2003 R53. Will crank but will not start, does not have spark.
I have DME/EWS programmed to be bypassed, has worked fine for over a year. I have a electrical drain somewhere I have not found, will kill the car in 2-3 days. Normally I jump it off and its fine till I let it sit again. However I went to start it the other day and will not fire.

I have done some troubleshooting, and I am not getting power/signal to the 2 wires from the DME to the ignition coil. I saw on diagram one is for 2 cylinders and the other is for the other 2. I have tested the pins on ecu while cranking and nothing. The grounds are good, the 12v red wire to ignition coil is good, just these 2 wires no signal/power.

Could something before the ecu be stopping it, such as a bad bcm? (ive read check for water damage, im working on checking it now). Or is this a sign of bad DME? Engine cranks fine, no codes stored, just no spark.

 

If your CPS (crankshaft position sensor) is bad or wiring to CPS is bad then it most likely won't generate any spark, because ECU won't know when exactly to give a spark. You need an oscilloscope to see if there is a signal from CPS.
Bad camshaft position sensor also may prevent from giving the spark.

 

I replaced the crankshaft position sensor because had a spare one laying around and it didnt change anything, i do have rpm fluctuations when cranking but havent checked the wiring yet. If it gets nicer outside I will later thank you for suggestion! Also have unplugged the electric power steering motor because I believe that was my draw, im charging battery now so I can test that. Sometimes when I would turn the key on (not cranked) it would run fan and motor full speed. And sometimes wouldnt. So im pretty sure its bad regardless but at least i wont have to keep charging battery to test no start

 

Any updat on it now?

 

How is everything going now?

 

First I would find your parasitic drain issue. The DME controls ignition pulse (ground-side switched), and we all know computers get temperamental when they don't have the right amount of voltage.

To find your parasitic drain problem, connect an amp clamp around the positive or negative battery cable; make sure you zero out the meter. How much amperage is the bad circuit drawing? Next, start pulling fuses one-by-one until the meter drops current reading drops to zero. Fix the bad circuit.

Your ignition circuit is a "waste-spark" system. Meaning, if your firing order is 1, 3, 4, 2. Cylinders 1 & 4 are paired. Cylinder 1 will spark at TDC on the compression stroke, and cylinder 4 will spark on TDC of the exhaust stroke (waste spark). You have 12 volts; that's good. Now it appears you don't have coil control. Meaning, the DME will connect the ground to the circuit to control the primary winding in the coil. You are right, pin 1 on the coil is for 2 cylinders while pin 3 is for the other 2. If you don't have coil control, it's either the DME doesn't have the input signal it needs (cam/crank etc) or the DME driver is bad. Remember, you won't have a solid signal on pins 1 or 3; the signal will pulsate. If you don't have a lab scope, you can use a test light on pins 1 & 3, the light should pulsate while cranking the engine. If the light doesn't come on at all, you need to verify input signals to the DME. The RPM gauge is a good indication that the crank sensor is working. Some engines require cam and crank to get an ignition signal, some only require the crank. I'm not sure if it's both on the R50/53.

Paul Danner (Scannerdanner.com) has some excellent troubleshooting videos on YouTube for troubleshooting waste spark systems. It doesn't matter if it's a 4 or 6 cylinder; the theory of operation is the same.

This may help.

 

Pretty sure power steering pump was drain, I unhooked it under car and battery has lasted 2 weeks vs few hours lol. Sorry been snow storm here and I have not felt like braving cold to tinker with it, but clearing up. And thank you for the video and footage. Yeah I used test light method on wiring and then on ecu pins themselves, and nothing for those two coil wires. Def have rpm bouncing, and scan tool shows rpms when crankin so have crank signal. I am going to try and check cam sensor today, I have not touched/looked at it yet.

*Also i thought I had checked kickwell fuse box good, but I removed all connectors and pulled it out and do have very little corrision. Not a bunch, and honestly dont think enough to cause issue but im going to clean all contacts and connector sides and slide them on/off few times to make sure good there.

*rereupdate well fuse box was not that bad, but I checked the connector below it and it was way worse. I believe one of the pins is broken off, and rest not looking good. im going to see if i can find replacement connector, or worse case hardwire it