Did white one to sov from intake side.
Too cold to go outside with flashlight. So from memory something makes me think there's one from sov to air pump? If so I seem to remember it "disappearing" behind the pump. Or am I having vacuum confusion of the brain?
Bob

The one you replaced is engine common feed vac to the SOVs [egr and air ].
There are 2 coming out of the SOVs...one goes to egr and the other goes to the flow valve between the air pump and the engine. That is a vac actuated valve to allow the pumps air to reach the engine. If the pump runs , then you want to check that valve and see if vac is going to it .That would be the other vac line you are referring to and a disconnect here would be the cause of your AIR code. [ air not flowing to engine even though the pump does run] and thus, the 02 sens does not see lean and fails test, triggering air code/ce lamp.
There is also a final check valve at the engine to allow one-way checking of exhaust so it can't get back to pump. That is the whole system.
I have seen some AIR codes that where caused by guys putting the wrong connectors or vac lines on the sovs when re-installing after repair work, as they are a piggy-backed unit. If this is done , the egr is getting the air sig and the air is getting the egr sig. Might want to check that if all other things check out..
There is an article about it in the archieves by me or SB....

I thought testing the o2 "black" wire would be easy. Unfortunately, I have TWO. Which one do I test?

Or am I looking at the wrong wire harness in passenger foot well?
Thanks Bob
See attached pik.

Attached Thumbnails

 

The grn wire is 02 sig feed to ECU, so the other side of that plug is 02 sensor output.
The two whites are heater [12v.] and the other is ground.
You want to use the ground wire for neg. lead when testing 02 sens output
b/c they do not use chassis ground on 4 wire sensor with HFM/SFI systems...
best place to catch that neg is at terminal # 3 of the 3 prong connector..that will be the blk coming out of that connector...

Vac hoses are connected correctly at SVO with tight fit.

Hoses to Air Pump and to EGR are soft, pliable and orange (not OEM). Never could "see" where vac hose to Air Pump is connected. It's routed between the pump and block. Is "special mirror tool" used to see the connection? Pump is very quiet, but never have noticed a clutch engaging or disengaging.


Meter at 200mV, Engine hot and at idle.

Yesterday meter consistently fluctuated between 47 and 53 with both vac hoses connected and with one at a time disconnected.

Today meter consistently fluctuated between 18.2 and 21.5 with both vac hoses connected,
with hose to fuel regulator disconnected between 21.5 and 23.6 and with hose to SOV disconnected between 21.7 and 24.4

Are these vastly different (47-53 vs 18-24) readings correct or am I doing something incorrectly?

Considering my reading (if correct) is not near the .9 for Rich, can I assume the o2 sensor needs to be replaced?

Bob

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Pump clutch circuit needs testing.
Criteria for pump:
10C-40C coolant temp
less than 3600rpm
02 sens-open loop
Max run time from start -110 secs.

First check would be fuse/power feed
Second would be ohms test at clutch magnet coil.
The top sov is AIR and the AIR sov gets the same electrical signal as the pump, so if you take the vac line off the sov [after sov, betwen sov and control valve] and you have vac, you know that you have electric sig from ECU to both sov and pump , as they are wired in parallel. Meaning the pump should run at the same time the sov is open. Or you coud just 12v test lamp either the pump or sov..


I do not undestand your meter readings at all.

I do not undestand your meter readings at all.
___sorry about the decimal point (.47 - .53 vs .18 - .24) Undersand now?

Pump clutch circuit needs testing.
___ I'll do tonight after engine is cold

I gave fuse #7 a twist per your comment on another post & continunity is ok.

SOV question
Out of curosity I tested vac to SOV from intake manifold is 19, but vac to EGR and Air Pump were "0" @ idle & 80 deg engine temp. Is this correct?

Bob