GM electric airpump installation

When it was time to get my 7 smogged, I needed to reinstall the cat and figure out how to replace the airpump, since it's belt position is now being used by Rob Golden's "yoohoo" 3L220 belt around the main pulley and water pump pulley.

After a bit of research, it seemed like a few folks were successfully using a GM airpump, from the LS1 C5 Corvette, successfully. The GM part number is 12554580, and it lists for $225. I read on the list that someone paid $180 for it, and managed to talk the friendly parts guy down to it. Later, I read on some chevy forums that some folks managed to get it for $120.

When I got the pump, it had a three pin connector on it. Hmm, power, ground, and... uhh. The assembly is held together with clips and RTV, and the plastic housing was easy enough to pop open.

Once I got it open, things were pretty easy to figure out. The pump exhaust feeds out underneath a solenoid valve, that keeps the exhaust port closed unless it's energized. Thats what the third pin does- The red wire on the connector. I read on the Chevy forums that GM has done some recalls because of the pump failing because of water damage, so it seems they added a solenoid to keep water from flowing in when the pump is off.

Since longevity isnt an issue in my application, and I didn't want to deal with the additional current drain and hassle of driving the solenoid, I popped it off with a bit of prying. It's really easy to remove cleanly- just snip the wires.

I isolated the wires in a glop of silicone, even though the only connected one is the black ground wire- why not be sure.

I wanted the pump to emulate the behavior of the airpump and air control valve I'd removed- the pump delivers air to the cat at engine speeds below 2500RPM. Luckily, the stock ECU controls this by turning on the Split Air Solenoid. I used this signal to control the airpump; by connecting the Split Air Solenoid connector to a generic 12 volt automotive relay.

Luckily, I had a spare ACV assembly; so I used the connector for the Split Air Solenoid. It connects to the engine harness right near the thermostat housing, where my wirecutters are pointing.

Here's the completed wiring- the black wire from the pump goes to ground, the Split Air Solenoid signal energizes the relay, and the other side of the relay contacts gets wired to a fused +12V.

I put the pump in the corner of the engine compartment, next to the charcoal canister. It fits well there. I used a "Help!" part supposed to be a PCV elbow as a 90 degree reducer, from the pump's 5/8" outlet to the rx's 1/2" airpump line.

Heres a picture from the front of the engine bay- you can barely tell it's in there ;-)

Last modified: Mon Jun 30 22:33:40 PDT 2003 v1.0 mghali