BMW VANOS Test

1995 BMW 525i E34 VANOS Test.
Find/locate and disconnect the VANOS solenoid connector. It is below the intake manifold, near the base of the oil filter housing.
This part is important: On the SOLENOID side connector, you will have 2 male pins. Use "gator clip" jumper wires to apply a GND to (-) and 12V to (+) pins while the engine is running. Don't let the clips touch or you will melt the wires and possibly have a bad day.
The connector is marked (+) and (-) so apply voltage accordingly. If the VANOS is working properly, the solenoid will open, oil pressure will flow into the VANOS cylinder unit, causing it to actuate the helical mechanism that advances the camshaft timing. If all of this goes well - the VANOS solenoid and VANOS unit are working properly - the engine will begin to idle poorly, as shown in the video. This is because the intake cam is opening the valves later during the intake stroke than it should be.
Explanation why: Below ~3,500 RPM, engines make more power when the camshaft opens the intake valves a little sooner during the intake stroke. It also makes the engine idle smoother too. When the engine is spinning ~3,500 RPM or higher, it makes more power when the camshaft opens the intake valves a little later during the intake stroke. It has to do with intake and cylinder head design, velocities and dynamics, etc. that I could explain but are WAY beyond the scope of this simple test video.
I made this video in response to someone in the forums suggesting that the VANOS in my engine was failing. I made this video to prove to them it was in fact working properly. I had no idea how many people were going to view this video! I have updated this description to convey a little more information about what I'm doing here.

[@SuperWP7]

I followed your post from the forums to this video. Did you ever fix the problem with loss of power when hot and AC on?

[@jsdsong313]

Hello, I use M50B20 Non-Vanos version. I want to increase torque in the low revs, but can accept to reduce power at high revs. So I thought that if I change the intake cam. The original specification was like this. Intake: 240º (9.7mm); open: 24º, close: 36º Exhaust: 228º (8.8mm); open: 38º, close: 10º If I replace the intake cam with the exhaust cam (In order to reduce the cam angle and lift), so that intake and exhaust cams are alike. What will the results be?

[@jachs7279]

Got it... thanks

[@bavarian3450]

Your comment is true, M50tu and M52 had only on/off solenoid valve positions (later were continously var.). Btw simple but good test, like a true oldskool mech. I had one question tho, i'm heaving the same whistle at idle as you (i searched and turns out it's the alt). Have you looked into this?

[@Adam-yl3gi]

No, I haven't looked into that. I do hear the whining from the alternator you're describing. I don't really hear it when the hood is closed though, the insulation on the hood probably helps a lot with this. Pretty much every car I've owned, the alternator makes a little whine at idle. I don't know if it is a problem or not, but the alternator is still working fine today. Now that I think about it, I ended up putting a new battery in it shortly after making this video because the old one would only stay charged for about 3 days then go dead if the car wasn't driven. I did parasitic drain tests and couldn't find anything abnormal which would discharge the battery so quickly. With the new battery the car can sit for 2-3 weeks at a time and still crank right up. Perhaps the old battery had an internal short, causing the alternator to work harder, I'm not sure. I'll have to look into it some more.

[@bavarian3450]

Adam Vickers didnt expect to still get an answer. You are partially right. It is true that a good working alternator is whistling a little bit, but 99% it's a refurbished alternator. The three phases induced in the windings are not properly aligned, like with oem alternators, so you can actually hear the electrical feedback, in the order of 1000Hz. Mine does the same, and i've come to live with it, since it works fine.

[@samnixon6198]

Correct - on the original single-vanos engines (M50tu), solenoid is an on/off proposition.

[@DeveroyB]

For mechanical minded people this video will be self explanatory but I think for others this test needs explanation. It's just to add a live and a earth to the vanos solenoid to engage and disengage

[@Adam-yl3gi]

Exactly! I had no idea so many people would view this video!

[@DeveroyB]

You sure did help a lot of people I did something similar on my channel but with the solenoid out of the engine and using a computer power supply.

[@bonisyafialdi2286]

Can we make idle sound like racing camshaft?

[@samnixon6198]

Very curious to know what you are doing with the brake booster vacuum line? :-)

[@Adam-yl3gi]

If I recall correctly, there was a small piece that snapped off from the side of the elbow, causing a vacuum leak. I just wrapped a piece of duct tape around it to seal it up.

[@toto883]

I have a rattle on my engine but I’m not sure if it’s timing chain tensioner, guides or maybe the vanos.

[@yovanatanasov4075]

I have rattle on my m54 too. One of my friends told me that he has the same rattle and it is from the vanos. I hear it a little bit closer to the oil cap, over the vanos inlet. Can someone help what to do?

[@scotty8131]

so if the idle is gong down , the vanos is good ?

[@Adam-yl3gi]

With the engine idling, if the VANOS is actuated with voltage AND it is working correctly, the idle will speed will change (which is exactly what you are seeing in this video: a properly functioning VANOS). The timing at idle is supposed to be slightly retarded (the intake valves open at, or a little later, than TDC of any given cylinder), allowing the engine to run more efficiently and smoothly with less vibration. When the camshaft is advanced at idle, the idle speed changes and vibrations increase because the camshaft is opening the intake valve too soon for optimal combustion to take place, causing the engine to "buck" as the computer tries to compensate for the change by altering the fuel delivery timing. It does the best it can, but the engine runs rough no matter what the computer tries, because the camshaft is allowing air to enter the combustion chamber too soon. At higher RPM's the timing can be advanced by the VANOS which results in more power output. The reasons why this happens is beyond the scope of my explanation here, you can search for KZbin videos to explain the details of why. Suffice to say that at higher RPM's, the motor is able to run more efficiently with the timing advanced (opening the valves sooner) and since it is more efficient at higher RPM's with the timing advanced, it can make more power. Hence the purpose of VANOS and all variations of camshaft timing adjustment systems (VTECH, VVTLI, etc.) on modern motors: to provide a wider power band throughout the rpm range.

[@chucklechuckle7127]

Adam Vickers so what should timing say at idle with a working vanos because I'm idling at 10° advanced at operating temperature ?

[@I.Odnamra]

chuckle chuckle another way to tell if your VANOS is working is to turn the AC on while driving. If your car bogs between gear changes then it's the VANOS. Probably one of the easiest ways to test your VANOS IMO

[@willk3807]

Who fucking knows...dipshit didn't explain himself

[@mikemillslv]

without disconnecting my solenoid my s50 engine makes the same noise your engine makes after you connected the voltage to the unplugged solenoid. does this mean i have a bad vanos solenoid?

[@Adam-yl3gi]

I doubt it. The Vanos has a spring that returns it to its "home" position. In the home position, the Vanos is disengaged. In other words, the engine should idle smoothly if there is something wrong with the Vanos seals. There are several things that can cause the engine to idle rough. Sticky injector, bad spark plug, bad ignition coil, oil soaked ignition coil boot, etc. With the engine idling, unplug the electrical connector to one ignition coil at a time and observe how the engine runs. You should notice a difference in the idle when you unplug each coil. If you unplug one and there is no change in the idle, you have isolated the problem to one cylinder. Hope that helps.

[@Joshua_N-A]

Is it possible to tweak the factory ECU?

[@redlineperformancebalkan]

Yes.

[@mikefoster4306]

Hi I did this to my car and the idle drops and the engine stumbles but to the point the engine will stall. I cannot keep the positive terminal on for longer than say 5 seconds otherwise it will stall. So is this good or bad

[@1pizzadox632]

I have the same question?

[@paulloper8333]

Then it's a good vanos, if nothing happens then it's a bad vanos.

[@fernandoyas3642]

@@paulloper8333 Mi M52 tambien se detiene cuando hago esta prueba

[@matscarlsen]

I tried this, and it did start to run rough. But when i pulled the vanos, my seals was worn out. After replacement, tha car has alot more power.

[@StuartOliver83]

Good or bad?

[@Adam-yl3gi]

+Stuart oliver This is a good VANOS.

[@FX-fk8yt]

How do you know the valve opens fully ? Could I observe by this test any symptoms of oil leakage through old sealants? I have double vanos, and sometimes I feel single jerks while accelerating (1-2gear 2-3krpm). Another odd issue, I feel a bit less power when accelerating constantly than accelerating with short breaks: Let say I accelerate on 2nd gear in range 1,5-3,5krpm, the acceleration is quite even, but when I hold on by 2krpm (const. speed for few seconds) and then carry on accelerating the power is visible better. Is it first symptom of sealant issue or sticking/failed solenoids ?

[@Adam-yl3gi]

FX The valve is a simple solenoid, it is either open or closed. When it is open, it allows pressure to flow to the VANOS unit. I assume you are asking if there is a way to test the seals in the VANOS unit, to see if they are leaking or holding pressure? To the best of my knowledge, I don't know of an easy way to do this. If you suspect the seals are leaking, you'll need to remove the VANOS unit to inspect the seals. I suggest you eliminate all other possibilities before pulling the VANOS unit out because this is a chore. Try disconnecting one or both solenoids and observe the engine performance while driving. The ECU will likely throw a check engine light, but you could observe if your surging and inconsistent power issue goes away or not.

[@cihangirasi]

Vanos dont work...

[@ThePharmacist-qg9hz]

Why? The revs go down you can hear it.

[@mikhailkoshkin8790]

А по русски кто-нибудь может написать?

[@shoora813]

Да :-) А что тут не ясного? VANOS, как я понимаю, влияет на фазу клапанов в двигателе. А электромагнит влияет на VANOS. Если бросить провод от обмотки на +12 то при работающей катушке ты услышишь изменение в работе движка. Если катушка сгорела, то нет :)

[@sennamski]

ванос работает потомучто при подаче напряжения на клапан двигатель колбасит

[@Adam-yl3gi]

Прошу прощения за то, что не объяснил это. Русский не мой родной язык. Другие ответы верны, когда напряжение подается на соленоид Vanos, масло поступает в блок Vanos, а затем фазовый угол распределительного вала увеличивается с помощью винтового механизма. Это приводит к плохой работе двигателя на холостом ходу. Если ванос работает правильно, вот что произойдет.