Electrical Gremlin Reappears
Thread Starter
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Electrical Gremlin Reappears
I have an issue with an electrical problem on my '87 roadster.
Seems that if you have a hard burn out at a slow speed, the anti lock light will illuminate in the central warning display. This indicates that the ABS is no longer functioning. It also takes out the charging system. Turns out that the guage fuse (10A) blows in the main fuse block. Replace the fuse, and all works properly again. There are no additional loads (shift light, ignition controller, etc, etc.) attached to any of these circuits. This has happened many times (6x in 6 months). It has become common enough that I carry spare 10A fuses in the car at all times. Only happens at low speeds during hard spinning of the tires (i.e. leads me to believe something with the different speeds of the wheels). I did not have my foot on the brakes when this has taken place.
Any thoughts, or has anyone experienced this?
Thanks in advance.
Aaron
Seems that if you have a hard burn out at a slow speed, the anti lock light will illuminate in the central warning display. This indicates that the ABS is no longer functioning. It also takes out the charging system. Turns out that the guage fuse (10A) blows in the main fuse block. Replace the fuse, and all works properly again. There are no additional loads (shift light, ignition controller, etc, etc.) attached to any of these circuits. This has happened many times (6x in 6 months). It has become common enough that I carry spare 10A fuses in the car at all times. Only happens at low speeds during hard spinning of the tires (i.e. leads me to believe something with the different speeds of the wheels). I did not have my foot on the brakes when this has taken place.
Any thoughts, or has anyone experienced this?
Thanks in advance.
Aaron
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Electrical Gremlin Reappears (AKS Racing)
The fuse blows because that circuit consumes more than 10 amps. I think that under large acceleration a wire supplied by that fuse moves and rubs on a piece of metal at ground potential and has done so so many times that it has worn the insulation and now it shorts and draws much more than 10 amps. Your job will be to find that wire. Good Luck.
Burning Brakes
Joined: May 1999
Posts: 760
Likes: 1
From: Greenwich, CT
Re: Electrical Gremlin Reappears (AKS Racing)
Never seen what you describe myself, but here are two free (you get what you pay for) thoughts:
Hypothesis 1: You get the ABS light because the ABS computer is seeing a big speed differential between the front & rear wheels, and this trips the fault light - or maybe the ABS comuter is just screwing the pooch, and needs to be looked at. Don't know on an 87 if it draws any power through the gage cluster or not.
Hypothesis 2: When you rev high for burnout, the alternator is overspeeding and throwing a voltage spike - have you looked at the voltage reg lately? Don't know why this would affect the gage/ABS system first, unless they have a voltage clamp that dumps the spike to ground before anything else is fried.
Good luck
drj
Thread Starter
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Re: Electrical Gremlin Reappears (DOCTOR J)
On an '87, all these systems do tie back through the gages fuse.
The car was probably at a very hard spin at 4000 rpm in 1st when the fuse popped. Maybe it is an alternator issue. This just started this last May. Last alternator was probably installed about 2 years ago, but the direction of rotation was switched during installation of the blower in March of '00. Who knows.
I do not think it would be a chaffing issue, as this car has only about 30K miles and is in very nice shape as many who have seen it can attest to.
Thanks for the feedback. Any other takers?
Aaron
The car was probably at a very hard spin at 4000 rpm in 1st when the fuse popped. Maybe it is an alternator issue. This just started this last May. Last alternator was probably installed about 2 years ago, but the direction of rotation was switched during installation of the blower in March of '00. Who knows.
I do not think it would be a chaffing issue, as this car has only about 30K miles and is in very nice shape as many who have seen it can attest to.
Thanks for the feedback. Any other takers?
Aaron
