4.4i cranking for longer than usual...

[frozenwaffles]

Hi guys and gals,
So recently I've noticed my X5 E53 2001 4.4i has started to take longer in the start-up process...she is on 180,000kms.
Basically what would normally take 1-2 seconds now takes 3-5.

I have recently put a new fuel filter on the beast.
Plugs where replaced with Iridium Bosch plugs only 10,000kms ago.
Oil change with Valvoline MaxLife 20W-50 only a couple of months ago.
Primary O2 sensors replaced 10,000kms ago.
Secondary O2 still possible original.
MAF still possibly original.
I have owned the car since 160,000kms (bought it in January 2012).

So why would or where should start looking to find out why its taking longer to start???

[upallnight]

Extended crank can be attributed to a bad FPR (Fuel Pressure Regulator). One check is to remove the vacuum hose that is attached to the FPR and smell the hose for gasoline. If you smell gasoline in the hose, that will mean that the diaphragm is torn and permitting gasoline to enter the vacuum line. A torn diaphragm will also present a wide open throttle condition since it can't hold vacuum. You can also connect a fuel pressure gauge to the fuel rail and perform the following check. With the engine running note the reading on the fuel pressure gauge. Pull the vacuum line off the FPR, the pressure gauge should show an increase in pressure, if not you have a bad FPR.

FPR is a relative cheap part to buy for the BM Trouble U. Here's a link to show what you need to replace.

2000-2004 BMW X5 Fuel Pressure Regulator - Fuel Injection - Bosch 00-04 X5 Fuel Pressure Regulator - 1185-05252070 - PartsGeek

[frozenwaffles]

Thanks for this! That's a really good reply

[pezho405]

Wait why are you using 20w50?

[frozenwaffles]

Well after lots and lots of research, I was lead to believe that it would be the most suitable for my engine given its age and kms...
Its almost on 112,000 miles. Do you think I should be one something else?

[BigBlack48is]

Originally Posted by frozenwaffles

Well after lots and lots of research, I was lead to believe that it would be the most suitable for my engine given its age and kms...
Its almost on 112,000 miles. Do you think I should be one something else?

I would stick with 5w30 or 0x40 with your motor

[TiAgX5]

To verify if this is a pump/filter/regulator issue you will need to hook up a fuel pressure gage ($20 at Harbor Freight) to the schraeder valve on the fuel rail and read rail pressure. With the key in the run position it should be 51 +/- 3 psi. and only take 2 or 3 seconds to reach that pressure (if it rises slowly you have a clogged filter or bad pump, see NOTE 1 below to identify). Next step, start the engine and let set at idle for 1 minute (high vacuum), pressure should now read 36 to 46 psi. Now disconnect vacuum line from pressure regulator to simulate full load, pressure must increase 6 to 10 psi.
NOTE 1; If pressure did not come up to 51 +/- 3psi, repeat test while gradually pinching return hose to fuel tank. Rapid rise in pressure reading at rail with each pinch verifies pressure regulator is bad. No rise in pressure verifies fuel pump is bad.

+1 on avoiding higher weight oil, this can cause oil starvation on cold start up.

[pezho405]

Yeah i would just out of curiosity try to use 5-30 oil first. 20-50 is usually what i use fow wayyy older cars like my Porsche and a e21 320i i had

[frozenwaffles]

cool, thanks for the tips gents. Will try and sort it in the next week or two. Will change the fuel filter (and PR) asap.

[upallnight]

Post back if any of the comments corrects the problem.