Quick history,

A few months back, this engine was so, so smooth.... I had to have my transmission rebuilt, after the rebuild, the engine was just as smooth and the transmission shifted beautiful.

This test is done at a stop with transmission in neutral. So theres no chance it is drivetrain related.

The engine has developed a harsh unbalanced feel . The engine is very smooth as idle no real shacking but it is a big V8 engine. its smooth from idle up to 2500rpm where it starts to feel like a shudder. It then smooths out a little from 2500rpm to 3800rpm. At 4000rpm the shudder gets real bad to the point where you feel the shudder in the floor pan but from 4500-6000rpm it is very smooth.

When hard accelerating you really feel that the engine has a very rough/harsh unbalanced feel. I was hoping when I installed the new Torque Converter, it would cure it.... its the same, so its not the Torque Converter.

Any ideas?

I was having the engine harshness/viabration before I got this code.
P-1173 check engine code. My PVC valve and pipes are new so it has to be the O2 sensors but again,I was having trouble with this vibration before the check engine.


Do you think faulty coils could cause this? I would like to check them today if possible

This is driving me nuts!!!! After this winter Transmission rebuilt/removed 3 times, new front passenger side strut after blow out , new drivers side strut after leak, water pump failure , front diff failure ect... ect.....

I would really like a easy fix this time.

The worst part is, I still like the truck and can forgive it after the torture this winter IF I can get this engine shudder taken care of.

Please help

Coil packs aren't too expensive, the best way to test is by substitution.
http://cgi.ebay.co.uk/4-4-BMW-COIL-PACK-UN...3ca3419cb9

If you buy a good one you can swap it out one by one. However, usually when a coil pack starts to go the MIL flashes in time with the shudder. It's often caused by leaking valve cover gaskets that leak oil into the plug wells.

When you say your PCV pipes are new, did you change the lower two? So four in total? 

Hi Dan,

yes, all the PVC pipes are in good shape, I got a great view of them when the transmission was out 3 times and on a hoist 6feet in the air for weeks

I just pulled all 8 spark plugs yesterday and they are the correct BMW plugs, they look like new but I am going to purchase a new set just to see if maybe a faulty plug could be the problem. I really dont think so and feel like its wasting $$$.

I just do not want to start buying coils and there not even the problem.

You think a intake leak or some exhaust emission fault could cause this. When I start the truck in the morning, theres a solenoid that starts ticking like crazy, I think its connected to the fuel vapour circuit some how. Its the solenoid on the front of the engine near the right ( when standing in front) cylinder head.

The noise you can hear could be the Secondary Air Injection system.

Dan

ps. Could you fill your profile info out so we know what year car you have... 

I have been meaning to do that....

It is a 2003 4.4 BMW engine.

Thanks 2003 RR 4.4 only 40k miles (current)
2004 RR 4.4 ( just sold)
2000 RR 4.6 (sold)

1959 series 2 109
1956 series 1 1956

Coilpacks can be likely. The Bosch ECU *should* have individual cylinder misfire detection being a ME7.2 but don't quote me on that...

A test on the lambda sensors is to unplug them to see if they improve things. Only as a very short temporary measure.

Does sounds to me the hesistation though could be the MAF sensor (Airflow sensor). Again unplug to see if it improves.

It's hard as normally if it is unbalanced I would of said coilpacks, but it would normally fail all over the RPM range... Which makes me say more the MAF or a lambda sensor. Used to have:
2005 FFRR 4.4 Vogue - BRC LPG Conversion & Remapped

Now have:
2008 SSRR 3.6 TDV8 - HSE and plenty of toys

BigJ wrote:

Coilpacks can be likely. The Bosch ECU *should* have individual cylinder misfire detection being a ME7.2 but don't quote me on that...

A test on the lambda sensors is to unplug them to see if they improve things. Only as a very short temporary measure.

Does sounds to me the hesistation though could be the MAF sensor (Airflow sensor). Again unplug to see if it improves.

It's hard as normally if it is unbalanced I would of said coilpacks, but it would normally fail all over the RPM range... Which makes me say more the MAF or a lambda sensor.

Ideally as it will run on an assumed figure. The pre cat ones are the main ones, the post simply check the cat is functioning. Used to have:
2005 FFRR 4.4 Vogue - BRC LPG Conversion & Remapped

Now have:
2008 SSRR 3.6 TDV8 - HSE and plenty of toys

When I had to check coil packs on a Jaguar Supercharged, I got one I knew to be good, then just went through swapping this with each of the existing ones, and trying the engine each time. After checking a few, the engine was suddenly smooth, job done! 2012 SDV8 Vogue SE

bozmandb9 wrote:

When I had to check coil packs on a Jaguar Supercharged, I got one I knew to be good, then just went through swapping this with each of the existing ones, and trying the engine each time. After checking a few, the engine was suddenly smooth, job done!

 

Well, heres what I did yesterday ....

I bought 4 new spark plugs, tried them on the left bank, No different. Tried them on the right bank, no different. So its not spark plugs.

Tried disconnecting all 4 O2 sensors, it ran pretty much the same and shutter around 4k rpm was still there.

Disconnected MAF, engine dies right away.

So, I moved to the coil packs. I went and grabbed 4 coils out from my dads BMW. Tried the coils on the left bank, No different . Tried them on the right bank, no different.


So, unless I am living in the twilight zone my problem is not spark plugs , O2 sensors , or Coil packs.

Is it still possible its the MAF?


Really pretty frustrated . I guess next, I will check the cylinder compression . Is there some procedure for the MK3 RR when checking compression? ( ex- pulling the fuel pump fuse ect...)


I even tried spraying starter fluid on the intake while the engine was running to see IF there was any intake leaks. I did not notice anything.


To make things even more strange, if I slowly Blip the gas and slowly raise the rpm, I wont get the shutter.

Then, if I slowly raise the rpm without blipping the gas, I get a vibrations that you feel in the floor pan.

Really pretty strange, HELP  2003 RR 4.4 only 40k miles (current)
2004 RR 4.4 ( just sold)
2000 RR 4.6 (sold)

1959 series 2 109
1956 series 1 1956

Does your Dad's BMW have the same engine? If so try the MAF off that? Used to have:
2005 FFRR 4.4 Vogue - BRC LPG Conversion & Remapped

Now have:
2008 SSRR 3.6 TDV8 - HSE and plenty of toys

BigJ wrote:

Does your Dad's BMW have the same engine? If so try the MAF off that?

Do you leave the A/C on all the time.......

Gazellio wrote:

Do you leave the A/C on all the time.......