SMG Pump Priming Randomly

[Deen HK]

Hey all, I was doing some work in the garage the other day and noticed that my SMG pump started priming by itself without me unlocking the car/opening the door. I never thought anything of it, but it happened again a few days later. Yesterday I got in the car to go on a drive; however the battery seems to be dead because the car wouldn't start without a jump. I have it on a trickle charger at the moment, does the pump prime randomly if the battery is on its way out?

Thanks in advance

[eacmen]

The pump will prime randomly if you leave the key in the ignition. Just sitting there it shouldnt.


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[Da Jemster]

Same thing happened to me when my battery was about to go out.

[Deen HK]

Same thing happened to me when my battery was about to go out.

Do you know of a way to stop the pump from priming before I replace the battery? I’m concerned I might put extra stress on the pump

[eacmen]

Do you know of a way to stop the pump from priming before I replace the battery? I’m concerned I might put extra stress on the pump

Disconnect the battery.


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[sapote]

easier: pull the salmon relay or the nearby fuse.

[nextelbuddy]

Hood switch for the factory alarm near the drug bin. Either it's bad or is not become depressed far enough down when there good closed and the car still thinks the hood is open keeping the car from going to deep sleep this causing the SMG pump to prime randomly.

[eacmen]

Hood switch for the factory alarm near the drug bin. Either it's bad or is not become depressed far enough down when there good closed and the car still thinks the hood is open keeping the car from going to deep sleep this causing the SMG pump to prime randomly.

I leave my hood open in the garage all the time and the SMG pump does not prime randomly.

The door latch switches, and trunk switch however could definitely cause this.


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[nextelbuddy]

I leave my hood open in the garage all the time and the SMG pump does not prime randomly.

The door latch switches, and trunk switch however could definitely cause this.


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I had a 2006 M3 SMG and the battery would die every 1 to 2 days and I would always hear the SMG pump priming when I would go outside just randomly it would prime.. I open the hood I checked the hood switch by the drug bin And I added a rubber piece to the top of the little pin to make it taller so that when the hood closed it would push the switch all the way down and I never had the problem again So that's why I stated that that's possible scenario. Maybe it was coincidence or something but that's what happened to me.

[eacmen]

I had a 2006 M3 SMG and the battery would die every 1 to 2 days and I would always hear the SMG pump priming when I would go outside just randomly it would prime.. I open the hood I checked the hood switch by the drug bin And I added a rubber piece to the top of the little pin to make it taller so that when the hood closed it would push the switch all the way down and I never had the problem again So that's why I stated that that's possible scenario. Maybe it was coincidence or something but that's what happened to me.

Interesting. So I just tested this in the garage. If you open the hood or close the hood, the SMG pump will in fact prime. But if you leave it open or closed it does not. So its the change in state (hood, door, trunk) that causes the pump to prime. I bet lock and unlock also does it.

[sapote]

I I open the hood I checked the hood switch by the drug bin And I added a rubber piece to the top of the little pin to make it taller so that when the hood closed it would push the switch all the way down and I never had the problem again .

If the SMG system uses the hood switch near the drug bin, then what are those 2 switches near the hood latches for? I believe it uses the two front hood switches only for the hood.

[eacmen]

If the SMG system uses the hood switch near the drug bin, then what are those 2 switches near the hood latches for? I believe it uses the two front hood switches only for the hood.

The two hood pin switches are also used but as an interlock. You can't go into gear with the hood up (or even popped).


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[TexaZ3]

SMG would not go into gear when the hood is open - for obvious reasons. So, there is definitely some sort of connection between the switch and SMG starting to prime.

[Da Jemster]

Interesting. So I just tested this in the garage. If you open the hood or close the hood, the SMG pump will in fact prime. But if you leave it open or closed it does not. So its the change in state (hood, door, trunk) that causes the pump to prime. I bet lock and unlock also does it.

This ^^ I also leave my hood open on the E46 and E93 when I get home. An old-school mechanic gave me that tip - Let the heat out of the engine bay. I didn't replace my belts and hoses until 110K (11 years) in the E46 (there were just a very few aging marks on the belt). The E93 has 113K and I haven't changed any yet.

[Rickyrosh]

This ^^ I also leave my hood open on the E46 and E93 when I get home. An old-school mechanic gave me that tip - Let the heat out of the engine bay. I didn't replace my belts and hoses until 110K (11 years) in the E46 (there were just a very few aging marks on the belt). The E93 has 113K and I haven't changed any yet.

Thanks for confirming this works. I’ve started to do this in addition to running an external fan pointed at the bay. Hopefully this helps lifespan of the SMG pumps as well.