3.4 ping under load

[jgr]

Hello all,

I need some direction for diagnosis. I have a 98 4Runner SR5 with a 3.4 liter, automatic, 4wd, all stock with 155k miles. It's been pinging with a resultant loss of power. I've tuned it up (plugs, air & fuel filter), cleaned the MAF, and run some techron fuel cleaner thru it but it still pings unless I run 89 octane fuel.

It also as a strong exhaust odor that is noticable after coming to a stop, and it idles a little rough (but that may be within the normal range).

Any suggestions or common problems that I should be looking at?

Thank you!

 

[4x4]

Do you always get your gas from the same gas station?

I found that the 87 gas at a cheap-o gas station was causing my 3.4 to ping.

I did the same things you did - cleaned maf, fuel filter, new plugs.. it helped slightly.

I finally realized it must be the gas, so I started filling up at a shell station and it hasn't pinged since..

 

[jgr]

Thanks, I've tried different gas stations but I'll try Shell next.

I'm wondering if I should SeaFoam the engine to clean out the gunk....

 

[plcfcng]

can not tell threw the video what the sound is. Can you describe it better. A squeal, tap or knock. Moving or sitting still ect:lalala:

 

[RS Dude]

Hello all,

I need some direction for diagnosis. I have a 98 4Runner SR5 with a 3.4 liter, automatic, 4wd, all stock with 155k miles. It's been pinging with a resultant loss of power. I've tuned it up (plugs, air & fuel filter), cleaned the MAF, and run some techron fuel cleaner thru it but it still pings unless I run 89 octane fuel.

It also as a strong exhaust odor that is noticable after coming to a stop, and it idles a little rough (but that may be within the normal range).

Any suggestions or common problems that I should be looking at?

Thank you!

I had the same problems until I replaced the O2 sensors.:nod:

 

[pluton]

Pinging, in theory, comes from 1. Spark too advanced, 2. Fuel mix too lean or 3. Gas w/octane too low. Also engine/combustion chamber too hot, carbon build up on pistons or in cylinder head.
If I switch to the lowest grade of regular gas, I can get momentary pinging on my 3.4 during brief spells of lugging the engine when accelerating in too low a gear.
Goes away with the next higher octane level gas.

 

[dogtail]

I had the same problems until I replaced the O2 sensors.:nod:

I've found that a bad rear O2 sensor in particular is the one that causes the ping. You can confirm by unplugging the front one and driving it.

 

[4runnerfiend]

think I'm having this as well. Just had new heads put on, so the compression ratio went up and engine runs hotter.

To me it sounds like the valves have a slight tap at certain rpms/engine load.
going to try better gas next tank.

 

[gamefreakgc]

Thanks, I've tried different gas stations but I'll try Shell next.

I'm wondering if I should SeaFoam the engine to clean out the gunk....

Yes on Seafoam or, I just used Royal Purple's Max Atomizer in mine (I also get ping but for different reasons) and it helped and also smoothed out the idle. It could very well be a injector that's clogged up so give it a try. Only cost $7.

 

[4runnerfiend]

Just want to confirm you are referring to the sound in the video I posted?

My engine seems to run hot as well...but I’m in a hot part of Costa Rica and I run the a/c constantly too...so it’s a bit tough to get a feel for that and I’ve also never owned a Toyota before this so have no comparable.

Thanks for your input

No sorry that is how my engine sounds. I listed to your video and could not make it out. sorry.

 

[Toy2play]

Just want to confirm you are referring to the sound in the video I posted?

My engine seems to run hot as well...but I’m in a hot part of Costa Rica and I run the a/c constantly too...so it’s a bit tough to get a feel for that and I’ve also never vowned a Toyota before this so have no comparable.

Thanks for your input

How hot are your temperatures and is it only increase in temperature at certain times?

 

[4runnerfiend]

How hot are your temperatures and is it only increase in temperature at certain times?

I need to monitor it more. Temps are 195 or higher. if I get on it it will go over 200 easy.
I don't know for sure if it is a ping..
All I know is it makes a funny sound like the valves are tappigng at certain times. it runs a little hot, and with new heads i have a higher compression ratio

My MPG suck and power is Ok..

 

[plcfcng]

well you have to start some where I would start with a compression test and a spark plug reading. (which means pull the spark plugs out keep them in order and look at there condition there are reference pictures on the internet. They should be a light white to maybe a little tan.) then do a compression test to see if all is normal. pull the timing cover to see if the belt slipped the you could check valve lash buy pulling the valve covers but that's a lot of work I don't know your skill level but thats a bit advanced. Maybe one of the smarter people can come up with something else:baby: