Engine pinging in hot weather

Few weeks ago we had hot weather and I noticed my engine pinging under light load 1500rpm 30 to 40 MPH. As the weather cooled I changed the spark plugs to OEM correctly gapped and made sure it had 91 brand gas and the pinging fully stopped. Today the weather got hot again, almost 97 degrees and my truck started pinging again pound enough to hear it inside the truck with the radio off.

I'm sure it is engine knock and it appears to be related to the heat, plus the crapy gas here in CA does not help.

Anyone out there have noticed this issue?

 

Strange to be pinging only when its hot outside.

 

Do you have a scanguage, any idea of the true engine temp?

No codes I take it?

 

No scan gauge and no codes at all

 

sure its not just piston slap?

 

Op, maybe try doing a google search on this again. There is at least one really long thread here on TW where a number of people have been dealing with this. The last I saw was that it gets worse and Toy does not yet have a fix.

 

I saw that one. I wonder why so many pinging issues lately?

 

Are you still using high octane gas? These engines have high compression which will make them more vulnerable to engine ping. I believe the older models recommended high octane. Not sure why they don't anymore.

 

I'm using 91, the highest octane here.

 

Try the 89 octane, I usually run that with no issues

 

Ahh...we'll all enjoy pinging once they raise the ethanol levels.

 

I too have had some pinging in hot weather. It's most noticeable below 2K rpm with the A/C on when running 87 and sometimes 89 octane. When you consider that my AIT reading on the scan gauge is reading at least 116+ degrees when this happens isn't a surprise. When you feed engines hot air, there is always a greater chance of pre detonation. It doesn't seem to hardly happen when running 93 octane.

Solution:

Run the highest octane you can buy.

Don't load the engine as hard at lower RPMs, run a lower gear and or allow a few more revs at a lighter throttle position(less ignition advance from the ecu).

At a note as well, as engines get older, carbon deposits will form. These deposits tend to stay very hot in the combustion chamber even between the different combustion events ( 4 cycle events "Suck , Squeeze, Bang, Blow" ) and can set off pre ignition when the mixture is just right. This is the reason that some engines benefit as they age from higher octane fuel as they age. I've personally seen this numerous times on very different engines.

 

I too have had some pinging in hot weather. It's most noticeable below 2K rpm with the A/C on when running 87 and sometimes 89 octane. When you consider that my AIT reading on the scan gauge is reading at least 116+ degrees when this happens isn't a surprise. When you feed engines hot air, there is always a greater chance of pre detonation. It doesn't seem to hardly happen when running 93 octane.

Solution:

Run the highest octane you can buy.

Don't load the engine as hard at lower RPMs, run a lower gear and or allow a few more revs at a lighter throttle position(less ignition advance from the ecu).

At a note as well, as engines get older, carbon deposits will form. These deposits tend to stay very hot in the combustion chamber even between the different combustion events ( 4 cycle events "Suck , Squeeze, Bang, Blow" ) and can set off pre ignition when the mixture is just right. This is the reason that some engines benefit as they age from higher octane fuel as they age. I've personally seen this numerous times on very different engines.

 

You should not have to run higher octane then the manufacturer recommends and they recommend 87 min. If the vehicle is pinging then it could be anything from a dirty air filter to a bad ECU, bad knock sensor, carbon build up, or something else, but it should not ping. I assure you it did not ping on regular gas when new and it should never ping on premium. You may have to take it into the dealer and have it checked out. If left alone it could trash your engine.

 

75 degrees today in the morning. I could not replicate the pinging. Let's see later today when it gets in the 90s to see if it pings. Still with same gas in it.

 

I, too, have noticed a weird sound once the warm weather hit this year. When I am accelerating at a low RPM with the A/C on, I hear almost what sounds like a piece of plastic vibrating in the engine compartment. It is VERY intermittent. It that considered knock or piston slap?

 

I've had the same problem with the pinging on hot days. I live in south florida and its always 85 degrees here. First I switched to 93 octane which helped some but wasn't a total fix. Then I installed a cold air intake and insulated the entire thing and installed

$9 Denso IKH22 Iridium Power Spark Plug, (Pack of 1)

Denso IKH22 iridium spark plugs( which are a considerably colder plug) and I also add a bottle of Lucas octane booster per tank. This is a lot to go through just to make your truck run properly, however from what I hear Toyota's knock sensor does squat until 3000 rpm. Unfortunately there's really no other choice but to address the problem considering the amount of engine damage thats accuring during preignition or detonation. The problem is also compounded if you live at sea level with higher atmospheric pressure, thus higher combustion temp and pressure.

 

The CPU should be able to adjust for 87, so if you're running 91 or 93, it shouldn't ping. When it's hot and you notice pinging, try disconnecting the battery for like 10 minutes while you're at your destination and reconnecting for the ride home. That should reset the ECU and may solve the issue...just an idea...

 

Disconnecting the battery will reset any advance timing learned. I can't see how that it's going to work. Someone mentioned that the ECU won't listen to the knock sensor until 3,000 RPM. Probably because the knock is not as dangerous as it would be at higher RPMs.

I am just curious why so many Tacomas are pinging lately. This seems more frequent in newer trucks.

 

If you look at the parts diagrams all kinds of engine internals have been changed on later models. This is probably due to lighten the rotating mass and reach even further for that ever elusive CAFE fuel standard. It is also probable that ToMoCo has changed the fuel mapping in the engine ECU to make the engine run even leaner.

When I read that large thread those with the pinging were trying everything including aviation gas, better fuel and higher octane fuel from the top tier stations, changing spark plugs, the whole works. The fact is their engines were still making racket when hot outside, at high elevations, and/or with the A/C on. Nothing was eliminating the problem and ToMoCo does not yet seem to have a fix.

OP you might want to go back to that large thread about this problem and send that one guy who has posted so much there a PM. It seems to me he was on top of the matter and would likely know the latest.