Engine ping under light throttle
 

Need some expert advice about this issue. It is for our G37S with 7AT.

The car is totally normal at all time with the exception of occasional engine ping during take off from dead stop or slight rolling with light throttle. Car would start fine, idle and run smoothly otherwise.

We just have to let go the throttle for a second and everything would be back to normal. Engine ping never occur under any other situation. My guess is for some reason the fuel mixture become lean and cause the ping.

I have cleaned the MAF numerous times and run through a few fuel system cleaners already. Fresh air filters and oil etc. Car is totally stock.

TIA.

Get an OBD scanner and see if the ECM has thrown a knock DTC. If not, then I'm guessing that you are hearing something loose in the engine compartment that is rattling around and not engine knock.

No code from the scanner, not even pending. My mechanic did say that the fuel trim indicated lean condition and we have reset the ecu, but condition didn't go away.

It is a fairly fast clicking sound accompanied by a slight engine vibration. Everything's back to normal once you lift the throttle and re-accelerate fine subsequently.

Stock tune? Any mods? Of yes and no, I had this bad MAP sensor on the top of the intake manifold, it made all kind of problems, including being lean then wet, then lean, basically change randomly under load.

If you're knocking, the ECM ought to see it and throw a DTC. So I'm still guessing you have some other problem besides knocking. But that's just a guess.

bad tank of gas, try another brand?

That's what I thought as well, expected to see the warning light on the dash as well as the code, but nothing. The pinging noise only occurs under the condition I described in the above post. The engine is very quiet and smooth otherwise. It is actually quieter than the Z which has less miles.

This has been going on for awhile and we have tried every single brand of gasoline available. The engine is stock.

As for the MAP sensor, can I clean it with MAF cleaner? Looks like it is held by just one screw?

Remembering now, some one came to me with a low rpm engine knock, asked me what is wrong, as i remember the car was at idle and you can hear the valves ticking like a slight knock, then pass 1500rpm it goes away.

Solution, changed brand of oil used in the engine from Valvoline to Royal purple or Nissan Easter oil 5w-30.

The tick was gone, but in my opinion it does that on old oil.(filter is clogged and less oil travel through the engine during low rpm.)

the engine is quiet and smooth during idle or any other rpm. I am familiar with the ticking (vvel) and that's not it. The ping only occurs occasionally during take off from stop or rolling as described above. It doesn't occur under any other situation. I can floor it at 2000 rpm and it runs just fine.

I read a bit about the MAP senor you mentioned. It appears to detect the engine vacuum and send signal to the ecu etc.... Can it be cleaned with MAF cleaner without damaging the internal of the sensor which might contain rubber components? Wouldn't it also throw a P0106 code for the bad MAP sensor?

Nop, mine didnt, i mean it was .4V off, and didnt trigger the fault, it did trigger all O2 sensors like flame.....actually i later found bank two O2 sensor2 was bad, but this due to the MAP being off by a bit and when i floored it at high rpm the fuel delivery is set to 11.40afr(stock), the MAP sensor was flooding it 10.xxafr.....which destroyed my O2 sensor+cat. In any case i was thinking it could have leaned it out and cause slight ping, on load.

In this case get a Torque App and a Bluetooth OBII adapter. Check out ur fuel delivery at these rpms and maybe it might have a the ability to see what the KNOCK sensors are showing.(i dont own the app, i use Uprev tuner.)

Very simple... Don't load up (giving it gas) the engine below 2000rpm. The VVEL runs exceptionally well at low RPMs but no engine likes being run hard below 2k. If it sounds funny, don't run it there. Your're gong to f-up your engine! If you're launching a manual off the line you should be starting at 3-4k and feathering the clutch. In an automatic you can ride the brakes for a second or two to bring up the rpm (while in drive of course) for launch. Don't do it for too long since it's pretty hard on the transmission and will heat up your fluid quickly.

maybe but it is just a workaround for a potential problem...

I'm looking for a solution.

I had the same issue but i'm on Uprev and mechanic made knock sensor more sensitive and it went away, maybe you should try replacing it.

thought about the knock sensor, but the engine shouldn't ping under light throttle condition so the knock sensor shouldn't have to kick in to retard the timing.

furthermore, i think it should throw a code for bad knock sensor?

Mine was doing this once, I had a intake manifold leak, try checking that?

any tips on how? where was the leak on the intake manifold?

did it only occur under light throttle? I wonder if the vacuum leak from the intake manifold would result in leaner (more engine ping) condition under more load?

The amount of air that leaks is dependent on the difference in pressure (delta P) between manifold and ambient. Delta P is lowest at WOT, so the least leakage occurs.

Post a Video.......

First question. how many miles on the car (carbon build up)? Do you have access to a scanner with data access to see knock counts? Are you sure it is knock and not something else like an exhaust leak, not common on this car from what I've read but have had some pin hole exhaust leak that can sound like pinging under part throttle load.

I don't have a scanner. It is my wife's DD and the ping started around 60k miles under condition described on the first post. It occurs intermittently and can't be reproduce at will (unfortunately).

Carbon build up was my first guess. We ran through many different kind of fuel cleaners but didn't really help much. However, it may not be the cause since it doesn't occur under load.

As for exhaust leaks, should be noticeable at idle during the cold start? Engine idles smooth and quiet under all condition.

Hey, I just posted this in another thread. Recently bought a 370 and have some pinging too under light throttle + some engine load. Found this in the manual: "Now and then you may notice light spark knock for a short time while accelerating OR driving up hills. This is no cause for concern, because you get the greatest fuel benefit when there is light spark knock for a short time under heavy engine load." Seems to be normal if nissan has it in the manual

That's interesting... it said under heavy engine load.... curious if taking off is considered heavy engine load?

Is your an 7A also? How do you get rid of the engine ping? My wife usually just let off the throttle for like a second and it would be fine afterward. It never occur once it gets going or any other gear higher than 1st.

Usually if it pings it tends to be part throttle load right at tip in for most cars and will go away as soon as the load is less and ign correction occurs. I see you live in socal so you are warmer climate and 91 octane. I have been told the z is actually designed for 93 octane and they do have a constant ign correction with 91. I never heard any ping with mine in oem tune but you live right by one of the best tuners, may consider going to him (Seb) for a custom tune as they actually take out some of the ign advance for 91, if it really bugs you. Otherwise it is most likely doing as designed, going to the limit and then backing off when it detects knock. It's hard to say without being there and hearing it.

According to most, the best way to get rid of it is higher octane fuel. Another option is to get on it more in first- you're wife may be lugging the engine a little. I can't say for sure, but the situation your wife describes may constitute a heavy load.

Mine is a 6MT. I notice it in 2nd + 3rd when lower than 2k RPM and evenly accelerating. Anytime the load is lessened it stops.

Also, if you're at 60k, it wouldn't hurt to replace or check the gaps on the plugs.

that sounds logical. It probably got worse with some carbon build up due to higher mileage. Fortunately, it only occurs during initial take off rather than pinging at higher rpm/speed.

Curious if it would cause engine damage with the 'as designed' ping in our situation?

Looks to be similar condition.

can you recreate the ping at will? how many miles do you have?

This is what I meant when I said most cars I have worked with (so that's not the z as I only have my own for comparison) but if they ping it is right at throttle tip in from cruise and is momentary. Typically this is in a part of the map with high ignition timing as they want good throttle response and max torque since you are trying to accelerate. Not every car does it even within the same type of car and climate and fuel quality play a roll (acura MDX were fairly picky since they are also heavy and use high comp ratio as well). As for long term damage, not being able to hear if yours is a light ping that instantly gets corrected or if it's bad knock and not correcting would make a big difference, the first one I personally have not seen one fail catastrophically by light ping that gets corrected quickly.

Again if you really want it gone I would go to Seb and he will actually tune it for 91 octane with two ign maps one for summer and one for winter (hot climate/cold climate).

I can recreate it on essentially any incline. It's very light pinging. Not the kind of pinging when you almost stall this car if it's a MT.

I have 7000 miles.

great explanation. it is a quick metallic ping. it goes away as soon as she lift the throttle and re-accelerate fine within a second or two and runs well from there at any speed.

Again, the engine is quieter and smoother than my newer/lower mileage Z. And the exhaust also sounds much better, but that's a different discussion ;)

Our main concern is the long term effect of this issue. The ping normally last just 1 to 2 seconds at 1500 rpm or less.

Also may want to go to dealer and see if you pcm has the latest flash. It's not super common for the Japanese lines I have worked on to do a lot of re flashing like the German and GM to fix issues but there have been some and it doesn't hurt to ensure your running latest software.

I also experience this condition when everything has warmed up, exactly as described, taking off from a stop where I have been just sitting in traffic idling for a bit. I always wondered what it was and it was never tuned out, or couldn't be tuned out. :driving:

Have you ever had any issues from it?

No I have not. :driving:

were there any pcm flashes available in the last few years for our motor?

we took the car in for transmission fluid change in 2015 and they didn't mention anything outstanding for the car. do the dealers only offer them for cars under warranty?

at what mileage did this condition start?

our car started around 60k miles.... it was fine before that.

After putting in a tank of 93 (about 4.5 gallons of 91 left in the tank), I no longer here any pinging after about 50 miles. I assume the ECU had to adjust or something.

As long as I can remember. Both when NA and now boosted.

Well it should be able to be tuned out if it truly is ping from ign. I see your on uprev and from what I have heard is that it doesn't have as much control over timing as ecutek. Maybe do a log and look for knock detect/ ign correction and see what's going, just a thought.

As to post above asking about if the dealer will check if your car has latest software. The answer there is most likely a big fat NO. Sadly techs are paid by a system called flat rate which is a time focused pay system not a quality focused pay system so they are there to get your car in and out as fast as possible with zero ***** given. Very few will go the extra mile and they usually end up leaving the industry after a while cause of all the BS, glad I'm out but miss the diag.

What octane gas, NOT brand that is important. Run min. 92 for several tanks and see what happens.

What oil are you using? The VVEL requires the right oil. Go to Nissan and get the Ester oil if recommended by your owners manual. Otherwise, don't use a conventional oil, at the very least, try Mobil 1 5w30.