LIMP MODE in 4th Gear

[AllAboutViper]

Hello guys

2014 Viper SRT: (8400 Miles)

- Belanger Headers (Catless Midpipe)
- Corsa Catback
- HP Tuners

it was dyno tuned (using pumpgas) before more than one year, i raced a lot, it was running perfectly all this time. From two months, i did fill the tank with VP MS109, i wanted to sure i'm running safe that day (because they did decrease the Octane in our Country), raced that day, car went to limp mode in 4th gear, i thought it may be possible from the MS109,

Today i did 3 datalogs, with (pump gas), when i floor it from 4th gear, the car is fine, but limp mode happens Only when i floor it from 1st,( keeping in mind that i'm not lifting while shifting, so the gas pedal is all the way down, i do this all the time),, reaching mid range in 4th gear (around 5000RPM) , car goes to limp mode, no codes, turn OFF/ON and everthing is fine

What is weird, that this is happening only when racing from 1st gear+ no lift shift, and i'm sure it's not from the tune, i used to do so for more than a year!


Thanks

[aNinjaneer]

It's pretty common with cars tuned on HPT. There are many tables they allow you to tweak, but in doing so, it will almost invariably cause limp mode at some point. The throttle mapping is one of those tables, where if you get too aggressive with the mapping, it will go into limp mode consistently. They've only unlocked a small portion of the tables in the ECU, and only a few Viper tuners have really figured out what you can and can't do with it.

[AllAboutViper]

But what is weird, that i used to race for more than a year, itwas perfect, this only happened recently!!

Thanks

[aNinjaneer]

It could have been right on the edge, and a change in weather, or some other minor change, just kicked it over the edge. If I had to bet money on it, I'd say it's related to the tune.

[Jack B]

1. There is a code, a scan tool will display the code. Until you give us the code, there are no good answers.

2. 5000 rpm is near peak torque, that will narrow down the issue.

3. HPT can turn off codes.

[AllAboutViper]

It could have been right on the edge, and a change in weather, or some other minor change, just kicked it over the edge. If I had to bet money on it, I'd say it's related to the tune.


Sounds right

[AllAboutViper]

I just ordered a scan tool to check codes that car is not showing

[Jack B]

Check the code right after the CEL comes on. If you drive after the code is set, it may reset itself. A good scan tool should be able to see codes in history. You will find it. In addition, look for "Pending" codes. I am not quite sure how a "Miss-Fire" shows up, but, that is one possibility, The code did not make it to the Dashboard Screen, because it is not an environmental code, such as a cat or header created code. Even if you have a specific code show up on the Dashboard, there may be multiple coodes that do not show up.


I just ordered a scan tool to check codes that car is not showing

[texasram]

What was your dyno numbers for those mods before the issue by the way

[AllAboutViper]

Thanks, i'll wait for the scan tool, hope it helps����

[COLOR="silver"]- - - Updated - - -[/COLO

[AllAboutViper]

What was your dyno numbers for those mods before the issue by the way

Around 580 WHP, 40WHP gain

[The_Ruski_Driver]

Around 580 WHP, 40WHP gain

Pretty low numbers, who did the tune?

[texasram]

Pretty low numbers, who did the tune?

i was going to say same

[Jack B]

Here is another explanation, the typical diff between a Mustang and a Dynojet can be over 30 HP. The diff between SAE correction and STD correction can easily be 5%. If you use a lot of smoothing, you can also lower the max hp. My point is, there is not enough info to claim low hp.


Pretty low numbers, who did the tune?

[AllAboutViper]

Absolutely true, i've been racing C7 Z06's with full Bolts on + Pulley + Methanol Injection, Pushing more than 630 on the wheels, and still, they are suffering with more than 50WHP difference,

[The_Ruski_Driver]

Here is another explanation, the typical diff between a Mustang and a Dynojet can be over 30 HP. The diff between SAE correction and STD correction can easily be 5%. If you use a lot of smoothing, you can also lower the max hp. My point is, there is not enough info to claim low hp.

I agree there, but I was assuming he did before and after on the same dyno, with the same tuner.

[Jack B]

The 13's and early 14's had a problem with a too restrictive pcm. The protective scheme (lack of timing/rich mixture) robbed a lot of hp. When the pcm was fixed (flash update) at the dealer, usually without the owners knowledge, the average hp increased, therefore, the hp increase via tuning was less - just throwing that out there.



I agree there, but I was assuming he did before and after on the same dyno, with the same tuner.

[AllAboutViper]

Update: (13/2/2017)

Received the Scan tool to see if there are any hidden codes, here is what i found:

P0014 (camshaft position timing over " this one appeared when the oil pressure sensor was not working properly, changed the sensor and did not reset the code")

P0521 (Engine oil pressure sensor " this one appeared when the oil pressure sensor was not working properly, changed the sensor and did not reset the code")

P0300 (Random/Multiple Cylinder Misfire Detected) This is a hidden/pending code i found only using the scan tool

Thoughts?

[Jack B]

Use the scan tool to reset the codes. Some codes do not auto reset when things are normal. In some cases you have to operate at or near the rpm/load where the fault occurred.