Engine accelerates at 1500 RPM preventing engine braking when going downhill

I have a 2017 TRD OffRoad with a 6-speed manual transmission.

When I go down my driveway with my foot off the gas as soon as the RPMs reach 1500 the truck accelerates then lets off at approx 2500 rpm then decelerates to 1500 and the cycle starts all over again unless I use the brake forcing the truck to slow below the 1500rpm range. I know I cannot be the only one that has this problem but it drives me insane when I have to ride the brake all the way down my driveway. Any way to fix this, possibly with a DIY tune?

Any help would be appreciated.

 

Maybe try going down the driveway in neutral?

 

I had a 2016 that I took hunting when I got it. I was able to drive around in 4 low and second gear and it would hold the truck back and not let it accelerate. Now I have a 2019 and it dose what you described. It’s the one thing I hate about this truck. I run 4 low quite a bit in second gear especially going slow down hill and it drives me nuts when it runs away like that.

 

6MT

 

Mat from OVtune has been looking into this for us for quite a while now. No solution yet. It is absolutely the stock calibration causing it.

 

What a bummer. I was hoping there was a resolution out there. It is at least encouraging that this is an acknowledged problem even if its only by the customers.
I watched the video and while he did mention drivability changes, no mention of manual transmissions was made.
Hopefully this can be fixed some time in the future.
Thanks for chiming in.

 

2020 AT does the same: hope Mat can fix it.

 

DFCO? @tonered didju ever figure anything out in VF with this?

 

That's exactly what it is. Above 1450rpm or so, gravity is pushing everything and no fuel is being used. Below that, fuel kicks in and the engine is pushing everything again and you feel the transition.

 

For whatever reason these trucks don't compression brake below 1500 rpm. Don't believe this has anything to do with fuel and is done and made possible by the wide range variable valve timing.

 

Yep. OVT 2.0 has been tuned with big changes there.

 

2.7L MT doesn't do this, FWIW.

 

I have the OV 2.0 and it still does it.

 

I don't know what, if anything, was done on the AT tunes, but the MT side is lovely. If you're AT, you might asked OVT about what can be done in vF.

 

Below 1500 rpm the computer is worried about stalling so it starts to inject fuel, even with no throttle.

Above 1500, let’s say you are engine braking down a steep hill at 2800 rpm with no throttle, the injectors are t spraying, it’s just compressing and dumping air.

Edit: that’s how it works on my truck, yours will be different.

 

Sounds like the correct diagnosis, just wish it would hold the compression better; even in 1st Low it dumps much more than my 09' 4.0 did

 

About all that I can say is that the MT tunes are set to near idle and there is zero stalling risk. On the various test tunes that I tried, only one produced a stumble. We've been this way, going on 2/3s of a year.

The other thing was that on Stock, 1.05b, and 2.0 Betas, we would get a solid lurch forward when the injectors cut back in and was very inconsistent. Now, it is quite smooth and a dramatic improvement when wheeling and in traffic.

 

Yep, none of that happening on my premium SFOB tune. I can coast below 1000 in gear with DFCO engaged. Pretty sure i could do that on the stock tune too though. Like lets say coasting in 6th to a red light.

 

Sorry, but no. It was just more subtle in the higher gears. Toss Stock back on there and monitor the Fuel Status. The injector cut in was right around 1,400 in all gears.

 

Weird that the MTs having issues.
Do the MTs have any kind of drive modes that could be causing the lurching?


I find my stock 17 AT a bit frustrating besides the classic AT issues at highway speeds, slowly going up my driveway it surges a bit.
Not sure if it’s poor drive by wire feedback or hill assist that lets me roll back in the driveway then trac wigs out.

It’s a lot less precise than my 93 pathfinder that had a cable.