I'm trying to get rid of this ping in my 22re. It has new plugs and wires, new distributor cap and rotor, good fuel filter i'm assuming by how new it looks (i know that is still a possibility), valves recently adjusted, which got rid of much of the ping, but there is some still there when i really push it hard up a hill. Timing is dead on...don't really know where to go from here. But i do know, the o2 sensors are old, and i'm wondering if this would be the next logical thing to do. Thank you. If you have any other input as to what i should look at, i'd really appreciate it.

 

It's possible, but good insurance if it has any age on it to replace with a Denso (no Bosch). There is a way to test them with an OHM meter with specs from FSM. If it's the original and you have over 100K on the truck, I would replace it. Definitely will improve gas milage some as by nature the 02 sensors lose their efficiency from age and wear.

sparkplugs.com have the best price on Denso I have seen.

 

It's crappy gas/to much timing advance that's the problem.

 

no, that's definitely not the problem, as i've been running it on chevron and 76 premium for the past 3-4 months to keep the ping quiet. when i adjusted the valves and did the spark plugs, i filled it up with regular (still 76 - i don't use crap gas) to see how the ping is, and it did quiet down a lot but not completely. and as i said, the timing is dead on. I am buying o2 sensors tomorrow

 

O2 won't help pinging. O2's when they die or get slow usually cause over fueling which would lessen pinging. Might want have a injection flush or top end cleaning done, could be carbon build up.

 

I've seen it both ways. O2 reading wrong and giving too much fuel, which is most common and reading wrong and leaning out the least common.

 

O2 will almost, if not ever, give you a lean condition. That is because of how they work. They generate a voltage between 0 and 1 Volt. The high voltage will say that the engine is running rich and cause the ECU to lean out. Stick a volt meter on the O2 plug in the diagnostic termnial and the T1 ( I think) terminal and it will tell you the voltage.

How is you engine Temp? Could be a sign of head gasket going as well, blowing between cylinders.

 

Pinging = pre ignition...if your getting pinging that means that either:

A) your timing is too advanced or...

B) your intake is getting hot and igniting your fuel too early.

Is there a noticeable lack in power?

If you are sure your timing is dead on then you are left pretty much with your engine heating. Your O2 sensor could be creating a lean condition which would heat up your valves and cause the pre-ignition, check it out.

Later,

Jon

 

Exactly! Good job explaining.

 

the truck does not overheat, but it does occasionally get hot if i have the heater on while its warming up (the whole thermostat deal - i just dont use the heater in the morning anymore)

i am 100% sure the timing is dead on. but...some have said to retard it a couple degrees to find the sweet spot. i dont know anything about this. it is to factory spec

there is a noticable lack in power when i use regular fuel. it pings horribly under load. with premium, and only with premium, it runs perfectly, with no ping or a very quiet occasional one when its floored, with more power than it has ever had before (since we adjusted the valves). i can't run it on regular, and i don't know if you guys have noticed, but it will be 3.50 a gallon for premium in not too long
the two things i have been told to look at are the O2 sensor, and the knock sensor. i dont know anything about the knock sensor, but i do know these o2 sensors are very old and it couldnt hurt to change them out

 

Probably a good idea to change out the O2 sensor(s). It will hurt a little, but only your pocketbook. To be honest, I would play with the timing just because it is easy and it sounds like you do have a timing issue. Check your plugs too. If they are white, you are running too hot. with your thermostat being gay I would think that your are just heating the head up a bit but...

I think that at this point it is critical to fix your thermostat and do some more serious diagnosing before you drive the thing around too much. I am sure that you don't want to burn one of those nice new valves out of your head already.


Once again:
check the spark plugs, they might give you some more info...

Hope this helps,

Jon

 

shoot!!!! just thought of something...maye if you constrict the air flow into the engine momentarily you could test the MAF/O2 sensor loop. If your rpm's go up, even momentarily, when you block off some of the air intake, you are almost definitely running lean. I know this sounds like a weird idea but, it works on Harley's...

just my $.02,

Jon

 

WHat he said plus I'd add check the EGR system and make sure its not running too warm. Temp should be dead center on the gauge

 

i changed the spark plugs when we adjusted the valves. they were indeed white and burned to ☺☺☺☺. i will replace the thermostat, for sure. but as far as the temperature gauge goes, it stays dead center, and as long as there's no heater on while warming up, it never goes past there

 

I have had a pinging problem for the last few months. I bought a 91 4runner a couple of months ago. I have tried retarding timing, 89 octane, replace fuel filter, plugs. I was dirving the other day and the battery light came on. The alternator was going. I have heard that a weak alternator may be causing pinging issues. Now logical, hard to imagin, but I replaced the alternator and the pinging has stopped completely. I have tried to drive in 5th, at low speeds and put my foot into it, no pinging. I have only driven the truck, with a new alternator, for about 20 miles. But I will keep you informed, to pinging in the future.

Mike