Secondary air injection pump

Paul M · 11 January 2007, 15:34:38

I'm getting a sort of buzzing noise on startup that sounds like an electric motor with failing bearings. After reading posts on here I'm suspecting the secondary air injection pump (the one in the front nearside wing) so I want to disconnect it to check. Is there any way of doing so without having to get into the wheel arch? I was thinking maybe a fuse can be removed, hopefully without disabling anything else that may be important.

The noise has been there since I bought the car, I just never spent much time investigating it as it's reasonably subtle (especially with my crappy exhaust!) and it goes away reasonably quickly. Strangely though it seems to change frequency if I rev the engine, does this sound normal for a secondary air pump?

Cheers.

TheBoy · 11 January 2007, 15:36:51

Look under bumper on that side - you can see the connector

Paul M · 11 January 2007, 15:58:54

From underneath the car? I did have a look there last week, and could see the big cylinder thing in front of the wheel I assume is the pump, but not the connector. Will have a better look this weekend in the daylight and with that side of the car raised.

Cheers.

TheBoy · 11 January 2007, 16:01:09

QuoteFrom underneath the car? I did have a look there last week, and could see the big cylinder thing in front of the wheel I assume is the pump, but not the connector. Will have a better look this weekend in the daylight and with that side of the car raised.

Cheers.

Thats the area to look in.

I bet Markjay has a picture....

bob.dent · 11 January 2007, 16:34:25

QuoteI'm getting a sort of buzzing noise on startup that sounds like an electric motor with failing bearings. After reading posts on here I'm suspecting the secondary air injection pump (the one in the front nearside wing) so I want to disconnect it to check. Is there any way of doing so without having to get into the wheel arch? I was thinking maybe a fuse can be removed, hopefully without disabling anything else that may be important.

The noise has been there since I bought the car, I just never spent much time investigating it as it's reasonably subtle (especially with my crappy exhaust!) and it goes away reasonably quickly. Strangely though it seems to change frequency if I rev the engine, does this sound normal for a secondary air pump?

Cheers.

My Omega has also done this from time to time since I got it over a year ago - doesn't appear to be causing any problems, and as you say, it goes away after the engines warmed up.

Paul M · 11 January 2007, 16:48:25

Cheers guys, I'll have a look at the weekend, it's too dark in the evenings.

It doesn't cause me any problems either, but if I can easily fix it then I will as it's a bit of an annoyance. Even more so if I get a decent exhaust meaning the car should be near silent at idle.

JasonH · 11 January 2007, 19:19:06

There is a fuse in the engine bay fuse box that just supplies the secondary air pump. I think it's the orange 30A one.
There is also a relay that just controls the SAP. Pull either of these - dead easy.

The reason the noise changes with the revs is the battery voltage changes a little too.

JasonH · 11 January 2007, 19:27:22

Hopefully some better info.

The fuse is here (F5 in red):

Plus, from the Haynes wiring diagrams:

Fuse F49, 50Amp is the fuse that supplies the SAP (and nothing else)
Relay K12 switches the power (and nothing else)

Paul M · 11 January 2007, 21:43:38

Nice one I'll try pulling the fuse, that being the easiest way to try

sophos9 · 12 January 2007, 13:52:56

I know this may sound a stupid question but do you actually need the secondary airpump?

Matchless · 12 January 2007, 14:17:21

QuoteI know this may sound a stupid question but do you actually need the secondary airpump?

No.
You can remove the pump and pipework.
Remove the metal pipe etc that runs across the cambelt cover, disconnect it at the 2" rubber joiner pipes where it connects to the exhaust manifold pipes. Use a piece of 1/2" steel or alloy rod to blank off the pipes to the exhaust manifolds.
You can remove the vacuum operated switch-off valve but you must re-fit the vacuum solenoid to the electrical connector else the eml will light. The solenoid ty-raps neatly to the radiator fan bracket.

bob.dent · 12 January 2007, 14:51:37

Quote
QuoteI know this may sound a stupid question but do you actually need the secondary airpump?

No.
You can remove the pump and pipework.
Remove the metal pipe etc that runs across the cambelt cover, disconnect it at the 2" rubber joiner pipes where it connects to the exhaust manifold pipes. Use a piece of 1/2" steel or alloy rod to blank off the pipes to the exhaust manifolds.
You can remove the vacuum operated switch-off valve but you must re-fit the vacuum solenoid to the electrical connector else the eml will light. The solenoid ty-raps neatly to the radiator fan bracket.

Forgive my ignorance guys, but if you don't need it why would they bother fitting one in the first place? :-?

Paul M · 12 January 2007, 15:17:12

It reduces emissions at start up (when rich mixtures cause a lot of partially burnt crap like CO) by injecting air into the exhaust manifolds, the heat and excess oxygen allow some of the gases to combine with oxygen (CO -> CO2), both reducing noxious gases and producing extra heat in the process which speeds warm up of the cats.

After a few minutes it's no longer needed as the engine has started to warm, so it's switched off.

bob.dent · 12 January 2007, 17:02:19

QuoteIt reduces emissions at start up (when rich mixtures cause a lot of partially burnt crap like CO) by injecting air into the exhaust manifolds, the heat and excess oxygen allow some of the gases to combine with oxygen (CO -> CO2), both reducing noxious gases and producing extra heat in the process which speeds warm up of the cats.

After a few minutes it's no longer needed as the engine has started to warm, so it's switched off.

Thanks for educating me on that one Paul.

Paul M · 14 January 2007, 13:15:30

QuoteHopefully some better info.

The fuse is here (F5 in red):

Plus, from the Haynes wiring diagrams:

Fuse F49, 50Amp is the fuse that supplies the SAP (and nothing else)
Relay K12 switches the power (and nothing else)

I removed the fuse, although it's a 30 A in mine and the fuse box layout is a little different, but it hasn't made any difference. So either it's something else making the noise, or that fuse doesn't control the air injection pump in my car. Nothing else seemed to be disabled though so I wonder what it does if not the pump. I may try the relay too, but I'm beginning to suspect it may be something else making the noise

News:

Secondary air injection pump