1994 530i rough idle, cylinder miss?

[Kalevera]

The other thing you should order is a few new bolts for both the PCV and the throttle body. They're Torx T30s and, let me tell you, they're a big pain to get out because they usually fuse themselves in there, especially after 11 years. Yes, it's illogical but a big pain, nonetheless. They'll probably strip out and have to be removed with vice grips. Put it back together with some antiseize grease (yes, I know the intake is plastic).

You're lucky it's a 5 speed. If the engine ever has to come out, you won't have to mess around with a trans cooler. That added a lot of time and expense to the job I did. Only thing is, good luck finding a 3.0 replacement block -- our boy Sajen's been on the prowl for one with no luck, TMK (did he ever find one?!)

best, whit

[Kalevera]

Also, be sure to get a code reader on the thing before you do ANYTHING...even a compression test. If the DME knows something's up, might as well know that before taking a shot in the dark.

best, whit

[Tiger]

Add valve cover gasket to your list... don't forget 8 orings for the plug holes.

[Been-Jammin]

Updated Parts list: (thanks to Lowell and Bill R.! )
BTW- I really appreciate the pictures!

8 Spark Plug Connector; Coil To Spark Plug; Updated Version 1.8kOhms
1 Intake Manifold Gasket; Front Intake Manifold to Throttle Housing
4 Intake Manifold Gasket; Intake Manifold to Cylinder Head
1 Intake Manifold Gasket; Rear Intake Manifold Cover O-Ring; 20x3.55mm
1 PCV Valve Grommet; Grommet for Ventilation Valve and Idle Control Valve
Added to the parts list:
1 Valve Cover Gasket Set; Left - Cylinders 5-8 (inner & outer)
1 Valve Cover Gasket Set; Right - Cylinders 1-4 (inner & outer)
22 Valve Cover Grommet Gasket; Valve Cover Nut Seal
1 Intake Manifold Cover (Rear PCV Plate)
1 Intake Manifold Gasket (at Rear PCV Plate)
Total: ~$200.00

I've already installed the Bosch 4417 Platinum +4's.

I didn't see the "O" ring Valve Cover Grommet Gaskets, would have completely over looked them, thanks Lowell for adding that in! Wow, 22 of them.

FYI- I'm ordering everything except the PCV Plate from autohausaz.com, the PCV Plate & gasket is coming from bmwwholesaleparts.com and it's labeled as an : "Intake Manifold Cover ".

[Been-Jammin]

On a cold engine, idling, A/C off, I sprayed the Throttle body where it attaches to the intake, then sprayed all around the intake covering every place along where it seals.

There was an instant idle increase when the carb choke cleaner first hit the throttle body gasket area. Idle returned to "normal" (still rough). No change for everywhere else I sprayed. Emptied an entire can.

I drove for about 11 miles and with and with a hot engine, sprayed everything again. No change in idle while spraying. However I did notice a significantly smoother idle all around. Still skipping a beat in the exaust rythm regularly enough to shake the car.

I did notice a loud "Whistle" while under the hood. Sounded almost like a turbo spooling up when I twisted the throttle body open and the engine revved up. There is also a loud constant "sucking" sound coming from somewhere around the intake. Spraying it with cleaner & didn't affect it at all. I spun the throttle body and as the engine revved, the "sucking" faded and the "whistling" took over. This leads me to believe that there might be a leak.

Not sure of the conclusion, except it's enough for me to replace all the gaskets/seals & PCV plate. The ICV will be a last resort due to it's price tag...

I'm going to try another test, by removing the oil cap/dipstick to see if the "sucking" sound or the "whistle" are affected. Will post the results shortly.

[winfred]

the o-rings are on the 6 cylinder, the v8 just has a smaller gasket that rings the whole plug area and comes with the valve cover gasket, 11 rubber grommits per valve cover for each nut don't come with the gasket kit but they should, they are what actually applys pressure to the valve cover and reusing the old ones can cause problems with possible leaks

I didn't see the "O" ring Valve Cover Grommet Gaskets, would have completely over looked them, thanks Lowell for adding that in! Wow, 22 of them.

[Been-Jammin]

I started it up, AC off, at idle I removed the dipstick and the oil filler cover. Left it loose as to prevent "oil fling" from the timing chains. When I twist the throttle, I can hear a pronounced "whistle" coming from the rear of the engine while it's revving up. There is no idle difference with the cap/dipstick out vs. installed properly. The "whistle" is a short, turbo spooling type sound. It's brief and happens only when increasing the RPM's.

Is this normal or an indication of a PCV failure?

Thanks!

BTW- I did clean out the dipstick seal as well as all the corrosion where the oil cap seals. What's with that nasty gold left over fried egg like stuff anyway?

[632 Regal]

After you replace (or before) the gaskets reboot the thing. When my intake was leaking last winter it ran just like yours, check light, the miss, everything. I rebooted the computer and it read that the leak was a "normal" leak and the car ran a lot better for several months until I got to the gaskets. When I had my intake off there was one of them air horns rolling around in there and that could have caused the intermittant miss by blocking an intake port.
Before that after I bought the car it had a real bad miss that I chased with coils, plugs, Injectors only to have the same miss which was "Caused by Nikasil" until I replaced the plug boots...they all checked out with the ohm meter but the new ones solved the whole dilema...40k or so ago.
Also, them specialty plugs can cause strange idle/miss problems, stick with the stocker plugs.
Good luck to you!

[Been-Jammin]

Also, be sure to get a code reader on the thing before you do ANYTHING...even a compression test. If the DME knows something's up, might as well know that before taking a shot in the dark.

best, whit

I've tried the stomp test a few times to no avail, but will keep trying as I would really like to see what the codes are. I think the local auto parts store has a diagnostic code reader and will test for free... time to find out.

[winfred]

whistle is not normal, the crud on the cap/dipstick is somewhat normal, i think it's a mixture of old oil and condenced and dried comtaminates from the oil, it seems to only really show up on the newer motors, m20/30s don't seem to do it, they will show a gooey sludge if not maintained and not the dried powdery **** of the m42/50/60 type motors