2014 5.3L 6 Speed RPM Fluctuations

morrislee · January 10, 2016

Got my truck back while they are ordering the torque converter.

Did more testing, looks like the torque slipping happens at 5th gear too if you hold a steady speed long enough. 5th gear was keeping up at 100km/h at 2000rpm, later on, it jumped up to 2100~2200rpm and fuel eco was at 18L/100km was also showing!

If you have the above symptoms, dont let it go. I am sure if you dont get it fixed, it will get worse!

morrislee · January 20, 2016

Got my truck back, did not have the problem occur just yet, drive from dealer to home was too short, time will tell.

They replaced whole bunch of things, while they replaced the converter, they saw crack at the radiator, apparently it is a "common issue" so it was replaced the same day they replaced the torque converter. Replaced a temperature sensor or some sort related to coolant and a gasket.

morrislee · January 20, 2016

i got it back yesterday after the converter replaced, did it again this morning.

Here is a video of it happening at 1:35

andyhaug · January 20, 2016

Is it the downhill assist? It seems like it is trying to slow you down while going downhill by downshifting to 5th. I assume you are using cruise in the video? Try it without. You could also try holding in the tow haul button until it turns off downhill assist.

morrislee · January 21, 2016

Is it the downhill assist? It seems like it is trying to slow you down while going downhill by downshifting to 5th. I assume you are using cruise in the video? Try it without. You could also try holding in the tow haul button until it turns off downhill assist.

Nope, not cruise control, happens both up, down and flate roads. The slope was not very steep at all. Only a slight angle and I was trying to prove that even little resistance still jumps RPM

Had a check engine light on the way home today, it was P219A, maybe I had ice in the fuel?? Fresh tank of 91 shell v-power and see if it makes it smoother

morrislee · February 11, 2016

RPM is still fluctuating and jumps up to 1800 to 1900 rpm range during cold temp and when the truck is still cold. Dealership found my posts here and said I have a tune and unwilling to do further testing unless I pay them to reflash the computer to get it back to stock. Even though this happens when I remove the tune, and only happens when the ambient temperature is cold, it is more of a mechanical problem than a programming problem. I find the dealership automatically pointing finger at the tune without processing the information through the brain is just rude. And I have seen this happen at different temperature reading on the gauge, so it is not the temperature reading triggering the issue.

Really need some pointer guys, I am out of ideas

rm -rf · February 14, 2016

unwilling to do further testing unless I pay them to reflash the computer to get it back to stock.

Really need some pointer guys, I am out of ideas

Pay them to return the tune to stock.

Edited February 14, 2016 by rm -rf

morrislee · February 14, 2016

Pay them to return the tune to stock.

I had it at stock when I had them test for the issue, they said they could not replicate the issue when I could and even got it on the video. They said when they were testing, it was functioning as it should. Pay them returning to stock for what? They wont be able to find the problem anyway.

Afterall, if when I returned it to stock myself, they already said it is functionjng as it should, why pay them and most likely that it wont do anything other than having to wait a few more days to hear that the "problem" is not there.

rm -rf · February 15, 2016

It sounds like the torque converter is unlocking when it should stay locked. On a modern vehicle, that's software, right? (I.E it's not vacuum driven anymore, and there is no mechanical link between the carburetor and the transmission like there was in the '70's.)

If I were the service manager I wouldn't try to troubleshoot a software problem on a tuned truck.

HondaHawkGT · February 15, 2016

If they were going to make me pay for it out of pocket I'd just take the truck to a transmission shop and have a good aftermarket TC installed. A good aftermarket unit plus a tune will make for a nice upgrade.

morrislee · February 16, 2016

It sounds like the torque converter is unlocking when it should stay locked. On a modern vehicle, that's software, right? (I.E it's not vacuum driven anymore, and there is no mechanical link between the carburetor and the transmission like there was in the '70's.)

If I were the service manager I wouldn't try to troubleshoot a software problem on a tuned truck.

Seems to be ambient temp related, and does not matter if both engine and tranny is fully warmed up or if they are ice cold. I am a programmer, nothing I could think of that has digital reading for temperature would cause a different behavior other than the intake MAF would have the most sensitive area to ambient temp. seems to be anything below 0 degree C will have higher chance to trigger the problem, anything above, very very hard to reproduce the problem. Something mechanical is tripping it, something else icing up?

If they were going to make me pay for it out of pocket I'd just take the truck to a transmission shop and have a good aftermarket TC installed. A good aftermarket unit plus a tune will make for a nice upgrade.

They replaced the torque converter under warranty, I almost do want to find a custom tuner in town to reduce the TC slipping allowance (according to the shop, anything below 100 or 150 rpm difference is allowed and when they test drove it, everything is working as it should when I returned it back to stock).

HondaHawkGT · February 16, 2016

Might be worthwhile to make a post in the tuning section. Maybe somebody knows how ambient temps come into play in the TCM/TCC apply pressures.

HondaHawkGT · February 16, 2016

If you're really curious... it'll cost $50.

http://6l80etuning.com

Hammertime93 · February 18, 2016

I'm interested to see the outcome of this.

But just so i get this straight from reading your posts, you stated that once you removed your diablo tune and took it to the dealer in stock tune, they could not reproduce the issue. Then when you got it back from the dealer with a fresh torque converter you had the same problem. When experiencing the problem then had you re-installed your Diablo tune?

morrislee · February 19, 2016

I'm interested to see the outcome of this.

But just so i get this straight from reading your posts, you stated that once you removed your diablo tune and took it to the dealer in stock tune, they could not reproduce the issue. Then when you got it back from the dealer with a fresh torque converter you had the same problem. When experiencing the problem then had you re-installed your Diablo tune?

I was able to reproduce it with AND without the tune, so I brought it back with the tune completely removed and they could not reproduce the problem at all.

They did not wish to spent time chasing the problem is all, they are just ignorant and lazy.

Problem came back today with the torque converter pressure already pushed up slightly by the tuner. So it is something else, not the transmission by the looks of it, it could very well be fuel related tripping it......