The car is a 97 Integra LS A/T.
Car has no CEL or ABS light on
Yes when you first turn the key over they light up so a bulb isn't an issue.
Once and a great while when you turn the car over the ABS light will flash and the pump will vibrate for half a second but it hasn't done it in a while..
Now whenever im driving it and it hits 40 mph the car will have a vibration like the ABS pump is kickin on. The car still drives perfectly normal and the brakes work fine.
It was raining yesterday and I jacked on the brake to test the ABS and it worked normal. All sensors, relucter rings LOOK fine.

Any ideas why this pump would be turning on randomly at 40?
Well im almost positive its the pump

 

I have a 95, so some differences in abs, but, I first did the o-ring fix, and then accumulator leaked, and I got appropriate codes. I replaced that and next had the pump rum more ofter, and finally got the code for a high pressure leak or failure. My pump and system internal to the abs body do not hold pressure well. I hear it run when the car is quiet enough, and it seems worse when everything is hot. Occasionally the abs light comes on and again tells me that the high pressure fails. It works fine when the light is not on, just runs the pump more. I save it for rain and snow, and for track, so as to not flat spot tires, otherwise pull the fuse. You might try a flush, sometimes dirt stops the seal. I suspect early failure if not dirty. So, back to why 40? Possible engine noise and other harmonics drown out the pump other times, and it is just running more frequently.

 

No codes,

And its completly stock so no noise to cover it its deff only happening right at 40.
If you keep it close to 40 it will go on for a few secs, if you accel or drop speed if will stop quickly

There are no leaks at all

 

After I fixed the accumulator, I had no codes for a while, just more pump running to get back up to pressure, which I finally realized when I started getting the high pressure fail codes. I hade enough tire and road noise that I did not always hear it. Just wonder if it runs at other times, and you hear it best because of lack of ambient noise at 40. No other ideas.

 

Yea im pretty positive its only right at 40mph but ill keep and ear out, thanks for the input

 

So I've confirmed it is only happening exactly at 40mph

If you keep it at 40 it will keep up but if you decel or accelerate it cuts off.

Almost positive its the abs, sounds identical to it.

Hope to god it has nothin to do with the tranny

 

Odd for ABS as it seems to pump and not shut off if at 40. It should reach it proper pressure and shut off. Just thinking out loud, in print. Sorry, probably does not help you.

 

Pulled the abs pump fuse, still does it.

What the hell else would be making a pump sound like that?

 

torque converter shudder.

 

Always exactly at 40?? What would make it do that?