Hard to Start after sitting a few hours

[angusbn]

Suddenly experiencing a problem starting after it's been sitting for an hours or two. Outside air temperature is 70F.

Replace plugs today, cleaned ICV and the MAF looks OK.

Battery checks OK using multimeter.

Don't know history of fuel pump, or fuel pump sender/receiver or fuel filter. No fuel check value is installed on top of fuel pump sender/receiver.

Starts perfectly once it gets going and idles fine.

Any suggestions would be appreciated.

Blair...

[Rus]

Sounds like a fuel drain issue. It can be caused by several things:
1) Check valve in fuel pump is kaput. Fix by installing an external checkvalve (OEM part # is somewhere on this forum).
2) One or more injectors is leaking. Fix by replacing injector(s).
3) Fuel pressure regulator is kaput. Happened to me on my 535i. Diagnosed by doing steps 1 and 2 and eventually finding gasoline in the vacuum line going to the FPR. Internal diaphragm in FPR broke and let fuel into vacuum line. You can check for this by pulling off the vacuum line right after running the car. If you smell gas or see it coming out of the nipple on the FPR (like it did on my car), the FPR is toast. Not sure how to test for leaks between the feed and return ports of the FPR.

Hope this helps.

[632 Regal]

leaky fuel check valve or leaky injectors.

[bayviewsbb]

Suddenly experiencing a problem starting after it's been sitting for an hours or two. Outside air temperature is 70F.

Replace plugs today, cleaned ICV and the MAF looks OK.

Battery checks OK using multimeter.

Don't know history of fuel pump, or fuel pump sender/receiver or fuel filter. No fuel check value is installed on top of fuel pump sender/receiver.

Starts perfectly once it gets going and idles fine.

Any suggestions would be appreciated.

Blair...

Earlier threads are on the money...change the Bosche FPR (cheap) and your starts will be fine...

[angusbn]

Apparently BMW doesn't sell this part any longer - #16-14-9-068-988 - inline fuel check valve. Go figure.

Thankfully BMA Auto Parts (Yves) had one left in stock for $7.50 so I'll get that and report back after it's installed.

Thanks to all the helpfull suggestions.