Well, _something_ has to be happening at the O2 sensor to make open loop happen. It's gotta be "fakeable"... Even if you had to use a PIC or a Stamp.


cool. I think that'll help a lot.

 

yea, i just finished the 3vz-e cam testing and am putting the 4runner back together. Then ill jump into the taco and put back the esc1

lol i was looking at the old yotatech thread and you have about 30 posts back then...

 

The old big SMT thread? You have it archived?

Yeah, I've become quite the babbler on here.

 

Bump.

*UPDATE* I am currently running 10 degrees of timing retard, mainly in the 2100 - 2600 RPM cells. Argh. I thought I had the HG/LR ping issue ironed out until I was heading up a hill at 2600 RPM or so, in 90 degree weather, fully loaded, at 4000ft this past weekend and got pinging during sudden throttle openings. I "fixed" the problem by down-shifting. When I got home I bumped my timing retard from 8 degrees to 10.

I should post a screenshot of my fuel/timing maps. I just cannot believe that people say they have no pinging issues without any fuel/timing mods. I mean, can you believe it? 10 degrees and "5's" for fuel enhancement.

Any thoughts?

 

Yeah.. Even around here at about 400-800' in 70* weather I can force it to ping under load uphill. Like you, I get around it by kicking it down a gear (either kick the skinny pedal for the auto kick-down or turn off overdrive).

I'm running -6 & -7 in those areas.. The Supra MAF helped a bit since I (well, the ECU) can dump more fuel in there now, and frequent resets of the ECU allow "me" to have more control than the ECU itself in closed loop.

I just put in IK22's gapped at .050" yesterday (I was running IK20's at .040"). That had an effect, but I also snapped one of the studs off of my front O2 sensor, so I'm sucking air which is hosing my A/FR reading which is making me run WAY rich (LTFT's are like +10 and higher) which is actually reducing ping.

weeeeeeeeeeeee!

 

I'm at -6 tops...with lots of fuel pull...

My AFR is at 12.6:1 too...for some reason my Tacoma LOVES the leaner mixture. NO ping and the egt sits at 1400deg....

if this dyno thing comes through ill be able to test all your theory's!

 

BUMP!!!! I can't wait to hear how this turns out!!!

BTW, I have been having a lot of ping issues too. It seemed to start about the time the gas prices went up. Never been a big issue before but now a moderate acceleration run will throw a CE light. (PO330) I haven't had a chance to check it but I think the knock sensor has retarded the timing to the ECU limit and causing the code. If I drive very conservatively for a few days the light goes out. I wonder if there is something going on with the gas formulations? We even have 94 octane available around here but no help.

 

It's wild to see how this stuff varies from truck to truck yet when it comes down to it, we're all basically running the same bolt-ons. Interesting.

 

That is interesting Mark. I wonder how much location has to do with it as well.

For my rig I think audible ping came back for a couple reasons:

1. I had tweaked my maps for winter (more timing, less fuel) and failed to change them back completely for summer (I should use the A/B map feature for this).
2. The weather is much warmer here now (30 degrees or more).
3. My 02 sensor might be getting “tired” (I have 93K miles on it – could that be part of the problem?)
4. PHX only has 91 octane available.

I am also wondering if a Cold Air Intake would help a bit. I have been eyeing the fender area for some kind of custom CAI set-up. Of course my fear would be water crossings and cleaning the filter, but colder air has got to make a difference (see #2 above).

I still need to get an EGT gauge going.

 

Yea i am going to be switching to my summer maps as well soon. I gotta mount a switch somewhere.

And yes the ESC 1 testing will come soon. I am still focusing on the 5vz thats going into my mr2...it is looking amazing, the cams are coming in today Wonder how my engine will idle with 284 cams

 

Some random babbling thoughts on this stuff...

---------
I (finally!) remembered that the Auterra OBDII reader can graph and record O2 sensor output. I snapped a graph of my output as it went into open loop this morning. The lower sample rate makes it less accurate as a trace from a storage 'scope, but it may help. I have my Palm here at my desk and will look at it in a bit.


---------
My truck LOVES to run at 80+ mph. I took a 160 mile trip this weekend. I got 18.5mpg with most of the ride between 75-80, and at least 20 miles above 90 on the way back. My normal around-town with mixed stop & go highway is 13.5.

never let anyone tell you that a S/C tweaked truck won't get good mileage. It's all in how you drive that HP!


---------
Christian, check into your O2 sensor needs and see if the front and rear are the same - I think they are. If so, swap 'em - since the rear one is behind that cat, it'll stay cleaner and thus wears out slower. See if you notice a difference in fuel consumption, power, anything. Don't forget to reset the ECU to get your fuel trims back to zero.

If you don't see a change, then I don't think that I'll be using the one I just got from URD yesterday. Lemme know if you want to try it and I'm happy to sell it to you for what I paid for it. Aww heck, I'lll even pick up postage! It's a Denso -4162 which I think is what you use. I'll know if I'll need it after this weekend. I think if I seal up my O2 bung then I won't need a new sensor.

 

I have info from the Auterra graph.

The sample rate is undefined from the info I have here (i.e., I'm too lazy to download the Auterra software package, open it, and look in the docs ) but I can say that it's "good enough" to show the normal O2 swing. That said...

It's VERY CLEAR when I hit open loop. The graph flattens out, the swing is gone. Looking at the specific data points, they are all between 0.82v and 0.86v. There is some _slight_ oscillation, but it's hard to say if a faster sample rate would have showed something more dramatic given that it was fine picking up the normal bouncing during closed loop in great detail.

I think this is fun data...

Basically, I think the key here is to generate a .1vp2p sine wave biased with about .7vdc. The biasing is probably optional - if you fed a fast enough sine into the ECU, it'd freak and flip to open loop.

I have to dig out my Heathkit signal generator. I knew my geekiness back in the 70's would come in handy at some point!

 

Mark -

So to clarify, you want me to swap my 02 sensors, front to back, if they are the same? I can do that. Maybe today in fact.

Also, should I be resetting the ECU each time I make an SMT adjustment to the fuel graph? I haven't been. In fact, the last time I reset the ECU was a few weeks ago when I killed my battery by leaving the ignition ON overnight.

 

its not the o2 sensor voltage that creates the open loop trip....im still set on how fast the O2 oscillates between rich and lean that the ecu will be like "oh snap lots of load here"

 

Yeup! It may help you out and stave off having to spend $90 on a sensor.


Well, this goes back to what I feel that I found a while back. Basically, the ECU in closed loop will do what it has to to run 14.7:1. "After a while" the ECU fuel trims will end up such that the piggyback is useless for fuel in closed loop. (it's still valid for timing)

So, lets say that you reset the ECU, create a map and things seem fine. If you then let things set "for a while", the ECU will encroach on your work and force everything to 14.7:1. So then if you go in and make a fuel change, the effect will be "bogus" based on two things... 1) the change you made will be relative to a 14.7:1 map - NOT the previous value you had in the cell; 2) the change you made will _quickly_ be "undone" by the ECU since it has little distance in value to cover for that cell.

I'm in the habit now of resetting my ECU at least once/week. I think I said this in the other thread, but I have 3 switches to add the next time I get into electrical (possibly this weekend), one of them is a momentary push-button which will be to reset the ECU.

My "habit" will become hitting that button a LOT to keep the net effect of the SMT in closed loop at it's maximum potential.



Right, I agree. I brought up the voltage's 'cause the signal is still oscillating, and there's obviously a max threshold. Dunno if the MAX is relevant or not... Like I say, I'd bet that stuffing a 10khz sine in there with a peak of .9v will trip it into open loop.

 

I still see no real performance drop mid throttle even after 2000km now....

Its the cams i tell you they work wonders

 

The O2 sensor output flattens out whenever you trigger open loop. The oscillation is created and controlled by the ECU when in closed loop. That is the question...You can trigger open loop with a fake WOT signal; You can trigger open loop with a fake "cold engine" coolant temp sensor signal; But the ESC guys figured out a way to trigger open loop with a fake O2 sensor signal that doesn't trigger a "bad O2 sensor" CE light. All the other methods have undesireable side effects, like the auto-tranny shifting problem. If we can figure out what the signal produced by the ESC is we can use it for you A/T guys.

It's gotta be whatever signal a healthy O2 sensor produces when it gets too hot to be effective for closed-loop feedback. It can't just be a too-fast sine wave oscillation because the ECU controls the oscillation rate and could slow it down if it wanted to.

Sorry. I'm getting anxious to hear what the 'scope results are gonna be...

 

Interesting info. I was wondering, are you running one of the cooler thermostats, Mark? I didn't see it on your mods list. I have been thinking about going to a 170 degree thermo but I don't know how bad it will be on my fuel economy.

 

I run the 170 thermo. In fact, I performed the following mods prior to supercharging:
Walbro 190
2-step colder plugs
60/40 water/coolant mix + water wetter
170 thermo

I lost about .5 ~1 mpg without being supercharged and adding these mods. After I added the SC'r and SMT, I stayed at this average loss. Hopefully that will give you somewhat of an indication of what to expect; a .5 mpg loss or so.

I am currently at 16.5 mpg on average.

 

Yeah... I put a 170 in a long while ago, the mods list on the sig (and on my site) is kinda' short. I was actually gonna go back to a 180 when I did my timing belt a bit ago, but I pulled the thermostat out of the box and it was missing that bleeder hole - weird - so I skipped it and left the 170 in.

ANYWAY! Don't let my mileage sway you moving to a 170. I can't say what difference it made if any. A LOT has happened since that went in.


I'm hoping to get a chance to try the signal generator on the O2 sensor lead this weekend. We'll see. I have a list of other things I want to do as well - as always!