Testing my air / smog pump.

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Sep 20, 2005
Boulder, CO
Sorry if this is a repeat of another post, but I didn't find anything quite like this in the archives.

If I disconnect the hose that goes between the air pump and the air cleaner, from the air cleaner, it should be sucking. Correct? I recently failed an emissions test, so I was thinking this would be a reasonable test of the air pump.

I don't want it to seem like I'm just jumping in and replacing random emissions parts. Sometime last year that hose was disconnected from the pump end for a while. Probably a long while from amount of crud that had built up in and around the opening. I also had a leaking power steering pump which from what I read here, isn't good for the air pump either. And if this test is valid, than it's dead because there was absolutely no suction at all. For that matter it didn't seem to be blowing either which would be the alternative if it isn't supposed to suck.

I called a mechanic around here who basically recommended that I buy a new car after telling me that it would probably be at least a couple hundred dollars just to diagnose the problem. So I was thinking for that much I can buy myself an FSM and the parts to fix, particularly since it didn't fail by much.

The CO is the only thing that failed with a score of 52 and a limit of 45. HC was 4.2 with a limit of 6, and NO 4.8 out of 12.
Mister Bean,
You can usually pick up a rebuilt air pump from NAPA for around a hundred bucks. I'd encourage you to go ahead and change it out. It's not that tough of a job, just kind of a knuckle buster type of job.
If when you get it hooked up and running if you still do not have air blowing to the injector rail it's probably the AIR valve (that big thing mounted to the fender well). Mine failed emmisions and it was a brand new engine. I bypassed the AIR valve and routed the output from the pump directly to the injector rail and the guy testing it said he had never seen one blow so clean before.
Hope this helps.
You're correct on the "suck" assumption. However, sometimes the pump will be moving air, but not enough to do the job. The air pump is not a pressure pump, but a volume pump.

Replacing the smog pump should solve your emissions test problem.

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