Running good except on warm up first thing in morning. 91 850i

[2001740il]

Getting this 91 850i 6sp closer to running smoth.

I was hopping someone had these symptoms and did one thing that fixed them.

it starts right up cold by misses and even backfires slightly. Once it warms up everything fine maybe a very slight miss at idle

Had a code of 02 sensor changed sensor no change and still get 02 code. Once in a while if your at a prolonged idle the check engine light comes on and if you push gas it goes off.

[Timm]

Most likely inlet manifold leak....

[Wuffer]

Yup

[2001740il]

That was my conclusion as well. Just wanted a 2nd/third opinion to get myself motivated to do that job. ;-( Ugh

[htrdbmr]

This is not only serious, it's dangerous- I recommend you give the car to me immediately!

[TxGR8White]

Get a tube of REINZOSIL and get at it.
$14 and about 3 hours later everything will be just fine...

[PabloRock]

I need to do this as well. Is there a 3 hour write up for this? I have the write up for a topend refurb (from George Fontes), but that looks like it's doing a lot more than just the intake leak (and took a lot longer than an afternoon). It's probably better to do everything just because I'm there, but as a newbe to these larger (and slightly more complicated) jobs, I would prefer the quicker/easier fix, and get back in there if need be once I know what I'm doing (not to mention I don't have a ton of time and I don't want to leave my engine apart for days).

Never mind, just found what I was looking for. Here's the link for others;
http://bmwe32.masscom.net/sean750/V1...ughIdleFix.htm

[TxGR8White]

I need to do this as well. Is there a 3 hour write up for this?...

If you are doing this, then it is really prudent to do the Valve Cover Gaskets as well. (If your car is burning a little oil, then I would do the valve stem seals also.) Remember, in order to do valve cover gaskets, you will need to remove the intake gaskets again, and reseal them again. It is VERY important that you get 4 new lord mounts (the rubber mounts that support the actual intake runners - this is important so as to insure they mate up to the intake gaskets at the correct angle, otherwise you will have leaks again.

When using REINZOSIL, use a small continuous bead around the "lip" on the intake gaskets. Allow the REINZOSIL to set for about 10 minutes before you tighten the nuts down to the torque spec. This will make certain that there is a positive seal between the surfaces. Once the intake gaskets are tightened down you can install the intake runners - add the REINZOSIL bead to the aluminum runners and slide it over the intake gasket studs. Make just enough contact with the sealant t "stick" everything together. Wait the 10-15 minutes again and tighten down. Repeat this for the other side.

This is by far the biggest "mission creep" repair there is on the car, next to changing the rear end bushings....


Good luck!

[8eights]

...and if you remove the valve covers, Please check your Banjo Bolts. They loosen up and can cause poor lubrication up top, Can't believe TX didn't mention it, I learned it from him,}

[TxGR8White]

Gettin' older Marv - just gettin' older.....

[m6bigdog]

That was my conclusion as well. Just wanted a 2nd/third opinion to get myself motivated to do that job. ;-( Ugh

Prove it to yourself. Some with the tools will use a smoke machine however there is another way!!

Get a can of Dust-Off and 24" long, 1/8"-3/16" (small) flexible tube.
Take the intake manifold cover off and start the engine when cold or when it would typically misfire.
Observe the misfire/engine shake (you could also use a vacuum gauge on the intake runner ("tee" off the fuel pressure regulator or other direct manifold pressure port).
if you have an automatic trans the misfire can be exaggerated by putting the transmission in gear to load the engine.
Insert the Dust-Off straw into the small tube and locate the other end of the tube near each cylinder intake runner entering the head and discharge 1-2 seconds of the Dust-Off inert gas to flood each area with inert gas in succession. Initially there is no need to wait and observe the affect as it will be evident almost immediately.
If there is an intake manifold gasket leak the inert gas will displace the air/oxygen entering the intake manifold gasket leak and the engine will stop misfiring for a few seconds and the idle will smooth out until the gas is dissipated. Repeat as necessary to confirm the improvement, idle smoothness observation, at the cylinders that are affected. Also, you can anticipate several cylinders can have a leak so don't be discouraged if the engine idle only partially improves.

Assuming you do not find a intake manifold gasket location that is affected by the gas, I would move on to the other areas that have seals/gaskets on the intake manifold to include around the throttles and crankcase vent.

Of course you are working against the clock of the engine warming up, so of the engine starts to idle without misfiring you will want to allow the engine to become cold again to retest.