M20B25 hard to start

[D.Martijn]

Hey guys,

I'm having some problems with my 325ix.
When I let it sit for a full night, it starts almost always on the first time cranking. When I go of to work and come back to my car when I go home (8-9h later) it's difficult to start.

I can crank it for 10-20 sec and it'll fire up but die again. When giving it some gas it'll start up when letting go of the gas it'll die again. If I keep the revs up for a few seconds it'll idle fine.

A guy that I know who used to work in a garage told me to try and put some injector cleaner in my tank and see it that would solve it. I tried some stuff from my local car shop and I haven't had a problem since.

Now that I drove a full tank and filled it up again I'm having the same problem again. Would it be my injectors going bad? Giving that it starts fine with the product, I think it's fuel related.

Any thoughts on what it could be?

Thanks

[turbo55]

Doesn't really sound like injectors failing to me, especially given the car starts fine in the morning. Almost sound like a fuel vapor in the lines issue. At the time when the car has trouble starting (the after work time), I'd try priming the fuel system by pulling the fuel relay and jumping the connection to run the fuel pump for 10-15 seconds (it's easy to do, the Bentley book explains it. I think its pins 30 & 87 under the orange relay). If there is any vapor in the lines, running the fuel pump should work them out, then try starting the car and see if starts easily. If yes, then the problem is vapor-related and you might need to get a check valve for the gas line.

[D.Martijn]

Doesn't really sound like injectors failing to me, especially given the car starts fine in the morning. Almost sound like a fuel vapor in the lines issue. At the time when the car has trouble starting (the after work time), I'd try priming the fuel system by pulling the fuel relay and jumping the connection to run the fuel pump for 10-15 seconds (it's easy to do, the Bentley book explains it. I think its pins 30 & 87 under the orange relay). If there is any vapor in the lines, running the fuel pump should work them out, then try starting the car and see if starts easily. If yes, then the problem is vapor-related and you might need to get a check valve for the gas line.

I was also thinking it could be fuel pressure/fumes related. Thanks for explaining the proces, I'll look into it further.
Still weird that it seems to be solve with the product though?

[zaq123]

check your thermal time switch.

[D.Martijn]

check your thermal time switch.

Thanks for the comment but I checked this one just recently and all was good.

Doesn't really sound like injectors failing to me, especially given the car starts fine in the morning. Almost sound like a fuel vapor in the lines issue. At the time when the car has trouble starting (the after work time), I'd try priming the fuel system by pulling the fuel relay and jumping the connection to run the fuel pump for 10-15 seconds (it's easy to do, the Bentley book explains it. I think its pins 30 & 87 under the orange relay). If there is any vapor in the lines, running the fuel pump should work them out, then try starting the car and see if starts easily. If yes, then the problem is vapor-related and you might need to get a check valve for the gas line.

I just tested jumping the relais twice, first time I tried it, it just stalled again after cranking.
I let it sit some more and tried again. This time it did barely stalled but wasn't very convincing. So I'm not sure if this would be the solution, Might have to try some more. Although placing a check valve isn't a whole lot of work and expensive. I'll try it anyway.

[SecludedPlayer2]

When the hard starting occurs does it ever stop cranking kinda like it gets stuck for a second and then continue cranking and does the oil smell like gas.

[D.Martijn]

When the hard starting occurs does it ever stop cranking kinda like it gets stuck for a second and then continue cranking and does the oil smell like gas.

It does not stop, I can keep cranking the engine fine.
Oil doesn't smell like gas, I checked it again yesterday when checking the oil level.

[D.Martijn]

Doesn't really sound like injectors failing to me, especially given the car starts fine in the morning. Almost sound like a fuel vapor in the lines issue. At the time when the car has trouble starting (the after work time), I'd try priming the fuel system by pulling the fuel relay and jumping the connection to run the fuel pump for 10-15 seconds (it's easy to do, the Bentley book explains it. I think its pins 30 & 87 under the orange relay). If there is any vapor in the lines, running the fuel pump should work them out, then try starting the car and see if starts easily. If yes, then the problem is vapor-related and you might need to get a check valve for the gas line.

Last Saturday I added the check valve just after my fuel pump. It's did improve but when I wanted to start my car this evening after work is stumbled again when starting although not as bad like before.
I might have to get an fuel pressure gauge so I can determine if it's the injectors or FPR thats leaking a little.

edit: just had to move my car again after coming home one hour ago. Still hard to start, had to crank several seconds, twice for it to start.

[salvageland]

I had the same issue. Turned out to be a loose fuel line clamp coming out of the tank/pump. It had a slow enough leak not to puddle on the ground, but enough to drop pressure if parked for more than 30mins-1hr.

[D.Martijn]

Just to help others out with the same problem, it turned out that my fuel pressure regulator went bad and caused fuel to leak into my intake manifold thus also losing fuel pressure. Since replacing this week my engine starts up again great.

[superj]

I was wondering if that was the trouble