How good is the factory LED tach/boost lights?

T

"Turbo-T"

V6 on steroids
Joined
Jan 10, 2007
87 Turbo T here....with the analog style dash that has the little LED's in it at the bottom right corner for the boost and RPM.

I don't have an aftermarket tach but I do have an aftermarket boost gauge by VDO. I noticed the boost LED's read a few PSI's higher than what the VDO boost gauge is.

I'm going to guess the LED's were inacurate at best?

Or perhaps the boost gauge is off?

How good of a brand of gauge is VDO?

Can the LED's be disabled?
 
The led setup is notoriously inaccurate. If you had a schematic you could disconnect the power to them and they wouldn't light up. I just left mine running. It looks cool and no one else knows they suck!:cool:
 
The factory tach is useless unless you like cool 80's flashing lights. The factory boost guage is even more useless and has probably caused more than a few blown head gaskets by someone actually trying to use them to tune. Dont feel too bad though...at least the analog dash cars had some type of guage...the digital dash cars have no tach at all and only came with 2 boost lights...orange means low boost and red means you are about to blow a head gasket:eek: I disconnected my useless 2 lights and bought a VDO 30psi boost guage.
 
They are useless. Spend the money and get good gauges now, or spend the money later for head gaskets. :)
 
BlackBandit said:
The led setup is notoriously inaccurate. If you had a schematic you could disconnect the power to them and they wouldn't light up. I just left mine running. It looks cool and no one else knows they suck!:cool:
Click to expand...

Is there a way of unplugging those little LED's? Or is the circuit board they're attached to somehow attached in a manner that can't be easily disconnected?

coldair85GN said:
The factory tach is useless unless you like cool 80's flashing lights. The factory boost guage is even more useless and has probably caused more than a few blown head gaskets by someone actually trying to use them to tune. Dont feel too bad though...at least the analog dash cars had some type of guage...the digital dash cars have no tach at all and only came with 2 boost lights...orange means low boost and red means you are about to blow a head gasket:eek:
Click to expand...

LOL yeah I was reading up on that...on how the digital dashes have two lights, one was for like 2 psi and the other for 10 psi...

Though the LED's sort of remind me of KITT the Knight Rider car....that car had LED's everywhere....

SS_Sean said:
They are useless. Spend the money and get good gauges now, or spend the money later for head gaskets. :)
Click to expand...

Thanx, my car does have a VDO boost gauge....how acurate are VDO's? Or should I replace it with an Autometer boost gauge?
 
84Regal3.8 said:
Is there a way of unplugging those little LED's? Or is the circuit board they're attached to somehow attached in a manner that can't be easily disconnected?



LOL yeah I was reading up on that...on how the digital dashes have two lights, one was for like 2 psi and the other for 10 psi...

Though the LED's sort of remind me of KITT the Knight Rider car....that car had LED's everywhere....



Thanx, my car does have a VDO boost gauge....how acurate are VDO's? Or should I replace it with an Autometer boost gauge?
Click to expand...

You can just remove the vac. line from the MAP sensor on the RH fender well and your boost gauge will stop, as far as the tach there is a white black wire running from the module plug in, that is a tach lead, you could run that to an aftermarket tach and the factory tach will be inop....
 
would it make any sense to do a gnx conversion dash as i know i have spent800+ on gauges and the gnx dash is like 1100 and less clutter?:confused:
 
Yeah, I remember when I bought my TR a few months ago. When driving from Md to Va I was paying a little too much attention to the lights. I started to think that the car was about to go crazy. Anyhow, I figured that they were inaccurate and a buddy of mine from the area told me last weekend that they are useless. :) I'm planing in buying the gauges very soon.
 
My factory tach is off by about 1000 rpm in the top end, its rather comical to watch the tach and boost gauge bury themselves simultaniously!!! (pardon the spelling.....)
 
BetMinesFaster said:
You can just remove the vac. line from the MAP sensor on the RH fender well and your boost gauge will stop, as far as the tach there is a white black wire running from the module plug in, that is a tach lead, you could run that to an aftermarket tach and the factory tach will be inop....
Click to expand...

The white wire for the tach...is this the same white wire inder the hood near the a/c compressor that has a green plastic plug on it? Cuz mine doesn't go to anything, but I've read here that's where you can plug in the tach to.

Also the MAP sensor...not sure which one this is....can you please post a pic? Is this the same place you'd hook a boost gauge up to?
 
BetMinesFaster said:
You can just remove the vac. line from the MAP sensor on the RH fender well and your boost gauge will stop
Click to expand...

Not sure if this is the MAP sensor or not but I popped my hood and looked, I did see a black looking thing on the inner right fender next to two relays close to the coolant catch can....it has a black plug with some green rubber around it and theres three wires coming out of the plug...a black a green and a grey....then I saw what looked like a vacuum line that comes off of it....the line tees into another line that comes off of the throttle body and the other line I'm thinking goes to my boost gauge...but I have an aftermarket VDO boost gauge as well, so I'm not sure but does this sound like the MAP sensor? And so do the LED's for the factory tach operate off of pressure differences instead of electronic signals?

Sorry for the long post, just trying to learn. Thanks!
 
84Regal3.8 said:
Not sure if this is the MAP sensor or not but I popped my hood and looked, I did see a black looking thing on the inner right fender next to two relays close to the coolant catch can....it has a black plug with some green rubber around it and theres three wires coming out of the plug...a black a green and a grey....then I saw what looked like a vacuum line that comes off of it....the line tees into another line that comes off of the throttle body and the other line I'm thinking goes to my boost gauge...but I have an aftermarket VDO boost gauge as well, so I'm not sure but does this sound like the MAP sensor? And so do the LED's for the factory tach operate off of pressure differences instead of electronic signals?

Sorry for the long post, just trying to learn. Thanks!
Click to expand...

That's the MAP. It sends a signal on the green wire to your factory boost leds.
 
Thanx Dave. Would it be better just to unplug the 3 wire connector? Otherwise I'm guessing if I remove the line off of the throttle body I'd need to cap it off?
 
disconnecting the map

doesn't the computer use the map sensor for engine control, all the other gm cars use them and they don't have boost gauges in them, just wondering mine are pegged as soon as you turn the key
 
Our stock turbo buicks only use the MAP sensor to send an electronic signal to the dash led boost gauge. The error creeps in over the years from corrosion etc at the dash end of the electronics. The MAP sensor itself is not usually a problem...
 
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