How is an air pump tested? My 460 failed emissions testing with a high CO level. I've changed the oxygen sensor, thermostat (had a low temperature unit in), and the engine squeals upon start-up. I've dressed the belts but I'm still looking of the noise and think the air pump may be bad. It goes away after two three minutes of running.

 

I don't know how they are tested but the couple that I have seen failed on family cars were either frozen solid or were very tight and had screachy bearings.

I would guess your engine squeal on start up is due to bad bearings in the pump and maybe it goes away as the bearing warms up and gets a little oil spread around in the bearing.

Good Luck,

Jim Henderson

Good Luck,

Jim Henderson

 

I believe you can buy a new air pump from LMC Truck. They shouldn't be that expensive, but you do need to send your old smog pump back for the core fee refund...