Strange sound.
Thread Starter
6th Gear
Joined: Sep 2019
Posts: 6
Likes: 0
From: Botkins, Oh.
Strange sound.
I recently bought an '87 C4 Convertible automatic. Whenever I put, it in drive and roll ahead just a few feet I hear a strange sound like an electric motor that runs for just a very few seconds and then stops. So far I haven't found anyone who knows what it is.. Can anyone help?
Administrator
Joined: Mar 2001
Posts: 367,947
Likes: 24,704
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
Moved to C4 Tech.
Safety Car
Joined: May 2001
Posts: 4,747
Likes: 1,642
From: Fairfax Virginia
I have a 1988 C4 coupe with ABS brakes but I never heard any motors running when first driving the Corvette.
From what I know there is no motor in the entire ABS system in the early C4's. All I have in my system is a bunch of relays and solenoids, there is NO ABS PUMP on the 1988 Corvettes. The 1988 is a one year only when it come to brakes. The Master cylinder has two holes, one "out" and one "in" and the ABS box does all the distribution to three entities, Left front, Right Front and Rear. There is no individual control over the rear brakes, it is a very early version of ABS and a real PIA to work on or to get worked on. I finally just bought an entire spare system from another 1988.
Is it possible the person is describing the priming of the fuel system instead?
Best regards,
Chris
From what I know there is no motor in the entire ABS system in the early C4's. All I have in my system is a bunch of relays and solenoids, there is NO ABS PUMP on the 1988 Corvettes. The 1988 is a one year only when it come to brakes. The Master cylinder has two holes, one "out" and one "in" and the ABS box does all the distribution to three entities, Left front, Right Front and Rear. There is no individual control over the rear brakes, it is a very early version of ABS and a real PIA to work on or to get worked on. I finally just bought an entire spare system from another 1988.
Is it possible the person is describing the priming of the fuel system instead?
Best regards,
Chris
Racer
Joined: Jan 2015
Posts: 499
Likes: 63
From: Arkansas
ctmccloskey is correct, the 84-87 are a very basic ABS system.
If you have never driven this Car before this strange noise occurred, then it would be a good idea to get her on a Rack and check the underneath of the entire car, especially in the area Driveline, Half Shaft fasteners and u-joints.
If you have never driven this Car before this strange noise occurred, then it would be a good idea to get her on a Rack and check the underneath of the entire car, especially in the area Driveline, Half Shaft fasteners and u-joints.
Racer
Joined: Jan 2015
Posts: 499
Likes: 63
From: Arkansas
This may help with your diagnostics,
See if this noise happens when rolling slowly in reverse.
Roll forward gently apply a small amount of e-brake,,,, hold in the release so s to not latch the handle.
Keep trying each time with additional e-brake applied. '84 to '87 have Drum e-brakes, the rotor is a combination with a small drub. This is very Rare, but something may be inside the drum.
Applying e-brake resistance to the car moving forward may or may not change the symptoms, but if it does then the is the possibility on u-joint issues. A Dry, Rusty or worn u-joint can make some very odd noises. You Do Not want a u-joint to Fail while Driving !!
If there's no change in the noise, try the same process But while applying the Brakes.
This noise could also be something very simple, like a small Tree Branch rubbing on a moving component...
Good Luck !!
Michael
See if this noise happens when rolling slowly in reverse.
Roll forward gently apply a small amount of e-brake,,,, hold in the release so s to not latch the handle.
Keep trying each time with additional e-brake applied. '84 to '87 have Drum e-brakes, the rotor is a combination with a small drub. This is very Rare, but something may be inside the drum.
Applying e-brake resistance to the car moving forward may or may not change the symptoms, but if it does then the is the possibility on u-joint issues. A Dry, Rusty or worn u-joint can make some very odd noises. You Do Not want a u-joint to Fail while Driving !!
If there's no change in the noise, try the same process But while applying the Brakes.
This noise could also be something very simple, like a small Tree Branch rubbing on a moving component...
Good Luck !!
Michael
