3 cranks to start cold - 98 328i

[david_wotipka]

1998 328i 140 k miles.

Ok..when cold only (overnight or setting long time during day)....

When turn key to start first time, starter turns but will not start, almost no signs of life.

when turn key to start second time, starter turns but will not start, almost no signs of life.

When turn key third time, engine starts and runs perfectly.

Almost always 3 times required to start when cold, somtimes more.

When warm, starts and runs perfectly.
No codes or warnings are shown/given.

Changed fuel pump, fuel pump relay, pressure regulator, all spark plugs, O2 sensors.

Was thinking it was a fuel issue as I can not smell excess fuel after first two cranks; not so sure now.

Would like to get some opinions before changing any more parts out.

[markdas]

Sounds like it could be fuel related,

with a fuel pressure gauge in the line, turn the key to position 2 and you should hear the fuel pump kick in and pressure up the system to 3.5barg.

When started the fuel pressure regulator should maintain that 3.5, try pinching the return hose and see if the pump is strong enough to build a head of pressure rapidly, don't pinch the hose for too long!

when you shut the engine off, the pressure should not bleed off for quite a whiile (im not sure how long). There is also a flow test, where you run the pump with the fuel hose off and into a bottle, I think you are supposed to get 1/2 pint in 30 seconds (but check on that)

[Manolito]

You have several temperature sensors on this car and I suspect that one of them is not accurate.

The water temperature sensor is under the top plastic cover, near the front of the head, right next to the crankcase vent hose.

@ 14F 7k - 11.6k ohms
@ 68F 2.1k - 2.9k ohms
@ 176F 0.27k - 0.40 k ohms

The resistance specs are the same for the air temperature sensor. The Bentley says that your air temperature sensor is screwed into the intake manifold. I was thinking that it was in the mass airflow sensor. Bentley is far more reliable than my memory.

The temperature sensor in the right end of the radiator does not talk to the fuel injection, so you can ignore that one.

[david_wotipka]

Thanks all for the suggestions. I will dig deeper this week into your comments and hopefully will post my 'successful' repair.

[david_wotipka]

Changed all temp sensors and still have same problem..