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jojo94 01-23-2013 06:24 PM

2004 x5 (Fuel System Issue)
Hi All .. I am new to this forum and it seems like a lot of issues have been resolved here. However couldnt find anything that matched whats happening to my x5... hopefully someone out here has had some experience with this.

Go outside yesterday morning (very cold in the single digits first time this year) Car cranks normally but no ignition. Having had a similar symptom with my 330xi and ended up being the fuel pump... I went to the pump on the x5 first. I disconnected the plug and wired a 12 v power supply to the pump and it started pumping. Next put a volt meter on the plug to the pump while it was unplugged. Turned the key to the first click (not all the way to engage the starter) and saw 12 V for appx 3 seconds then 0 volts. Next connected the plug again and pierced into the wires in order to get a volt reading while plug was attached to the pump. Turned the key.. same as before and 0 volts the whole time. Repeated the test again and the same results. I am baffled. Is there a possible relay that may be bad and limiting the current going to the pump?? If so where? Or maybe a bad connection somewhere.. seems that the cold weather has something to do with the problem. As this did happen previously on one other cold morning and after letting the car sit till the day warmed up it started perfectly..... uugggggggggg.. Well my hands are to cold to type anymore as I just called it a night with this car. ANY help would be greatly appreciated.

upallnight 01-27-2013 02:43 PM

Unless the engine starts, the computer will send a signal to the pump to preprime the pump and then shut it off. Once the computer acknowledge that the engine is running it will continue to send a signal to the pump to run. Sound like it's doing what it is suppose to do.

Do you have a CEL or SES or MIL? If you do you need to scan for the trouble code. That will tell you what the problem is. If the pump is energizing and the preprime procedure is occurring I would look to see if you have a spark. Could also be that you might have flooded the engine in your attempts at trying to start the engine. On the previous time that this happened to you you let the engine sit and if the engine was flooded, letting the engine sit will allow any gasoline to evaporate into a vapor. It's the vapor that is explosive, not the wet gasoline.

jojo94 01-29-2013 06:03 AM

updated info
Thanks for the reply upall night.. NOw with the problem being over a week old and having plenty of time to gather data I can be more clear on what is going on. DEFINITELY a pump power issue. In COLD (less then 32 deg) If I turn the key the first time to acc. NO power to the pump for the pre purge. If I wait till the day warms up turn the key to acc starts right up... already replaced the pump relay under the hood. no change. Also if i short the switch part of the relay.. i think its 30 and 87 the pump turns right on... Im now leaning towards the control side of the relay...(ECM or one of the periferals that tell the ecm to turm on the fuel relay) Now in for 3 days of warm weather.. Have to wait till cold again to see problem. This is the first winter i have ever prayed for more

upallnight 01-29-2013 08:32 AM

The control side of the relay receive it signal from the DME (ECU/Computer). I would unseat the relay and clean the contacts and maybe bend the contacts ever so slightly so that it will make a positive contact with the relay harness.

Could be that the cold weather is just cold enough for the contacts to contract and you will have an open circuit.

jojo94 01-29-2013 05:32 PM

Thanks again for the response Upallnight... Early this morning before going off to work . I start the x5 now pretty warm here in the 50s take it for a ride Runs great like no proplem. On a whim I decided to hook up my engine fault analyzer to see if anything was there even thought there was no service light on. Behold a 604 code saying ecu ram error. So I clear it and go to work.. On the way home tonight and wife calls ... says the car is making strange noises.. Get home .... there is no key in the ignition and the fuel pump is cycling rythmically like every 15 seconds for 10 seconds.There is nothing else in the x5 running or trying to run... Is this vehicle possesed? I pulled the fuel relay to preserve the battery. Now regrouping for tomorrows escapades.

upallnight 01-29-2013 08:53 PM

I believe the Powertrain Control Module (PCM aka. DME) is connected to a circuit that is Hot all the time. P0604 is pcm random access mem ( ram error. it may mean the pcm has failed, have it checked out.

upallnight 01-30-2013 08:19 AM

Other option is that you maybe able to get the DME reprogrammed.

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