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  #16  
Old 04-14-2009, 06:39 PM
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Thanks... I posted a comment on your other thread and read up on it. I hope its not that hose that took you hours to replace! That would be my luck though.

My car runs smoothly, even at idle, so does it still sound like it could be a vacuum leak?

Also my stalling started very suddenly. It did it once one day, then three times the next time I drove it which was like 3 days later... it had never did it at all before.

Quote:
Originally Posted by tinypanzer View Post
Check out the idle air hoses. They get loose at the ends and start sucking in air.

Had the same problem with my car, thought it was OVP. Started out intermittent and infrequent, but slowly got worse and worse. Like you, it would always stall as I was coming to a stop - when the engine is transitioning from a running mixture to idle.

Eventually, the idle got really rough and it was obvious something was very wrong, but that was 6 months from the start of symptoms.

Good luck.

I think like me, you will find a vacuum leak somewhere under your hood if you poke around. Listen carefully under there with the motor running. You might hear hissing.


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  #17  
Old 04-14-2009, 07:45 PM
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One would think that those symptoms rule out a vacuum leak, but they didn't in my case.

I think what happens is that the hose ends expand and contract with heat, and that the leak only shows up in certain conditions.

I'm not saying for sure that this is your issue, but the symptoms match mine exactly. My idle was very smooth too, until the leak got so bad I was stalling at every light. Then the idle was noticeably rough. I think the system manages to compensate for minor leaks okay, but once it gets too big, you stall. You do have a different engine than I do.

Hopefully, your idle air hoses are less buried than mine are.

In any case, I would spend some time poking around in there and looking for vacuum leaks.
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-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition
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  #18  
Old 04-14-2009, 09:54 PM
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Oh, you're talking about your 300SEL, so I guess it's not a different motor.

Well in that case, I can tell you several spots to check for vacuum leaks. One nasty one is the breather hose that goes from the middle of the valve cover to the intake manifold. Cracks develop on the underside of this hose (if it's original) and those can be problematic to say the least. In fact, this hose needs to seal perfectly so replace it if it's not right.

If your idle air hoses are original as mine were (on my '90) then you can assume that they probably do need replacing. I would try to avoid the CRP brand hose for this application. The other breather hoses they make seem fine.

It is a total ***** to replace that idle air hose the first time, but I feel I could do it again in about an hour. You just have to pull the electrical connections to the sensors, pull off the breather and cover, use a 15mm (I think) flare wrench to undo the fuel injector lines, and a 12mm (I think) flare wrench to undo the cold start injector. Then you remove the cold start injector with an allen wrench. Then you loosen the clamp for the rubber boot underneath air flap, and the three 10mm hex nuts holding the fuel distributor down. Then you lift off the fuel distributor and have an assistant lift it out of the way as you reach under and swap the hose.

Here's a cool trick for dealing with that spring loaded hose clamp. After getting the hose and clamp off, take the clamp and use pliers to open up the clamp and get the three tabs on the top lined up. Then you shove a small wire tie through the three loopholes. Voila! Your hose clamp is now held open and will not impede you as you try to shove the new hose on! Once you have the new hose on, you spin the clamp so that the wire tie is near the top where you can get to it. Then you just touch it with a hot soldering iron. The wire tie melts and the clamp snaps shut without any grief at all.

Anyway, I digress, and I have some work to tend to at the moment. I guess my point is, do some snooping for old brittle vacuum hoses, elbows, and and possible place for a leak. If your rubber is original under there, there WILL be leaks, and in all likelihood you will find and solve your problem by being methodical and patient.

As for your leaky EHA valve, replace the two O-rings under there first. It's probably not the valve. Order them here, or at the dealership, etc.... Wear goggles and gloves, it will squirt like a grapefruit. Torque the two screws down evenly, alternating between screws every half turn starting when the valve is seated flush and the screws are finger tight.

Good luck!
__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition
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  #19  
Old 04-15-2009, 12:02 AM
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Thanks for the detailed info! WOW, it sounds like something I could definitely screw up! I wonder how much my local indy shop would charge to check/repair this.... I will have to find out. All of this coming at a time when I need very costly maintainence to my other car and the MB needs some other things as well. It may have to just set in the driveway for awhile.

Thanks again.

For some reason I am now wishing I had of kept my '84 190D.

In fact, I really think I am going to be sick... very sick.


Quote:
Originally Posted by tinypanzer View Post
Oh, you're talking about your 300SEL, so I guess it's not a different motor.

Well in that case, I can tell you several spots to check for vacuum leaks. One nasty one is the breather hose that goes from the middle of the valve cover to the intake manifold. Cracks develop on the underside of this hose (if it's original) and those can be problematic to say the least. In fact, this hose needs to seal perfectly so replace it if it's not right.

If your idle air hoses are original as mine were (on my '90) then you can assume that they probably do need replacing. I would try to avoid the CRP brand hose for this application. The other breather hoses they make seem fine.

It is a total ***** to replace that idle air hose the first time, but I feel I could do it again in about an hour. You just have to pull the electrical connections to the sensors, pull off the breather and cover, use a 15mm (I think) flare wrench to undo the fuel injector lines, and a 12mm (I think) flare wrench to undo the cold start injector. Then you remove the cold start injector with an allen wrench. Then you loosen the clamp for the rubber boot underneath air flap, and the three 10mm hex nuts holding the fuel distributor down. Then you lift off the fuel distributor and have an assistant lift it out of the way as you reach under and swap the hose.

Here's a cool trick for dealing with that spring loaded hose clamp. After getting the hose and clamp off, take the clamp and use pliers to open up the clamp and get the three tabs on the top lined up. Then you shove a small wire tie through the three loopholes. Voila! Your hose clamp is now held open and will not impede you as you try to shove the new hose on! Once you have the new hose on, you spin the clamp so that the wire tie is near the top where you can get to it. Then you just touch it with a hot soldering iron. The wire tie melts and the clamp snaps shut without any grief at all.

Anyway, I digress, and I have some work to tend to at the moment. I guess my point is, do some snooping for old brittle vacuum hoses, elbows, and and possible place for a leak. If your rubber is original under there, there WILL be leaks, and in all likelihood you will find and solve your problem by being methodical and patient.

As for your leaky EHA valve, replace the two O-rings under there first. It's probably not the valve. Order them here, or at the dealership, etc.... Wear goggles and gloves, it will squirt like a grapefruit. Torque the two screws down evenly, alternating between screws every half turn starting when the valve is seated flush and the screws are finger tight.

Good luck!

Last edited by 86560SEL; 04-15-2009 at 12:18 AM.
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  #20  
Old 04-19-2009, 01:19 AM
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I cant get the car to the shop until next week, but....

I drove the car today anyway to see how it behaved today and ironically, the car did not stall out, not even once. Strange. There was an odd occurance this morning however when I first went to start it, my battery cable connection was bad and I had to get out and tighten the cable. Its probably a long shot, but wondering somehow if maybe the cable was making an occasional poor connection that day when I was driving it and it causing the car to stall. I know some cars will continue to run awhile without the battery connected, but not sure if this is something that causes a MB to go bonkers or not - like cutting off even power to the OVP and causing it to stall. I guess its wishful thinking that was the issue. I will drive it more this week to see if the stalling is continuing.

Either way it really needs to go to the shop to check out the possible seeping EHA valve.
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  #21  
Old 04-19-2009, 09:01 PM
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Strange... drove it another 60 miles today and it didnt stall out. Seems strange. I really wonder if perhaps it was not that battery connection causing it to do that stalling that day.

edit - I talked to the Mercedes tech that used to work on my old 380SE and he said that where my battery cable was loose it could have caused the odd stalling that day, especially since the car has not stalled since then. We will see.


Last edited by 86560SEL; 04-20-2009 at 04:58 PM.
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