Abs inop? - LS1TECH



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Abs inop?

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Old 03-04-2017, 10:23 PM   #1
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Default Abs inop?

So this has happened a couple of times and it has really gotten annoying/dangerous. During my 3rd or 4th autocross run I'll get the ABS INOP indicator on the dash and my brake pedal would go soft like there's air in the system. I've almost crashed a couple times because I would accidentally lock up the front tires. What is causing this? I read it could be the wheel sensors but this goes away if I turn the car off for over 10-15 min. Light only comes on during hard braking.
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Old 03-06-2017, 10:05 AM   #2
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Are you getting wheel hop under braking or accelerating? Are the rear wheels ever jumping off the ground at any time during your run? How old are the front hubs your using? What hubs are you using? Alot of things i've experienced can do this
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Old 03-06-2017, 10:38 AM   #3
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Are you getting wheel hop under braking or accelerating? Are the rear wheels ever jumping off the ground at any time during your run? How old are the front hubs your using? What hubs are you using? Alot of things i've experienced can do this
I am getting some brake hop over the rough areas of the track. Front hubs are moogs which are on their last legs, I'm in the process of installing SKF corvette hubs.

I really don't want to delete abs if I don't have to...
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Old 03-06-2017, 11:03 AM   #4
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If hubs are old and you have a lot of knock back, sure it can be a soft pedal, or you need to pump it up quick. I've had ABS inoperable light come on with heavy driving, not so much at AX but on a road course when everything was hot and overstressed. Maybe at AX a few times, I don't even remember. I'd say get the new hubs on asap and put the Strano brace on and see if it's improved.
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Old 03-06-2017, 06:03 PM   #5
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The ABS in these cars is extremely easy to fix. Tear it out, throw it in the garbage where it belongs, and enjoy better braking.
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Old 03-07-2017, 12:30 AM   #6
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The ABS inop is from your crappy moog hubs I can't believe you were able to run those. I broke one and lost a wheel on one autocross event with a co driver on hoosiers, next one ran was street tires, still one failed that day.

Wheel hop will also trigger trac loc sometimes or abs inop also
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Old 03-07-2017, 09:26 AM   #7
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I have had the same issue last season. I started racing the car in 2015 but only had it happen recently. Like the OP, you could pump the brakes a couple of times and all was well. I never noticed the light until the end of a run in grid.

Also switching to SKF hubs tonight so hopefully no more lights come on this season.
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Old 03-07-2017, 11:58 AM   #8
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Hopefully some good hubs and a full bleed will fix it. I will also try and make some adjustments to minimize brake hop. Next event is on the 19th so we'll see if it's fixed.

One more thing, could it be my battery? I'm running a lightweight Shorai LFX36A3-BS12 Lithium Ion battery. I do notice that every time I start the car all the gauges get pegged and the trip meter resets. Voltage reads normal though.
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Old 03-07-2017, 05:05 PM   #9
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It's the hubs save yourself time and money and invest in the adapters and x-tracers. Don't autocross with moog, timikins or any autoparts oem replacement.
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Old 03-07-2017, 06:20 PM   #10
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The SKF hubs keep the ABS from going haywire, but it doesn't change the fact the factory system is garbage and you can stop much better without it.
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Old 03-07-2017, 06:29 PM   #11
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Hm, that battery could be doing things too. It shouldn't peg the guages on startup, it could be an electrical gremlin. I haven't heard much about LiOn batts in cars, maybe it's spiking or going low for a second and the ECU thinks there's a problem? Maybe go back to stock battery for an event or 2 to rule it out?
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Old 03-07-2017, 07:03 PM   #12
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One side done

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Old 03-07-2017, 07:08 PM   #13
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Looks good.
You should get Blaine Fab's braced sway bar brackets. Those have been known to crack over time.
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Old 03-07-2017, 07:14 PM   #14
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I noticed UMI is now offering plates you can weld in...in reality it's a simple laser cut plate that I can do myself but still...options are there lol.

Just add it to "the list".
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Old 03-07-2017, 09:38 PM   #15
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Quote:
Originally Posted by 79_T/A View Post
The SKF hubs keep the ABS from going haywire, but it doesn't change the fact the factory system is garbage and you can stop much better without it.
I don't mind it at the track but I still plan to use this as a street car. I wouldn't feel that comfortable driving in the rain with no ABS...

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Hm, that battery could be doing things too. It shouldn't peg the guages on startup, it could be an electrical gremlin. I haven't heard much about LiOn batts in cars, maybe it's spiking or going low for a second and the ECU thinks there's a problem? Maybe go back to stock battery for an event or 2 to rule it out?
Good idea. Though it will be hard taking out this 5lb paperweight and lugging back in my 40lb Yellowtop

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One side done

Ohhhh...

I got mine sitting on a table waiting for a free evening to install them. Can't imagine how nice it would feel to not sit at the starting line of every event and hope that you finish with all four wheels
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Old 03-08-2017, 08:51 AM   #16
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I was never concerned, but then again I never ran anything bigger than old 275 V710's. This year I'm moving to 315 A6's and refused to start the season until I got the hubs on.
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Old 03-08-2017, 06:17 PM   #17
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Used A6s that are that old are going to be slow too, I wouldn't worry too much
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Old 03-08-2017, 08:20 PM   #18
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Maybe so, but still wasn't "hoping" the stock hubs would withstand even used A6's.

I'm more OK with losing a wheel on autocross course...it's riding with my wife on a weekend morning going to breakfast that I fear if a wheel departs the car.
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Old 03-08-2017, 09:28 PM   #19
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Fair enough. I ran used A6s once that were well past their due date. They were several seconds slower than current street tires.
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Old 03-09-2017, 06:53 AM   #20
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You do back to back runs on the same day same course?

One thing that bugs me about autocross is the always changing curses. Would be nice to have more time on one course to make adjustments...I guess that's what RR is for.
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