smog pump question

[89IROC&RS]

Im wondering if there is a way to test the output of the smog pump on my 89 IROC. i took the cat off thinking it was plugged cuz the emissions test blew, while i had it running with the cat off, i put my finger over the end of the pipe that feeds the air into the converter and i felt maybe a bit of cold air, but when i put my finger over the end, there wasnt any pressure at all. ive read that the smog pump puts out like 20psi of air pressure. even if thats not true, i figure i should feel SOMETHING. it could be a bad connection at the electrically controlled valves, it could be bad check valves, or it could be a bad pump.... im just out for suggestions.

and no.... taking off the emissions stuff is not an option.

[89IROC&RS]

ok well, the way i wound up testing it, was to undo the two bolts that hold the air tube to the back of the pump housing. and pushed the loose tube off to the side and started the engine. i could then put my hand over the hole on the back and feel the air output.

i then bolted it all back together, and let the engine run until it hits operating temp, and once it hit 220, i felt down under the car at the air tube by the catalytic converter and felt air coming out. so apparently when i couldnt feel the air before when the car was cold, that was normal. so i was worried for no reason.

[Genopsyde]

i coulda swore that the smog pump only pumps air into the cat when it's cold, allowing it to heat up faster.

[89IROC&RS]

i wasnt really sure, but it would make sense that it only blows when the cat is hot, because the air is cold, so it would actually make it take longer to warm up the cat in comparison to just exhaust gases, the added oxygen helps with the chemical reaction in the converter to reduce the HC and NOx levels.

[Morley]

Originally Posted by Genopsyde

i coulda swore that the smog pump only pumps air into the cat when it's cold, allowing it to heat up faster.

No, it pumps air into the manifolds when the engine is cold to get the exhaust gasses up to temp faster, then it ports air to the converter and on deceleration it vents the air to atmosphere.
There was a GM bulleitn quite a while ago to remove those electric smog pumps from the LT engines. They were a high failure item and turned out they wern't really needed.

[goldz28]

took my air pump off, heavy too.