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?

[^VooDoo^]

The heater problem is there is no flow, I tried to just run a garden hose through it and no go,, I belive the previous owners had a blown head gasket and used the crap you poor in the radiator to fix it.
I have another replacement core.

Trying to replace injectors again but I doubt those are the issue since the leanout is across all cylinders, Im limited on what I can use out of the 3 sets I have since most are cracked tips.

I have now gone down to the harness level, after testing it it seems ok but Im going to make another harness and replace some of the plugs.

What it might come down to is that the ECU might have a bad final in it, The 3VZE ECU and wiring harness are set up to group fire all 6 injectors at once alternating between the two finals.
I cant even tell which year ECU I have (lable gone) except it having the ECT module in it and know its V6 because the 4cyl version has different plugs.
Anyone run into a problem with running a older V6 ECU on a later year vehicle?, Just incase thats what my be troubleing me.

[Obi..]

Oooop, posted my reply in your ECU needed thread, did swapping in a different ECU fix it?

[^VooDoo^]

Could come to an outright conclusion.

I just put in the ECU from my 92 V6 MT runner and it fired right up.
I knew there would be transmission issues and it did detour me from doing a complete test.
the ECM button becomes useless (because its part of the ECU)&(was hoping the trans would do its own thing but it didnt).
D and 2nd only give you 3rd gear but 1st still works.
There wasnt much of an improvement as the ECU hasnt tuned itself to the running conditions and may have run just a hair ritcher, I cant test this fully ovr time without 2nd gear.
But the whole test told me the ECU want the issue.

The harness checks out with some heavy ohming out.

..........
Im now back working on the EGR modulator again for the 3rd time/replacement (This one is really pissing me off)

I know one injector has issues as the O2 gauge jitters at times insted of its normal wobble, but cannot tell which one it is since all plugs are white, I will look into another set since all the spares I have now have issues and broken pintels.
I need to ohm out the O2 sensor harness, It is slow at heating up sometimes, It is the second sensor tried and both Denso.

TPS checked again and Ohms out good and adjusted correctly.

Fuel pressure is 40-50psi and that tells me the fuelpump has been replaced.

Did a propane vavuum leak test and is good.

[Obi..]

FWIW (if your's has 2 O2's like mine) you wouldn't be the first to have to go through a few downstream O2 sensors to find one that hasn't been somehow damaged in shipping (people do throw boxes). Also even though my downstream was a Denso (WorldPac) it was a factory Toyota boxed Denso with the correct length wire coming out of the sensor to the plug that worked properly.

~IMHO&E WP's downstream Denso O2 units have too long a pigtail since they only carry one part for (IIRC) 92-95 4Runners. Literally I would get such a minute difference in resistance you'd think it wouldn't matter, but in the end it did.

Hope that offers some insight.

[^VooDoo^]

I dont have the second O2 sensor after the CAT.