E46 Fanatics Forum banner

Still Suffering from hesitation/bucking even after VANOS seals? Look Inside!

224K views 411 replies 128 participants last post by  Cibby600 
#1 · (Edited by Moderator)
My car has suffered from a slight hesitation when taking off and under load, and also when suddenly accelerating under load at low rpm's up until 3k in 1st through 2nd even well after 3k miles on the beisansystems.com seals.

So I went in and looked at the MAF, cleaned it and also inside the connector I crimped down the pins inside so it would grab the receiving end pins better--that helped but the hesitation was still there.

Just 3 days ago I decided to clean and evenly crimped (using a pick) down the pins inside the connector for the exhaust VANOS solenoid; I took it for a spin and lo and behold the hesitation was pretty much gone! A few days went by and the more I drove the car the more low end torque it developed and it revved up smoother and smoother.

Yesterday, I did the same thing to the intake VANOS solenoid connector. Took it for a spin and the car felt as if the DME was relearning it's VANOS adaptations all over again! (felt sluggish at the beginning and started feeling stronger about 3 to 6 minutes later) 30 miles later the car feels great! and there is absolutely no hesitation under any circumstances!

The hesitation was caused due to shoddy and loose contact between the solenoid and it's receiving end [VANOS solenoid contacts]-- In other words

I believe that the issue is this..........

The contact width are set to the high side of the spec. The signal that is traveling across these contacts is quite weak. In other words, the current draw is very small. The device of interest, is not receiving the full signal strength from the PCM. Hence the sluggish performance of the VANOS. The best analogy that I can think of: Measuring the resistance of a conductor with a DMM. You will obtain one value when gently touching the conductor with the leads and a different reading when you press hard.
The pins inside both pigtails were spread open for some reason unknown to me.

The new found torque and instantaneous throttle response caught me off guard yesterday during a on and off drizzle when I punched it at 2750rpm in 2nd gear-- The rear end of the car kicked out to the side as if it had an LSD! (yes, I always drive with traction control off--at least when I can remember to turn it off.)



This is my MAF connector but the same concept applies to the VANOS connectors since they are the same in design.

You basically wedge a pick at the top and bottom of the filaments inside closing them together. Not all the way obviously but enough so that when it is plugged in it will open slighly and grab/bite the pins on the receiving end.

I've already done it to the image above. I don't have a before picture but the filaments were spread open and did not form a perfect rectangle as they do now.

Now after you have done so; Now when you are about to connect the pigtail you can feel some resistance ( which indicates the pins have a much better contact with the solenoid pins ) whereas before they simply just slid in like butter; Almost as if they were sliding into a void.

This trick would also work for MAF, DISA, IAT, Alternator pigtails, and all pigtails with the same design throughout the car.

Here's what Rajaie--Owner of besiansystems.com--had to say.

Congrats on the find and repair!
Thanks for sharing this important info!

I have not heard of this before. It seems reasonable it could be a problem.
There have been owners that complained of a hesitation that the vanos seals didn't resolve.

Some owners replace the vanos seals and receive little or no benefit. I know if they have another performance related problem they won't receive the benefits of the new seals until the problem is resolved. But in some cases it seems they have no performance problem. I've always wondered in these cases what is going on. Maybe what you found is a relevant cause.
Spray cleaning connectors with electrical contact cleaner is a good idea. But I had not considered crimping the pins.

Did your pins seem excessively open?
Which reminds me I need to detail my engine bay...

Lets try to keep this thread strictly on the topic at hand

For those who don't bother with searching [and newbs]...

For a in-depth VANOS walk-through

http://www.beisansystems.com/procedures/vanos_procedure.htm

To purchase

http://www.beisansystems.com/products.html

E46 besiansystems.com support thread

http://forum.e46fanatics.com/showthread.php?t=524336
 
See less See more
1
#358 · (Edited)
If you can I'd get a smoke test done. If that comes back good then you May be looking at a bad DISA based on your SES lights you had. Which is why I'm curious if you've resolved them yet

Make sure your DISA gasket is seated correctly and also perform the quick DISA test by moving the flapper and plugging the hole on the box. If the flapper only moves a tiny bit you're probably good. If it moves more than that then you may need a DISA
 
#360 ·
ICV not CCV just to make sure we're not misunderstanding each other. You can do a "ghetto" smoke test at home. Do you smoke? Either way grab a cheapo cigar (creates more smoke), and blow it into your intake hoses making sure you don't let any out. It'll take a lot and it won't work as well as a machine but hey. You can also make your own smoke machine or purchase one from the member here on the forum. Its a useful diagnostic tool that you could even charge people to use later on to help pay for it
 
#363 ·
I think the official way to test the fuel pump is:
Connect a pressure gauge to the port on the fuel rail (you need to remove the cabin filter housing and the intake manifold top plastic cover).
There is a small metal screw cap and underneath is the test port which is like a bicycle tire valve. You need a pressure gauge with the screw fitting that is the same size as the port such as this: http://www.ebay.com.au/itm/261068447283?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Connect it up and then turn the engine on, make sure you are not leaking fuel from the gauge.
It should read 45psi (+/- 10%)
Let it run abit and keep watch. It should run DEAD steady at the same psi. If it is fluctuating its busted.
Then turn the car off but keep watching the pressure, it should only go down a little bit after 5-10mins. If it drops pressure fast then the pump is leaking backwards and its busted.

^That's what it says in the Bentley manual, personally I did that and everything was fine BUT then I did the test again and this time I got my brother to blip the throttle a bit as I watched the pressure gauge and the pressure went down and then back up. So I bought a new pump and it fixed my idle and hesitation issues.

As for testing ICV, remove it and clean it out. Check that the valve inside moves freely. The first few degrees of the throttle does not move the throttle plate its self, it send a message to the icv, so if your car is running smoothly when you just slightly press the accelerator than the ICV is working.

I cleaned my ICV, cleaned MAF, new intake boots, valve cover gasket, throttle body gasket, disa gasket, new plugs, all based on forum advice. In the end it was just the fuel pump and all the other stuff was a waste of time/money. I hope you find your problem too.
 
#365 · (Edited)
Very interesting thread. I was skeptical for sure but after doing this procedure I have become a believer. My 2001 xi wagon has had an issue with bouncing idle and an occational stall for at least a year. I also was experiencing bucking and hesitation off idle in first gear. These symtoms were very random and seemed to manifest themselves in humid weather and when I use lights fans and other electronics requiring a power draw.I never had a CEL ever. I never suspected connectors to be the issue, but i suspected low or slow electrical signals in my system somewhere. After several hundred miles I can attest the hesitation off idle is nearly gone completely and car is much easier to drive and shift from takeoff. The bouncing idle is still there however but settles to a smooth idle much faster. Only an occational dip below 500rpm. I may have another issue which is causing this, but hey this is real progress! I plan on an ecu reflash which according to a TSB will address this issue.
For the record I have not replaced any components other than the Disa valve and normal maintenance items plugs filters etc. In retrospect my issues began to develop 2 yrs ago after I replaced alternator, battery, fuel pump, and fuel regulator. Maybe fiddling with those connectors cause the issue?? They are very fragile..
I tweeked every connector except the coolant temp sensor(under manifold ) and the crank position sensor. This included 11 connectors in all. I plan on doing the others too when i can figure how to access them. These connectors are very fragile and after having to repair the first one(I pushed it thru) It only takes a couple minutes to do each one!
I highly recommend this tweek for anyone with similar issues and basic mechanical skills.
 
#366 ·
This is a post that keeps on giving! I was suffering major hesitation on take-off and a rough idle. A quick spray of contact cleaner on just the two Vanos connectors solved the issue. A very rewarding 2 minute fix! Thank you.
 
#372 ·
I did my vanos seals yesterday and put 100 km almost but I didn't feel any gains that much. 170k km I noticed it idled better and lower rpm (just above 500) I took out intake side solenoid to test if wires are the problem because the whole vanos unit was covered in oil did font oil in the plugs and car felt the same. Do you guys think the contact points are the problem now? 2004 330i Auto
 
#376 ·
Does anybody recommend a connector-additive substance, like deoxit or dielectric grease? (dielectric grease; like those little packets you get for lightbulb sockets at the auto parts store). I've had good results (on various other connectors; including MAFs) with deoxit, but it does not rain/snow where I live.
 
#379 ·
I attempted to do this last night and when I stuck my pick in I realized those prongs/clips are kinda movable at the base. I was worried they would snap at the base if I pushed much harder. So I just left good enough alone.

I still have "bucking", like a misfiring feeling happening. The weird thing is, is if I turn the car off and on again enough times it eventually stops. Sometimes it takes 1 time, other times 3-4 times.
 
#380 ·
^Yeah. My (Mango's) official position on this thread and the info in it is that it's myth busted. AFAIK these are industry standard connectors and nowhere else am I hearing about these pins having a problem. I've seen people totally fvck up their cars because they tried to jerk the pins off and destroyed them. Now they have tape wrapped around them causing TRUE intermittent connections. Do not mess with these connectors, they are delicate.
 
#387 ·
My 323i used to make a sucking noise just for a split second on acceleration and at the same time hesitated. Also had a wandering idle every now and then.
Final fixed it with a new throttle body gasket, its an orange ring, my old one looked ok but compared to the new one it had shrunk and was thinner.
Hope that helps someone.
 
#400 ·
Well I guess that is my problem. I've noticed that when I accelerate I have that odd sucking noise. At first I thought it was brake system but that was a dead end. My boots were fine, I never even thought of the TB gasket.

Just recently got my 328Ci so going to try this "crimp" the plugs thing and change out that gasket see where it gets me.
 
#388 ·
I had the same symptoms for a couple years on my 04 330i. My car would actually stall on occasion too. Finally did the O2 sensors Vanos, ICV and cleaned my MAF and threw out my oiled K&N air filter. Now my car is running like brand new. Reason I tossed the K&N is that I had multiple engine lights showing MAF system. Even after I had changed everything. I would clean the MAF and the idle would be nice and steady until I'd bring the car up to 4k RPM and I guess that would be enough to mist oil on my MAF again. The idle would be jumpy and my gas mileage would drop about 4mpg and an engine light would follow after a couple days. All good now... Very happy
 
#389 ·
Ok , I have a question. I have random idle surges. Seems like cold mornings when I push the clutch in my idle will dip to about 200 rpm then surge to bout 1300 rpm. Sometimes it will level out and sometimes it stalls. If I unplug the MAF the problem goes away. Have replaced MAF, all intake hoses, fuel filter, ff vacuum line, throttle body,and disa gasket,ccv, vanos and both vanos solenoids. Problem still there... Any ideas?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top