05 525i No spark after fuel pump repl., idle control valve hums all the time

[Sbanker123]

I did a head gasket job on this 05 525i which had been sitting for at least a year. It started after I finished head job but ran rough as the fuel was old so I drained it. Pulled the fuel pump, filter and drained the tank. Upon completion, the car would no longer start and I have verified there is power to the coils, coils ohmed out okay, and I have 180 psi in all cylinders and I even pulled the injectors and did a bench clean just to verify they were opening. There is no spark at the plug when I grounded it to the engine and I even ran a separate ground in case it had a bad ground. The idle control valve also now hums continuously and does not stop indicating that something is not resetting.

I disconnected the battery when I did the fuel draining and pump removal and wonder if it has something to do with the Intelligent Battery Sensor (IBS). I unplugged the small wire going from the positive terminal to the negative terminal and it has not done anything to create spark or stop the idle control valve hum. The battery in the car is a spare (from my volvo) that I had that seems to have plenty of cranking power and holds a charge.

I have searched a lot and verified a lot of things but have had no success in getting it to fire those plugs and could use some input from those that may have some ideas.

Thanks in advance.

[Sbanker123]

Also, maybe unrelated. I have an error on the dash panel saying that there is a problem with the passenger side restraint.

[Sbanker123]

This thing isn't gonna fix itself. No ideas from anyone?

Also, the idle control valve does shut off after a bit now.

[Oleh007]

Have you checked if the car had any codes? Double check the relays, I remember reading that a crankshaft position sensor will not give you spark on another forum.

[jtbgonesailing]

A bad crank position sensor will give you a long crank before starting.

[Oleh007]

Thank you jtbgonesailing for correcting me, I appreciate it!! So maybe it is not that sensor, but still good to check the codes if anything is popping up in the system.

[Sbanker123]

Thanks for the responses. I will re-scan it tonight but I did get a P1511 (no DTC definition found) at one point in time. That may have been when I was checking connectors or had removed the DTC to get to the ICV that was humming. I'll stick all things together tonight and try again to see if that code is still there or if I get any others and update teh thread.

I checked the CPS and compared it to a cam position sensor and found the cam position sensor was much more responsive to putting metal in front of it. With nothing engaging the CPS, it would sit steady at 4.9 volts or so. When a metal tool was placed in front of the sensor, it would drop to ~0.22 volts but never zero and was not doing it consistently. Is this indicative of a bad CPS? The cam position sensor was much more repeatable and responsive. I plan to get another CPS and try that.

[Sbanker123]

Don’t you hate it when you see a post with the same issue you have but no resolution? Me too. Turns out I was able to correct the issue and get it fired up by disconnecting the battery, hooking the cables together with zip ties for several hours which supposedly discharges diodes or something like that and resets the modules. Fired right up. I had no diagnostic tools other than a basic code reader. In restrospect I should have gotten a BMW diagnostic tool sooner and used that to help find the issue. Thanks for the help!