tunayballa

I have a big problem with my 89' W201

After a cold start, the car will start up right away and idle fine. I drive to my destination and turn off. I warm start the car and it will start, however, the idle will be below 500 to the point where it's barely running. I throw it in drive and it dies. I believe this is the cold start valve correct?

That's only one of my problems. The major problem is this. After I finally get the car running after a warm start the engine will make a noise. You ever heard a starter grinding noise? That's exactly what it sounds like while it idles. The noise will go away when I am in drive and will come back if I have to idle at a stop light etc. Also, while I am idling at a stop light, all the lights on the instrument cluster will show very dimly. The dim will also go away after I step on the gas.

Can you guys please help? I have no idea where to start to find this grinding noise. The noise sounds like it's coming from around the front of the engine. Anything in particular I should look for or check? I appreciate any input. Thanks!

kepla

Ah ! Two problems for the price of one - it must be 'summer sale' time.
That would be my first guess, but it is only a guess so you need to test. There's several things that can make for poor warm idling.
This sounds like one of the ancilliaries driven by the engine has a worn bearing, as you don't mention any oil pressure, cooling or steering problem. Given the behaviour of the dash warning lights, I'd be looking at the alternator to begin with.
If you get yourself a long rod, or a very long screwdriver, and - with the engine idling - let the 'business end' press gently on the the casing of the alternator. Crook your thumb over the top of the handle and place the joint of your thumb in your ear - so any sound picked up by the tool passes along it and you hear it clearly. You can use it like a stethescope to check for bad bearing in the alternator, water pump, power steering pump and aircon pump (if fitted). Just be carefull that you don't get it caught in the drive belt at the front of the engine !

tunayballa

Well I was reading a post on the cold start valve and how it would likely be the cause of it causing it to die when I put it in drive. I tried to take it off to clean, but had to difficulty. Do you or anyone know what size allen wrench to use to take it off?

I have been dealing with poor idle since I got the car sometime ago. It just won't go away! As long as the car doesn't die, it won't bother me. Several thousands of dollars later to correct it and it still comes back.

"This sounds like one of the ancilliaries driven by the engine has a worn bearing, as you don't mention any oil pressure, cooling or steering problem."
Is this something I can do by myself? Or how should I go about looking for this bearing?

I am going to check for noise with the alternator sometime this evening and give an update later on. Thanks.

tunayballa

I checked for noise and heard nothing. I'll start pulling everything off and getting them tested.

As for the noise, any ideas on where to start even looking?

kepla

Are you saying that the noise has vanished or that you just couldn't detect it fom the alternator ?
If the noise has vanished then, if I were you, I would stop worrying about it as it was probably just some kind of foreign body which had come to rest in a place where something was rubbing against it - and has now departed.
If you are saying that you can still hear the noise, but it doesn't come from the alternator, then try using the 'probe & ear' technique to spot where it is coming from. It sounds like some sort of bearing in something on the way out. If the alternator has passed muster, then also check the power steering pump and the aircon pump if you have aircon fitted. Also the water pump, and don't forget the belt tensioner. Once a car has done much more than about 100000 miles then you can expect all of these to go sooner or later. It could possibly be a camshaft bearing or distributor bearing and you might spot it by using the same technique - though not quite as easy as they are more solidly part of the engine block so the sound will travel all over more. A worn distributor could also lead to problems with uneven idling. A worn camshaft bearing might indicate a lack of oil supply due to something like a partly-blocked oilway. Frequent oil and filter changes are your best guard against this.
The engine in your car is usually pretty long-lived and it is more likely to be one of the ancilliaries which have worn.

tunayballa

Sorry, I meant to post that I checked the alternator and it checked fine in regard to me having the dash board lights come on at stop lights. Would there be something else that would make my dash board lights come on? My starter and battery are less than one year old. They're gone while driving and dim to lit while at a stop light.

As for the water pump, that is fairly new also. I will check my steering pump tonight. My belt tensioner, however, needs adjusting. It's loose in the front a little bit. I found a post on how to adjust it, but it's so cramped in the front of the engine, I wasn't sure which bolt to loosen. I know the rod to adjust it, just not sure which bolt to first loosen. I'll try to post back a picture later on this evening so hopefully you could help me out

Distributor and rotor are only a few months old. I changed them hoping the idle problem would go away, but it did not.

The noise is definitely coming from the front part, near the distributor area.

kepla

If the alternator (battery charge) warning light just illuminates or flickers when the engine is slowly idling but goes out and stays out while the engine is running any faster than this then your charging circuit sounds like it is okay. Most alternators are able to give sufficient current to charge even when the engine is idling so it might indicate tht either it is running slightly slowly (slipping drive belt ?) or the brushes are getting a bit worn, but I wouldn;t worry about it too much.
You do need to find where that noise is coming from before it develops into a more major problem. Everything that spins round has bearings and any of them can get worn eventually and make a noise.
When I said that it could be a worn distributor which was causing the noise and maybe rough idling too, I didn't mean the distributor cap. I meant that it could be a sign of worn bearings in the body of the distributor itself. If you place your 'stethoscopic listening stick' (see previous posts in this thread) firmly onto the metal body of the distributor then you will be able to hear if there is a worn and noisy bearing in there. Also, if you quickly pop off the distributor cap and rotor arm the grasp the shaft firmly, you might be able to move it very slightly sideways and feel some bearing play. Maybe.
Try to find the source of te noise before you start pulling things off the engine or you might make some unnecessary work for yourself. Keep on trying and you shouldbe able to spot it. Sometimes a knowledgeable friend might spot something which you overlooked - it happens to the best of us !
If you know for certain that the belt tensioner needs attention, then you should really see to that first and then takestock of the situation. Loose belts and worn or maladjusted tensioners can cause no end of problems.
General method: first fix what is obvious and then see what you are left with.

tunayballa

Well here's an update. The first grinding noise was actually the alternator. I removed the drip pan underneath and found a long screw on it. I checked the back of the alternator and saw that it came from there. Also, there was one screw coming loose. That's where the grinding noise was coming from.

The second grinding noise was coming from the alternator as well. Even when I checked with the stick for the noise, I didn't hear anything until recently. The noise that was intermittent became steady. So I took it off and it couldn't even spin it freely. It was in bad shape...almost like the spinning wheel part was had to be forced to spin by the belt. That's how rough the wheel was to spin.

I'm waiting for a new one so that should take care of everything.

Thanks for your help Kepla!

kepla

Hi, glad to hear that you've got a solution in hand.
Suggest that you hang on to your old alternator and have it reconditoned, ready for next time !