Rough Idle P025B code

[Irishman85]

New Bimmer owner and new to the forums thanks in advanced for any help...I'll try to make this as short as possible.

Just bought a 2010 328xi 110,000 miles

Noticed a slight hesitation. During low end acceleration. Did some reading and learned VANOS was common.

Today i replaced both Solenoids (URO brand). Started didn't seem to have any issues.

Decided to clean MAF as a prevention.

Installed everything. Started car and it bounces between 600-900 rpm, shoots up to 1500. Falls to 600 and idles ok. Check engine light came on.

Low end power is weak on the road. Noticeable power loss but no sputtering or otherwise rough running.

Checked working connections, and vacuum lines that I could see. only thing found was the air intake tube down stream of the MAF was loose but still connected. Tighten clamp. Same issue.

Car running- sprayed MAF clearer around air intake etc.... no change in idle

Took MAF back out inspected filament and looked for damage... nothing visible.

Restarted same problem.

MAF unplugged, same problem

Took it to auto zone in town. Its throwing a P052B code. Cleared code. Started with same problem. drove home with same loss of low end power, never threw a code check engine stayed off.

Got back home turned car off restarted, same problem, check engine light came on.

Took out and cleaned crank shift position sensors. Still acting up..

Not sure where to go from here.... Any help would be greatly appreciated.

Keith

[Irishman85]

https://youtube.com/shorts/DbCvWL1X22g?feature=share

[bmwdirtracer]

Welcome to the forum.

Let's start with the fact that P-codes are a really bad way to diagnose a BMW; they are notoriously inaccurate generic emissions codes. You need to be reading BMW diagnostic codes with a BMW specific computer, not visiting Autozoo for diagnosis.

Secondly, Your thread is titled "P025b code", and the text says P052b; if the first is accurate, and also correctly represents the actual BMW code, it indicates a problem with the voltage supply to the fuel pump module. If the second is accurate to the BMW code, it indicates a problem with the intake VANOS. Since you just installed URO brand garbage, it might well be those, or maybe you plugged one in incorrectly? I'd recommend cleaning, and reinstalling the two original solenoids, making sure you have both the o-ring and the support ring in place one each. Never use URO part for crucial items like sensors or solenoids, especially. Buy OEM quality parts from a reliable supplier like FCP Euro, or genuine parts from the dealer.

The symptoms do not, however, match the code. I'd guess that you might have a significant intake leak. I'd recommend taking the car to a good BMW tech for a scan, diagnosis, and smoke test of the intake system.

[Irishman85]

Im sorry, it is the p052b. I swapped the new and old around multiple times and the problem persisted. From what I read on multiple sites it sounded like URO was a viable option. Guess i was mistaken.

What im not understanding is why after solenoid replacement and start up it ran fine. It wasnt until after cleaning the MAF that the issue came up... would a bad MAF trip the P052b code?

And thank you for your reply!

[Irishman85]

I was under the impression from multiple sites URO was a decent brand. guess i was mistaken. I am confident the plugs are correct.

I dont understand why the issues wasn't there after start up from changing the solenoids but came up only after cleaning the MAF. Could a bad MAF cause that code?

And it is the p052b. sorry

[bmwdirtracer]

Cleaning a MAF really isn't useful, unless you have oiled aftermarket air filters which contaminated it. When you cleaned the MAF, is there any chance that you accidentally ripped a rubber boot, or pulled too hard on a connection, causing an intake leak?

You should know that for many codes, the computer waits for the second start to illuminate the CEL.

Also, since we don't really know what the BMW code actually says, the VANOS issue might not be caused by the solenoid at all; it could be a cam sensor, or inadequate oil supply, cam gear bolts coming loose...or ??

If you're good with a computer, and own a laptop, you can set yourself up with INPA or even ISTA, very cheaply. Then you'll be able to communicate with, and read actual BMW codes from, every computer in your car. There's a "Diagnostic Software" forum, just below this Mechanical forum, on the list.

[Irishman85]

I took the air box and all connecting hoses all the way out inspected, reinstalled and confirmed everything was tight.I checked all the pins and connectors looking for damage and found nothing missing or broken.

It would just seem odd to me that the problem wasnt there until I cleaned the MAF. it seems like it would be one heck of a coincidence for a cam sensor or the like to suddenly act up at the exact moment I cleaned the MAF...

This is my plan im going to put the both old solenoids back in in the morning. If that doesnt fix it, throw in a new MAF. after that... look into software like you said. Does that seem like a viable approach to you?

[bmwdirtracer]

I would absolutely not recommend buying a new MAF, without some confirmation that it's bad. Any good scan tool can read MAF live data, to see whether it's working correctly. Even a code for a MAF doesn't mean the MAF is bad...and you don't even have such a code.

A quality MAF for your car is expensive: $175. (VDO is the OEM manufacturer)
https://www.fcpeuro.com/products/bmw...nsor-5wk97508z

After swapping solenoids, you're still going to need to read the codes, to see if you have any mixture codes. If you have a MAF CIRCUIT code, there's a good chance that you hurt the MAF, the wiring, or the plug.

As tempting as it is to throw parts at the problem, always remember that first you need to diagnose the issue, so you know what parts to throw.

I hope you will find the answer; we will be here to help.

[Irishman85]

ok, thank you for the information. I will put the old solenoids back in and see where that gets me. When I went to autozone (I know i know) the guy hooked up a regular scanner which came back with no codes. He had his personal scanner (looked like a tablet) that he let me hook up and thats where I got the code from. If i recall correctly i remember seeing an option for live data. If that in fact will work What exactly am I looking for for proper functionality?

Also, thanks for the info on the INPA program. I'll be ordering a cable tonight but would really like to get this figured out before having to wait for it to get here. Gotta get to work!

[Irishman85]

Replaced the new vanos solenoids with the old. Problem still persists. Rechecked connectors and lines. Not seeing anything amiss.

[Irishman85]

Well. at this point its going to head to the shop. I want to thank you Mr. Powell for your assistance. I really do appreciate your expertise. I'll post what I find out here when I know. I hope its something small and stupid Im missing instead of a major repair!

Thanks again!

[bmwdirtracer]

Live data for the MAF should show a fairly low number of gm/sec or kg/hr at idle, and this number should increase steadily as you add throttle and revs increase.

[Irishman85]

****Update*****

This is probably going to be pretty lengthy so I apologize in advanced.

I took it to and indy shop near by. They replaced the MAF and replaced a cracked valve cover. When I got the car back its seemed to be better. it would be a little dody on the idle when it first started but not nearly as bad as it was.

A few days later while driving, the hesitation came back and the CEL came back on with the same codes as before. I decided to get it to a dealership even though its over an hour away.

While there they recommended replacing the spark plugs (really bad) and coils. That was done. They said the car was running as it should and that the n52 was know to be temperamental on cold starts. They recommended some fuel system cleaner so i bought some techron and put that in.

So even though it wasnt doing this even a little when i bought it i decided ok, they know what they are doing and i'll trust them..

After a few days I got in my car after a 5 min warm up and the CEL was on again...

I ordered a cable and bought Bimmergeeks protools as its crazy to drive an hour to the dealership to just get a code read. And that brings be to where I am now.-------------------------


The hesitation at low RPMs has NOT came back since it was at the dealership and the gas mileage has increased substantially.

The first code from protools it threw was a 29E1 system too lean (bank 2). Since I had just put in the techron fuel cleaner I thought maybe it dislodged something or effected it in some way. I cleared the code.

Drove for about 2 days and after warming up the car the CEL came back on. Same code but also added a bank 1 too lean code.

These are what I grabbed from the live data off protools not sure if any of it will help...

[Irishman85]

more.

[Irishman85]

and more

[Irishman85]

and thats all i grabbed so far..

[bmwdirtracer]

I still think you have an intake leak. And I still think you need a smoke test of the intake system. Inspecting things just doesn't do it. For instance, there's a brittle plastic hose at the very back of the valve cover which is very prone to breaking....especially if someone messes with it, changing the valvecover. The only way to find out if you have an intake / crankcase vent system leak is to get a professional smoke test with a smoke machine. Or, for probably the same price, you could buy an inexpensive smoke machine off Ebay, and do the test yourself. Smoke machine's used to be ~$1000, but you can now buy cheap Chinese ones for ~$130.

https://www.ebay.com/itm/18512146714...0AAOSw5n5iUP4q

[Irishman85]

I will look into that! Thank you!

[New Bimmer N20]

I still think you have an intake leak. And I still think you need a smoke test of the intake system. Inspecting things just doesn't do it. For instance, there's a brittle plastic hose at the very back of the valve cover which is very prone to breaking....especially if someone messes with it, changing the valvecover. The only way to find out if you have an intake / crankcase vent system leak is to get a professional smoke test with a smoke machine. Or, for probably the same price, you could buy an inexpensive smoke machine off Ebay, and do the test yourself. Smoke machine's used to be ~$1000, but you can now buy cheap Chinese ones for ~$130.

https://www.ebay.com/itm/18512146714...0AAOSw5n5iUP4q

Chris, Let me ask you this. You probably seen P054B BMW code 131401 Variable camshaft timing control (VANOS), intake, cold start: not controllable and
P052B BMW code 131501 Variable camshaft timing control (VANOS), intake, cold start: not controllable. I know I need to get BMW software. Have these on a 2013 328i N20.
Car has 147,000 on it. Long story short, about a year ago my son bought this from a kid. Then he had it shipped out to Cali where he go stationed. Well when he came back home for Christmas
he said that he has to buy a new car that he needed something reliable because the bimmer is dead. What do you mean, you can't drive it doesn't run right. So I asked him
what's he going to do with it and gave me a price and I bought it. So had it shipped back to NC. I will say that I couldn't believe the garbage he left in the car. But apparently
he kept up with the oil changes. And damn some how he broke the seat back. Damn thing is lying on the back seat. So I tried starting it, runs like it's got a misfire, like a poofing
sound. Had to describe. When it runs and you put it in gear it dies. So that's when I checked for codes and list them in the beginning. So I went through looking at wires,
clamps, connectors and only had to tighten the clamps on the charge pipe. So been trying to search on these two codes. I did say what the hell and changed out the 2 cam
position sensors but of course that didn't do anything. So I was reading and seen where the timing chain might need replacing or the vanso central valve might need to be
clean or replaced. So I started looking at that central valve and decide to take out the clip ring and remove the inners of the valve. Went and cleaned them up and stuck them back in.
Went to start the car and that thing started right up was running really good until it just slowly died. Now when you start it it just cranks. Did recheck to see if i
forgot to connect something and didn't see anything. But lucky for me the 2 codes are still stored lol. So I ask should I just bite the bullet and change the timing chain?
Don't know if it's ever been done or should I be checking something else.

[bmwdirtracer]

So I ask should I just bite the bullet and change the timing chain?

No. Hell no.

I'm not sure what "vanos central valve" refers to, or why you thought you should disassemble it, or indeed, whether such work should require retiming the engine.

What I do know is that the N20 isn't BMW's finest effort. Yes, it eats timing chains. And as soon as you get an indication that the timing chain may be an issue, you take it to a shop with ISTA, (BMW's diag system), and the timing tool set for the N20.

A 150K mile N20 that has timing codes (some of which might have been erased prior to your seeing it), ran like poop, had its vanos disassembled and reassembled by someone unfamiliar with the engine and not following a manual, and now won't run at all....

...if you want to bite a bullet, think big.

It would be a crying shame to do a job which lists as 14 hours (by a pro, with experience and every tool, including some very special ones), buying all the parts and tools (crank bolt requires a 3/4" drive tool, 600+ Nm), only to find out all the valves are bent.

I think there's a good chance you need an engine, not a timing chain. Being a pro makes me quite negative about certain engines. I'm not sure I've even seen an N20 with more than 150k miles.

I looked at Kelley Blue Book; Private Party value of your car, in Good condition, runs from $5K-$8K.

[New Bimmer N20]

- - - Updated - - -

Well it won't let me post a picture of the value in the diagram.

- - - Updated - - -

https://www.bmwpartsdeal.com/parts/b...367583820.html

[bmwdirtracer]

Okay; let's try assuming the best instead of the worst....although the "poofing sound" is worrying.

Try swapping the actuators from the exhaust and the intake (part 7 in the diagram you linked). Then clear the codes, and see if the engine will start. IF it starts, let it run ~30 seconds, then shut it off and start it again for 30 seconds, see if you get new codes.

If the impulse wheel moved when you unbolted the "center valve", the DME now believes the engine is out of time; and maybe it is. And maybe a timing chain set will fix it, or not.

[New Bimmer N20]

I'm not doubting you or anything. Basically it's a project car. Though I just need it running long enough to get it out of the street and into the driveway since there are no tags on it. And I have a steep driveway. Though I could probably get some of the neighborhood kids to help put it up the driveway lol. Well I didn't actually unbolt that center valve. Just removed the c clip and pulled the valve out first. But let me switch the actuators and see what it does. Thanks.