2005 525i Fuel Pressure Problem? (stalls on cold starts)
09-30-2009, 12:10 PM
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Hey All,
I'm looking for help with a problem that neither the dealer nor my repair shop can diagnose.
My 2005 525i sport (58k miles, out of warranty) stalls or won't start when cold starting... sometimes.
When I turn the key on a cold (more than 20 minutes since it last ran) start, one of three things happens:
1. It starts, but at low-ish RPM and stalls out quickly
2. The starter cranks away but it does not start
3. It starts!
If it actually starts, it stays running and purrs like a kitten. The computer reports no problems anywhere. My current mechanic indicates that the problem occurs when the vehicle is in a cold/damp condition, but the problem started when I was living in Florida in August which is not cold (though it is humid). I only use 93 octane Chevron/BP. I've run through multiple tanks of gas since the problem started.
I've had the crank sensor, the fuel pump, and the fuel filter (as well as the Schrader valve on the top of the engine) replaced, and the problem persists.
It *appears* that the vehicle is losing fuel pressure when not running and that may be contributing to the issue. Once I watched the pressure drop from 3.5 bars to 1.X bars in about 30 seconds once while a mechanic tried to start the vehicle. It does not appear to lose fuel pressure once running.
So, I'll ask a few questions and then hope someone knows what is going on:
1. Do e60s maintain 3.5 bars of fuel pressure constantly? Or is it normal for the pressure to drop when the vehicle is off.
2. When BMW NA and the dealer both won't help financially because the vehicle is out of warranty, am I truly just SOL?
3. Has anyone else seen this happening or know what is causing this? I've read the other threads about bad fuel pumps and such but that doesn't seem to be my problem.
Lots of thanks in advance.
-Matt
I'm looking for help with a problem that neither the dealer nor my repair shop can diagnose.
My 2005 525i sport (58k miles, out of warranty) stalls or won't start when cold starting... sometimes.
When I turn the key on a cold (more than 20 minutes since it last ran) start, one of three things happens:
1. It starts, but at low-ish RPM and stalls out quickly
2. The starter cranks away but it does not start
3. It starts!
If it actually starts, it stays running and purrs like a kitten. The computer reports no problems anywhere. My current mechanic indicates that the problem occurs when the vehicle is in a cold/damp condition, but the problem started when I was living in Florida in August which is not cold (though it is humid). I only use 93 octane Chevron/BP. I've run through multiple tanks of gas since the problem started.
I've had the crank sensor, the fuel pump, and the fuel filter (as well as the Schrader valve on the top of the engine) replaced, and the problem persists.
It *appears* that the vehicle is losing fuel pressure when not running and that may be contributing to the issue. Once I watched the pressure drop from 3.5 bars to 1.X bars in about 30 seconds once while a mechanic tried to start the vehicle. It does not appear to lose fuel pressure once running.
So, I'll ask a few questions and then hope someone knows what is going on:
1. Do e60s maintain 3.5 bars of fuel pressure constantly? Or is it normal for the pressure to drop when the vehicle is off.
2. When BMW NA and the dealer both won't help financially because the vehicle is out of warranty, am I truly just SOL?
3. Has anyone else seen this happening or know what is causing this? I've read the other threads about bad fuel pumps and such but that doesn't seem to be my problem.
Lots of thanks in advance.
-Matt
09-30-2009, 01:22 PM
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Hello, I am not an expert but all E60's on petrol, are designed and optimized for octane 98+. You can try to use premium fuel, it should improve your situation. using 93 Octane is not good because every day the fuel is in the car, the quality of the fuel degrades even more. Have you changed your spark plugs? Use the OEM! Hope this helps.
Originally Posted by mxp74' post='1021385' date='Sep 30 2009, 08:10 PM
Hey All,
I'm looking for help with a problem that neither the dealer nor my repair shop can diagnose.
My 2005 525i sport (58k miles, out of warranty) stalls or won't start when cold starting... sometimes.
When I turn the key on a cold (more than 20 minutes since it last ran) start, one of three things happens:
1. It starts, but at low-ish RPM and stalls out quickly
2. The starter cranks away but it does not start
3. It starts!
If it actually starts, it stays running and purrs like a kitten. The computer reports no problems anywhere. My current mechanic indicates that the problem occurs when the vehicle is in a cold/damp condition, but the problem started when I was living in Florida in August which is not cold (though it is humid). I only use 93 octane Chevron/BP. I've run through multiple tanks of gas since the problem started.
I've had the crank sensor, the fuel pump, and the fuel filter (as well as the Schrader valve on the top of the engine) replaced, and the problem persists.
It *appears* that the vehicle is losing fuel pressure when not running and that may be contributing to the issue. Once I watched the pressure drop from 3.5 bars to 1.X bars in about 30 seconds once while a mechanic tried to start the vehicle. It does not appear to lose fuel pressure once running.
So, I'll ask a few questions and then hope someone knows what is going on:
1. Do e60s maintain 3.5 bars of fuel pressure constantly? Or is it normal for the pressure to drop when the vehicle is off.
2. When BMW NA and the dealer both won't help financially because the vehicle is out of warranty, am I truly just SOL?
3. Has anyone else seen this happening or know what is causing this? I've read the other threads about bad fuel pumps and such but that doesn't seem to be my problem.
Lots of thanks in advance.
-Matt
I'm looking for help with a problem that neither the dealer nor my repair shop can diagnose.
My 2005 525i sport (58k miles, out of warranty) stalls or won't start when cold starting... sometimes.
When I turn the key on a cold (more than 20 minutes since it last ran) start, one of three things happens:
1. It starts, but at low-ish RPM and stalls out quickly
2. The starter cranks away but it does not start
3. It starts!
If it actually starts, it stays running and purrs like a kitten. The computer reports no problems anywhere. My current mechanic indicates that the problem occurs when the vehicle is in a cold/damp condition, but the problem started when I was living in Florida in August which is not cold (though it is humid). I only use 93 octane Chevron/BP. I've run through multiple tanks of gas since the problem started.
I've had the crank sensor, the fuel pump, and the fuel filter (as well as the Schrader valve on the top of the engine) replaced, and the problem persists.
It *appears* that the vehicle is losing fuel pressure when not running and that may be contributing to the issue. Once I watched the pressure drop from 3.5 bars to 1.X bars in about 30 seconds once while a mechanic tried to start the vehicle. It does not appear to lose fuel pressure once running.
So, I'll ask a few questions and then hope someone knows what is going on:
1. Do e60s maintain 3.5 bars of fuel pressure constantly? Or is it normal for the pressure to drop when the vehicle is off.
2. When BMW NA and the dealer both won't help financially because the vehicle is out of warranty, am I truly just SOL?
3. Has anyone else seen this happening or know what is causing this? I've read the other threads about bad fuel pumps and such but that doesn't seem to be my problem.
Lots of thanks in advance.
-Matt
09-30-2009, 06:13 PM
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Originally Posted by krieshan' post='1021476' date='Sep 30 2009, 05:22 PM
Hello, I am not an expert but all E60's on petrol, are designed and optimized for octane 98+. You can try to use premium fuel, it should improve your situation. using 93 Octane is not good because every day the fuel is in the car, the quality of the fuel degrades even more. Have you changed your spark plugs? Use the OEM! Hope this helps.
Also I have not replaced the spark plugs. I suppose they are relatively inexpensive to replace, so perhaps I should just do it.
Of course my mechanic has had my car for 2 weeks now and he can't even get the problem to happen reliably enough this week to do anything about it...
10-01-2009, 05:49 AM
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My Ride: 2008 535i:
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Here's my guess:
You have a bad seal somewhere - since things generally contract in the winter due to the cold and expand in the summer when its warm, this could explain your problem.
You've replaced alot of things already in the fuel system. I really don't think there are any components that use rubber seals (like o-rings), otherwise gas would be leaking and you would smell it. You didn't mention it in your opening post so I'd assume all is ok there.
Have you checked/replaced the cap to your fuel tank (where you fill it with gas). A bad seal here could give you the same symptoms your car is having. Just because you hear it click when you tighten it does not mean it is sealing properly (I had this problem with my Camaro). Make sure you line the turn threads right and press firmly while turning.
Hope this helps.
You have a bad seal somewhere - since things generally contract in the winter due to the cold and expand in the summer when its warm, this could explain your problem.
You've replaced alot of things already in the fuel system. I really don't think there are any components that use rubber seals (like o-rings), otherwise gas would be leaking and you would smell it. You didn't mention it in your opening post so I'd assume all is ok there.
Have you checked/replaced the cap to your fuel tank (where you fill it with gas). A bad seal here could give you the same symptoms your car is having. Just because you hear it click when you tighten it does not mean it is sealing properly (I had this problem with my Camaro). Make sure you line the turn threads right and press firmly while turning.
Hope this helps.
10-01-2009, 06:11 AM
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My Ride: 2006 525XI, Jet black on Dakota beige. Premium and winter packages. I consider myself a purist and intend to keep my car absolutely stock and shiny.
2008 328I Convertible, Sapphire black on beige interior. Premium package, NAV, iPod adapter.
Retired: 2002 325I, Titanium silver on black leather. Premium package. Absolutely stock and proud of it.
Originally Posted by krieshan' post='1021476' date='Sep 30 2009, 05:22 PM
Hello, I am not an expert but all E60's on petrol, are designed and optimized for octane 98+. You can try to use premium fuel, it should improve your situation. using 93 Octane is not good because every day the fuel is in the car, the quality of the fuel degrades even more. Have you changed your spark plugs? Use the OEM! Hope this helps.
10-01-2009, 11:50 AM
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Originally Posted by porsche911targa' post='1022036' date='Oct 1 2009, 02:11 PM
Actually, our cars are designed to run on 91+ octane in the USA. Maybe you are reporting European numbers?
In Germany ( BMW-heaven) they even have Octane 100 + like V power racing. Some stores sell Octane boosters 
I would try to replace spark plugs first ( cheap and should give some results even when this does not solve your problem). I hope someone can help you out?
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