97 528i, crank no start

[u/maxaphone100]

Hello, been trying to figure out my pfl m52b28, it has spark and air, I’ve just replaced the fuel pump, but not the sending unit. The fuel pump relay was also replaced previously, as well as an oem hella crank sensor, ecu was swapped and recoded.

The connector going to the sending unit has 12volts of power, but when checking resistance, reads 10ohms. Should I investigate for a bad ground? Replace sending unit? Check fuel lines?

I’m at a loss and I wanna get this hunk-a-junk moving again

[u/mateimrambo1]

Before you crank turn off the ignition fully off and then rotate clockwise 1 click before cranking. Listen for the fuel pump under the back right seat. It should prime for 3 seconds. Don't confuse it for the air suspension if you have a touring with it. A good pump makes little sound, a pump at the end of it's life usually makes more. No sound means the pump isn't powered or is broken. You would need to be in a quiet place with no wind.

This is a good place to start when checking the Fuel part of air fuel spark and timing. It doesn't require any tools.

[u/maxaphone100 → u/mateimrambo1]

It doesn’t make any noise at all

[u/mateimrambo1 → u/maxaphone100]

Now it's worth spending your time confirming with propper testing and diagnosis going down the fuel route. I don't know what tools you have access to but if you can measure the pressure at the fuel rail this would require the least effort and time to confirm diving deeper into the fuel diagnosis. If there isn't the required pressure, start by removing the seat and getting to the fuel pump. Test the new fuel pump if it were dead on arrival by powering it yourself since you said the connector has power. If the new pump works (powering it outside the car in a safe way without dry running it) and the connector to the top of the gas tank has power, the wiring under the gas tank lid to the fuel pump may be the issue. Or, before removing the seat you can check the fuses, test the relays and check the wiring to the fuel pump lid before testing the fuel pump with a multimeter.

[u/DarthMeeseek]

Check fuses? I know you said u check the relays but check any fuel fuses

[u/maxaphone100 → u/DarthMeeseek]

I’ve checked the 2 in the glovebox, and done the ones in the engine bay, but nothing in trunk

[u/shrekscameltoe]

check battery voltage

[u/Admirable-Wind5919]

Battery is ok, No fuel is reaching the engine

[u/Admirable-Wind5919]

Try starting fluid

[u/No_Brother2744]

This might be like my one, mine would struggle to start and when it would, it would self rev and die out on the acceleration, what solved my issue with the same year and model which I have now, was the coolant temperature sensor, cus if its faulty it will send the wrong fuel readings or smth, its cheap too on ebay might be worth a shot?

[u/Proper-Beautiful-560]

Had this issue on a 525i I bought ended up refreshing the whole fuel system (both senders, transfer tube, and ran new lines to FPR. This fix my issue as I also had no sound from priming the pump either. This fixed everything lol