Severe Pinging

[Professor`]

car 2000 Nissan Maxima, Intake and Exhaust upgrades,Problem:

For the last few months my check engine light has been on, its throwing the lean codes, Ive tried several things and i cant resolve this problem, i replaced the intank fuel filter, MAF and i replaced all the upper intake gaskets, iam still getting severe and i mean really bad pinging, almost undriveable, it starts around 1800rpm and up to 3500 , i dont know what else to do.Also when i add gas its like 50 times worse for abit till i drive it around.

Please help me figure out what is causing this.
Modified by Professor` at 7:06 PM 7/28/2009

[navysnail]

so it stops after you drive the car around for a bit (warm it up)?

[Warped161]

does it ping with the stock intake on? i had a lean issue on another car that was caused by an aftermarket intake. it eventually melted the valves.

[Professor`]

so it stops after you drive the car around for a bit (warm it up)?

it tends to a little, its still there it never completely goes away, its severe when i fill it up , ive tried the oem intake and it still does it.I changed the plugs thinking they where just to hot, i went with a colder plug and there is no diff.

[navysnail]

you might consider having someone read your codes, i think even autozone does that now. it will read out any error codes thrown by seonsors in your engine, and is generally a good jumping off point.

[Professor`]

you might consider having someone read your codes, i think even autozone does that now. it will read out any error codes thrown by seonsors in your engine, and is generally a good jumping off point.

P0171 & P0174 banks one and two lean.
Modified by Professor` at 7:48 AM 7/31/2009

[Warped161]

so either its too much air or too little fuel. an injector issue or even air getting in after the maf (if you have one) im not too familiar with your engine. im just giving general info here.

[Professor`]

It does it with the OEM intake also.

[Professor`]

nothing is helping so far, i added 2 bottles of fuel injector cleaner, still no change.

[Professor`]

I beleive its the knock sensor, i just tested it and found it to be a open circut....

[navysnail]

did you find a solution to this problem?

[Professor`]

did you find a solution to this problem?

not yet, it backfired thru the intake and stalled, but now it seems to have gone away, 2 days now and no ping, i dont get it.

[Professor`]

So i believe i found the problem after countless hours of stress and research online, It appears my purge control valve is faulty, it is letting to much pressure build up in the fuel tank and iam assuming its forcing air into the fuel rails, I also think the boost sensor/map sensor up front is what monitors the pressure and when it reaches a limit it sends a signal to the purge valve to open and release the pressure, thats my theory because for some reason All Data calls the boost sensor a fuel pressure monitor, i dont know if this is true or not however i did a simple test, I opened the fuel cap and let it loose, closed the cover and drove home in 90+ degree weather and i did not have ANY pinging at all, so the issue seems to lay in that fuel tank pressure sensor or the purge valve. This is the first thing that ive gained results with, everything else ive tried gave me 0 results.

[Professor`]

so it was not any of that, it was the MAF, all symtoms gone with new MAF installed.