corellian vette

Afternoon all.

Just when I get EVERYTHING dialed-in to my '86, something new crops up.

Over the weekend I installed my Porken chips, FPR, fuel lines, and fixed some vacuum leaks and the car is running GREAT. Then all of a sudden I get the "!" and ANTILOCK on the dash.

This has never appeared before. I was reading some posts, and it looks like it's either a physical problem (ABS wire) or a Relay (?). I read a vague post that suggests the condition of the light may help diagnose.

In MY case, the light goes off when I restart the car. It does not come back on until I start driving down the road.

Does that help me figure out where to start?

Speedtoys

Welcome to the interwebz

https://www.google.com/webhp?sourcei...antilock+light

corellian vette

Thanks. I kept searching ANTILOCK which gave me a few threads. ABS would have helped.

Speedtoys

Mrmerlin

well lets go back to the last thing you fixed,
most likely you have broken a wire connection at the fender mounted ABS connector junctions.
If the light comes on when you start the engine then its the relay on the CE panel,
if it comes on after your moving then its a sensor fault, usually a broken ground wire or wire to a sensor

corellian vette

Yup after more reading, looks like a physical inspection is due. I will check it out and report back!

corellian vette

OK got it up on the lift. The good news (?) is that all the ABS cables look equally bad. They all have cracked insulation and/or exposed wiring. I was hoping to see an obvious break somewhere as that would drastically simplify the diagnosis. But alas - looks like I have to test each one.

Can anyone point me towards an example of how to test the units? Looking around it would be SUPER pricey to just change them all

EDIT - How about NLA? I can't even FIND the original ABS sensors anywhere.

So I definitely need to test and figure out which one is bad...

John Speake

Sounds like a sensor or sensor wire problem. If your '86 car isn't a "86.5" then the ABS sensors are NLA.

Mrmerlin

Over the weekend I installed my Porken chips, FPR, fuel lines, and fixed some vacuum leaks and the car is running GREAT. Then all of a sudden I get the "!" and ANTILOCK on the dash.


umm I would suggest to reread what my previous post was, since your last repair attempt was in the engine bay thats where I would be looking

From post 5
well lets go back to the last thing you fixed,
most likely you have broken a wire connection at the fender mounted ABS connector junctions.

FredR

Notwithstanding the excellent advice you have already been given you might also take a look at the sensor tips hidden behind this brake discs. I opened mine up recently and on the front was amazed at the magnetic crud built up there. I was not seeing any alarms but I understand such can trigger an alarm sooner or later.

If your items are no longer NLA then you need to contact Roger to find out if he [or our other parts champs] has an alternative available- whether or not they can be rebuilt with new wires might be another avenue to explore if the sensor itself is viable. I know on my front mounts those barrel connectors in mine look a bit sad and are a concern but until I get alarms that I cannot resolve they go on the list of potential problem areas these things throw at us - not entirely unreasonably after 31 years of service [in your case].

corellian vette

Thanks gents - so I did take everyone's advice (given the time I had) and checked the barrel connectors at the fenders (seemed fine and undisturbed), as well as the physical wires at all four wheels. I did not have time to dive deeper into the system given it was late.

I also found a good diagnosis technique at the ABS module for testing (although it's for a '90 I hope the process is the same)

https://rennlist.com/forums/924-931-...-resolved.html

Fortunately, I also have a year-matching parts-car with no ABS light that I may steal the relay from, just because that's a simple test.

So sounds like my next course is a more thorough diagnosis. Not sure when I'll have time to do that unfortunately.

Which brings me to my next question - can you just temporarily disable the system to remove the light? If I pull the relay for the unit, will that just take the system offline, or will I still get the AIRBAG light?

Mrmerlin

you can drive the car and do nothing,
the brakes will resort to non assisted ABS function.
the warning lamp will stay illuminated

corellian vette

Thanks MrMerlin - that's what I had to do today to bring the car back to storage.

The pedal feels more firm then I remember although the car stops fine. I've read that a hard pedal could be a result of the ABS system.

I guess I'm skipping ahead - if I can't find the problem, or if I can't find replacement sensors - is there a way to neutralize the system and prevent the light from being on?

I hate warning lights. I've spent far too much money on cars chasing warning lights. But if this proves really hard, or impossible, I'd like to get the car to a state where the warning light doesn't come on.

Thanks as always for the assist.

Speedtoys

Cleaning the sensor ends is easiest fix.
Next "easiest" is finding where the harness for the sensors is broken.

Thats 99% of the problems.

Mrmerlin

go back and check the areas that you worked on and see how you might have disturbed the ABS harness,