1986 325es no spark

[96Formula6spd]

So after fixing the wiring on the my buddies car we still have no spark. So here is a list of everything we have done.

1. Crank sensor wiring fixed. Only two wires one yellow and one black. New sensor install. For good measure we replaced both sensors.

2. Ohms on the sensors look good on both sensors.

3. Checked voltage at the coil. We have 12v.

4. Check Ohms on the coil and it looks good.

5. Checked the rotor and cap. Rotor was shot so replaced that. Cap was in decent shape so we left that.

6. Injectors are firing. Can smell fuel after turning car over.

7. Wires look good. Have not looked at plugs. Buddy says they are stuck in the head. Will try again tomorrow.

So right now we are kinda stumped. Previous owner said it just quit when going down the highway. Wiring for one of the crank sensors was junk. Yellow wire was broke so we figured that was the problem. Then we found the bad rotor button. So what should we check for now?

[jlevie]

A smell of fuel when cranking on this car doesn't necessarily mean that the injectors are firing. The fuel could be from the cold start valve.

The first check, given the car's history, would be to see if the timing belt broke.

[96Formula6spd]

A smell of fuel when cranking on this car doesn't necessarily mean that the injectors are firing. The fuel could be from the cold start valve.

The first check, given the car's history, would be to see if the timing belt broke.

Going to add and injector pulse check when cranking. Also timing belt is still tight and still in one piece. We have not checked to see if it has skipped but looks in decent shape.

[96Formula6spd]

Alright so we have some more stuff tested and changed along with some other issues.

We started with a injector pulse test. It does not sound like the injectors are firing. So we are looking into that.

Second we still have a no spark issue. We did find that the rotor button was blown out. So we replaced that with no change.

Next up I sent a spare main relay,coil,and fuel pump relay. All tested and working on my 87 325is. Each tested on its own and each ran the car.

Also we made sure that the main relay has power. Which it has 12 volts all the time at number 35. Coil also has power.

So next we are going to do the ecu testing. Anything special we should look for?

[Jaxx_]

lack of spark or fuel injector pulse usually means timing issue. inspect your work with the sensors, and ensure that they go all the way to the ECU pins.

[96Formula6spd]

lack of spark or fuel injector pulse usually means timing issue. inspect your work with the sensors, and ensure that they go all the way to the ECU pins.

Just inspected and both sensors are reading the right readings at the ecu. Right at 1000 ohms on both sensors. It is supposed to be 960+/- 96 so that fits the bill. Going to go threw every connection.

[jlevie]

Just inspected and both sensors are reading the right readings at the ecu. Right at 1000 ohms on both sensors. It is supposed to be 960+/- 96 so that fits the bill. Going to go threw every connection.

An ohms test will tell if a timing sensor is open or shorted, but not if it actually works. For that you have to look at the signal with an oscilloscope.

[96Formula6spd]

An ohms test will tell if a timing sensor is open or shorted, but not if it actually works. For that you have to look at the signal with an oscilloscope.

Alright we should do that. Will say that both sensors are brand new. Would doubt that both sensors are bad along with the one good one we pulled out of the car.

[96Formula6spd]

Well we found the problem. They flywheel was missing the pin for the crank sensor. It had rusted and flung off. The car was so rusty that we parted it out. Just posting this in case anybody had this problem.

Link to a picture

http://blog.bavauto.com/wp-content/uploads/2011/10/flywheel_manual_ref_pin_text.jpg