Re: lack of power/flatspots 2005 330i

[Andy70]

I posted a thread up on here quite a while ago regarding a lack of power in my car, but further to a much needed deep engine carbon clean which made all the difference I noticed as the power seemed to be more restored I noticed flat spots in the engine. As I described before I noticed it was most obvious at about 1200 revs in 3rd gear where its doesn't accelerate much then by 1700 revs suddenly pick up, I also noticed it doesn't always seem to pull at lower mid ranges, but does sometimes, its weird and difficult to describe. Now a couple of suggestions on here were the Vanos solenoids or Disa valves i done research regarding the solenoids and I thought that it seemed feasible enough but some sources suggest that you get rough idling when they are buggered, however mine ticks over perfect. so I eventually found the time to take them out and give them a clean and had a look around them and they seemed ok to me (part of my issue is I wouldn't know a duff one from a good one, same with the Disa Valves), Its also worth reminding you that there are no error codes at all. so whats my next step, do I have to just replace these potential parts and hope it cures it or would a trip to a BMW specialist more likely find the problem? its also worth pointing out that at around the same time as having my engine cleaned I had my throttle body ported by 4mm, so another suggestion I had was that it was confusing the map and a re map would sort it, so therefore would it be better to take it to a tuning specialist to sort it?

[essayer]

Steptronic?

[Andy70]

pardon? lol I assume you mean auto or something? but no its a manual

[essayer]

Andy70 said:

pardon? lol I assume you mean auto or something? but no its a manual

Yeah, auto. Just wondering, as I had similar symptoms on mine, and it was down to gearbox issues. But not for you, luckily!

[Andy70]

jolly good then, thanks for your input any way, I just don't just want to keep buying stuff on 'possibilities' even though all previous responses seemed reasonable enough. I found solenoids on ebay for £37 quid for a pair, but are they going to be crap? but I suppose as long as they worked for a while if that solved the problem then I could always get better ones later, I'm stumped really

[Elliot2000]

I mentioned it previously - n52 has valvetronic, (not to be confused with the vanos), it changes the amount the valves open rather than using the throttle butterfly to control the revs. They used to have a problem where they would be slow to move from low down in the Rev range. This gave it a real lack of power when first trying to accelerate and then would pickup straight after.

A fix would be to replace the valve tronic motor which needs the rocker cover removing to access it.

This would be my guess from what you have said

[Andy70]

Ah right I'll look into that one too then. Thanks

[stevesingo]

Elliot2000 said:

I mentioned it previously - n52 has valvetronic, (not to be confused with the vanos), it changes the amount the valves open rather than using the throttle butterfly to control the revs. They used to have a problem where they would be slow to move from low down in the Rev range. This gave it a real lack of power when first trying to accelerate and then would pickup straight after.

A fix would be to replace the valve tronic motor which needs the rocker cover removing to access it.

This would be my guess from what you have said

The N52 has Valvetronic AND VANOS.

There have been issues with failing eccentric shaft sensors caused by oil in the connector. http://www.e90post.com/forums/showthread.php?t=697...

VANOS solenoids are common problems as is the check valve/filters in the head.

DISA valves are easy to check, well maybe the small valve is tricky to get to.

If you search and download INPA and get a lead, you can check a lot of Valvetronic and VANOS functions.

[Sardonicus]

If you search and download INPA and get a lead, you can check a lot of Valvetronic and VANOS functions.

[/quote] This ^ you can then compare commanded values Vs realtime/actual values then you can gauge from this info , example ...

[Elliot2000]

stevesingo said:

The N52 has Valvetronic AND VANOS..

Yes, he knows- hence he has already tried checking the vanos solenoids! I was just making sure he didn’t confuse the two things with each other

[Andy70]

I wonder if I can swap the vanos solenoids around as they appear to be the same? Unlikely they are both duff. It's looking like I may have to start changing stuff and hope it fixes it as all your suggestions seem reasonable, it's where do I draw the line with it and just leave it which would irritate me

[stevesingo]

You can swap them from intake to exhaust as they are identical. This is useful if you are getting a fault code on one side and not the other. Good for confirmation.

Removing and leaning them with carb cleaner or suchlike goes someway to reduce symptoms.

There is also a pair of check valves in the head. These can get dirty and reduce oil flow to the VANOS, causing issues. http://www.e90post.com/forums/showthread.php?t=109...

www.bimmergeeks.net has a good link to a working BMW diagnostic tools download. You can get a lead for £20-30 and you have full diagnostic capability.

[Andy70]

stevesingo said:

You can swap them from intake to exhaust as they are identical. This is useful if you are getting a fault code on one side and not the other. Good for confirmation.

Removing and leaning them with carb cleaner or suchlike goes someway to reduce symptoms.

There is also a pair of check valves in the head. These can get dirty and reduce oil flow to the VANOS, causing issues. http://www.e90post.com/forums/showthread.php?t=109...

www.bimmergeeks.net has a good link to a working BMW diagnostic tools download. You can get a lead for £20-30 and you have full diagnostic capability.

I cleaned them with a solvent cleaner I grabbed from work, but I think I got some carb cleaner kicking around so might give them a go again then swap around, not sure if diagnostic kit will help as there are no fault codes flashing up at all as I've had the system checked already

[Sardonicus]

Andy70 said:

stevesingo said:

You can swap them from intake to exhaust as they are identical. This is useful if you are getting a fault code on one side and not the other. Good for confirmation.

Removing and leaning them with carb cleaner or suchlike goes someway to reduce symptoms.

There is also a pair of check valves in the head. These can get dirty and reduce oil flow to the VANOS, causing issues. http://www.e90post.com/forums/showthread.php?t=109...

www.bimmergeeks.net has a good link to a working BMW diagnostic tools download. You can get a lead for £20-30 and you have full diagnostic capability.

I cleaned them with a solvent cleaner I grabbed from work, but I think I got some carb cleaner kicking around so might give them a go again then swap around, not sure if diagnostic kit will help as there are no fault codes flashing up at all as I've had the system checked already

Some Vanos irregularity's dont always throw DTC's hence why I mentioned checking real-time data

[Andy70]

Sardonicus said:

Some Vanos irregularity's dont always throw DTC's hence why I mentioned checking real-time data

Ah right I didn't realise that was a different test, i'll try and look at that but im not that technically minded when it comes to that sort of thing, but i'll at least try

[Andy70]

I just had a peek at a youtube clip regarding the cleaning of the solenoids just to see if they seemed in a similar condition to mine and I noticed that there was a rubber washer on the solenoid which I didn't have on mine, but it did seem to be a snug fit, so not sure whatI'ms going on there, the one I viewed was a 328 not 330, but assume they still should be the same, the washers were half way down the solenoid, the confusing thing to me is im pretty sure I wouldn't be able to slip the solenoid back in if there were a rubber washer/seal on it, it was a tight enough squeeze as it was, unless the washer has come off and in the housing somewhere instead? but everything seemed to slip out and back in nicely. but this is the issue I have, I'm not a mechanic and don't know what certain things should look like in a good serviceable state

[Andy70]

Interesting, after searching on ebay there are solenoid repair kits which contain 4 O rings and 2 plastic rings, I saw the plastic rings on mine but no O rings, now some pictures I saw the large O ring was positioned half way down the solenoid and other pictures it seemed to be fitted in front of the plastic ring, now it could be the case that the large O ring is in the entrance of the housing somehow is it did feel like it was squeezing past something rubber I suppose, not sure where the small ones are located though, surely they wouldn't have come off and knocking around the engine would they? or are they set internally in the solenoid somewhere? Anyone shed any light on this please? cheers

[Elliot2000]

Why don’t you disconnect the valvetronic sensor and run it to see what it’s like- it will be a bit down on power but there will not be the initial flat spot that you mentioned if the valve tronic is at fault. If the fault is still there, then you have at least ruled it out.

The solenoids can come with or without the seals depending on the revision number and or the engine, so not having any on yours is not a sign that they are missing

[Andy70]

Elliot2000 said:

Why don’t you disconnect the valvetronic sensor and run it to see what it’s like- it will be a bit down on power but there will not be the initial flat spot that you mentioned if the valve tronic is at fault. If the fault is still there, then you have at least ruled it out.

The solenoids can come with or without the seals depending on the revision number and or the engine, so not having any on yours is not a sign that they are missing

yeah the solenoids seem to squeeze in so I assume the ) ring is in the entrance of the housing maybe? One does seem to go in easier than the other, although the easier one doesn't seem loose, i'll see if I can replace them. with regards the valvetronic sensor, I assume its a plug somewhere? I'll definitely have a look at that at least to eliminate it as you say, thanks for that

[Elliot2000]

If you remove the engine cover- on the top of the cam cover near to the front of the engine is a circular plug connection( further forward than cylinder 1 coil) - unplug that.

It will throw an engine light but you ca. Clear it by deleting the fault memory after you reconnect it