Car wont start

Sat Nov 05, 2011 4:26 am

Hi, last night my car decided to not start for me. I had been using my car all night and had no starting related issues what so ever, however it just suddenly stopped working. Whenever i try starting it now it just turns over, it's almost as if it has no petrol, it try's to start, and sometimes does but will stall almost imminently after. Im throwing my bets on the fuel pump but cant be sure, is there anyway to check if the fuel pump is still working? Any help or idea's would be apreciated, thanks.

Sat Nov 05, 2011 5:14 am

try taking the rear seats out and the carpet so you can see the top of the fuel pump and give it a couple of gentle taps with a screw driver handle or a hammer shaft.my guesss would be the fuel pump

Sat Nov 05, 2011 6:55 am

Agree sounds like the fuel pump to me.

Sat Nov 05, 2011 7:43 am

Crank sensor....

Sat Nov 05, 2011 7:57 am

maxfield wrote:Crank sensor....

Not if it tries and stumbles to fire. A dead CPS will turn off the spark. I'm with fuel on this one.

http://www.e30zone.net/e30zonewiki/inde ... _to_Engine

Sat Nov 05, 2011 8:39 am

Try bridging the fuel pump relay and then starting

Sat Nov 05, 2011 8:51 am

well just have a listen in the back for the pump running, there noisy buggers with the seat out.

Sat Nov 05, 2011 10:28 am

Fuel pump relay is the one with a green/violet wire attached to it's bum! Link this wire to the red/white and the pump should run continuosly regardless of ign switch position. I assume that fuse 11 has been checked?

If the fuel pump runs,then I'm with Maxfield and suspecting the CPS.

Sat Nov 05, 2011 10:37 am

What model E30 is it?

Sat Nov 05, 2011 3:19 pm

Thanks alot for the replies, its a 1990 316i billwill. Im towing my car home later so will have a play around then. What kind of noise should the fuel pump make if it works? Some sort of continuous buzzing noise?

Sat Nov 05, 2011 3:21 pm

Follow the steps in the wiki link I posted.

Sun Nov 06, 2011 4:28 am

ok i went to start my car today whilst at work and it started perfectly! I was able to drive it home without any problems, however after trying to start the car again whilst it was warm, it went back to its old habbits, dident start whatso ever. I left it for about half our and tried getting it running again, it stuttered, tried to start up but died. From what i've noticed it seems as if it starts, or atleasts makes an attempt at it when the engine is cold. Maybe its just coincidence but just seems a little weird.

Im starting to think pherhaps it isnt the fuel pump, i mean if i was able to drive it home, about a 5 minute journey then the fuel pump must be working, and its either gonna work perfectly or not work at all right?? If thats the case what else could it be? Something to do with the ignition maybe?

Sun Nov 06, 2011 4:42 am

if it only plays up when warm, then i would start thinking about the crank position sensor, although i'm afraid i don't know where it is located on the four pot cars, sorry.

Sun Nov 06, 2011 8:41 am

*bangs head*

This is why I spent all this time writing the Wiki page about this. If there's a hot start problem, you read about Hot Start problems:

http://www.e30zone.net/e30zonewiki/inde ... #Hot_Start

and that tells you the engine is probably running rich:

http://www.e30zone.net/e30zonewiki/inde ... ch_Running

which, since you probably won't read that either, tells you the problem is the Blue Temp Sensor:

http://www.e30zone.net/e30zonewiki/index.php/Blue_Plug

You could have had all your problems sorted yesterday morning if you'd just read this when I posted the first link.

Sun Nov 06, 2011 1:27 pm

Sorry for making you write that all out grrmachine but i have actualy read through the wiki link, however it dosent realy solve my issue, as for a start i dont have a multimeter to test for the blue plug. It also seems unlikely that it is running rich as it managed to pass its MOT a few weeks ago with perfect emmisions.

Sun Nov 06, 2011 4:12 pm

It was also working fine when it got it's MOT, and it's not now. Things can break any time.

Next time she won't start when hot, pull Fuse 11 out (fuel pump) and try and start her again. If she stumbles and tries to start, then the Blue Temp Sensor is definitely flooding the engine. It might not be the sensor itself, but the wiring to and from it, and the way to confirm that is to pull the plug off the sensor and bridge the wires with a 330-Ohm resistor.

Sun Nov 06, 2011 4:48 pm

Ok thaught i'd give then car a test, nothing, been left over night, cold as... something very cold, and it dident even stumble, just kept turning over. I was kind of expecting something to happen. Anyway all these issues kind of contradict each other, im totaly stumped now! Maybe i should stop being tight and fork out some cash for a mechanic...

I tried taking fuse 11 out last night and it made no difference to how it was trying to start.

Sun Nov 06, 2011 5:03 pm

If it is a 1990 316i then it has the M40 motor.
Reason I asked this is because on the M40 316i and 318i the fuel pump does not run as soon as the ignition is turned on. The ECU waits for pulses coming off the crank sensor....when you turn the motor over....and then energises two relays. One relay supplies power to the fuel pump and the other relay supplies power to the fuel injectors. You will see these two relays under the black plastic cover that runs along under the wipers in the engine bay. They do this so that in an accident if the motor stops running but the ignition is still ON then there is less fire risk.
The reason I mention this is that you must not be alarmed that you do not hear the fuel pump running when you turn the ignition on. The first relay that picks is for the injectors; one of the contacts on this relay actually supplies ground to the second (fuel pump) relay via the green/brown wire. You can ground this green/brown wire so that with ignition ON the pump will run but only do this for fault-finding.
You mainly need to observe (or measure) the two relays to see that they do energise when the motor is turned over. If not, then suspect a fuse or the Crank Sensor that supplies the pulses to the ECU. Check the Crank Sensor is clean...has the correct gap and the leads off the sensor are not shorting to ground or one of the rotating pulleys.
Why the problem is related to engine temperature I am not sure....you have seen the advise on how to check the Blue sensor.

Wed Nov 09, 2011 2:28 pm

okay so i got my self a multimeter, whacked the needle things into the relay terminal and pow, power going into the pump, nothing coming out the other side. I popped to my local car part dealer, got myself a new pump, rebuilt the assembly which was a bit of a bastad and voila! My car lives again, just in time to go go-karting! So im happy, and many man thanks to the people that contributed to this thread, wouldent of done it without u lot <3333