Issues after timing belt

[davey101]

Hey guys. Been absent for a few years since my car somehow hasn't had any issues in the last few years. Decided to tackle the timing belt on it again. I've done the job four times before and feel pretty confident with it. I did go a little over kill washing and scrubbing the engine bay before hand but the car did sit for about 2 weeks in a heated garage with the battery unplugged before I started the job so I have to image things dried pretty well. Everything went pretty smooth for the most part, minus some stubborn bolts that snapped. Got the new belt and tensioner on (Bav Auto continental kit) and the timing was spot on after a few rotations. Got it all back together and fired it up and it seemed ok. Idled fine but once i gave it some throttle it had a loud whining noise from the timing area that sounded like a belt.

Decided to tear it all down again and double check everything. Everything looked normal. TDC marks still all lined up correctly. Tension seemed a little loose but tensioner was fully sprung out. Noticed the new one from the Conti kit looked a little bit different so just for haha's I put the old one back in. Made sure to rotate the engine a few times before the final tighten on the tensioner. All went back together again and starting it up it seemed quieter, however there was still some noise when giving it some throttle. I continued to bleed it out when the engine wanted to stall out and then over compensated and started idling all over the place. Quickly shut it off and let it sit for a moment. Started it back up and it idled normal but after 30 seconds or so the idle started going crazy again and the check engine light popped on and it shut off. Attempted the stomp test however I couldn't get the CEL to flash and get the codes. So I decided to stop before I caused any damage. Does anyone have any ideas? The valve train was always pretty loud before and it's certainly due for a valve adjustment...could manually turning over the engine cause an issue there? Could it be off by a single tooth? Did I mess something up electrically by washing the engine bay out? Crazy ECU relearn since it was reset? Any help would be amazing, thank you!!

[95BMWIC]

Why did you think the whining noise came from the timing belt?

Depending on what you mean - a whine would come from a bad (or rusty or dried out) bearing (idler (tensioner) - alternator - PS pulley - water pump). If the timing belt is off you would have a misfire - timing would be off - have a real hard time starting - foul your plugs.
A "squeal" would be a loose or worn drive belt..

This problem may have nothing to do with a timing belt change.

[davey101]

Noise seems to be coming from the front of the engine. Figured it was just a belt or a component so I wasn't too worried. The erratic idle and CEL/shut off has me concerned now.

[95BMWIC]

just a few thoughts.

Rotating the engine with the belt on and the belt tight would not cause the issue. Rotating the engine with the belt loose could cause timing to be off. If timing is off - the car will not ever idle smoothly - not even for 30 sec - you'd have popping, backfiring and you would know immediately something is wrong. The ECU takes care of the timing.

To start with - just make sure everything is dry (main relay especially) and everything is plugged in (and dry). Next methodically check for vacuum leaks. Once you ruled both of those out - I would starting with intake.

The idle symptom sounds like the AFM is not reading - For a quick check you could pull the plug on the AFM - then start the vehicle and see if that makes the idle more steady.

[95BMWIC]

Also - just know if you cant get the STOMP test to work - most likely your WOT switch (throttle switch) is not reading. This is the black switch that sits below the throttle body.

[davey101]

Also - just know if you cant get the STOMP test to work - most likely your WOT switch (throttle switch) is not reading. This is the black switch that sits below the throttle body.

This was a great note! I went and unplugged the TPS and it was filled with sludgey water in the connection. Just cleaned it out with some electrical cleaner and I'm gonna let it dry overnight. I think that certainly could cause a weird idle or a stalling condition. Hoping this solves that issue. Thanks for all your advice!

[msservices]

Are you test running with, or without the accessory belts connected? The wirring sound could be the alternator bearings if it got wet and then sat for a while.

[davey101]

Are you test running with, or without the accessory belts connected? The wirring sound could be the alternator bearings if it got wet and then sat for a while.

Haven't run it with them off yet. That'll be the next thing I do once I figure out the idling issue.

[msservices]

The idle issue might smooth out after it runs a bit. Not sure about the check engine light, unless the TPS got wet, and like mentioned above, isn’t working atm

[95BMWIC]

This was a great note! I went and unplugged the TPS and it was filled with sludgey water in the connection. Just cleaned it out with some electrical cleaner and I'm gonna let it dry overnight. I think that certainly could cause a weird idle or a stalling condition. Hoping this solves that issue. Thanks for all your advice!

I would definitely unplug the other connectors also to make sure they are dry (if you have water in one, your may have water in others).

Also - to do a quick check - listen for a click when opening the throttle butterfly. the click should come from the TPS just as its opening - if you don't hear a "click" then it may be bad or full of oil (or water).
Its a switch -its either on or off - I can tell you how to check it with a motometer if need be.

[superj]

and maybe your cps has a bad connection on one end. I noticed mine as bad by wiggling the cps wire when the car was running. it turned out the end had pulled out a little and I could see the fine wires inside the sheath by the sensor end. try wiggling it when the car is running, also. that will surely make your car run badly