X5 35d won't start after CBU cleaning

[Rsoxs19]

Hi everyone, I just I just got done walnut blasting the intake ports on my x5 (m57), put everything back together and now it won't start but only crank.

I made sure valves were closed when walnut blasting and used lots of air to clean everything out and inspected with a small camera to double check it all looked good.

I put everything back together, including the swirl flap deletes and egr delete I did at the same time. It will sit there and only crank. Every plug is plugged in (besides egr ones), I even took manifold off and put it back on to make sure with no luck. I plugged in the stock egr parts and let them rest on the engine but still nothing. I didn't disconnect any fuel line stuff besides the plugs so there shouldn't be air in the system.

No codes (besides emissions ones) right now but they were there before when the car ran just fine about a week ago. I sat in the car and let it start in bursts ≈15 seconds until the battery eventually died even on the charger. Anyone have any ideas? It doesn't make any sense to me. I appreciate the help.

[Rsoxs19]

Update - I finally got the car to start. I let the battery charge all night and tried to start it in the morning. It cranked over for about 5 seconds and it started. It ran rough for about 10 seconds then idled fine. I started it a few times throughout the day with no issues.

I still have no idea what the problem and it makes no sense to me but was just glad it finally started. For anyone having the same issue my advice would be to just keep trying to start it. It took me 2 days of charging, and cranking over for it to finally start. Just don't crank it over for too long at a time you don't want to burn out the starter.

[dang2407]

Could it have been air in the injector lines?

[RL18]

Originally Posted by dang2407

Could it have been air in the injector lines?

Most likely. You could run the fuel pump beforehand with something like the foxwell schwaben scanner and crack one of the injector lines to help bleed them quicker without trying to crank it a million times

[wcs531]

I see you're in Albany, was this in a heated garage or just outside/unheated garage?

Just thinking out loud but if the car was extremely cold could be either (or both) of the following:
1. Diesel could have been gelled depending on temp and the quality of the diesel?
2. Could glow plugs be nearing the end of their life? I feel like you would get a fault though.

Also I can imagine a low battery would exacerbate any glow plug issues.


On another note, did you follow any DIYs? I am thinking about doing carbon cleaning at some point. Soaking the manifold seems fairly straightforward, but cleaning the ports in the head seems rough.

[Rsoxs19]

Originally Posted by RL18

Most likely. You could run the fuel pump beforehand with something like the foxwell schwaben scanner and crack one of the injector lines to help bleed them quicker without trying to crank it a million times

The fuel system was not touched. Not really sure how air could have gotten in.

[Rsoxs19]

Originally Posted by wcs531

I see you're in Albany, was this in a heated garage or just outside/unheated garage?

Just thinking out loud but if the car was extremely cold could be either (or both) of the following:
1. Diesel could have been gelled depending on temp and the quality of the diesel?
2. Could glow plugs be nearing the end of their life? I feel like you would get a fault though.

Also I can imagine a low battery would exacerbate any glow plug issues.


On another note, did you follow any DIYs? I am thinking about doing carbon cleaning at some point. Soaking the manifold seems fairly straightforward, but cleaning the ports in the head seems rough.

Yeah it was not in a heated garage and was very cold out. I'm sure that was also working against me. At the time I was also wondering if the diesel could have been gelled or if the glow plugs weren't working right. No codes for the glow plugs though. Tried using a blow dryer to warm up the fuel rail (it was a last ditch effort) which didn't help unsurprisingly.

I followed this thread- https://www.e90post.com/forums/showthread.php?t=1058497

There could have been more info on how to actually perform the walnut blasting but overall was a good resource. I do want to point out a few things though.

1. I think technically you should take the valve cover off as to not eat away the plastic on the valve cover for the swirl ports. I just went quickly and made sure to stick the wand far enough down and everything went fine. I used a pick with the valves closed to scrape as much off the ports as I could before walnut blasting.

2. I found the carbon in the intake manifold basically turned to cement and was very hard to get off. I soaked it for a few hours but it wouldn't budge. It didn't help that since it's so cold out in NY (December) I couldn't pressure wash it. I ended up taking plastic bristle brushes and cleaned out each port as it was soaked. Then took a pick and scraped as much off as the pick would reach. It certainly wasn't perfect but much better than before.

3. Make sure to not get any shells in the engine at all. Air out every port to make sure it is spotless. Move the wand around and confirm its all cleaned out with a small borescope before moving onto the next cylinder.

I walnut blasted my N54 and it started right up after, so the X5 not starting threw me off. Ultimately I think a completely charged battery really helped. Now it starts up great no issues no matter how cold it is out. Threw some liqui moly diesel purge in and it has been running perfect.