Ok guys I've dealt with this pinging issue with my 1994 Toyota 4runner 22re since I got it about three years ago. The truck otherwise runs great, I've been through a ton of things checking it out changing trying new things and in the end no matter what if I set it at 5 deg of timing it pings like mad. If I set it at 0 deg or right around there it runs perfect. I had read that this was in a Toyota Service Bulletin at some point. It's not all the trucks, but some of the 90's series had this issue, but I've recently been toying with it trying to get it right on regular gas at 5 deg. If I want to turn the timing closer to 5 deg I have to run premium gas which adds up over the years. So I've given in to leaving it around 0 deg of timing and running Costco ethanol free regular gas. BTW I have tried nearly all types of gas available in Hawai'i and it hasn't made a difference only gotten worse unless it was higher octane.

I emailed the guys at 22re Performance and Jerry got back to me quite quickly with this info confirming what I've seen as a "fix" for the last couple years.


Jerry

"I've run across the same issue on a late model year truck just like yours. after 12+ hours of diagnostics I came up with the same thing. retard the timing. I found an ancient history TSB for this exact problem and it was "retard the timing by 2 degrees, if it still detonates, retard it again by 2 degrees until it's gone". That was about 11 years ago, so i've since lost the bulletin.


There was no reason from toyota nor was there an actual "fix" besides retard the timing until it's gone.

When I did it, it cured it at just under 0 degrees, and it ran about 100 times better.

That's about the only advice I have."


I just wanted to post this for anyone else dealing with this issue in their 90's 22RE vehicle, I hope it saves them a lot of time and effort. Buy yourself a timing light (You can still can classic simple ones off ebay) and set the timing till it stops pinging. I had to go close to 0 because where I live it's hella hot nearly year round and there's some big hills. On a side note the truck would NOT ping at 5 deg of timing if it was cool out. I did try a lower temp thermostat from the 22RTE and that didn't solve it.

I'm throwing in the towel on this one. I've got too many other things to figure out... Like why am I smelling gas in the wheel well by the filler but can't find any leaks (Maybe bad evap canister? Why does it idle low on warm restarts? Why is it clunking in the rear (probably diff lash) And where is the oil leak coming from (probably the front oil pump and seal)

IF possible maybe this could get stickied to cut down on time searching for anyone else that's dealing with this issue, I'm sure there have been others. Thank YOU!

Haribol

 

Just for info...mine is an '89 22RE manual trans. Got it from my bro w/140,000 miles or so. Pinged badly on 87 octane in hot wx. Used premium fuel in summer but still had to be real easy on the throttle. Asked bro about it. Said always done it and found no solution. I lived with it but it went away after #3 injector went bad at 180,000 few years ago, and all four replaced with some "rebuilt" ones. Doesn't ping at all since that time, even on a 105* day. Failed smog last month, but the tech did a general cleanup of the induction system and adjusted timing, cost ~ $150 or so, so nothing major. Passed OK on recheck. I assume that he adjusted timing to spec. I think the smog check system will catch timing not IAW the book. Don't know for sure. Anyway that's the story. How the injectors work is mystery to me, but maybe they came from factory w/lean injectors?

My $0.02 on the subject

 

I've had to retard the timing on my '94 22RE as well.

Incidentally, I owned a couple of GM J cars in the early 1990's with 4 cylinder engines. Both of those engines needed their timing retarded as well to stop the pinging.

 

Wow very interesting man! I haven’t touched the injectors other than running some cleaner through it. Mostly because it’s otherwise run so well. I have no reason to touch them if they’re not leaking and seem to be functioning properly, but you may be on to something! Maybe there’s a correlation to the warm restart low idle too! Could be an injector thing 🤔

That could very well be it, lean injectors, I wonder why Toyota wouldn’t have found that or if they did wouldn’t have posted about it.

Do you think it’s safe to replace with oem for that year injectors or better to get rebuilt ones that would possibly spray less lean?

Thank you for sharing. This little truck and motor has been quite the project and process of understanding.

 

Also super interesting 🧐 I guess this was still pretty early years for fuel injection? So maybe they were working the bugs out? I’m thinking they were trying to go as lean as possible for fuel mileage but maybe went too far?

 

Figured out the fuel leak today which may be causing some of the issues. The filler neck at the gas tank door is leaking somewhere by the frame. I had seen a stain but never liquid until today when I watched while filling up. Since it’s leaking I know it’s not sealing vacuum like it should so part of the system is out of wack. It’s venting fumes there instead of them ending up in the charcoal canister or burned off. It may be relating to the pinging and possibly the idle.

I’ll report back when I get it swapped.

Regardless it’s dangerous and I gotta get on it 😬

 

I switched to 91 octane for towing to eliminate pinging and only run 91 now. The added cost is evened out as 91 gives better fuel mileage. Truck runs so much better.

 

Has anyone had success adjusting the MAF to make it run richer? That ought to help also. Colder spark plugs, less timing and a richer mixture are the knobs to turn as I remember from my youth…