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Re: My ABS pump time - Ari? Anders? Anyone? Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Thu, 13 Apr 2006 12:18:22
In Reply to: My ABS pump time - Ari? Anders? Anyone?, Eiron, Thu, 13 Apr 2006 11:48:09 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Let me get this straight (I'm going to read some into this)
You turn on the car, and the ABS and Brake Fluid lights are on. The ABS pump is NOT running.
After about 60 seconds, the ABS pump starts to run. After about 15-30 seconds, the lights go out.
After an additional 15-30 seconds, the pump stops running.
So the pump doesn't run for 60 seconds after the car starts; once the pump is running, it does so for about a minute.
A few questions -
Are the ABS and Brake Fluid lights ON when the car is first started and the pump ISN'T running?
Are you sure it's the pump you're hearing? My recommendation is to have the hood open, and with the car off and having sat overnight, note the level of the brake fluid. Start the car, and quickly go to the open hood by the master cylinder. Do you hear the pump there? Is the level in the reservoir moving? Does it start to move (down) once you hear the pump run?
I can't really think of a failure mode that would include a built-in time delay. When the car is first started, there is low ABS pressure - that switch should be closed, and it turns on the light and triggers the ABS pump relay, which turns on the relay. Things like this don't need to warm up. It's usually the other way around - if there is a poor connection somewhere, when you try and pass current through it, it gets warm, and hotter is higher resistance. Motors don't just sit there with power on them for a minute before they start to turn.
The only thing I can come up with is that the actual switch contacts that close the ABS pump relay are different than the switch contacts that turn on the ABS light. That's because they trigger at different pressures (the ABS pump comes on at a higher pressure than the ABS lights).
The RPMs dropping is a concern - the ABS pump shouldn't pull so much power that it loads the engine. Something is amiss there.
Try this - make sure the headlights and blower fan are off (eliminate as many electrical loads as possible). Don't start the car, but turn the key to ON. See if you get the same problem, or if the timing is off. My only guess here is that the vibration of the engine running eventually kicks something over. That could be the pump, or it could be a sticky relay.
OK, you've got a good one here.
posted by 192.249....
, Thu, 13 Apr 2006 18:30:34, Thu, 13 Apr 2006 12:18:22 <-- Viewing This Message, Thu, 13 Apr 2006 22:01:46
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