Chr15j Posted July 24, 2013 Report Share Posted July 24, 2013 I'm working on my wife's old E30 BMW 320i SE Auto (G-Reg) and its turning over but no fuel is being delivered... No noise from fuel pump, but this isn't necessarily the prob ( I.e, fuel pump may be ok) as only .17 volts going into fuel pump. Checked fuse (number 11) and again only .17 volts Removed fuel pump relay and inserted multimeter prongs and reading 10.7 volts but still no noise from fuel pump on cranking so not sure if relay is the issue or not. At this point I'm now stuck...help Quote Link to comment Share on other sites More sharing options...
rabbiter Posted July 24, 2013 Report Share Posted July 24, 2013 im not an auto leccy mate but id go easiest option and replace relay first,then if that don't help it could mean a new pump,not very helpful I know but I thought id atleast give you my two penneth..................DAZ Quote Link to comment Share on other sites More sharing options...
johnlewis Posted July 24, 2013 Report Share Posted July 24, 2013 If possible short out relay connection and then you should hear fuel pump run if so then pump ok, if there is a sencor at injectors that not sencing fuel hence pump not running. Just go by fault finding and eliminate what works then you might have some luck. Quote Link to comment Share on other sites More sharing options...
Paul223 Posted July 25, 2013 Report Share Posted July 25, 2013 10.7 volts is flat, charge/replace/jump lead the battery first before going any further. Then if it dont work try a jumper lead across the relay terminals to energise the fuel pump, if that works the pump then check for power and negative for the few seconds after switching ignition on at the relay energising terminals (usually 85 and 86) Quote Link to comment Share on other sites More sharing options...
Chr15j Posted July 25, 2013 Author Report Share Posted July 25, 2013 Then if it dont work try a jumper lead across the relay terminals to energise the fuel pump, if that works the pump then check for power and negative for the few seconds after switching ignition on at the relay energising terminals (usually 85 and 86) Ok u lost me here, I thought I effectively did this by plugging multimeter into the two points to get the 10.7 volts. How would I check for power and neg? Quote Link to comment Share on other sites More sharing options...
Paul223 Posted July 25, 2013 Report Share Posted July 25, 2013 start by checking across the battery to know what voltage to look for, lets say it's 12.8 volt, then ground the black lead on the multimeter, door latch plate is usually a good place as they are usually free from paint, with the multimeter on a volts setting check the relay energizing pin ( usually 85 or 86) with the red lead of the multimeter, that should show good voltage, close to, if not 12.8 volt, then switch the multimeter to ohms and check the other terminal (85 / 86) again with the red lead whilst the black is on that door latch for a clean ground, should read 0 ohms on a basic setting Quote Link to comment Share on other sites More sharing options...
Paul223 Posted July 25, 2013 Report Share Posted July 25, 2013 ECU pin 3 gives the fuel pump a switched negative, so that relay should have a constant 12+ volts going to it on the energizing wire (not the switched current wire) the ecu gives it a negative 'earth' to power the relay, hope that helps Quote Link to comment Share on other sites More sharing options...
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