vF Tuner for the 3.5L Tacoma

Have you changed your spark plugs? I had misfires at less than 30k miles... turns out Toyota left my plugs loose.

 

Because of you guys mentioning having loose spark plugs I went ahead and had mine replaced a couple weeks ago at 56k miles. It definitely runs better and the power is more consistent.
I'm thinking mine were loose too.

 

It made a very noticeable difference on my truck as well

 

mine weren't even finger tight on my 2017

 

There is speculation here between bad factory torque and potential lean running in the Stock tune causing this. Do you have any idea here?

Thankfully, all of mine were good.


Also, how many 4Hi miles do you have now?

 

Hard to say, but if I had to guess, they were loose from the factory. Not sure how it running lean would make all 6 equally loose. Although I did have one of them, I believe it was specifically cylinder 6, that was so loose I'm surprised my engine didn't feel like it was running on 5 cylinders.



My truck is torn apart right now for pictures / install guide on the oil pan.
I'm also putting it back together with the larger 900+cc injectors and setting up a tune for 15-20+psi.

Mainly just to see how far the drivetrain goes before it really breaks. I wlll be very surprised if 4Hi survives 20psi launches

 

Cylinder 6 was very loose on mine as well. That’s the one that had a lot of blow by residue on the coil

 

Thanks! Someone posted an article where it was noted that an effect of lean running (don't want to say the word ) could cause plugs to back out. I tried searching for that post but couldn't find it.

All six of yours were loose? Wow! I think the most noted in other threads was two really loose with some under torqued.

Just curious.

Some seriously nice parts in the TT kit.

 

I had one that was loose - not falling out like some peoples, just like finger tight at best. I think it was the middle one on the drivers side, whatever number that is

 

yea all 6 were pretty loose but cyl 6 was practically just sitting in there hanging out not even in the head it was so loose. (not literally).



I think it's the opposite.
The loose plug will create a misfire condition.
Misfires are notoriously read as "lean" on an O2 sensor.
So the loose plug is creating the lean condition.

 

Again, wow! Hopefully, folks will get in there and check them. The left side wasn't as bad as I had thought it was going to be, with the plenum left on.

Good stuff. That makes a lot of sense.

Thanks!

 

Am I guessing correctly that loose plugs aka misfire condition could also give me that "bumpy road" feeling? There's one section of uphill I drive home on everyday and it did there, every time. That section is a little bumpy too so I was so conflicted
To explain it better it just felt like inconsistent power. I'm pretty sure it's gone now.

 

No, after testing, testing, and more testing, I think the actual cause of this is the exhaust cam.
From 1000 to about 2000 rpm, depending on load, the exhaust cam will go into a maximum retard state (for maximum overlap) and it causes this. I am able to consistently replicate it on my truck.
I've wrote a patch to simply exhaust cam tuning, but it's not out yet.

 

@OVTune - Thank you, can't wait for the patches......we need stinkin patches!

 

Nice! Thanks.

 

if you saw how Toyota controls the exhaust cam.... why? why? ...why? why???

 

FTFY:

 

Haven’t checked plugs. I changed the crankshaft position sensor, but didn’t affect or effect or whatever the misfire count. Truck runs fine on newest tune.... thought maybe it was tune related since it was the only thing that changed at the same time the misfires all but went away. Truck also ran fine on stock tune. I’ll check the spark plugs though. Thanks for the advise!

Added note: truck actually has fewer misfires on newest iteration of tune than it did stock. Nice work Mat!!

 

Mine also ran better with the tune. Once I changed the plugs it ran WAY better. I also didn’t get any more spark knock.

 

I wanna go find some loose plugs now. Probably won’t though.