Starting issue, with fuel and spark

[kaukula]

I have a 323i from 1985 (Jetronic) which have been standing still since beginning of 2015. When i tried to start it the other day it wouldn't start.

The engine turns over and there is fuel on the spark plugs, as well as spark when i hold a spark plug against ground.

I have tried the following:

• Good battery.
• New spark plugs.
• Fresh fuel.
• Cleaned the rotor contacts inside distributor cap.
• Compression is good on all cylinders.
• Fuel pump buzzes when ignition is switched on and fuel comes out of the fuelrail when removing the return line (when cranking).
• Checked and cleaned the air-slide valve.
• Checked the throttle position sensor.
• Measured resistance on the blue temp sensor (Was good).
• Measured resistance on the ignition coil. (Primary good, secondary about 500ohm under spec).
• Bridged the fuelpump relay, after bridging the relay i measured power to AFM, TPS, injectors and ECU. Note! these components only receive power when bridging relay or cranking engine, not when ignition is on.
• Verified connection from AFM, TPS and temp sensor to ECU.
• Measured power to the ignition control module.
• I have not found any cracked hoses or other air leaks.

I have not been able to test the following:

• Fuel pressure.
• Test spark with a spark tester.

When i removed the connector from the temp sensor the engine makes a few ignitions, but still won't start.

Any ideas?

[peterman]

Is it a weak spark at the plug or a nice hot blue one? Try changing the wires. If they are old and the car has been sitting for a year then the wires may be beat.

[kaukula]

Is it a weak spark at the plug or a nice hot blue one? Try changing the wires. If they are old and the car has been sitting for a year then the wires may be beat.

It looked to be a nice blue/white color, and when i put a screwdriver in the wire the spark jumped about 1cm (0.4 inches). Could measuring the resistance of the wires be a good indication of their condition?

[Seawolf]

Wet plugs indicate over fueling or no ignition spark, if you have a spark at the plugs then it should fire up under normal conditions.

It may be that the fuel pressure regulator has rotted and fuel is being fed into the intake manifold through the vacuum line. Disconnect the vacuum line and check for fuel coming out of it while cranking.

[kaukula]

Wet plugs indicate over fueling or no ignition spark, if you have a spark at the plugs then it should fire up under normal conditions.

It may be that the fuel pressure regulator has rotted and fuel is being fed into the intake manifold through the vacuum line. Disconnect the vacuum line and check for fuel coming out of it while cranking.

Thanks for the tip, i tried it and no fuel came out the vacuum line. I'm starting to believe it's a fuel related issue since it makes a few ignitions when i disconnect the temp sensor. I don't know if disconnecting it will lead to more or less fuel. I'm going to try and find a fuel pressure gauge, then i can at least eliminate any errors before the fuel rail.

[TobyB]

I know it's hard on the engine, but a shot of starting fluid helps verify
if you're getting decent sparks at the right time....

t

[bddog]

crank position sensor