3.slow pinging w/slushbox

[^VooDoo^]

Ive always had a stick trans and never had issues with pinging before due to the way I drive in the upper rpm range, Even with questionable gas.
Now a 3.0 and auto there is no control and creates the perfect circumstances for pinging.

I know the TPS isnt in the best of shape but it is set correctly, EGR is not the issue as I have checked this through.
AFM is unknown at this time but assume since there is no stutter/falloff its ok.

This leves the O2 sensor, I know this was a huge topic in the past about they get weak and dont use any brands other then Denso, I have not checked this as of yet as there is no way to tell is its bad except just plain out not working and throwing a code.
Also it only pings under cruise load and not under excelleration as that would be open loop.

Opinions on O2 sensor being the suspect?

[Seanz0rz]

certainly sounds like that could be the culprit.

i ordered my o2's from http://www.sparkplugs.com/ good prices and fast shipping. good place to order from. and certainly cheaper than alot of other places.

at least on my 3.4, the o2's will die without setting off the CEL. their failure mode is not life and death, but rather a long drawn out process, during which you will notice that the truck is no longer running correctly. or you could have another brand o2 which is just a recipe for failure.

[Obi..]

FWIW you can easily test the cycling of the O2's with a digital meter. They should cycle about 8-10 times in a 10 second period at 1500rpm. For my Cali rig the process is described on page EG-252 of the Engine Repair Manual.

Go to the OBD port under the hood and you use the "B+" post and Ox (first sensor) and Ox2 (second sensor if equipped).

Always go with a factory unit, there's been too many issues with different brands and don't hesitate to also drop the converter to see if it's gone south on you.

[CJM]

Ive had no problems so long as its not a bosch sensor.

[DHC6twinotter]

huh...I wonder if my 2nd gen pinging issues are because of an aftermarket o2 sensor. IIRC, the pinging started about the time I had the sensor swapped. I've never been able to figure it out. I never dug into it too much, but now that I have a 2nd vehicle, maybe I can fart around on my 2nd gen and try to figure it out.

I did run colder spark plugs which seemed to help, and I could get by with mid-grade gas. A few months ago, I had the spark plugs changed (NGK) and timing belt replaced, and now I have to run premium. It pings horrible when I run regular unleaded in it, so I just run premium. Even then, it pings a little bit.

Anyways, you might be able to try some spark plugs that are one or two steps colder. Some places will look at you stupid when you ask for colder spark plugs, but some folks know what you are talking about. I don't understand the physics behind colder plugs or exactly what colder plugs do, but it seemed to help in my case.

Just my $.02.

[L33T35T Tacoma]

I could be way off on this, but check the timing. Long ago when I paid people to work on my truck, the mechanic that did my timing belt somehow set everything off one tooth, advancing the timing to 20 degrees BTDC. It would ping under load in the higher RPMs. I discovered the timing was off when I went to go get it smogged. Once I fixed everything, it ran fine, and passed smog and didn't ping.

[^VooDoo^]

Well I have since retard the timing a few deg and no change, I changed out the injectors, FPR, TPS, AFM, Sparkplugs along with SRS elimination and checked for vacuum leaks.
Its got alot more low end snap but ping is still there but the range of pinging starts a tiny bit higher in the rpm range.

This makes me think low fuel pressure or filter change time, I do have a FP sensor on my fuel rail now but havent hooked the gauge up yet.

I also know that the thermastat is bad or non-existant as I have no heat and if I turn it on the temp drops alot, Im changing that this weekend.
Word is if the temp does not come to temp the ECU stays in open circuit mode and possibly not compisate for Lean out.

[Robinhood4x4]

That sounds reasonable. 3.0's are not known for pinging.

Good luck.

[^VooDoo^]

Well pfft.

Replaced thermastat and a bunch of other thing so the engine comes to temp.
Failed smog again, No changes in the test, CH and CO are great but NO is 3x over limit.
Only thing not changed is the CAT.
So this coming weekend if no rain I change the CAT and check the timing belt.

[Robinhood4x4]

Did changing out the t-stat fix the heater problem?