The 3VZ-E in my 94' pickup is pinging, and I don't know why. It has had a recent full tune-up (including cap, rotor, plugs, and wires), and an injector cleaning as well as a new O2 sensor. The only things that haven't been done to it are a timing belt and a valve adjustment, but i may be able to do the belt soon (needs the idler pulleys bad). Other than that, I wouldn't know what else would cause it. It's done it for a long time, even when it belonged to my grandpa, but I had never really thought much about it until i got a hold of it. Another thing is that it only does it at operating temp when it is under load, at any RPM up to about 3500. I want to try some octane booster and see if it goes away, but I don't think that it'll work. Any ideas?

 

I think pinging under load is usually wither excessive carbon build up or ignition problems usually. Have you tried regular high octane gas in it?

I had a thread about the same problem in my 22RE that has a lot of good info in it for you to read up on and try. My problem went away when I did a new radiator and water pump... I'll dig up a link.

https://www.yotatech.com/forums/f116...-octane-91929/

 

Skip the cans of octane booster, they don't really do much. Fill up with some high octane. Carbon buildup could be one possibility. Another is you could have a fuel pressure problem, has the fuel filter ever been changed? Hows your MPG?

 

The MPG is pretty good (a hell of a lot better than my 4runner), but I'm pretty sure that the fuel filter has never been changed. As for carbon buildup, what do you think about seafoam?

 

Mine has always been:
regular unleaded = ping ping ping
anything better = no ping

 

I always put in 88 octane, which is plus here where I'm at and it still does it. I put the same gas in my 4runner and it doesn't ping (never has though) so I don't think its the octane rating

 

That's a sign it could be running lean for some reason, one possibility could be a fuel pressure problem. I'm guessing a clogged fuel filter could cause a drop in fuel pressure. Another possibily is a vac leak somewhere downline of the AFM or an AFM problem.

Never tried it, but be very careful about dumping it too fast it into a vac hose.

 

Until you get it figured out take it easy on those mountain climbs around Taos. Running too lean causes very hot exhaust temps and the 3VZ is known for burning up a valve sometimes. Not to mention pinging is very hard on the motor too. How's the coolant temps?

 

I don't think that its running lean because the place that it was taken to to get the tune-up said something about it running too rich, so they leaned it out, but i think that it was running rich because it was only firing on like 4 cylinders, but the fuel filter causing problems makes sense. As for the coolant temp, its just a tiny bit over the halfway mark (my 4runner's temp is exactly in the middle) so it should be in spec, but maybe a coolant flush could fix that

 

Hold on... red flag. How did they do that? The ECU controls the A/F ratio and they can't adjust the ECU.

 

You know what, I don't know. Thats just what the tech told me

 

Take it back to them and ask. Tell them you're getting pinging and think it may be running too lean. How's it idle?

 

The idle is a little high, but thats where I adjusted it after I cleaned the throttle body. It's at like 900 RPM's but its pretty smooth

 

So the idle didn't get higher after they did "something" to lean it out?

 

have to side with sqiddy.my 91 runner on reg unleaded-ping ping ping.I run 93 octane all the time in it-no ping.engine just rblt.timing right on.new fuel filter & pump.try the 93 for a couple tanks just to see if it helps

 

Actually, it did. I remember it being at about 1300-1400 RPM's at operating temp, so we took it back and had them adjust the idle

Thats what I was thinking of doing

 

I'll bet you a beer they leaned it out by causing a vac leak some where.

Anyway, yeah go ahead and fill up with high octane and try that.

Look for a vac leak (could be a hose off or plug removed)

Check your timing too, make sure its less than 12 degrees advanced. https://www.yotatech.com/forums/f116...timing-134386/

 

Thanks for the help, I'm going to check the timing today just to make sure

 

Problem solved! Timing was set at 13 degrees BTDC, reset to 10 degrees and pinging dissapeared. Now runs like a champ, thanks for all the input!

 

Great!