Bogging power issue M54 3.0i

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 10:00 am

Hi guys, got an issue on my 3.0i m54 E85 in that around 3.5k rpm the power seems to dip and rev lags then picks up again, power in 1st seems low but otherwise no noises, idling well and generally running fine. I have changed the Vanos seals around 4k miles ago and sorted the disa valve with upgraded flaps. I have also changed the coil packs and spark plugs. I originally thought it could be the vanos or solenoids as I have not cleaned the solenoids but at the time had no issues so was changing the vanos seals as a preventative maintenance job, any ideas what it could be, don’t want to start stripping components and going over stuff I have done previously if anyone has a better ideas, camshaft sensor maybe?

Thanks

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 10:29 am

Have you checked for codes?
Look for air leaks, especially the inlet elbow top pipe.

I had a problem with one vanos overhaul I did, where the shuttle valves that the solenoids open and close were sticking slightly in their bores, due to years of 'varnish' build up. I took the valves out and gave them a light rub with fine wet'n'dry. I found this by finding a code that said 'cam adjustment sticking' then seeing on live data on my Autophix that the cam angles weren't changing.

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 10:36 am

Hi, yeah I was going to mention no fault codes at all but when I did the rebuild I didn’t do the anti rattle or bearings, just did the seals and didn’t really check the functioning of the seats. Was thinking to just buy a full rebuild kit and a second hand vanos and rebuild then replace a complete unit. I replaced all the air intake hoses to the vanos so definitely not an air leak as I know they get brittle after a while. Just didn’t want to spend on a new kit and secondhand unit if it could possibly be something else but does sound like it could be poorly functioning vanos

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 11:31 am

No air pipes on the vanos?
I meant check the pipe that goes into the throttle body

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 11:55 am

Sorry was thinking of the oil return pipes, just checked the air inlet manifold hoses and all fine, think it worth another refurb on the vanos and solenoids?

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 12:26 pm

Wookster78 wrote: ↑Sun Feb 11, 2024 11:55 am Sorry was thinking of the oil return pipes, just checked the air inlet manifold hoses and all fine, think it worth another refurb on the vanos and solenoids?

Thats a lot of expense and unless you can hear it rattling I doubt very much that the extra bits will make the difference.
I would definitely try cleaning out those shuttle valves first.
Also try to get some live data to see if the cam angles do change when you rev the engine.

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 12:31 pm

Ok, not sure I can get the solenoid valves off though without removing the vanos, top one looks ok but not sure I can get to the bottom one. Will Carly or BimmerCode give me live data?

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 12:50 pm

Wookster78 wrote: ↑Sun Feb 11, 2024 12:31 pm Ok, not sure I can get the solenoid valves off though without removing the vanos, top one looks ok but not sure I can get to the bottom one. Will Carly or BimmerCode give me live data?

I'm not sure, never used them. Autophix did it for me.

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 1:08 pm

Ok, will see if it has the features. What’s the best way to clean the solenoids and get the shuttle out as the early ones look like it’s all inside the body unlike the later solenoids on the N52 engine?

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 1:17 pm

The solenoid unscrews, then the valve just sits inside the housing. You can draw it out with a magnet if needed. There is a spring at the far end of it, so don't lose that.
Of course gravity will be more your enemy than your friend for the lower one.

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 1:19 pm

Ok cool will give that a go, getting the lower one with the vanos in place will definitely be the issue, cheers

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 1:24 pm

We shouldn't get too blinkered on this yet though.
Camshaft position sensors?
Even remotely possible it's a MAF problem.

Have you tried resetting the vanos adaptations to see it that makes a difference?
Or disconnecting the MAF so it runs on the DME's default map?

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 1:28 pm

Nope not tried that yet, took the MAF off though and looked really clean but could be faulty, where are the camshaft sensors, do I need to take off the rocker cover to access them? Assume if they are cheap and easily accessed could replace anyway

Wookster78 · Post by **Wookster78** » Sun Feb 11, 2024 1:48 pm

Top one came off easy enough but can’t seem to get the little pin out even with a magnet, any other tips, seems pretty stuck and gunky in there ?

enuff_zed · Post by **enuff_zed** » Sun Feb 11, 2024 1:51 pm

Wookster78 wrote: ↑Sun Feb 11, 2024 1:48 pm Top one came off easy enough but can’t seem to get the little pin out even with a magnet, any other tips, seems pretty stuck and gunky in there ?

Try a little squirt of plusgas or wd40, then push it in against the spring. Nothing much to get hold of I know, but a twist can help too.
Should be free to move so it sounds like we've found one issue at least.

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