Title. Curious as to what voltage I should be seeing on my multi meter at the car side airpump connector?

 

its just on and off, so 12?

 

Yep, 12v. It gets a constant 12v on one wire and the other wire the ECU grounds out when it commands the air pump to run.

Dale

 

you can usually hear the clunk when it turns on too

 

1. Can a Power FC run the air pump?

2. Can you have the air pump running constantly (say if the Power FC doe not have a function for it)?

3. If you have the air pump constantly pumping air just back to the cat, is there a potential problem with that?

(The thought here is to have the emission benefit without retrofitting a deleted ACV. Right now my air pump is essentially acting as an idler pulley with the associated air hoses missing or blocked off and the harness side connector absent. I want to return to at least to have the look of having the system complete, if there is some actual functional purpose, even better.)

 

the PFC does run the air pump. most of the time the air pump air is going to "Port Air", the exhaust ports.
if you have it running all the time things get hot, its been done though.

just the air pump at port air cuts down the unbourned hydrocarbons by a lot, like ~5000ppm to 1900ppm.

 

I think I would need to reinstall the ACV to run to port air?

I am thinking just to connect the pipes straight through to the cat.

Would that cause the cat to heat up too much?

If I connect the wires back to the ecu, will the ecu expect the extra air to be there, when it tells the air pump to come on?

Although my air pump has been disconnected, and the EM wires deleted, I suspect the wiring back from x-05 to the ecu (through F harness and the relay) have been left in place.

Does a Power FC actually use data from the O2 sensor (which would be affected by the extra air in the port)?

By that, I mean, would the ecu expect to see the extra O2, when it tells the air pump to turn on?

And if the o2 does not show up, get confused?

 

read this thread https://www.rx7club.com/3rd-generati...ntrols-841963/

The air pump defaults to flowing to the exhaust ports. In some cruising areas, it switches air to the cat. If the ECU doesn't want to flow air to either of them, the air goes out the relief valve in the ACV and the ECU can disconnect the pump by using the clutch. Older rotaries did not have a clutch for the air pump, and used the relief valve only. When the Rx-8 came out the air pump was fully electric and only ran for a limited time after a cold start.

When the air is flowing to the exhaust ports the o2 sensor is ignored, but in cruising areas it is used. The Power FC mostly copies this type of control, but only if it's using a mostly stock mapping. Most tuned Power FC's turn off the O2 sensor, but that doesn't affect the air pump as long as the clutch and ACV are working right.

 

Mine was somewhere in the realm of 400mV DC. So I think its safe to say it's not getting a 12v connection. I have working A/C, so it's not the fuse, I'm assuming its either the harness or the relay, which I'm hoping its the relay.

 

Okay, so I hate to ask, but I tried pulling the relay out of the box to look at, and for the life of me I could not get that relay out.

I didn't want to force it and break something. Can someone kindly instruct me in how to get that air pump relay out so I can test it? Pulling does nothing, so I must be doing something wrong.

Edit: I also tried pushing inwards on the white looking tabs on both sides before pulling, same thing.

 

Before going crazy on the relay check the fuse, it's common for it to blow since the air pump wiring gets cracked and janky over time and it touches the air pump bracket and shorts out.

I believe it's on it's own circuit, it doesn't share with the AC compressor.

Dale

 

I thought they both shared one fuse? I've seen numerous threads about it. Not that I'm doubting your knowledge by any means, moreso confirming. Where would it be located?

 

It's a small 15A fuse in the driver side shock tower fuse box. Mine had the same frayed wiring at the air pump connector and blew the fuse.

 

I just want to make sure I'm on the same page, because looking at the wiring diagram, it says it runs to the A/C fuse, unless I'm interpreting it wrong.

 

I could've worded that better. Yes the 15A Air Conditioning fuse feeds constant 12v to the air pump clutch.
Mine read about .8v at the connector with a blown fuse. I replaced the fuse and passed smog easily.

 

That's the thing though, my AC works perfectly fine. Nice and cool. I'll check the fuse to be sure though. I think at the connector (harness side) for the air pump I was getting 400mV.

 

Still trying to find "Zen and the art of Relay Removal". Seems to be out of print.

Sure would like to know how to get those relays out.

Do they get fused (no pun) in place sometimes?

 

Well, I heard back from my technician today. It seems the pump actually is getting 12v, the resistance at the air pump is fine on the pump side plug as well. However, it still will not kick on. He mentioned that when he grounds out the respective ground wire on the harness side of the car, with the plug connected to the air pump, the pump kicks on.

What could be the final issue here? I'm thinking the relay?

 

Maybe tie a string around the top of the relay and connect it to a doorknob, and slam the door?


( I am kidding.)


But I have not heard an answer on how to get a stubborn relay out, yet.

 

1) Ground source is bad. Check the Ground #2.
2) Signal from ECU to air pump relay isn't working or getting to the relay, Pin 2J.
3) If wiring is good, relay is malfunctioning.

I don't have any tips for relay removal, but you should be able to probe the wiring and check for signal/continuity.

 

It may be a clue that you can't pull it out. Maybe fused in place.