BMW E30 325i Diagnosis M20 NO START - Bluepty: The Boosted Beater Video 3 

Great video with a ton of accurate nuanced information. Key highlights that are worth repeating: 1. Confirming check engine light in accessory mode is critical as it shows that the DME has power; with main relay being first place to check. 2. There are default maps on the DME that the car will use in the case of an unplugged sensor. Instead of shotguning parts, just simply unplug and test. 3. Unlike modern cars, the fuel pump only runs while cranking. 4. The primary relays are segregated for a reason in the engine bay; they are critical to the operation of the car, and if original, changing them makes a ton of sense. A couple suggestions and more nuanced detail: A. One area missed in the video is the importance of a good engine to body ground. B. Pre 1988 M20's had a dual fuel pump system, and no detachable fuel injector harness. Main pump is in front of the drivers side rear wheel. C. A suggestion for a future video would be to show how the car runs with each sensor unplugged. I can't confirm off the top, but I believe the car will start and idle with the AFM unplugged as well. In the video it made it sound as though that was one sensor you absolutely needed plugged in for a no start. Keep up the great videos!

24:00-33:00 is pretty quiet... First half had great info!

Hi thanks for the video. I’m not getting my car to crank at all. The previous owner ran a wire from the fuel pump fuse to somewhere else I guess to bypass the 7.5a fuse. The car was starting a few months ago. But the fuel pump stopped working. I swapped in a new and better fuel pump which I think burned out. When I touch the wires harness for the fuel pump(under back seat) it was extremely hot. The next problem is that the car is not cranking. My friend said that the starter is not working. But he put power directly to the starter and it came on but did not engage to crank the engine. Right now I have a new alternator to install, I’ve installed a new main relay and new fuel pump relay (I don't think that was the problem at all). The dme is on because the check engine light is on and ICV is humming.

Having an issue with an 1989 325i starter and igniton. Someone added a push button start to the car completely separate to the car but runs off the battery with a 25amp fuse in the wire from the battery, So i removed the push botton start wire from the starter and connected up the blk/ylw signal wire to the starter but of course it does not crank at all. I believe its the ignition switch or a relay. and thats why the wired up push button start to bypass it.

I think the crank position sensor typical resistance is around 500 ohms.

Great video! Lots of information here. Do you have any suggestions for a no crank situation? I have 90 325i automatic. It stranded me at a parking lot. Changed the starter, ignition switch, ignition relay, neutral safety switch and the DME relay. Still no crank. Stuck at this point. Thanks!

Would the CPS prevent the fuel regulator from switching on the fuel pump but still allow the car to produce spark? 1988 325i. Runs on ether…. Won’t fire the fuel pump or injectors… even when I jump the fuel pump relay…

Hey Jake. Figured out my no spark issue. It turned out to be the OBC relay box/immobilizer that fried. Now I have spark, fuel, compression, and the engine is in time, but after reassembling the engine, still wont start. CPS is tested and working, spark plugs are replaced, and still fire, and come out wet after cranking. Fuel pressure is also good. What on earth could this be?

Hello, thank you for your content! I will be very grateful if you can help me. Im trying bring back to live my E34 M20B25 1988 more than a year (i dont have too much time). One day I backed out of the garden and when I ran over a little hump, the car died, I thought fuel pump, but jumping relay showed its ok. Then CPS, via ohm test it was ok but I bought new OEM one, didnt help. Then i recognized there are no sparks and ICV dont hum/buzz. Some troubleshooting diagrams went me to faulty DME, I was checking cables grounds, multiple times.. so I bought an used one, but its probably bad too. Then magic happened. With my oem DME ICV starter buzzing, but weirdly like when cable is broken and you are movin with him. Then it stabilised and buzz continuously and engine starts. BUT !!! I hear buzzing from dme too, then its stops and engine dies. I did some gently taps to the dme and start buzzing and engine runs.. I thought its broken cable somewhere near the connector, I tested the powers and the green one, grounds.. everything OK. With the used one DME this doesnt happen. Im really sorry for my english, but do you have an opinion where I can found the bad thing? Does your DME buzz too? Can send video. Im away from now for test if the engine lights is blinking whet this happens. Thank you

Hi Jake. I have power down to coil. Crank, no spark. The power doesn't pulse. CPS works. Wires to ECU from CPS are OK. Cps is giving me 2v A/C but no engine speed seen by the DME. Should I check the earth from the coil to the DME?

Hi, I've watched your whole video and I have a question. My car is a e34 m20b20 from 1988, that was running properly and all in a sudden, started to stop by itself, two or three times at idle, then stopped a last time and do not want to start again. I have: good fuel pump (I deduct good crank position sensor). No fuel in cylinder Spark plugs are not working as well. Could it be a bad ecu? How could I test it before trying to find a replacement? Thanks, and again thank you for the clear and useful video.

I’m getting power to the fuel pump relay and fuse 11, but not to the fuel pump. At this point do you recommend chasing down the wire to the pump?

my m20 will start and die immediatly when cold, but fine when warm any ideas? new coolant sensor didnt fix. i have to hold the throttle on cold starts

My fuel pump runs but I have no spark coil has .6 ohms on pos & neg secondary has 5.92k Ohms but I’ve got no spark when coil is in car

I got to the end of this video and it still just cranks without starting :'(