Sudden Engine Crank but No Start Issue

[Matt214]

Hoping to get some insight from our community on a sudden issue where my 2016 was running perfectly and then a couple days later, cranks and won't start. I know any number of things could potentially cause a symptom of crank but no start but let's start with the givens. Mechanically, the car has no known issues prior to this one. No codes/CELs being thrown previously. Vehicle is a 2016 with 108K miles on it.

I drove it just a few days ago and parked it when I got home like always. Got inside it yesterday so I could take it out to wash it and when I clicked the start button, it just cranks. All the accessories came on like normal and the cranking was healthy and quick so no battery issue. Just so odd that it would be running just fine and then come out to start it a couple days later and just cranks and cranks. I'll attach the codes it's throwing and also the gauge read out showing there is low pressure fuel and appears from cranking there is positive high pressure fuel as well.

Any ideas? Something apparently happened spontaneously, between the time I pulled back into my place, parked it and then went out to start it back up, a couple days later. It was purring like a kitten as they say, when I drove it last.

[n8dgr84]

My first thought was a crank angle sensor.
Good place to start.
Also check engine bay and wiring for rodent damage.

[Matt214]

Originally Posted by n8dgr84

My first thought was a crank angle sensor.
Good place to start.
Also check engine bay and wiring for rodent damage.

Thanks, yah with 108K miles, would make sense for a sensor to fail but after doing some digging is appears 'CAS' stands for 'Car Access System'. There are apparently a number of people on other forums for other bmw models, that came up when I was doing some searching about a 'hidden fuse' that's 15 amps that if it blows then it creates these codes and a no-start situation.

Definitely checking for any visible rodent damage too. I actually had a rat chew a wiring harness on my 335xi that I sold years ago. Was $1600 bucks and insurance actually paid that out. So I definitely know how possible that kind of thing is!

[b_w.]

follow the lines back to the ECU which is under the intake manifold to see if anything is damaged.

[Matt214]

UPDATE: I have replaced the red Positive Power Distribution Box (part #922775205) and no change. Cranks with no start. Hoping for some insight or other things that are likely culprits.

UPDATE #2: I have discovered f'ing rat damage. Thankfully it only appears to be two wires. They are the green and brown wires that actually connect to the top connector of the IVR (see pic - sorry it was hard to get a decent pic). I repaired the wires as I was able to strip the ends and do a good solder and re-wrap of the wires and got it plugged back in.

Now, the car will start but stutter and stumble. Pressing the throttle doesn't have much effect but if I depress the throttle 1/3 of the way and hold it was revving up but some but hesitantly. I was only attempting to let it rev gently to see if it would clear up but it doesn't. Now the JB4 keeps saying 'invalid read' when I try to read the codes so I'm guessing the original rat damage may have let to the IVR blowing one of its internal fuses? Sucks because those things are like 400 bucks if I'm not mistaken.

[Matt214]

UPDATE: Used a Dremel to neatly remove the top part of the plastic housing on the IVM and saw the array of fuses. I used my multimeter and checked the continuity across the fuses and all of them were intact (not burned out). I bonded the plastic top of the housing back together and reinstalled. Issue still exists.

I'm hearing that there is more to the IVM than just the fuses though. Does anyone have any knowledge? Or am I pioneering this problem? I did find where someone had posted a circuit diagram that shows the IVM and from what I see, there are some relays also included with the module. This post is here:
https://f80.bimmerpost.com/forums/sh...20&postcount=1

[n8dgr84]

This seems like a question for a BMW Engineer lol.
Good luck man!
Do you have ISTA?

[Matt214]

Originally Posted by n8dgr84

This seems like a question for a BMW Engineer lol.
Good luck man!
Do you have ISTA?

I just replaced the tank purge valve as a preventative and confirmation, since it wasn't terribly expensive and it was throwing that code. Still same bad idle and stall issue so just order the IVM. Just ordered a brand new genuine OEM IVM (Integrated Supply Module) for $320 so will see if that fixes the issue.

I'll fully open the old one to settle the question once and for all. I expect I'll find more hidden fuses and relays, when I do. After doing more searching, this damn box is apparently a known failure and plagues multiple models of BMWs.

[Matt214]

CONCLUSION: Thanks for those who took the time to try to help. I have replaced the IVM and the issue has fully resolved.