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Lateral Accelerometer
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,257
Likes: 4
From: North Carolina
Lateral Accelerometer
Hello,
I was doing a little reading a couple of days ago and I found some info suggesting my 89 Vette may have a "Lateral Accelerometer." When I purchased the car a year ago I remember taking it out for a little afternoon fun. Decided to do a couple of donuts. About 180* power got cut to the engine. Couldn't figure it out. Haven't done that since then. Was doing a little reading; found some info on this Lateral Accelerometer. Is this what this device does? Does my vehicle have one? Should i remove it and if so, how?
DG
I was doing a little reading a couple of days ago and I found some info suggesting my 89 Vette may have a "Lateral Accelerometer." When I purchased the car a year ago I remember taking it out for a little afternoon fun. Decided to do a couple of donuts. About 180* power got cut to the engine. Couldn't figure it out. Haven't done that since then. Was doing a little reading; found some info on this Lateral Accelerometer. Is this what this device does? Does my vehicle have one? Should i remove it and if so, how?
DG
Safety Car
Joined: Apr 2004
Posts: 4,532
Likes: 7
From: Lahaina Hi
I doubt your car has one ,but you never know.
It should be located in the center under the radio.
It is a little black box and it usually controls fuel.Are you sure your tank was not low on fuel?
It should be located in the center under the radio.
It is a little black box and it usually controls fuel.Are you sure your tank was not low on fuel?
- 1986 Original Owner -
Joined: Apr 1999
Posts: 3,193
Likes: 139
From: North Yorkshire, England
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Yes. ABS started in 1986 and your 1989 does have one.
No.
Drifting
Joined: Jun 2005
Posts: 1,426
Likes: 1
From: brookville pa.
sensor
not sure what year they started but my 90 has one, has nothing to do with fuel, it is part of the abs braking sys, when you come into a turn to fast or car is in a hard lean, sensor tells abs how to react to keep you stable, the name is lateral accelerometer
Last edited by geogolf; Jan 17, 2008 at 08:08 AM.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The accelerometer in the earlier cars only provided input to ABS.
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Verdad Gallardo
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
When ASR was introduced in 92, the new system took input from the lateral accelerometer and used it to make changes to ignition timing and throttle position. ASR will retard timing and close the throttle if it sees input showing excessive yaw. Finally it will send input to the ABS pump.
The accelerometer in the earlier cars only provided input to ABS.
The accelerometer in the earlier cars only provided input to ABS.
ASR is integrated with the ABS and uses the ABS pump for an ASR event.
As you have stated, ASR will determine whether it needs throttle close-down and igntion retard if in a high lateral G-Force condition.
But, ASR also determines whether to use application of either or both rear brakes if there is no lateral G-Force -- it therefore can use the ABS pump for an ASR event even if there is no ABS event.
What I don't know for sure is if vehicles without ASR have a lateral accelerometer sensor.
Does anyone know for a fact that they have a C4 without ASR that has a lateral accelerometer?
Tom Piper
Le Mans Master
Joined: Apr 2002
Posts: 5,726
Likes: 46
From: Waukesha WI
St. Jude Donor '15
According to my 90 FSM, the ABS system does incorporate a lateral accelerometer that out puts a voltage proportional to the lat. accel.
The manual for the 86 refers to a lat. accel switch which it describes as two mercury switches wired in series.
Just so everyone knows, ASR was not around in 90.
The manual for the 86 refers to a lat. accel switch which it describes as two mercury switches wired in series.
Just so everyone knows, ASR was not around in 90.
Race Director
Joined: May 2006
Posts: 10,691
Likes: 71
From: Phoenix Arizona
I believe it's under the AC controller, on the hump just in front of the shifter. A flat 1/2" thick board about two inches square. As the cars became more sophisticated, they controled more.
Melting Slicks
Joined: Apr 2003
Posts: 3,110
Likes: 6
From: Red Sox Nation! RI
Yes, the early C4's starting in '86 (no ASR available) have a lateral accelerometer. It is only used to feed info to the ABS computer and has no function on engine controls.
Thread Starter
Drifting
Joined: Oct 2005
Posts: 1,257
Likes: 4
From: North Carolina
There seems to be alot of different ideas on how this system works. I am going to take the car out this weekend,... fill it up with gas, and find out for sure.
Also, what I was reading also referred to it as a mercury switch, but did not give a description of what it did.
DG
Also, what I was reading also referred to it as a mercury switch, but did not give a description of what it did.
DG
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Melting Slicks
Joined: Apr 2003
Posts: 3,110
Likes: 6
From: Red Sox Nation! RI
I'll +1 on the low fuel tank as a possibility, too. I'd occasionally get a big hesitation or flat spot if I punched it from a dead stop. I never considered the problem being caused by less than a 1/2 tank of gas until I read it somewhere on the forum.
I don't know anything about the ASR system, but speaking for at least the 86-87 (probably '88 too), the lateral acceleration switch is a mercury switch.
I don't know anything about the ASR system, but speaking for at least the 86-87 (probably '88 too), the lateral acceleration switch is a mercury switch.
Drifting
Joined: Mar 2002
Posts: 1,251
Likes: 2
From: Thomson Georgia
My 89 and both 90s have the lateral accelerometer. Pull the front console out, under the radio, held with 2 screws, square connector.
Take it loose turn it sideways for over 7 minutes, then see what your ABS light and brakes do. Scanner will tell you also.
Just to let you know, it will turn the system off.
BTW, behind the black plastic is the SIR control box, be careful beating, or drilling in there
Take it loose turn it sideways for over 7 minutes, then see what your ABS light and brakes do. Scanner will tell you also.
Just to let you know, it will turn the system off.
BTW, behind the black plastic is the SIR control box, be careful beating, or drilling in there
Instructor
Joined: Sep 2005
Posts: 113
Likes: 0
From: Albuquerque NM
Lateral Acceleration
I was led to believe the lateral acceleration sensor was for disabling the ABS system on hard turns. I was making a hard turn and in the middle hit the brakes. The steering wheel was nearly jerked out of my hands, I assumed from the sensor not functioning. Any way of checking it out?