2006 bmw z4 - Crank No Start

D

dabuseck

Member
Hi everyone,

I recently picked up a salvage Z4 as a project car and have been working on fixing it up. So far, things have been going okay. I reached out to the previous mechanic who worked on it, and they mentioned it had a cracked oil pan, which I’ve since repaired. The oil pump appears to be in good condition, and oil is reaching the filter and engine.

However, I’m still facing a "crank but no start" issue. I tried replacing and diluting some of the old gas (the car sat in a lot for about four months), but it hasn’t resolved the problem. Do you think I should go ahead and fully siphon the remaining fuel and start fresh? After a couple attempts at starting it, there is some blueish gray smoke that comes out the exhaust.

I’m relatively new to car repairs, so I’m not sure if this is simply a fuel issue or something else. I’ve already confirmed that the fuel injectors are active during startup. Any advice would be greatly appreciated!

Videos of belt:
https://youtu.be/Xf-0foCP4ko

Video of inside crank shaft:
https://youtube.com/shorts/PTNJQ8HX-Zo

Thanks!
 
The accident was the oil pan having a GIANT gash in it. Amongst other various subframe supports, plastics covers, and bumper.
 
In further inspection, I found that the lower Crankcase house is broken. I did not believe that would affect the start up of the engine, but let me know!
 
If its been run (even briefly) with no oil in then it might be seized, or at least partially so.
 
I would start by removing spark plugs to check their condition. If car has been cranking then I would expect plugs to be wet and smelling of petrol, you will then need to check whether a spark is reaching each plug. This will help narrow down the issue. A new set of plugs would probably be a good idea.
 
Replaced the spark plugs! They were carbon fouled.

I can check the crankshaft sensor. How would I know if it is damaged?
 
dabuseck said:
Replaced the spark plugs! They were carbon fouled.

I can check the crankshaft sensor. How would I know if it is damaged?
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Tbh, I've thought on it again and it would give a code, so not that then. Sorry.
 
enuff_zed said:
dabuseck said:
Replaced the spark plugs! They were carbon fouled.

I can check the crankshaft sensor. How would I know if it is damaged?
Click to expand...
Tbh, I've thought on it again and it would give a code, so not that then. Sorry.
Click to expand...
I am using a cheapish Amazon OBD reader, and a Carly. Neither show any major codes. I have stuff about ambient air sensors and a few other minor things like windows, ac, etc.
 
Mike6 said:
But have you got a spark at the plugs.
Click to expand...
So because of the shorts cables to the coilpacks, I was not able to test each spark plug hole. But I was able to move each coilpack to the first spark plug and all packs lit the tester. Just ordered a longer cable.
 
Okay so tested all the cables, coils, and sparks. Each are at least lighting up the tester.

Sometimes the car will start cranking and then it will let out like a loud puff/sputter but then wont do it again for a few start attempts.
 
So, if you are getting a spark what about fuel. I think you can disconnect at the fuel rail and turn ignition key to see petrol pumping out. Could be fuel pump or filter related . I would have expected a strong smell of fuel anyway .
 
I pulled the fuel injectors rail off to see if the injectors were going. All of them sprayed in sequence.

Idk the exact order but it seemed 1/2 sprayed, then the other 1/2 sprayed. So it seems like I’m getting fuel. I did take the new plugs off too see if they had any new build up. They were clean but smelt of gas.
 
Okay, just tested compression. There is 0-20psi in each cylinder. I tested each cylinder with the fuel pump disconnected.

Once again, I just hand cranked the engine and the pistons are in fact moving. So possibly a blown head gasket?
 
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