Mystery (engine?) problem - car doesn't feel right

Got me Puzzled,but one thing for certain it is not something to do with your plug leads

I was gonna say the problem is your missing 4 cylinders, but...as you say your a bit upset, i wont.
( sorry mate, hope you get it sorted)
Les

Could be any number of things:

Dirty injectors
Vacuum air leak
Dirty air mass-flow sensor
(clogged intake filter?)

I'd also check that your getting a spark on each cylinder, but a bit difficult to do this with the integrated coils. These coil packs sometimes go faulty.

BTW, not sure how your "specialist" checked the ignition leads as there are none. The engine has integrated coils:

http://bmwfans.info/original/E…998/02/mg-12/ill-12_0409/

Is your idle RPM unsteady, or is it less than 700 rpm?

Check the rearmost cylinders on both banks to make sure the plugs are'nt running in oil from the infamous cam cover gasket leaks. Then check the breather valve assy on the rear of the inlet manifold.
Another thing to check is the security of the induction hose from the AF meter to the inlet manifold.......they come loose/adrift. Injectors will be fine.

8Tech.

Try resetting the engine computer.

I have had my 840 "adaptive" itself into mediocrity. A reset cured it immediately.

Zitat von 8Tech

Check the rearmost cylinders on both banks to make sure the plugs are'nt running in oil from the infamous cam cover gasket leaks. Then check the breather valve assy on the rear of the inlet manifold.
Another thing to check is the security of the induction hose from the AF meter to the inlet manifold.......they come loose/adrift. Injectors will be fine.

8Tech.

Hey Sebtake no notice of Les he's not know as a big fan of anything V8 , What Gerry has described re the big induction hose, it happened to me & rendered the car undrivable before it was diagnosed, my local Independent didn't even spot it but instead told me I had ecu problems so check for air leakages on anything on the inlet side of the engine.

Mystery (engine?) problem - car doesn't feel right

Hi Seb
I had a similar problem, not on the 8 but another and it was simply air leakage problem, which was narrowed down to the hose for the servo unit.

Don't read the following bit Seb,,,,,,its for everybody else!!

Long time ago, I was told by a very good mechanic with inside knowledge of the early BMW 840i engine failure and warranty issues, that there was a design fault in the cylinder lining material/property/hardening process that ultimately lead to "wash out" in particular where the fuel mixture had been consistently rich etc.... this would lead at first to unexplainable and erratic idle below 7-800 rpm. and sudden death.
Perhaps this is why the second 840i was in actual fact 84.4i ????? I don't know much about this.....just feel bad for Seb. please don't tell him.
Mat

Re: Mystery (engine?) problem - car doesn't feel right

Zitat von MK

Hi Seb
I had a similar problem, not on the 8 but another and it was simply air leakage problem, which was narrowed down to the hose for the servo unit.

Don't read the following bit Seb,,,,,,its for everybody else!!

Long time ago, I was told by a very good mechanic with inside knowledge of the early BMW 840i engine failure and warranty issues, that there was a design fault in the cylinder lining material/property/hardening process that ultimately lead to "wash out" in particular where the fuel mixture had been consistently rich etc.... this would lead at first to unexplainable and erratic idle below 7-800 rpm. and sudden death.
Perhaps this is why the second 840i was in actual fact 84.4i ????? I don't know much about this.....just feel bad for Seb. please don't tell him.
Mat

Not sure what your getting at Mat but Sebs car is a 4.4 M62 engined car

I believe MK is referring to the Nikasil problems on the earlier 4.0 M60 engines. This was caused by the high Sulphur content of our fuels and stripped the coating from the lining of the bores. This can also be caused by excessively rich fuel mixtures "washing" the oil from the bores causing increased ring/bore wear.
This caused initially, poor starting due to low compression and high oil consumption, followed by, in severe cases, poor idle.

I don't think this is Sebs problem with an M62.

8Tech.

Mystery (engine?) problem - car doesn't feel right

Hi Steve
About six years ago I took my 840ci with around 80K miles to a secondhand topend/enthusiasts car dealer somewhere in Birmingham city centre, to part exchange it for a very low mileage R reg 840ci sports(4.4) with a full pack of extras etc. The dealer was recommended to me as truly knowing his stuff and trustworthy etc. no need to say that my car as always was absolutely tiptop, and I never thought that it missed the beat. the salesman checked my car over turned it on, fiddled with it a bit, then looking concerned, went and got the organ grinder to look at the rev counter.... basically they revealed to me that by 90K my engine could potentially totally die because of the cylinder lining properties of some of the 840 engines, and that the chap would make some enquiries as to whether my car had had cylinder block modifications or engine changeover. This was not at all a sales scam to pull one over me. Somehow, I never went back. But later I tried to make some enquiries of my own through main BMW dealers regarding warranty issues regarding these engines etc. NO one officially denied this fact and I was thoroughly hindered at every turn to find out more. I presumed not to let others know??? some exBMW mechanics since have confirmed similar accounts. That is honestly all I can tell you. Apart from assuming the larger bore of the later engine may have something to do with sleeving/different hardening processes etc. I thought that some of you out there would know more.
regards
Mat

My m60 engine had a replacement block under the previous owners warranty at 34,000 miles, I bought the car on 37500 miles , with this Knowledge I went ahead with the S/C Conversion & 52000 miles.

I am also aware that Bmw where replacing like for like Nikasil Engines when the problems 1st started,not realising what exactly was the problem.

Hi,

I have had a similar problem when I have bought my 850, it was due to the sonde lambda.

Nikasil coated cylinder bores need not necessarily be a problem. BMW used this process with their motor-cycle engines and many clocked up over 200,000 miles without issues.

In the US, steel cylinder liners were used instead of this coating. In Europe, generally there were no problems. The Nikasil problem was thought to be predominantly in the north of the UK where imported, high-sulphur fuel was being distributed for a while.

Re: Mystery (engine?) problem - car doesn't feel right

Seb, Don't know if this helps but I remembered a post on a similar subject from about a year ago when I joined. It mentioned the "dreaded" idle problem, and refers to even older posts on the subject - the implication being that you're not the first to suffer. Here's the old link. Good Luck.

http://www.clube31.net/forum/viewtopic.php?t=4306

Zitat von arnie

Nikasil coated cylinder bores need not necessarily be a problem. BMW used this process with their motor-cycle engines and many clocked up over 200,000 miles without issues.

In the US, steel cylinder liners were used instead of this coating. In Europe, generally there were no problems. The Nikasil problem was thought to be predominantly in the north of the UK where imported, high-sulphur fuel was being distributed for a while.

BTW BMW never used steel linings in the V8. The high sulfur fuel caused the same Nicasil erosion here in the US as in the UK.

The sulphuric acid produced from burning high sulfur gasoline ate the nickel plating holding the silicon carbide particles in place and the walls pitted and scarred.

Without the sulfur problem the Nicasil linings should have gone nearly forever

Zitat von 8Tech

Check the rearmost cylinders on both banks to make sure the plugs are'nt running in oil from the infamous cam cover gasket leaks. Then check the breather valve assy on the rear of the inlet manifold.
Another thing to check is the security of the induction hose from the AF meter to the inlet manifold.......they come loose/adrift. Injectors will be fine.

8Tech.

I'd go with 8tech's suggestion...I had EXACTLY this problem - idle & low power - a symptom like a misfire...it was caused by oil leaking from C/H gaskets.

2 new gaskets...bingo....beeeeautiful smooth running.