Power brakes / ABS power (when running standalone)

[truegearhead]

Long story aside I’m running stand alone engine management and, while I now have the engine running, I don’t have power brakes or ABS. I’m assuming the ABS module is looking for a 12v signal that it’s not receiving. I know this is a super open ended post but…help..ha.

[78F350]

It's been a while since I looked at the diagrams, but pretty sure the wheel speed sensors are routed to the DME, then on to the ABS controller. I'd suggest looking at a pinout of the ABS module and wiring diagram for the brake system. Are you running on the stand alone engine management with the DME completely removed?

[truegearhead]

Originally Posted by 78F350

It's been a while since I looked at the diagrams, but pretty sure the wheel speed sensors are routed to the DME, then on to the ABS controller. I'd suggest looking at a pinout of the ABS module and wiring diagram for the brake system. Are you running on the stand alone engine management with the DME completely removed?

I still have the DME there. I’m not sure if it’s working through… sounds like this could get complicated.

[78F350]

I don't think it will be that bad.

I just looked it up. I was wrong about the speed sensors. The four wheel sensors are direct to the ABS unit. ABS 5.3 sends the rear left wheel speed to the DME (out of the ABS on pin 23).

What I'd check:

1. Do you have a good vacuum connection from the engine intake to the brake booster?
2. Check pins 17 and 18 on the ABS connector for +12V. They should be hot at all times.
3. Check pin 15 for switched +12V.

[truegearhead]

Originally Posted by 78F350

I don't think it will be that bad.

I just looked it up. I was wrong about the speed sensors. The four wheel sensors are direct to the ABS unit. ABS 5.3 sends the rear left wheel speed to the DME (out of the ABS on pin 23).

What I'd check:

1. Do you have a good vacuum connection from the engine intake to the brake booster?
2. Check pins 17 and 18 on the ABS connector for +12V. They should be hot at all times.
3. Check pin 15 for switched +12V.

Awesome thanks! I'll check this weekend and report back.