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bc540
04-02-2013, 06:34 AM
Strange issue with my 98 540. When the car sits in the sun on a warm day (65+) it is very hard to start. I have to try two or three times, when it starts it "sputters" to life, but runs smooth when started. When cold outside or if parked in the shade it fires right up and goes.

At times I have a rough idle. I also have an intermittent hesitation issue when above 4k. My Indy is saying I have low fuel pressure.

1. I put a new MAF in less than 7 months ago.
2. Fuel pump was replaced last week, it actually helped curb the issue with hesitation slightly....
3. New fuel filter a little less than a year ago.
4. Fresh oil changes with Mobil one synthetic 5w/30 every 3k (overkill I know)
5. Use non-ethanol 93 octane fuel.
6. Coils test good
7. Plugs and boots are less than a year old.

I'm thinking at the moment I have a bad or clogged injector in the mix, but this is what I have gleaned from some reading. I am also thinking it could be a bad crankshaft position sensor.

Obviously I don't know which is why I am posting here. Anyone have these experiences? Looking for ideas....

larrym3711
04-02-2013, 07:18 AM
Not likely crankshaft position sensor. More likely is ICV is malfunctioning...usually gets sticky and behaves poorly. It could be other things, of course, such as input leaks, bad O2 sensors, etc. You might want to attach an OBD I and see what it shows for codes.

larrym3711
2001 540iA Sport

bc540
04-02-2013, 08:58 AM
My Indy is going to clean the ICV today and connect for codes. However, we have looked in the past on this issue and seen no codes at all....