Engine stalls when ABS Pump cycles

[lobitoxx]

Greetins.
Need help. Got 1999 100 Series LC 150K Miles. Have had engine stalling when ABS pump kicks in. Cleaned out MAS Sensor, Cleaned Throttle Body. Cleaned Fuse Box and have left two auto electrical techs stummped. The unit leaks Break Fluid from the Accuator Module (Black Box) Other then that the brakes work fine , with the exception of stalling. I heard the only way to fix the leak is to buy the assembly($1800) Ouch! If anyone has had a similar issue i would greatly appreciate it.-
Thanks!

 

[OregonLC]

Does the engine stall when the cabin fans are all on high also? High beams? The brake pump is electric so there's no correlation to engine stall other than electrical load. If a load on the alternator is causing a stumble then there's something else going on. Or conversely, you have a weak battery and the pump load is drawing more current than can sustain both ignition and pump.

Regardless, I'd have the brake leak fixed before you (and somebody else) has a bigger problem. There's an overhaul thread here somewhere that could be an easy fix if it's only a bad MC.

 

[lobitoxx]

Stalling

Thank you for your quick rely.
It stalls with everthing on, off,(Lights,A/C PWR,2Nd,heater) in Neutral, in drive etc... As of today the stalling has been at times yes ,at times no. No consistency. With the excpetion of when the pump cuts in. I have noticed it is at the first instant the pump runs. I know because after a stall i'll restart the engine and pump is still cycling but does not hamper start up. Starts and runs fine. As for the leak, it's coming out from in between the accuator module and the actuator block itself. I was told o-rings not a part i can get from dealer.
-Lobitoxx

 

[OregonLC]

Interesting. I'm not in front of a parts diagram to try to help figure it out, but it doesn't sound like the 'normal' failure path we see here where the pedal travel lengthens and even takes multiple pumps. Wondering if there isn't something electronic going on in the controller that's tricking the truck into thinking it's been in an accident and killing fuel? The pump alone shouldn't be enough draw to kill ignition and if it were it would blow a fuse in an otherwise healthy electrical system.

Rather than spending the $$ on a new unit, you may be able to find a used one with only a bad MC that you could build. I haven't looked so this may not be the case.

 

[Skidoo]

From where the leak is, does not sound like the MC rebuild will fix it.
Wonder if there is some interlock which senses fluid leak from pump behavior and shuts down engine to prevent someone from hurting themselves. Naw that's too smart.
If the leak is on driver side (assume left hand drive) of brake unit, side where all the wires attach, bite the bullet and get a new unit.

 

[lobitoxx]

Thank you for your replies guys. I'm heading to get a new battery today see if it helps. As for the leak a second hand pump assembly might be my better option at this time. Any leads as to a reliable parts provider?

 

[Skidoo]

Pump is on other side of unit from black box, thought leak was on black box side?
If so replacing the pump is not going to fix leak.