118i no compression after cold start

[bekkerhenk02]

Hi there all you fanatics.

I've got a e87 118i with a problem that puzzles the hell out of me and I hope someone can give me some advice.

A client brought his 118i in to me with a complaint that it sometimes does not want to start and that the engine was noisy. First off we checked the battery which checked out fine.

The car started fine though everytime he brought the car in. I had it stay over one night and saw what he meant the next day. The car turns over and fires up immediately. There is some chain noise but as soon as the oil pressure goes up the noise almost dissapears. Now the problem. At first start when cold, as soon as the revs pick up to more than 2200 - 2500rpm the engine stutters and dies. When immediately trying to restart the engine turns over with absolutely no compression. If you leave it for 2 min it starts up again like nothing was ever wrong with it.

The thing is this only happens with first start in the morning. If you start it and let it idle for 5min you can rev it up to the limiter without any problems.

Because of the chain noise we decided to change the chain, guides and tensioner. That solved the noise but the problem still persists.

My theory is that when the oil is cold (and thicker) the oil pressure goes to high and the hydraulic valve adjuster over-compress and causes the valves not to close completely. As soon as the engine dies the lifter are bleeded out again and in about 2 min the compression is fine again.

The car runs on Castrol Magnatec 5W30 oil which is supposed to be correct. We replaced the oil filter and oil and flushed the engine a few times with no luck.

I also see that the profiled gasket underneath the oil filter housing keeps leaking, even after replacing. (like the pressure there is also too much)

My question is now, have anyone else had a similar problem with a n46/n43 engine? What was your remedy?

My next step is to remove the oil pressure relieve valve and make sure it's not stuck but I would appreciate and info from all the techies out there.

Hope you had a great SONA2015 or Cirque de Afrique as some called it :tiptoe:and a wonderfull loadshedfull day.......

 

[Charlie Brown]

Hi have a look at my past threads, there should be one titled "is this plausible" watch the clip I posted in that thread.

 

[hoosain]

sounds like cam timing is out
the chain may have stretched causing it to jump a tooth or two

 

[Blue Shirt]

Have a look to see if the valvetronic motor is working OK. This is a common failure on the N46 engines and if cam timing is wonky, valves may not close properly and you will have no compression.

 

[francoishensen11]

What blue shirt said, willing to bet money on a vvt issue, either the unit,vvt ecu unit or the vvt needs re-learning,1st thing before you crank that engine unplug the vvt if there's no compression issue you know where the problem lies, had a similar problem on a n42 recently, turned out the vvt in my case was wonky, it would open the "3rd" cam fully when I swing which caused the low compression issue, unplugged the vvt and the compression was full on swing.

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[bekkerhenk02]

Hi guys, Sorry for the reply delay. Got the car sorted.

After speculating that the oil pressure might be the culprit I made a fitting to fit a mechanical oil pressure gauge to check what the oil pressure is doing when the problem shows up. To some relief I found that when cold the oil pressure was running at above 10 BAR!! That's way to high. When the oil heated up somewhat it dropped to just above 6 bar which is still way to high. This would explain the hydraulic valve adjusters to "overcompress" and cause the valves not to close completely. This would also explain why I could not get this engine not to leak oil!!!

First of the timing chain tensioner guide rail broke. It's made of plastic so over time it becomes brittle and starts to disintergrate. The same goes for the oil pickup. This is also plastic and the same as with the chain rails, becomes brittle and breaks up into small little pieces. This small pieces goes directly into and through the oil pump. The oil pump is 2 metal gears meshing into each other so the plastic pieces would just be crushed and pushed through so that would not really cause a problem. The problem though was caused by a small piece of plastic that was caught in the oil pressure relieve valve, which is part of the oil pump housing. This caused the relieve valve to jam in a closed position and not do it's job, relieving oil pressure!!!

Seeing that the small piston and the oil pump housing was damaged I decided to replace the oil pump. With a shock i found out that the only oil pump available for these engines is from BMW themselves at about R24000!!! I started phoning around and found a very good second hand one for R2500.

To replace the pump means that the engine has to be taken out completely to get the sump off. The engine balance shafts is also timed by the oil pump so you need the special timing tools to get everything in sync again. Replaced the timing chain, rails, tensioner, oil pump and oil pickup, did the timing and replaced the engine.

The car started immediately and revved up perfectly. The oil leaks also dissapeared.

Car has been running without problems for almost 5000km after this was done.

Hope this will help someone in the future........

 

[clyde95]

I had same syptoms on a 320i e90.found that someone had fitted oil pump relief valve incorrectly causing high oil pressure on start up.

---

big thanks Henk!:ty:

 

[DeutschwerX]

Hi guys,

I'm new here, I just joined up as I've had this problem for so long!

About 2 years ago my 2003 318Ci Convertible started making a noise, this was the timing chain guide disintegrating. I changed the chain and guides and all was well for quite some time. Around June this year, It began more difficult to start every day to the point that the car would only start if 'bumped'

I changed various things that put in the odd fault, cam position sensors, crank position sensor, I removed the oil filter housing one day to get to something and found there was a load of debris jamming up a little valve in there so cleaned all of that out but still it wouldn't start.

The symptoms being the same, crank from cold, run for a few seconds and cut out. When restarted, the no compression noise. I recently took the cam cover off it and locked it all up to check the timing and it had jumped! I re-timed everything, dropped the sump to give it a clean out and did the oil pickup also. Put it all back together and it started and ran but not very well, after it ticked over for 20 mins it appeared to be ok. I drove it to an MOT station and he passed it. Parked it up and the next morning it was exactly the same again!! No compression.

I dropped the sump today again as I found this post, undid the hex key plug in the oil pump and all I have is hole behind it, no piston or spring at all!?

Could this be the problem all along??

 

[fredlington89]

It sounds more like you're losing compression past your rings. Remove the plugs, pour in 5ml oil into each cylinder and it should start. Maybe the fuel injectors are washing the cylinders.

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[DeutschwerX]

Well the new part arrived from BMW today and from what I can see, when I undid the plug the spring and piston should have popped out but the piston part didn't move its stuck solid which l imagine is the problem judging by the symptoms and what I've found upon removing the plug!

 

[DeutschwerX]

Well here's what happened, I could not remove the piston/spring so I removed and stripped the oil pump, see pics for the result!

Intensively cleaned, rebuilt and put the car back together, started first time!

 

[The_surgeoN]

Hi guys, Sorry for the reply delay. Got the car sorted.

After speculating that the oil pressure might be the culprit I made a fitting to fit a mechanical oil pressure gauge to check what the oil pressure is doing when the problem shows up. To some relief I found that when cold the oil pressure was running at above 10 BAR!! That's way to high. When the oil heated up somewhat it dropped to just above 6 bar which is still way to high. This would explain the hydraulic valve adjusters to "overcompress" and cause the valves not to close completely. This would also explain why I could not get this engine not to leak oil!!!

First of the timing chain tensioner guide rail broke. It's made of plastic so over time it becomes brittle and starts to disintergrate. The same goes for the oil pickup. This is also plastic and the same as with the chain rails, becomes brittle and breaks up into small little pieces. This small pieces goes directly into and through the oil pump. The oil pump is 2 metal gears meshing into each other so the plastic pieces would just be crushed and pushed through so that would not really cause a problem. The problem though was caused by a small piece of plastic that was caught in the oil pressure relieve valve, which is part of the oil pump housing. This caused the relieve valve to jam in a closed position and not do it's job, relieving oil pressure!!!

Seeing that the small piston and the oil pump housing was damaged I decided to replace the oil pump. With a shock i found out that the only oil pump available for these engines is from BMW themselves at about R24000!!! I started phoning around and found a very good second hand one for R2500.

To replace the pump means that the engine has to be taken out completely to get the sump off. The engine balance shafts is also timed by the oil pump so you need the special timing tools to get everything in sync again. Replaced the timing chain, rails, tensioner, oil pump and oil pickup, did the timing and replaced the engine.

The car started immediately and revved up perfectly. The oil leaks also dissapeared.

Car has been running without problems for almost 5000km after this was done.

Hope this will help someone in the future........

I would like to know if the oil pressure relief valve was the problem, I am having the exact same problem with my 120i and it just happens to be that I replaced a broken timing chain rail about a year ago.