03 e46 325ci starting problem.

[seano]

Lads,

My car has developed an annoying problem. It occurs when trying to start after it's been idle for a few days. It will fire up but cuts out immediately and I can't rev it, I can hear the throttle open but nothing. It's deffo a fuel supply problem but has a new Mann filter and the fuel pump is functioning, I reckon, as it starts after turning on the battery a few times.

So the car does start and run but needs several cranks initially. Anyone know the cause of this.

Thanks..

[seano]

Gonna bump this as I still have this problem and it's wrecking my head. I'm fairly convinced the car is losing fuel pressure when sitting for round an hour or two. Since starting this thread I have replaced the fuel pump and filter/regulator. Checked the injectors today and no leaks. There is no smell of petrol anywhere and can't see any signs of leaks. I cleaned the throttle body last year and the car has done very little mileage since, also I have checked the fuel pump relay and no scorching.

I think I have covered every possible cause mentioned on the various forums but no luck.

I need to turn on the battery round 15-20 times to get pressure back up before it will start. If I don't do this the car will fire but conks immediately.

Anyone, please, have any idea what the f@*% is causing this to happen.

[Roberto]

Camshaft and or Crankshaft sensor?

[318 iS Cosmos]

Have you actually checked the fuel pressure though? I think there's a pressure tap on the fuel rail in the engine bay. Should read 3.5 bar afaik

[mac7]

May or may not be related or possibly answer part of your problem .
What can happen on some m54 engines if they don't fire first turn or are only driven a few feet and switched off again.
Fuel leaks into cylinders loosing compression making any subsequent starts very difficult.
Happened my self last year when I pulled the car up a few feet closer the house to avoid frosty weather, the following day it took a full minute of turning the car over before it fired, ran like a bag of shite for a minute but after that perfect and not a bother since.

[dergside]

In fairness, this probably wouldn't be limited to occurring only when stood for a few days but check for air leas on the inlet bellows. If there is something amiss there it could be throwing off the fuel/air mix.

[seano]

Hi Lads,

Not been here for a while. Thanks for the suggestions. Was thinking cam or crank sensors myself because there is actually no real constant. Have driven it a lot lately and sometimes it will start after turning on the battery twice others it could be 10 or 15 and it could happen after the car has been sitting for fifteen minutes and other days it will fire straight up after sitting for a few hours.
This all started after the car had been in sitting in a shed for three or four months which led me to believe something in the fuel system had perished. The car was running very rough when I bought it so along with the usual vanos and disa overhauls I think I have found all the vacuum leaks. I haven't tested the fuel pressure which I should have done but don't possess the necessary technology.

I'll get it onto a diagnostic machine before I spend any more time and money on it.

[Venom]

Hi Lads,

Not been here for a while. Thanks for the suggestions. Was thinking cam or crank sensors myself because there is actually no real constant. Have driven it a lot lately and sometimes it will start after turning on the battery twice others it could be 10 or 15 and it could happen after the car has been sitting for fifteen minutes and other days it will fire straight up after sitting for a few hours.
This all started after the car had been in sitting in a shed for three or four months which led me to believe something in the fuel system had perished. The car was running very rough when I bought it so along with the usual vanos and disa overhauls I think I have found all the vacuum leaks. I haven't tested the fuel pressure which I should have done but don't possess the necessary technology.

I'll get it onto a diagnostic machine before I spend any more time and money on it.

I'd normally say bad fuel. What's your cat like?

Sent from my Vodafone Smart II using Tapatalk 2

[seano]

For anyone who googles this problem, it turned out to be the maf in the end.

Car sitting there for 6 months, got a lend of a diagnostic machine and problem solved in 3 minutes.