shift lights early???
Thread Starter
Racer
Joined: Dec 2015
Posts: 314
Likes: 154
shift lights early???
Is anyone familiar with the shift lights displaying early - like to shift around 5k? Car is warmed up (about 180 coolant/170 oil)and the yellow is gone from the tach, but lights start early and are flashing way before redline?
anyone know what factors into the shiftlight display - i had assumed just rpm but maybe coolant temp, how about oil temp?
thx
anyone know what factors into the shiftlight display - i had assumed just rpm but maybe coolant temp, how about oil temp?
thx
6th Gear
Joined: Feb 2015
Posts: 6
Likes: 7
I’m having the same problem. Car is warmed up and shift light flashing blue at 5k. I assume it’s a software issue but want to make sure it’s not indicative of a problem. Was gonna check with the dealership given that I can’t find anything about it online.
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,820
From: Charlotte, NC (formerly Endicott, NY)
The HUD shift lights start flashing before you reach the red line. The display starts flashing with outer lights lighting at a certain rpm before redline and as rpm increases lights further inward light up until just before redline is reached they start flashing and when redline is reached the line fills in and flashes brightly.
Bill
Bill
Melting Slicks
Joined: Feb 2006
Posts: 3,271
Likes: 182
From: Manassas VA
The shift lights are spaced different rpm's depending on what gear you are in and assume you are at full throttle. For instance the rpm lead is larger in 1st gear compared to 4th. This is standard stuff in drag race control system applications simply because the engine is accelerating a lot faster in 1stt then it is in say 4th. In those systems you can tailor each lead band depending on how fast you can shift. This variable lead enables you to shift before you hit the rev limiter in the lower gears and not to early in the higher gears. You can observe the lead rpm range by putting the car in gear with the clutch in and slowly revving the engine. You will note in 1st gear the spread between shift light and rev limit rpm is rather wide, decreasing as you go up in gear selection. .
6th Gear
Joined: Feb 2015
Posts: 6
Likes: 7
Partial throttle acceleration in first gear and second gear and the shift lights still come on early. It is not consistent. Some times it will flash blue at 5k some times at 6500. Understood the idea of lead at WOT, but its not that in this case. Called the dealership and awaiting response.
6th Gear
Joined: Feb 2015
Posts: 6
Likes: 7
Problem Solved. Turns out the thermostat was starting to stick, staying open more than it should have. Coolant temperature was too low and causing shift lights to come on during normal operation. Replaced thermostat with OEM replacements and issue went away. Coolant temps are easily 15-20deg higher now (195ish).
