Does the e53 key send a security signal to crank?

[workingonit]

Originally Posted by andrewwynn

... if the button key won't crank, hold the valet key right next to the button key when it's in the ignition: if it will crank and especially start that indicates the EWS circuit in the button key has a bad solder joint....

That would explain why my OEM diamond key fob (button key) has been having intermittent no crank, no start problems. I know that there's at least one bad solder joint in it, maybe more. The Valet key has no such problems.

If my X5 wasn't currently down, I'd be using the Valet key and my generic remote-only fob, and finally open up the OEM key to repair it (I can't bring myself to try it, yet, because I fear I'll do more harm than good, hahaha).

[andrewwynn]

I misread something in the past and thought EWS never stopped the crank (which i think is really dumb), glad to find out it can stop crank but only if you put in what the car considers a non key.

It's my opinion that it's asinine to ever crank with a rejected key. Put up a security alert on the dash to indicate a problem don't just frustrate the owner/mechanic!

I'm super glad that was clarified !


–awr–

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[timmyc]

I've been going through this exact scenario recently and because we don't drive the X much, it is VERY intermittent. I did go back through my notes and I found that I replaced the ignition switch (which I ended up finding the old one in the new box) and got a new key from the dealer and that seemed to fix the problem, but now that we have been driving it a bit more (the i3 does not do well in snow) the no crank/no start has reared it's ugly head.

So what I think I am reading here in this thread is that the key must be the culprit and not necessarily the EWS or ignition switch? I have been using the old key only because it worked almost 98% of the time and I didn't want to use the new one unless I needed to, we just needed a factory spare. Once the X is back from the shop, I'll try using the new key and see if we have any issues with that one. Again, since we don't drive it often, the response may be a bit of a wait.

Cheers!

[X5chemist]

If anyone is not worried about their X5 being stolen, by pass the EWS. Easy to do. I did it on mine while chasing a parasitic draw. Once I found the problem, it was easy to reinstall. Basically, have the DME programmed. Remove the EWS module. Stick a 30 amp fuse in the EWS harness so the starter cranks. The alarm works normally. Only issue is that any key or screwdriver in the key cylinder will crank it.

[Clockwork]

Sadly, my e53 2005 has been having an issue for years that started off very randomly, (once per month or 2) and now its up to every week) where the engine cranks over very strongly but never catches/fires up. So I turn key off, sometimes remove it, and try the auto-ignition again (turn key, let it go, as my model has the early "push to start" sort of feature). It used to then fire up on the second attempt, but now when this is happenning its taking 2-4 times to FINALLY have the engine catch and fire up.

SO I thought it was the original key RFID signal chip was being funky, so I swapped to my other OE key and that seemed to ahve solved the issue for a few weeks... but then same symptoms with that key. sno now I'm at a loss.
Perhaps the EWS module has gone funky?
AND this ONLY happens when car has been sitting for hours (in warm or cold weather). When engine finally starts, if I turn off right away again and attempt to restart, it instantly fires up.
SO I'm wondering about EWS now...

[80stech]

Sounds like maybe a fuel problem. I'm not sure how the V8s work with that auto start but maybe try going from off to ignition (but not start) a few times to activate the fuel pump a couple of times before cranking.

[andrewwynn]

The 4.4 with the "start help" doesn't prime the pump until you turn the key. At that point it acts like a push to start and will crank xx seconds.

A hard start usually means the check valve is not holding pressure at the FPR.

Have you tested rail pressure after the car sits a while?

If it will reliablely start on the 2nd or 3rd attempt it's almost certainly FPR/fuel pump (check valve).


–awr–

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