yng_750 247 Report post Posted May 13, 2011 hey guys having a little trouble with my 94 e38 740i it has always started first pop until about a week ago when it cranked for about 10 seconds before catching and running fine then yesterday morning it would only crank over but would fire at all, no coughing or spluttering at all then after trying to start it about 4 times for 20 seconds each time it started and ran fine once it had warmed up it started again with no hesitation that evening it did the same thing and i had to try for a while to start it but when it started it ran fine this morning it did the same thing but wont start at all i smelt the exhaust after cranking for a while and could smell no fuel i had a play this evening to rule out a couple of common issues i have read about removed the fuel pump relay and opened it up and checked it moved when i tried to start the car it did not react i then held it open with a piece of plastic after this i could hear the fuel pump running under the car (quite a loud hum) but still no sign of starting at all i will check tomorrow in daylight whether it has fuel pressure at the rail and im not sure if i can with coil packs but will try to check whether it has spark anyone have any idea what my problem could be? or easy tests i could do to narrow down the issue? thanks in advance Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 13, 2011 btw there are no warnings or check engine light etc on the dash Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 13, 2011 from reading around sounds like it may be my crankshaft position sensor will try to give that a test tomorow Quote Share this post Link to post Share on other sites
Greg111 13 Report post Posted May 13, 2011 Was thinking cam or crank sensor, seen a few V8s with cam sensor faults doing the same thing. Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 13, 2011 on a whim i tried to do a stomp test turns out my check engine light doesnt come on at all suspected blown bulb though cam and crank angle sensors supposedly give some strange error codes its been raining heavily here and the sensor is meant to run around 650 ohms im told, so any water in the plug will mess with things another thing to check Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 13, 2011 bah enough of this now im watching some boston legal and going to bed deal with this crap tomorow Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 13, 2011 i pulled the cam position and crank position sensors the cam tests look normal however the crank sensor apparently should read around 650 with the multimeter on 2Kohm setting mine reds nothing there and only read when i put the meter in 200Kohm setting and then it just slowly raises in resistance constantly but if you touch the pins it goes back to where it started so somehow my inductance pick up coil is acting like a capacitor not much to go on but everything else is checking out so im gonna take a wild stab in the dark and replace it anyone know where i can get a crank sensor on a saturday in taupo....... Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 21, 2011 Back up and running thanks to HARTGE535i for the crank sensor as a quick tip to anyone running into either long cranking issues or no start at all take the engine cover off and at the front of each of the plug boxes there is a plug on the intake side the left one runs to the crank position sensor and the right runs to the cam position sensor you can test them in place just unplug and measure the resistance between pin one and two it should be around 550 ohms if its much higher like mine was then its probably stuffed Quote Share this post Link to post Share on other sites
BM WORLD 1283 Report post Posted May 21, 2011 good work . i bet your glad its back up and running Quote Share this post Link to post Share on other sites
yng_750 247 Report post Posted May 21, 2011 yup took the opportunity to do a coolant change doing an oil change also this week probably going to sell it in the near future as im hopefully off to europe in September Quote Share this post Link to post Share on other sites