HELP: Engine cannot idle

simoncpw · #1 02-21-2009, 11:38 PM

Hi all,

My X5 4.6is has been having this consistent problem. The engine failed to maintain at idle RPM after starting up the car:

1) Engine starts without any problem
2) as soon as engine is started and without touching the gas pedal, I can hear the car tries to rev the engine up/down slightly to try to get to the idle speed
3) but after a few seconds or so, the engine would shut down

- if I press the gas pedal, the engine sometimes would response accordingly, but some times it wouldn't, and the engine would stop eventually regardless.
- if I switch from P to D IMMEDIATELY after the engine starts, the engine is able to keep at idle RPM and I could drive the car as per normal (no problem stopping at traffic light, in P or N.. etc)
- usually this problem would trigger the "Engine Fail Safe Prog" message, but not always
- usually this problem happens after about an hour the car is parked (drive to lunch ok, but problem comes up after I return from lunch)
- but went out for the first drive this morning, the problem comes up immediately.

Since this problem started about a month ago, I've had the following replaced already:
- air flow sensor
- fuel tank sender (which happened to be not working properly at the same time)
- fuel pump
- fuel filter
- battery

Any idea what else this can possibly be?

Here's the video I took when it happened this morning.

Thanks

Simon

simoncpw · #2 02-22-2009, 12:58 PM

Anyone?

randytheace · #3 02-22-2009, 01:30 PM

My 05 4.8is was doing the same thing! I took it in and they found the oil cap was loose on the valve cover. Evidently the crankcase pressure was lost which is used in the fuel mixture calculation, so the computer was full of codes. They tightened the oil cap and cleared the codes and all is good now!!

simoncpw · #4 02-22-2009, 07:55 PM

Thanks so much for your reply. Can you let me know where the "oil cap" is located?

Quote:

Originally Posted by randytheace

My 05 4.8is was doing the same thing! I took it in and they found the oil cap was loose on the valve cover. Evidently the crankcase pressure was lost which is used in the fuel mixture calculation, so the computer was full of codes. They tightened the oil cap and cleared the codes and all is good now!!

Thanks so much for your reply. Can you let me know where the "oil cap" is located?

Quote:

Originally Posted by swissfrank

sounds suspiciously like a vacuum leak or a loose connection, and if you have a k&n air filter, a dirty maf. These are all easy to check and easy to remedy, good luck, let us know.

Thanks, swissfrank. Regarding the vacuum leak, any where in particular that I should check? I want check as much as I can before bringing it to the shop as it has caused a lot of money already. (I don't have the k&n filter). Thanks.

swissfrank · #5 02-22-2009, 05:33 PM

sounds suspiciously like a vacuum leak or a loose connection, and if you have a k&n air filter, a dirty maf. These are all easy to check and easy to remedy, good luck, let us know.

randytheace · #6 02-22-2009, 09:25 PM

its in the right side valve cover(left if you are looking at the motor), all the way in the front. you can also find it in the owners manual under "adding oil". I was only charged $100 for the diagnostics and the fix at dealership, so it didn't hurt at all.

simoncpw · #7 02-22-2009, 09:59 PM

Quote:

Originally Posted by randytheace

its in the right side valve cover(left if you are looking at the motor), all the way in the front. you can also find it in the owners manual under "adding oil". I was only charged $100 for the diagnostics and the fix at dealership, so it didn't hurt at all.

Oh, you mean the one for the Engine lubricant oil?