Weird E46 no start issue

[GusPaterson]

Hey guys,

Had a weird issue where my car alarm would randomly go off. I isolated to the interior motion sensor, because it stopped completely when I locked it with the key and not the fob. I left the car for a few days, unlocked it and the car turns over but won't start.

Here's what I've tried/checked:

-Checked the battery, was showing 11.6V (possible parasitic drain? possible faulty multimeter?)

-Jump started the car (wouldn't turn over)

-Bought a brand new battery; still not starting

-Unplugged MAF

-I can hear the fuel pump priming, there's quarter of a tank of fuel

I suspected that the alarm issue was caused by a parasitic drain, probably by a faulty FSR but I locked the car with the fob and sure enough... the alarm goes off again. I'm now starting to suspect its an alarm or immobilizer issue. Does anyone have any ideas?

[danb79]

GusPaterson said:

Hey guys,

Had a weird issue where my car alarm would randomly go off. I isolated to the interior motion sensor, because it stopped completely when I locked it with the key and not the fob. I left the car for a few days, unlocked it and the car turns over but won't start.

Here's what I've tried/checked:

-Checked the battery, was showing 11.6V (possible parasitic drain? possible faulty multimeter?)

-Jump started the car (wouldn't turn over)

-Bought a brand new battery; still not starting

-Unplugged MAF

-I can hear the fuel pump priming, there's quarter of a tank of fuel

I suspected that the alarm issue was caused by a parasitic drain, probably by a faulty FSR but I locked the car with the fob and sure enough... the alarm goes off again. I'm now starting to suspect its an alarm or immobilizer issue. Does anyone have any ideas?

Could be an EWS issue; or ignition barrel issue

Plenty of info re these on Google have a read into them

[HealeyV8]

I had similar issue, then car started but ran rough, then wouldn't start at all. Turned out to be fuel pump was failing, broken up parts had blocked the fuel line.
New pump and line cleared and all good.

[E-bmw]

FWIW 11.6v is flatter than a flat thing!

12.6 or 12.7 for a fully charged battery in good condition, for every 0.1v below this subtract around 10/15% battery capacity lost.

[4rephill]

E-bmw said:

FWIW 11.6v is flatter than a flat thing!

12.6 or 12.7 for a fully charged battery in good condition, for every 0.1v below this subtract around 10/15% battery capacity lost.

+1

Added to that, modern batteries can be showing 12V plus, and still be faulty, no longer having enough cranking amps available to turn the engine over!

Some useful battery information can be found here: https://www.batterystuff.com/blog/how-to-tell-if-y...