Turns over, no spark...what the!?

[FrictionTape]

My "new to me" '87 325is turns over, but I don't seem to be getting a spark. Any insights into possible causes?

[RobDog]

Possible causes are:
1)bad crank shaft position sensor
2)bad main relay
3)broken/ bad rotor
4)bad coil or coil wire
5)OBC relay disabled ignition
6)pin#1 of the ECU wire is broken between the ECU and coil
7)bad ECU

[TobyB]

8) broken timing belt- pop the oil cap and see if the cam turns while you crank.

t

[FrictionTape]

Thanks! Fuel pump seems to be the culprit.

[e30onBBSs]

Thanks! Fuel pump seems to be the culprit.

How did you conclude it is the fuel pump?

[FrictionTape]

[QUOTE=e30onBBSs;4695446]How did you conclude it is the fuel pump?[/QUOTE

I disconnected the fuel line off the motor, not fuel came out when the ignition was turned on. Faulty logic?

[hyperE30]

[QUOTE=FrictionTape;4696471]

How did you conclude it is the fuel pump?[/QUOTE

I disconnected the fuel line off the motor, not fuel came out when the ignition was turned on. Faulty logic?

Did you get spark? f you have no spark and no fuel then check the main relay, crank sensor.

[Cayoncrusier93]

[QUOTE=FrictionTape;4696471]

How did you conclude it is the fuel pump?[/QUOTE

I disconnected the fuel line off the motor, not fuel came out when the ignition was turned on. Faulty logic?

From my understanding the fuel pump only turns on when the motor is cranking NOT when the key is turned to the ON position.

[Yungbimmer]

When your main relay or crank position sensor go out the engine wont recieve spark or fuel. The ecu only sends a signal to your fuel pump once it recognizes that the engine is spinning.

[FrictionTape]

When your main relay or crank position sensor go out the engine wont recieve spark or fuel. The ecu only sends a signal to your fuel pump once it recognizes that the engine is spinning.

Awesome.....I'll check that out. As an aside, there was no spark, but the rotor in the distributor cap does spin.

[e30onBBSs]

Make sure you have gas as well. As dumb as that sounds it happens. Sometimes the transfer from one side of the tank to the other won't happen (siphon jet or something) and the tank will read half, but the pump side has 0. So just because it's dry doesn't mean you necessarily need a new fuel pump.

After you verify you have gas, and still no spark, run the diag for the CPS in the Bentley. Also give this a read. It will help you understand the system and has some diagnoses pointers. http://www.e30zone.net/e30zonewiki/index.php/Ignition

Also, which hose did you disconnect? Top or bottom? Top is the feed line, bottom is the return.

A really easy way to check for fuel is to jump the fuel relay from pin 30 to 87. Verify those pins to the Bentley manual but I'm pretty sure that's them. This will force the fuel pump to run. Before you jump the pins, disconnect the fuel line that goes to the FPR (top line). Put this line into a bottle, then jump the pump. I would take the rear seat out to see/hear/feel the pump if it's doing anything. And this is how you would check for gas anyways, by opening the cover of the passenger side, removing the pump, and looking into the tank to confirm you have gas.

[FrictionTape]

Make sure you have gas as well. As dumb as that sounds it happens. Sometimes the transfer from one side of the tank to the other won't happen (siphon jet or something) and the tank will read half, but the pump side has 0. So just because it's dry doesn't mean you necessarily need a new fuel pump.

After you verify you have gas, and still no spark, run the diag for the CPS in the Bentley. Also give this a read. It will help you understand the system and has some diagnoses pointers. http://www.e30zone.net/e30zonewiki/index.php/Ignition

Also, which hose did you disconnect? Top or bottom? Top is the feed line, bottom is the return.

A really easy way to check for fuel is to jump the fuel relay from pin 30 to 87. Verify those pins to the Bentley manual but I'm pretty sure that's them. This will force the fuel pump to run. Before you jump the pins, disconnect the fuel line that goes to the FPR (top line). Put this line into a bottle, then jump the pump. I would take the rear seat out to see/hear/feel the pump if it's doing anything. And this is how you would check for gas anyways, by opening the cover of the passenger side, removing the pump, and looking into the tank to confirm you have gas.

I'll check this out as well...thanks!

This car sat for over 6 years and the previous owner must have planned on it sitting as it has a completely full tank of fuel. Now whether or not stabilizer was put in is anyone's guess. As for the gas line, we removed the upper hose.