive and quick.

Timing - I need to take it to the dealer for this one - correct? I hate going to the dealer.....

The 02 has had more repairs in the first 80k miles than the '00 in 190K! So I cringe at spending more money on it! And I always cringe at working on my cars during the Phoenix summer were the lows are sometimes in the 90's.

Thanks!

BronxSleeperMax187

Ask your mech which plugs he used, and if you have A warm air intake you might wanna go back to stock....110 degrees will kill performace

Love_00_Max

You need a complete coolant flush -- search the forum and I have a detailed writeup on cooling system flush. There are hotspots in the engine, improper cooling results in pinging.

Trust OEM coolant only.

gummydmilo

Hi

I think my car blew a head gasket - AGAIN. I have a different thread discussing that when it happened the first time about 6 months ago.

My mechanic asked if it was pinging and I said some times on a hot days under light load. He mentioned the MAF (which I mentioned changing above) may cause it to run lean which causes the pinging and stressing the head gasket.

So now the engine needs to pulled again to replace the head gasket - and put in colder plugs - and do the easy/cheap part - a new MAF.

I am kicking myself for not trying to fix it sooner, but it lasted 80k miles the first time, and now only 5k!

If I decide to have it fixed, I should know in about 2 weeks if it is still pinging.

Will let you know

SteveB123

iTrader: (2)

A design flaw would occur in every car, not two.

gummydmilo

I am going to have a new (used) engine put in - and a new MAF. Hopefully this one now last to 200k miles like our 2000 maxima (with acceptable repair bills).