Hesitation during low RPM acceleration

Lol

 

So just an update. Never actually figured out the issue. Ended up selling the truck and replaced it with a Honda CB500X and moved to Hawaii. When I move back to the mainland in a few years I'll see about getting another taco.

 

I have a 2022 mt trd off-road and I am having the same issue. It feels like a clogged carburetor on an old car. Every now and then after driving for a while the truck feels like a dream and 20min later is a disaster again. I have driven many manual cars (modern and old) and this Tacoma is the only one that does this.

I discovered that if I use a scanner and force port injection 100% the issue completely goes away. So no sure what is going on, there are many things that can disrupt direct injection and I have not been able to troubleshoot properly.

 

This is exactly where I think my problem was, the transition between port- and direct-injection. I suspect that at lower RPM and higher load the ECU struggles to decide if it wants direct-injection or port-injection and can bounce back and forth between the two due to increasing RPMs and reduction of throttle input. It's like the ECU on the manual was given the same fuel maps as the automatic, which only ever expects to see the throttle input match the RPM (ie: low-/mid-/high-throttle with low-/mid-/high-RPM respectively) even though some drivers like myself decide not to downshift in the manual if we've got enough power to accelerate as quickly as we want to (even if that means WOT).

I don't think the right answer is to disable either port or direct injection, but your experience does seem to indicate that the fuel maps and transition points need some massaging in the manual Taco's. Fortunately, I don't have to worry about it for at least another two years. Maybe it will be fixed by then, either by OEM or aftermarket tuners (if it isn't already, I didn't get a chance to get mine tuned before I found out I was leaving the continent).

 

Too much to unwrap here, but 3rd gen uses 3 modes: Port(0), Direct(1),Both(2). Computers are smart....

 

It is not the transition because if I force it to do direct injection only the weird behavior continues as if nothing was changed. I think there is something going on with the direct injection system. Desired and actual fuel pressure seem to be on spot. I will try to datalog tomorrow afr for port-only vs direct-only.

Of course since I am going to datalog tomorrow the truck will behave like a dream hahahah

Also, regarding tunes, I have tried coyoza, kdmax (several flavors), Blackhawk, OTT and they help a lot, but after some 300miles the truck re-learns how to be bad again, and the issue comes back. If I reset all learning values truck drives great again with whatever tune until 200 or 300 miles later

 

You just dashed my hopes for a tune!

This issue drives me nuts, if there is a way to improve it I'm all in. Not does my truck do this it's also a dog. I have never felt it go away either.

Fwiw, in mine when I log ltft I notice that it starts adding fuel as I increase throttle (at 0 or subtracting before that), but then at some ungodly low throttle input and enrichment it just stops adding fuel. I don't have exact specs on load but it's less than 40% load (say 1/4 throttle), and the ltft just stops at either +3.4% or +6%.

It's after this throttle level I definitely notice the surging and it very much does feel like it's too lean. The weird thing is even going to full throttle it doesn't get better, almost like Power Enrichment (PE, could be a GM term) isn't there.

Frankly I think it's lean and just not adding fuel.

Of note, unplugging the acis did help the situation but it is FAR from resolved.

 

Not entirely correct. They are only as smart as the programmers.

Then it sounds like the issue can't be resolved with a tune. The truck needs a whole new ECU... bollocks. "If you want something done right..."

 

you are logging LTFT, but you can't see AFR? It does not run lean.
Your issue are not related to fueling& injection mode.

 

Unless the truck has a wideband oxygen sensor afr is estimated. Not knowing if or when any enrichment routines come into play, let alone if afr is correct, means afr can be a red herring.

If it's not fuelling then what is it? The discussion here indicates it is in fact related to fueling.

 

The 3rd gens do use wideband O2 sensors.

 

Thanks for that info, I did not realize that.

 

Another 2022 manual TRD owner here with the same problem. I live in Montana and the cold seems to escalate this problem. I was wondering if it was to much fuel being dumped in...

 

So I have been checking a bit the stock tune in vftuner and I found that the DI ignition timing is the closest to TDC right at the load and rpm values that we feel the engine is struggling. I tried smoothing that out but I am very scared of flashing the car like this since I have zero experience playing with DI values. Any thoughts from someone who has experience with DI?

 

@tonered ?

 

OP, I have a 6mt as well and I’m not fully understanding the issue you are describing. Every internal combustion engine I have ever owned is not happy at low rpm, high throttle, and high load. I have noticed that the taco engine (and probably other modern engines with throttle by wire) tends to limit throttle under such conditions to protect itself. I hesitate to trust an aftermarket tune above the one provided by professional Toyota engineers, unless you are ok with the potential consequences.

 

I can't speak for op exactly but what he describes seems the same as what I have. It's not low rpm and high throttle, it's lowER in the rpm range and as little as mid throttle (but is the same all the way up to wot). Mine does it all the way up to ~3000 rpm and anywhere from say 1/4 throttle up to full throttle.

 

In my experience the engine does not accept more than 1/3 throttle or thereabouts until 3000 rpm or thereabouts. Above 4000 rpm it singsong. It’s annoying, but I’m not convinced it’s a defect.

I also rarely exceed 2000 rpm and 1/8 throttle during daily driving.

 

It's a truck, it damn well better be able to use below 3000 rpm. It's a literal pickup. It's designed and marketed for off road use. Having to limit throttle input for nearly the HALF of the rpm range, and the most used range at that, absolute would be a defect.

 

The marketing department can do pretty much whatever they want with little collaboration with the engineering department.