Secondary Air Pump DIY help

[DTM_Theory]

I've considered that but I think one of the rubber mounts is behind the headlight assembly; making it difficult to reach. I've got an LCI with headlight washers so I can't remove that either without removing the front bumper.

[andrewwynn]

I got to that third bolt/nut by removing the wheel arch and coming from below. Also I used a pump from a 7 series so if you didn’t find a replacement yet, many more options avail on the second hand market when including.


–awr–

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[DTM_Theory]

Update.

I managed to find the third bolt. It was hiding underneath the windshield washer pump line going to my headlight washers; it's sort of adjacent to the headlight assembly. That damn bolt was a pain in the a** to get it. I decided to leave it off for now.

After replacing the pump (I grabbed a used one out of an 04 X5 from the junk yard as well), connected everything back up... now the car won't fire up. The starter is turning, but it now won't run. I put the original SAP back in, same issue. The SAP can't prevent the car from starting right? Now i'm not sure if the used pump is even bad or not. What gives?

[80stech]

Try leaving everything disconnected, check for shorts. Maybe you pinched a wire under a bracket?? Back in the day it was possible that if one of the sensor reference voltage wires got shorted it would pull down more of the sensors and could cause a no start. I think the circuits are more protected and isolated these days but you never know.

Are you replacing the pump because of noise??

[80stech]

If you are putting on a used pump it might be seized or shorted and blew a fuse.

[andrewwynn]

SAP if malfunctioning will only set errors.

Pull codes see if you have an EWS problem also check for fuel pressure at the rail. Which motor? Did i miss?


–awr–

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[DTM_Theory]

I tried my best not to pull on the sensor plug underneath the pump or the sensor plug for the secondary air flow sensor next to it. During this process I was able attempting to put a valve cover trim over the shredder valve and o2 sensor plugs. I picked up the part from the junk yard also. I was shimming it around because the bolt holes wouldn't line up. Could that might've caused this?

So I could disconnected the pump and secondary airflow sensor plugs and try cranking again? How do I check for shorts? I'm not well versed in electronics.

[DTM_Theory]

Originally Posted by andrewwynn

SAP if malfunctioning will only set errors.

Pull codes see if you have an EWS problem also check for fuel pressure at the rail. Which motor? Did i miss?


–awr–

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I fired up OBDFusion right after and it pulled a few codes regarding vacuum leaks and a P0313. But I can hear my fuel pump priming as I turn the key. What sort of EWS problem am I looking for? I've got the M54 3litre.

[andrewwynn]

EWS can get out of sync it'll give you crank no start but I'm suspecting fuel. When wife's fuel filter pressure regulator failed it wouid crank for a very long time before firing up.

The very last time before replacing fuel filter it took no fewer than 8/9 5 second cranks to start it.

The o-ring fails due to age and apparently send fuel back to the tank vs. to the engine*. The weird part is once i got it started i was able to drive to the garage where I work on cars.

You need a "bmw level scanner" to scan for EWS codes i don't think fusion will read that module.

*It's a guess I've never determined exactly which fuel paths are divided by that o-ring.


–awr–

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[80stech]

Yes, disconnect the pump and sensor and try starting again. Check if you have power at the connectors, if not maybe you blew a fuse. Make really sure you didn't pinch or short any wires because chances are it's something you did.