bmwcrocop

2007 S550

6 months ago the car wouldn't start (in one out of four tries). The starting got progressively worse. I replaced the crank shaft sensor to no avail. The mechanic tested the fuel pump and it was good to go. He replaced the Fuel Pump Relay (A 002 542 13 19) and it worked perfectly for six months.

The last week the car has been slow to start. I drove the car 35 minutes and turned it off for thirty seconds and tried to restart it to no avail. After five or six tries the car wouldn't turn at all.

Got a jump from a stranger -- after twenty tries it started.

Any thoughts? Try another relay?

Thanks in advance.

alx

Try? Stop it right there

Instead have the car connected to star/ das and read for codes. While at it diagnose fuel pump pressure at crank time. Verify spark plug controller. A bad coil will cause a misfire, but a bad controller will produce no spark at all.

bmwcrocop

The mechanic tested and there were no codes. Guy tested everything and couldn't figure it out. Sent me a video as well. Fuel pump and pressure is good to go.

He replaced the fuel pump relay and it worked for six months. Hence, replace the relay again.

DRTYLNDY

This is the exact same scenario my father's S55 just went through. Random no start but once running was fine.
It would randomly be a no start even after replacing the CPS twice.
There never was a code just a no start. Then one day when it was a no start I told my dad to push the valve on the fuel line. Boom that was it no fuel pressure at all. Replaced the fuel pump and filter and has been great since. The car even runs much stronger.
This ended up being a multi month issue for us but a lesson well learned.
Hope this helps.
Johan

bmwcrocop

Fuel pump is good to go.

What else could it be? Bad key?

DRTYLNDY

Did you check to see if it had fuel pressure immediately after the no start?

alx

as mentioned in my previous post- next suspect is ignition module. have your mechanic check for spark by pulling a (connected) plug and observing for spark during (unsuccessful) crank

bmwcrocop

I'll just buy an ignition module and a fuel pump module. Do you have the part number?

bmwcrocop

Oh no it's like $500 -- I thought we were talking about relays. The ignition module is where you put your key into, right?

bmwcrocop

Yes to drtylady

bmwcrocop

I just started he car: first time two second delay. Second and third time it started right up.