Slight miss?

I am determined. Even if I do myself.

 

Bring it in, if everyone makes the complaint they cannot ignore it. Right now mine is still flaring from P-D, I lost all gears on Sunday for 15 min, I have no power on acceleration and I not have been notified today I have a oil leak on the Cam tower. This thing is wearing my last nerve.

 

Dealer told you this?

 

Yes just got the text 15 min ago or so from my advisor...

 

I've captured some of the surging in logs. Giant dips in timing going from 27 degrees, to -8.5 degrees back to 8 degrees in the span of 4 seconds. Indicative of massive knock correction which is consistent with seeing surging return using 87 octane. It appears that while this truck was tuned to use 87 octane, it's not doing a good job of preventing detonation on it, and in certain low RPM, moderate load conditions just at the brink of deciding whether or not to downshift, that's where the knock occurs, and that's where the correction is taking place, and thus the surging. I called my service advisor and let him know I'm able to replicate the surging and am waiting a callback to see how he wants to proceed. It's obviously going to take logging with techstream and submission to toyota engineering to assess if a modification to the tune is warranted.

 

This is exactly what is happening to me (good description!!) I'm gonna fill up with 89 today and see if that helps the issue at all. If not, it's a few more tanks of 87 and to the dealer for me!

Could this be related at all the the crank position sensor failures that have been reported? If the ECU is seeing the Crank position as something other than it actually is timing will be adjusted incorrectly and could definitely cause a miss/knock.

 

Nope, shouldn't be related, as it is virtually non-existent when I use 91 octane ethanol free, which is what I usually fill up with. I've ran a handful of tanks using 87 octane and I consistently see the surging/detonation occur when doing so. I'm almost empty on this tank and going to go fill back up with the usual good stuff and attempt to reproduce and log again to see if the timing dips are lessened to confirm the theory in numbers.

 

Damn - They just opened a new station with ethanol free right next to my office so maybe I'll give that a try for $0.30 more per gallon than 87. Hopefully I'll see some decent MPG increase with that too at least.

I did accidentally stumble in to a place that sells 116 octane today too while looking for a plumbing supply store...

 

Won't see much MPG improvement. I haven't been able to quantify any real difference that couldn't be argued for weather, commute or right foot variables.

I've ran some of that 116th octane in past builds. Great stuff, smells lovely...destroys catalytic converters. :-D

 

Nice work scooby24, hope your dealer takes it seriously.

 

THIS.IS.EPIC!

 

I have been watching this thread since its inception. I have also been in denial of this issue. Yesterday, I used the Torque app to run some diagnostics on my way home from work (30 miles/45 mins. one way). Below are the results I uploaded to my Drive account from Torque. This tank of gas I am running 87 octane with 10% ethanol. I need to fill up at some point this weekend and will try what @Scooby24 suggested and fill up with ethanol free 91.

I also ran into an issue while logging with Torque this morning to try and collect more data. My ABS warning and Traction light came on so I pulled over, removed the OBDII sensor, restarted the truck and the issue went away. I really don't want to fry the ECU. I think a few members have ran into the same issue.

 

Yeah I hope it's not a long term solution. Ethanol free 91 is almost $1.50/gal. more in my area. Only one gas station carries it so my hands are tied.

 

Wow! I have never seen a knock correction so large. What ECM calibration are you running?

 

Mine missed for the first 5 months, then quit for 7 months completely, then started up about 4 months ago.

 

Talked to my service manager. They recommend having it towed. I opted to drive it in later this afternoon to have it looked at. They are giving me a loaner for the time being. Will keep you all posted.

 

Running 88 octane ethanol free seems to have fixed the knock for me. But the bad news is that I can't count on this as a solution since I can't get it everywhere especially little towns out in BFE when I need the truck to not have any issues.

Next tank I'll try 89 octane and see how that goes. Kinda crappy that I've had 250k mile cars that I've run on stale 2 stroke gas that ran better than this truck runs on top tier 87 octane. I think I see a visit to the dealer in my future though.

 

The 0300 version from Rev 1. I've been testing and relogging and while the surging is less prevalent with the new tank of 91 E0, it's still there. As I'm watching the realtime info during the surging, I'm not actually seeing the negative timing values so I'm unsure it's timing related. Those huge dips I found in the log may not be the true culprit.

What I'm seeing realtime is that the scenario where you reproduce the surging, it's low RPM (1100-1500), with 25% throttle or so, just at the brink of the downshift occuring. The load conditions there are putting the timing right around 5 degrees advance which is pretty low, but it's staying relatively steady. I'm not seeing misfire counts high enough to point to the problem, and the timing isn't making a drastic dip during the surge so it doesn't look like knock correction now. I suspect what's really happening is that rpm/load table has an abrupt change in valve timing or even atkinson/otto cycle and it's jumping back and forth as the load varies just enough to where you feel the shifts in power.

In my estimation, not seeing inordinate misfire counts or timing dips realtime during the surging, I suspect there is no harm being done. I spoke to my service adviser yesterday and he's checking with local dispatch to see if a regional rep wants to check out the truck and do some logging where he can see a lot more values than I can, or if they are already aware of it and are working on an updated map. Will keep you posted.

 

This could be caused by a rapid advancing of the intake camshaft, resulting in spiking cylinder pressure, followed by too much timing (from the previous state of the retarded intake camshaft), with an abrupt ignition retard due to knock. Otherwise know as switching from Atkinson to Otto, and adjusting the timing abruptly. Just a thought. It would be interesting to see what is happening with the intake camshaft position around the time of the miss.

 

Long story short, dealer will not accept Torque data as sufficient evidence because "if there is a misfire, the check engine light would be on regardless of what your data says". I made an appointment for a weekday when they have time to run Toyota's diagnostics. Shop foreman thinks it's the transmission since I did not have TSB rev 1 applied yet. Guess we'll see.