$500 in parts- now have stumbling issue

[bimmerboy12]

I changed with a brand new temp coolant sensor, had the issue, put the old one back in, didn't change. Idled fine before the work so the old one is good.

The problem is still very much alive and pissing me off.

[clavinZERO]

Try spraying hoses and other possible leak areas with a can of carb cleaner... one at a time. Spray, wait, listen. Nothing? Move to another spot. Spray, wait, listen. If the idle changes, then you have an air leak where you sprayed. I have found a few issues on friends' cars this way.

Just another 2 or 3 cents...

Adjusting the throttle and the AFM need to be done specifically:
The throttle when full closed should have I think .010" of feeler gauge clearance between the butterfly valve inside and the wall of the body itself.

As for the AFM... I believe you need something to read your emissions/mixture and you do it with the o2 sensor disconnected.

Check/wiggle various electronic connectors like on the AFM, etc.

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And... do you have enough/good gas in there? :P

[twright]

Bad Idle

Most rough idle issues are caused by a vacuum leak. Check all the hoses and orings on the intake side. (There are a bunch of hoses.)

And don't forget that an oil leak on these engines is also a vacuum leak. This means that a bad oring on the dip stick or a leaking valve cover gasket can cause a bad idle.

[bimmerboy12]

Time for an update. The problem is still there. I got a stethoscope for detecting air leaks and dragged that thing over every hose, fitting, connection, gasket, etc. and i got nothing. When I pull a hose like the one to the fuel regulator, it sucks air like freakin vacuum cleaner and starts idling really rough. Plug it back in and its back to just idling kind of bad.

Here is a wild thought: I tested the coil and I am getting zero resistance when I should be getting resistance according to my Bentley manual. Therefore, it is not right. Since I replaced the wires, cap and rotor (which were all in pretty bad shape) would the car be more sensitive to the coil being bad/not good? What are the symptoms of a bad coil anyways?
Thanks for all your help guys.
Brian

Most rough idle issues are caused by a vacuum leak. Check all the hoses and orings on the intake side. (There are a bunch of hoses.)

And don't forget that an oil leak on these engines is also a vacuum leak. This means that a bad oring on the dip stick or a leaking valve cover gasket can cause a bad idle.

[320is4dr]

i know u said it only runs rough when it gets warm but try checking the rotor + cap for cracks (way diff car but) on my 240 back when i had it i had a hairline crack inside the cap and it did kind of the same thing and i thought it was the tps.... try swapping for the old cap if you still have it. (and yes on my 240 it ran fine when it wasnt warm for whatever reason so dont flame my 2cents)

[Stevie30]

Brian, Check to be sure all your plug wires are seated fully in the distributor cap. I had a nagging problem and I found one wire corroded and not fully seated. Good luck.

[xLibelle]

brake booster leak? you'd hear a hiss. pull that line and plug it. remember your brakes will be minimal if you go for a drive.

[SpecM]

Here is a wild thought: I tested the coil and I am getting zero resistance when I should be getting resistance according to my Bentley manual. Therefore, it is not right. Since I replaced the wires, cap and rotor (which were all in pretty bad shape) would the car be more sensitive to the coil being bad/not good? What are the symptoms of a bad coil anyways?
Thanks for all your help guys.
Brian

the coil resistance should NOT be zero... should be a few thousand ohms, I think

see if you can swap it out with another one, or my a cheap one at Advance Auto (new MSD blaster coil only $35)

[OrganicMechanic]

ground strap?

[bimmerboy12]

Update time... removed the ground strap and wire brushed all contact points. Checked for vacuum leaks at filler cap and dipstick. Bought new MSD Blaster coil and installed. Removed O2 sensor and bench tested OK.
The problem is unchanged.
Next I will be taking apart the cap/rotor/wires and search for anything... Im getting desperate.

[bimmerboy12]

Update- removed cap and inspected cap/rotor, everything looked fine. Verified all wires were plugged in all the way. Checked booster vacuum line, no leaks.
Problem is still there.

[evil_twin]

So you're positive that you put the t-belt on correctly?

[scabzzzz]

Have you tried to unplug the battery for 30 minutes and plug it back up? Doesnt the Motronic on your car adjust fuel rates on its own?

Did you put the CTS in the wrong spot? Mix the wires?
Have you checked the clearance on the throttle position sensor?

[bmwpower]

Which type/brand plugs did you use? Anything but the factory stuff makes my cars idle like shit.

[Funkmasta]

So you're positive that you put the t-belt on correctly?

Another vote for timing belt being a tooth off.