locklear

iTrader: (1)

I've had a problem with my '95 for a few years now. When it's hot outside and I am under a light to moderate load....say going up a hill on the freeway I get an engine ping/clatter. I've had the car since new, and always have used 91 or higher octane.....I've tried multiple fuel injector cleaners including the one Nissan does. Still I get the clatter.....and mostly when hot outside!
The ecu isn't throwing any codes either.
I was looking in my service manual today, and I read how to check the timing....so I went out and checked it.
The service manual says to get the temp up to normal operating temps....then shut off the engine, and put the ecu in "check mode", and re-start the engine and rev it to 2000 rpms a few times then check the timing.
Well, when I checked it....I wasn't getting the "standing still" effect of the timing marks staying stationary with the pointer thing.....instead the marks were just rolling by with the timing light.
So...finally my question.....does this mean my timing is off? If so, how do I correct it? The service manual says it's not adjustable. Could this be the reason I'm getting the clatter/detonation?
Thanks for any help

mzmtg

iTrader: (11)

I bet the BPT valve in your EGR system is what's making all the racket.

locklear

iTrader: (1)

The BPT would cause detonation? What about the timing marks not lining up?

mzmtg

iTrader: (11)

A bad BPT sounds just like pinging under light load at part throttle.

locklear

iTrader: (1)

Is there a way to test the BPT valve? My crappy Haynes manual doesn't show.
Any ideas about the timing marks not lining up?

locklear

iTrader: (1)

Co'mon.......... no one?
Am I atleast checking the timing right?

Oblongshapes

iTrader: (1)

Its unusual for the timing on these cars to mess up due to the chain, unless you have generated quite a bit of slack... I would say your timing marks are fine. It is most likely a sensor problem. Check your EGR with an ohmmeter for grounds or shorts and total resistance.

Shift_my vq

Dude I have this same problem. Let me know what it is if you get it. I alway's thought it was my jim wolf ecu. My only does it when it's hot, and in higher gear going like up hills and crap. Only happend like three times.

locklear

iTrader: (1)

I've been trying to figure it out for many years now....but yeah, like yours, mine only does it when it's HOT outside......like 95 degrees or higher.
So.....i'm stumped. I'm not sure it would be the BPT valve since it only pings in hot weather.
I'm thinking something to do with the timing since when I hook a timing light up to it the timing marks are not stationary with the pointer thing.
Sometimes it pings so bad it throws the detnation sensor code.
Any ideas?

Oblongshapes

iTrader: (1)

This is what your drivability Mechanic will call a Intermittent problem. These are the hardest to diagnose, compared to the scannable hardfault codes that usually throw a light and keep it available for viewing. Intermittent codes are thrown only when the right conditions are present. This is what makes it so hard to find, the mechanic isnt there when these problems occur to check the code with a scan tool.

MORE times than NOT, these problems are not because of faulty mechanics/sensors of the car. They are simply a bad terminal on a connector, ripped insulation of a wire, or other electrical components that feed current to each input/output device. At these conditions the connections will open up the circuit and get infinate resistance, cutting out flow, hence throwing your CEL or not... Remember, Knock Sensors DO NO always throw a CEL because, if the ECU has no communication with it, the KS cant tell the ECU theres detonations, hence NO code...

Common Intermittent codes are listed in the official Nissan Maxima Service Guide, I bet you dont have one, like myself, because they are about 130-150 bucks. So I would tell you to start checking wires and connections with a DVOM for proper specs of voltage and ohms. And look at each connector terminal to make sure its securly fastened and not water damaged ect.

Remember, just because its pinging doesnt mean its the KS or the EGR, which can trigger detonation due to high voltage interference. WHICH REMINDS ME! Make sure that your KS or EGR valve wires are NO WHERE near your spark plug/ coil cables, this will cause interference, and cause the ECU to read distorted data and throw a code. But, back to what I was saying.... IT could be any sensor, because the ECU uses many sensors to calculate EGR and KS including your ECT and O2's.....KS will even "sense" detonation because of a bad pulley, engine mount, or other sudden harsh jerk to the engine.

Hope you found this helpful,

Good luck