Rough idle for 40 seconds followed by white smoke

[cooljess76]

Originally Posted by applefan

How do I do a leak down test ? is it something I can do myself or better done outside for accurate result?
does the leakdown test procedure in the link below explains the correct procedure?
http://www.pelicanparts.com/bmw/tech..._rebuild-1.htm

That's it. Harbor Freight sells a leak down tester for 40 bucks. The test is a little more involved than a basic compression test. You're going to have to manually turn the engine over by hand to position each piston at TDC. I use a dial indicator with an extended probe and a spark plug adapter, but that's really only necessary for critical work such as timing/degreeing cams. Instead to find TDC of each piston you can simply use a long skinny object such as a long bladed screwdriver or a piece of a wire coat hanger. Don't drop a pen in there or anything short as the distance from the piston to the top of the spark plug hole is pretty deep. Put the car in neutral and set the parking brake. Remove the spark plugs, this will allow the crankshaft to turn with slightly less resistance. Then take your long skinny object and lower it in the hole until it rests on the piston. Don't just drop it in there, hold onto it until you feel it touch the piston. Now you're going to need a big socket and a breaker bar to turn the crank pulley CLOCKWISE. Watch the object VERY CLOSELY as you turn the crankshaft. You'll see it move up as the piston travels up, it will pause at the top of the stroke and then drop down as the piston goes down. You want to stop turning the crank at the very beginning of that pause. Note it takes two rotations to complete a stroke, so if you're doing the test and air just dumps out of the cylinder or it won't pressurize, the valves are open and you need to give it another rotation. Then you're going to pressurize the cylinder to whatever the test says and measure the pressure as it leaks down. Repeat this on each cylinder.

[applefan]

Here is how the exhaust smoke looks

http://www.youtube.com/watch?v=Oi_aW-nAu_g

[applefan]

another video
This isn't as bad as the fist one
http://www.youtube.com/watch?v=_4xA5fO5B1Y

[cooljess76]

^^^Yeah that doesn't look good. Still keepin my fingers crossed for you.

[J!m]

How does the white smoke smell? It LOOKS like coolant steam, and if it smells like maple syrup, it is coolant.

If it smells like burnt rice from the bottom of the pan, it is oil. But, generally oil is a bit more blue in color in the exhaust. It would be easier to tell color in person, but that looks more white than blue.

How much oil do you use in 3000 miles? More than a quart? If so it could be oil, but it is more likley an oil leak at this point... (that makes it harder to pin down)

You did mention losing water, so take Jess' advice and do a pressure test of the coolant system, or have a local garage do it for you.

[applefan]

Originally Posted by J!m

How does the white smoke smell? It LOOKS like coolant steam, and if it smells like maple syrup, it is coolant.

If it smells like burnt rice from the bottom of the pan, it is oil. But, generally oil is a bit more blue in color in the exhaust. It would be easier to tell color in person, but that looks more white than blue.

How much oil do you use in 3000 miles? More than a quart? If so it could be oil, but it is more likley an oil leak at this point... (that makes it harder to pin down)

You did mention losing water, so take Jess' advice and do a pressure test of the coolant system, or have a local garage do it for you.

going to stop by at harbor freight tonight to get the kit. will do the leak down test this weekend.

Some other observation: I tried to start it this morning and to my surprise, there were no rough idle. It was giving rough idle last night (That's after the oil cleanup from plug #2 over the weekend), but not this morning, may need to observe it few more days to see if the rough idle gone for sure
So I drove it to work today( 45 miles). Was watching the exhaust and temperature gauge all way along. The only time I saw smoke from exhaust was when I was punching the gas pedal above 4000 rpm on a freeway entrance ramp, uphill. There was no smoke at all when cruising at 70mph and at idle. Temp gauge goes up till 12 o'clock and stayed there all along the drive

[applefan]

Originally Posted by applefan

going to stop by at harbor freight tonight to get the kit. will do the leak down test this weekend.

Some other observation: I tried to start it this morning and to my surprise, there were no rough idle. It was giving rough idle last night (That's after the oil cleanup from plug #2 over the weekend), but not this morning, may need to observe it few more days to see if the rough idle gone for sure
So I drove it to work today( 45 miles). Was watching the exhaust and temperature gauge all way along. The only time I saw smoke from exhaust was when I was punching the gas pedal above 4000 rpm on a freeway entrance ramp, uphill. There was no smoke at all when cruising at 70mph and at idle. Temp gauge goes up till 12 o'clock and stayed there all along the drive

Jim, I usually change oil every 5000 miles, its around 1 quart less when I empty the used oil

[applefan]

Update:
Over the weekend, I was all set to do the leak down test /radiator pressure test and the chemical test to check the exhaust gas presence in the coolant.
started with the chemical test. rev up to 6000 rpm, no white smoke.
In fact no smoke at all. exhaust was perfectly clear.
Have no idea how it disappeared. dunno if it was because of weather, it was 100+ degrees out side Saturday. Tried many time Saturday and Sunday too. No white smoke.

I end up replacing the valve cover gasket and spark plugs yesterday.Drove it to work today; Car runs much better, although the rough idle at cold start still there. Duration of the rough idle is much less ( may be 10 seconds or less) compared to a a minute or more before

Going to watch the coolant level from now on and will take it from there

[J!m]

Oil consumption seems right- maybe a bit low for 5000 miles even. I think I used a quart every 3000 or so. Check the level at every gas fill-up.

I was thinking the PCV might be clogged up a bit. I think it is on the rocker cover near the front (someone who still has an M44 please help my memory!).

It is a long-ish shot, but maybe this is a problem.

I would also check all the vacuum hoses for leaks. Temperature changes cause hoses to swell and/or contract and this can close off cracks or make them smaller. The ICV may also need a cleaning- I don't remember if you did that already or not...

At least for the moment, the head gasket seems to be less likely...

[98318ti]

CCCV is middle back near firewall on the intake manifold. Black round thingy.

[applefan]

i replaced CCCV two years ago. It was making noise ( very confusing noice as if it was coming from the motor). May be its clogged again ?
ICV was cleaned as part of an attempt to solve the rough idle at cold start issue

[cooljess76]

Bad piston rings will cause you to burn oil. In your case I think it was a few issues contributing to the problem. First off, the plug wire being submerged in oil would definitely cause a misfire. Over a long enough period of time it could've damaged the plug wire or even the coil, which could explain it still having a rough idle. If oil was getting past the spark plug and dripping down into the combustion chamber, that could explain some of the smoke, although in that video it looked more like white billowy smoke. Moisture in the gas could also cause a rough idle, smoke and if bad enough could lead to a blown head gasket, bent valves and other things. I recommended running a can of seafoam through your fuel tank with at least 8 gallons of gas. If you hear any hissing, particularly behind the intake manifold, it's a good indication that your CCV is bad. The CCV has a hose that runs to the rear driver's side of the valve cover. Sometimes the orifice on the valve cover that the hose attaches to gets clogged up with gunk which in turn will cause excessive pressure build up in the crank case and cylinder head. This can also lead to oil loss and burning. A good indication of that orifice being clogged would be if you see oil residue in the throttle body, intake boots or air filter. I recommended cleaning out that orifice with brake cleaner when you had the valve cover off.Have you replaced the oil filter housing o-rings and gasket yet? My clubsport dumped about a quart of oil over the course of only a couple days when the o-rings went bad. Like I said before, the coolant loss isn't something to ignore. You probably have a crack in your radiator or one of the plastic coolant fittings causing coolant to slowly leak and evaporate and letting air into the system. Does your heater blow hot air? Really hot? If too much air gets into the system, you'll get air-lock which will prevent the coolant from circulating which will lead to the coolant evaporating inside the engine causing even more air and pressure to build up and eventually a blown headgasket.

[applefan]

Jess, I cleaned the plug wire with the cleaner specifically meant for that purpose. Bought from autozone(don't remember the brand)

If it is the a bad plug wire or coil, it should give problem all along the way right ? That's what confuses me. This morning, it gave rough idle for a few seconds, may be less than 10 seconds, and that's it. Car runs great afterwards. no more rough idle nothing.
Plenty of power (yes what a 1.9L engine can produce :-) ) makes no crazy noise etc

another FYI - I did a complete cooling system overhaul , 2 or 3 years ago. I followed the DIY in this forum , replaced 2 plastic pipes, radiator, water pump, hoses etc. Car has been running great since then, until this rough idle issue

[applefan]

Jess, I will check if the heater blow hot air. It's been a while since I used or checked heater for its functionality. Thanks

[cooljess76]

I've seen coolant leaks so small that you can't easily detect where they're coming from. No drops in the driveway or in the bottom of the bumper underpanel. The coolant evaporates quickly on the outside of a hot radiator or engine block. A good way to check the cooling system is to pressurize it and listen for leaks. You have to park the car in a closed environment with no ambient noise. I took an old radiator cap, drilled a hole in it that was slightly smaller than a tire valve stem. Then I pushed the valve stem through the hole, fastened the radiator cap onto the radiator and pumped it up to 5psi with a bicycle pump. I heard it hissing and traced it down to a hairline crack between the radiator and expansion tank.

This may or may not work on your car, but if you take it up to 5 psi and it holds pressure then you could rule out a leak. Also, check the carpet by the heater core and see if it feels moist. Cracked heater cores are a common issue on old cars. If you don't hear any hissing, still look around because you might see coolant seeping out of the engine or one of the coolant lines somewhere. If you start your car and notice smoke after you've pressurized the system, maybe you do have a BHG if the coolant somehow got pushed into the combustion chamber when you pressurized it. I wouldn't take it past 5psi though, you don't want to make things worse by overpressurizing it.