Air leak secondary air pump

[PRB]

I've been trying for some time to clear a fault code that I've been told is an air leak.

On startup this morning I noticed a slight hissing, which on closer look was air passing through the joints on the secondary air pump (part 1 on this link https://www.realoem.com/bmw/enUS/showparts?id=CM12-EUR-04-2001-Z3-BMW-Z3_19&diagId=11_1659).

Firstly I assume that air through the joints is not normal - has anyone any experience on repairing one of these, or does not have to be a replacement?

Thanks, Paul

 

[t-tony]

I've been trying for some time to clear a fault code that I've been told is an air leak.

On startup this morning I noticed a slight hissing, which on closer look was air passing through the joints on the secondary air pump (part 1 on this link https://www.realoem.com/bmw/enUS/showparts?id=CM12-EUR-04-2001-Z3-BMW-Z3_19&diagId=11_1659).

Firstly I assume that air through the joints is not normal - has anyone any experience on repairing one of these, or does not have to be a replacement?

Thanks, Paul

Hi Paul, do neither of the above. Take it all off and bin it, you do not need it, it's just extra weight you don't need to carry. Will make no difference to your exhaust emissions at MOT time. You just need to blank the port on the cylinder head.

Tony.

 

[PRB]

Thanks Tony,

That's a different idea! So is that just a blanking plate under part 11 on the diagram?

Please excuse my ignorance, but what is this system supposed to do, if it can be so readily removed?

 

[colb]

On a cold start the secondary air pump will pump air into the exhaust to lower the emmisions, it only runs for a short time and switches itself off as the engine warms up. So apart from the use at a cold start it sits there doing nothing. As Tony says it will not affect MOT testing of the emisions if its removed and a blanking plate is fitted.

 

[t-tony]

Thank you Col.

Auxiliary air pump blanking plate kit - please PM for info.(2 available)

Not just telling you this for the obvious reason, but if you decide to do the delete I can supply a blanking plate for you to use.

Tony.

 

[PRB]

Thanks Tony,
Does it also need to some of electrical termination to stop the ECU recognising that the pump is missing?
Paul

 

[Eddie Zedder]

Just unplug it, blank off at cylinder head and plug the vacuum pipe (if fitted).

 

[PRB]

Ok, so more thinking here (always dangerous!)

I was hoping that the air leak on the pump may resolve the issues that I've been trying to find for a while.
https://zroadster.org/threads/error-code-8d-oxygen-sensor-control-p0170.34511/#post-547367

Presumably if the air pump isn't connected to the ECU, then it can't be the source of the error code.

To give some more context, I found a leak on the pipe between secondary air pump and manifold valve, and rest the error. Driving Bradford to Chesterfield and back one Saturday morning,and the light stayed off... Until I got stuck in traffic 1/2 mile from home and the light suddenly came on again. Whilst there may be a leak on the pump, it's unlikely to solve the error code?

Any thoughts very gratefully received!!!

 

[colb]

I think your right in thinking that the air pump leak may not be the cause of the EML, as it passes through a regulating valve that prevents blowback so when not running the air pump line would/should be sealed, can only think it would be the cause if its stuck open otherwise you may have a leak somewhere else in the system. Put a code reader on it and see what the code(s) are to narrow it down.
If you get fuel trim errors then more than likely to be an air leak betwen the Maf and exhaust. Let us know what codes you get.

 

[PRB]

Puzzle deepens! Read the fault codes - the first I'm used to seeing, the later 2 not seen before (picture attached)

I've reset the codes and let the engine run for about 10 mins revving it time to time and getting it warm enough the fan kicked in - the EML hasn't returned!

So moving slightly I then looked at the Oxygen sensors at both tick over and revving the engine. I don't get any reading at all from the post-cat sensor! Could it be a genuine sensor fault?

Again any advice very gratefully received!

 

[colb]

OK thats helpful seeing those codes. Before shelling out on a post cat sensor it looks like you have a Maf sensor gone bad, you could try cleaning it with Maf cleaning spray, don't use anything else. If cleaning makes no difference then change the Maf for a oem one either Bosch or Seimens brands, leave the cheap options on ebay. The fact that you have a Oxygen sensor control code leads me back to the Maf, I reckon thats not reporting correct airflow and as a consequence the fueling of the car has reached its maximum, the EML will light up sooner or later if you run the car without sorting the cause. I am not too concerned not seeing a voltage on the post cat sensor, they do not range up and down the voltages like a pre cat sensor. Lets see what effect a new Maf on the car has. Best fit it, clear all the codes then run the car on a short drive before scanning it again to see if its set any codes again.

 

[PRB]

Great - thanks for the help - let's see how we get on!