740i M60 slight shaking vibrating at idle

funcrab

funcrab

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#1
Hello,

my 740i Model 1994 95kMls (built Spet. 1993) is shaking a little at idle. I heard about the Nikasil issue, BMW Shop says thats not the reason.
The air pressure has been tested for leakage (at oil fill in) and with 2.5 (of whatever) it is okay, says the mechanic. 3.5 and above would be bad, he says. Their solution to solve the shaking is to replace the engine and transmission mounts (890.00 US$ total), but I dont agree with them, since the shaking is visible at the engine block, and THAT is not normal. Every now and then (+-3 seconds) a slightly stronger shake is noticeable. It is not really dramatical, just anoying, and definitely not normal, since the engine doesnt run smoothly round (my dad has the same car, so I know how nice it can be).
Recently the spark plugs and rocker gaskets have been replaced.

If anyone has any idea what to look for next, I would really appreciate comments!

Vielen Dank!
Marcus[:)]
 
dwayne

dwayne

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#5
um..

[confused] Well all i can say is i heard that the motor mounts are
oil filled and sometimes they can leak with out notice also check out this website called all data.com really helpful site in diagnose
your car with some info ..also they have a recall list and the service report that the dealers use , i wrote a little info in the
8 series chat about the nikasil issue in checking your block casting numbers as well also get a complete scan with the code
numbers ..i think theres a cite with the code fault numbers which can direct you striaght to the problem i use a scan tool for my 740il i hope that helps ..Dwayne
 
funcrab

funcrab

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#7
thanks dwayne for your post.

I have read the article you linked to me. I would not describe the shaking as 'EXCESSIVELY rough idle'... it is just an anoying vibration, coming from the engine not running smooth... and a bad mpg (city 14-15), wich might be caused by the high temperatures here 115°F day, night 100°F.

Andrew sent me an email, wich might solve my problem. I still want to get other opinions on that...

Marcus I had the same problem. The shaking is going to get worse. What I did is replaced the intake manifold gaskets as well as the rear plate and the front gasket aroung the tune port. All the parts cost me under $200. I purchased them all from Crevier BMW. More than likely the rear plate is starting to go bad on your car, and this can be changed without taking the manifold off. But be very careful that you do not strip the torx bolts. Mine were stripped so I just took the whole mainfold off. Took me about 4 hours to do the job. But now the car runs better than before and you do not even know the egine is running when you are at idle. Hope this helps you.
 
dwayne

dwayne

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#8
Thank god you got it fixed

I heard about those gaskets leaking like that over time as you described i am sure happy you nip that little problem thank god i hadnt had that happen to me yet ..i am glad you fixed it as we know it can lead to something else [thumb]
 
funcrab

funcrab

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#9
not fixed yet

dwayne,

I did not fix it yet. You kind of scare me with saying "it can lead to something else " cause I am driving like that for a while. WHAT can it lead to??????
 
funcrab

funcrab

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other comments

I received other coments:

Posted by: ewysock
Message:

Marcus:

I have a 93 and am still trying to find out why it does this. Mine has a slight anoying shake about 50% of the time at idle and clears up if I press on the gas pedal a little. I have replaced the motor and trans mounts, all the intake gasgets, rear cover, and lines with no luck. After having all these things fixed I have been told by the dealer that I have two cylinders that are weaker than the others and this is causing a balance problem at idle. If I knew about this I would not have spent all the money fixing this motor. I would get a leakdown test done first to make sure before investing any more into repairing it.

Ed


Posted by: LJMartin

Message:

You might want to check for vacum leaks. Take the engine covers off and take a butane bottle open the valve and spray around the intake system from the air sensor to the intake manifold with engine idling, if the rpms pick up and the engine smooths out you have a vacum leak. It is very possible that it is indeed the engine and tranny mounts if you have no other problems. The V8 by design is not a very smooth running engine and BMW added to the roughness by blessing us with a mild exotic cam for added performance. If the mounts are bad they will let the engine rock. Good luck.
 
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