95 530i Engine will crank, but not start

[R1daveg]

Replace the EGO's. It may not be the ultimate cause for not starting, but its not helping either. Engine will run much smoother and get much better economy too.

[eelley]

Probably crank position sensor.

I resistance tested the crank position sensor and the resistance read within specification of the Bentley Repair Manual. Could it be faulty and still be within electrical spec?

Eric

[eelley]

Replace the EGO's. It may not be the ultimate cause for not starting, but its not helping either. Engine will run much smoother and get much better economy too.

I agree. I ordered the parts yesterday.

[632 Regal]

why???

Replace the EGO's. It may not be the ultimate cause for not starting, but its not helping either. Engine will run much smoother and get much better economy too.

the o2 sensors dont work when starting the car so this advice is absolutely incorrect!

[eelley]

Found the thread! Thanks

Well, rebooting the computer did not solve it. Darn. Just in case...I will perform the reboot again. Hoping that this would point to the DME itself.

Here are the things I have already checked:

Voltage at fuel pump during starting...OK (Assuming fuel and DME relays are fine)
All resistance checks on the coils measure within spec...OK
Resistance check on the crank position sensor within specs, (but on the low side) ..OK?
Tried to disconnect the fuel line at the rail, did not manage to remove it. The darn hose was on the fitting so tight and there is not that much slack on it. I did not want to risk of destroying it. I was going to disconnect at the fuel filters but decided to reinstall the DME. Thats when I tried to restart the car and it worked. So I figured problem solved......nope.

Now that the car is back at my apartment, I need to get it towed to a gargage to check to see if fuel is being pumped up to the fuel rail...again.

GGrrrrrrrr!

Eric

[eelley]

why??? the o2 sensors dont work when starting the car so this advice is absolutely incorrect!

The idle is rough when it does start. And another person at the parts counter of my local BMW dealer said that with a rough idle, and a check engine sensor throwing a code, the second O2 sensor is bad.

Separate problem, I figured.

[632 Regal]

let us know

[eelley]

let us know

Okay... Rebooted the computer one more time. Car does not start. However I have retested and now I see that I am not getting any power to the fuel pump relay. (swear I was before)

The DME/ECM relay is fine and engauges (which sends battery voltage to one side of the fuel pump relay coil when the ingition key is turned. The other side of the coil is connected to the DME module (pin1) which supplies the negative to turn the relay on.

This is not happening.

Has anyone seen this before?

[632 Regal]

bump for Javiar

[Javier]

it may not be energized if the engine is not running, no matter you are trying to start it. Best way to test fuel system is to bypass the pump relay, you will have a permanent pumping condition as long as the pump is OK. You can even hear the hissing of the fuel going trough the fuel pressure regulator. I would put the jumper there and try starting with the jumper in. If the car starts OK with the jumper, but not with the relay, then either your relay is wrong or your DME driving transistor responsible of energizing the relay is damaged.

To jump the relay you have to wire a jumper from the relay socket hole corresponding to pin 30 to the hole corresponding to pin 87. Careful not to miss it, as you can damage DME if connect 30 to 85. You can also wire jump some power to fuse F23 from a known good 12 Volts (Vbatt) source.

Guess you have already checked your CPS. No CPS means no spark and no fuel pump.

Javier