Bimmerfest BMW banner

1 - 6 of 6 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1 (Edited)
I bought a 2004 325i last year in May and have been having the same issue since I've had it. I cannot for the life of me figure out what is wrong. I replaced the fuel filter today and the first two times it cranked right up then it went back to taking 2-3 cranks. I can only hear the fuel pump priming sometimes when I turn the key in the second position so I'm thinking that might be starting to fail but I'm not sure can anyone help me please?!? I'm getting so frustrated with this car!!
 

·
Keeping it surreal
Joined
·
43,083 Posts
I bought a 2004 325i last year in May and have been having the same issue since I've had it. I cannot for the life of me figure out what is wrong. I replaced the fuel filter today and the first two times it cranked right up then it went back to taking 2-3 cranks. I can only hear the fuel pump priming sometimes when I turn the key in the second position so I'm thinking that might be starting to fail but I'm not sure can anyone help me please?!? I'm getting so frustrated with this car!!
You can check the pressure at the fuel rail under the hood, there is a Schraeder valve provided for that purpose. Pressure should be consistent, at ~ 50 psi. Parts stores will usually loan or rent you a gauge.
 

·
Registered
Joined
·
5,349 Posts
What brand of fuel filter did you install? The fuel filter contains the fuel pressure regulator. The trusted brands of fuel filters are Mahle and Keyser. Both supply fuel filters to BMW.

Definitely check the fuel pressure as Fast Bob recommended. The pressure has to be at least 50psi at all engine speeds and engine loads. Your fuel pump may be soft failing. That means it can’t provide the needed volume of fuel at 50psi. The ONLY brand of fuel pump to buy is Siemens/VDO. Aftermarket pumps will fail quickly.

Also, there are 2 salmon colored relays in the panel above the fuse panel. One is for the horn and the other is for the fuel pump. If all else fails swap them.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #4
Update on problem: after checking my fuel pressure and seeing that it didn***8217;t hold at ~50 psi and rapidly dropped after about 30 seconds I ordered VDO fuel pump and replaced the original. After it got replaced, it got up to around 50psi and held it***8217;s pressure. I figured my issue would be solved now but It still cranks for a while before it finally starts up. Also I***8217;m not hearing the pump I literally just installed every time I turn the key only usually after it sits for a short amount of time or sometimes after it sits for a while. I checked the voltage on the battery and for some reason it only holds 11.9 until I start to crank the car then it***8217;ll build up enough volts to get it started. I just bought this battery last year and I got my car load tested and everything checked out. I***8217;m literally so confused and have no idea what could be the issue at this point can someone help me?
 

·
Keeping it surreal
Joined
·
43,083 Posts
Update on problem: after checking my fuel pressure and seeing that it didn't hold at ~50 psi and rapidly dropped after about 30 seconds I ordered VDO fuel pump and replaced the original. After it got replaced, it got up to around 50psi and held it's pressure. I figured my issue would be solved now but It still cranks for a while before it finally starts up. Also I'm not hearing the pump I literally just installed every time I turn the key only usually after it sits for a short amount of time or sometimes after it sits for a while. I checked the voltage on the battery and for some reason it only holds 11.9 until I start to crank the car then it'll build up enough volts to get it started. I just bought this battery last year and I got my car load tested and everything checked out. I'm literally so confused and have no idea what could be the issue at this point can someone help me?
In the E46 Wiki, it explains how to access and utilize the OBD "Hidden Functions", which will help you to run a self-test on the charging system. This may reveal the cause of your problem.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
I did test 19-9 on the dash and before I began to crank my car it read 12.4 volts after sitting for about 4 hours. After I began to crank it, it went down to 11ish volts and charged up as I cranked it and didn***8217;t start until it charged up to about 12 volts from me cranking it then it idoled real low for a sec at 12 volts and suddenly kicked up to 14 volts. I turned on all the accessories to see if maybe it was the alternator but it stayed at 14ish volts with all the accessories on.
 
1 - 6 of 6 Posts
Top