Won't start on hot days

[DrThomas430]

Hello all and thanks for the help in advance.

Issue started when daily temps started to climb. Key works just fine to open doors and turn ignition. It would start eventually, but has made me late a couple times. I'm sure it is a transponder issue. I ordered another key because I only had one when I bought the car and I know similar issues happen with the cars that I work on. That didn't fix it. I've done few searches here and on google and only found old threads that didn't have fixes. A another tech here used to work for BMW and says that it might be the sensor ring for the ignition, but I want more opinions before I throw more parts at it. I don't have a decent scanner available for a few more days. Any ideas?

[Johnmadd]

My old e30 did this although I can't for sure say it's the same issue because of all the extra electronic modules. When it was hot out it would take minutes of cranking to get started and it turned out to be the injectors were on the way out, replacing them fixed the issue immediately. Just sharing my experience, maybe this will give you something to research and see if anyone's had a similar situation. Any check engine light on?

[PetesZ]

Concur-

Would expect it to be more of a fuel issue than Key. Dead battery keys work fine without issues starting car.

If you have a leaking injector or the fuel pressure regulator on the filter - all fuel in the line can drain out.

Check the fuel line pressure at the Schrader Valve on the fuel rail.

[DrThomas430]

its not even turning over. So I dont think its a fuel issue. Lights will come on in dash, key turns but not trying to start. Have my test light hooked up to starter to see if its the starter. (currently starting so I have to wait for it to mess up). Talked to a BMW tech, he thinks it may be the EWS. Eliminating the easy diag stuff first.

[Newjack]

Have you checked battery voltage?

[DrThomas430]

Yes battery voltage is good. Battery was recently replaced.

[PetesZ]

Ok missed the not even turning over part.

Does the starter even try. Does it make any sound at all ?

[ryankokesh]

Is this confined to cold starts, or does it also happen after the car has been running?

[DrThomas430]

only happens when the car has been sitting in the sun with the windows up. I scanned it and it has a fault for the EWS. Going to order a replacement and have it coded.