air pump discharge pressure?

[60 toy ota]

Hi all, working with the 60 emissions that haven't been passing since September:whoops:, and the problem is in the CO levels. HC and NOx are fine, but the CO deviation is just too big at low rpms, and it increases as the rpms raise. from what i understand in the fsm (the good one), the air injection system and the oxidation catalyst are to blame. converter tested and is good, although not oem and doesn't receive the thermal sensor (what i have read, that wouldn't help anyway). I've replaced the check valve to the converter with oem, replaced abv and asv valves with used oem, and replaced air pump with used oem. almost all the AI tests from the fsm are passing, but it feels like the pressure from the pump is way too little...like one of those little air mattress pumps. the manual never mentioned a specific pressure, just that it should be in the "green zone" of the SST.
long story short, is my discharge pressure normal from your experiences or should it be pumping out air like crazy?

 

[60 toy ota]

for the record, i am not done going through the manual and have not yet addressed the one problem i have found so far, this is just something i noticed and would like to see if its a worry or not

 

[TS888]

I have no specs, but my seat of the pants (or heel of the hand, in this case) measurement on my pump before it was devaned says it delivers in the ballpark of 10-15 psi, maybe a bit more? It's more of a volume pump than a pressure pump.

 

[Spike Strip]

This is the dial on the SST for measuring the air pump output.

So it looks like anything above 3 lbs/in-sq is good. My experience is they should run about 7 PSI.

.

 

[haryv]

google it

Check it on Google. High hc means rich, misfire, to far advanced ignition, carbon in cylinders and so on. High co means running lean. Check EGR for being stuck a little open. Could mean a vacuum leak in the plenum. If its on a intake runner, have characteristic miss on one cylinder.

 

[haryv]

Ohh and it is passes hc/co and nox at crusing speed, the air pump is doing its job.

 

[haryv]

Should be no more then 2 psi restriction in exhaust system. That means output from pump would be in this ball park.

I have no specs, but my seat of the pants (or heel of the hand, in this case) measurement on my pump before it was devaned says it delivers in the ballpark of 10-15 psi, maybe a bit more? It's more of a volume pump than a pressure pump.

 

[60 toy ota]

Thanks for the replies, it sounds like this isn't likely my issue, but should check. i also have a new oem egr valve installed only a few thousand miles ago. how i envy de-smogs

 

[2mbb]

the SST checks flow rate in a round about way. It wants to see a certain pressure maintained while pushing air through a defined orifice (the FSM has the orifice size). so a "dead head" pressure check may not be a good way to test. Also, the air needs to get into the exhaust gases. the achieved pressure needs to overcome the check valve springs. So you should also make sure the two check valves are working properly (opening and closing).

 

[Pighead]

Hehehe...

 

[60 toy ota]

the achieved pressure needs to overcome the check valve springs. So you should also make sure the two check valves are working properly (opening and closing).

hmm. going to check the upper check valve tomorrow, but the lower one is almost brand new. does that mean the somewhat tired air pump is going to have a struggle pushing air past those new springs? dang.