Shut off valve replacement W124 602/3 300D 2.5 - PeachParts Mercedes-Benz Forum

pdrayton · #1 06-09-2007, 03:45 PM

I had my shut off valve fail and my car not shut off with the key and I couldn't find any info on how to replace the valve either in the forum or in the FSM.

Anyway, I tackled the job today, and got it done. Not the easiest job in the world - but not difficult, just a little weird. It's really just a matter of not thinking it's a case of pulling the old one out and putting the new one in.
What you really have to do is pull off a lot of other stuff, find the extra hidden bonus bolt and then do some other stuff and then pull it out. It's not that bad really - it sounds harder than it is. It would probably take me 30 minutes if I had to do it again. Anyway, enough blabber, here's the spiel...

1.Remove the idle servo connector. That's the black plastic connector just behind the vacuum shut off valve looking from the driver's front wheel side. It has to be removed to get the shut off valve (SOV) out. To get the plastic connector out, twist the black plastic tab on the lower ring towards you (counter-clockwise). It should turn about 1/4 turn and release the top part of the connector which can now be wiggled out. Remove the Cruise control actuator first to make it easier to get at things (it is the big gold thing on the intake manifold)

Now we remove the ALDA so we can get at the back bolt of the SOV (yes, I know - SOV sounds like something else doesn't it!

). To remove the ALDA I twisted the entire body of the ALDA using channel locks, while holding the locknut at it's base with a crescent wrench. Turn the ALDA anticlockwise. It only takes a 1/4 turn to loosen it and then it's easy pickings to get it out. Also a great time to adjust the ALDA if your car is sluggish, or if you are not a moron who drives with his foot on the floor the whole time.

Now that they're both out the way, we're on easy street. Sort of....

EDIT: DO NOT REMOVE THE STOP LEVER or circlip holding the stop lever shaft in the IP - it is not necessary, and it can make you put the lever in the wrong place. I thought it was necessary, and had pictures etc about it in the first version of this post. But it is not necessary, in fact, it can screw things up. I did this, and spent the whole day trying to figure out why my car had no power, the EDS said air sensor error, and the car was a total dog, even when I rigged the turbo to work manually. What's happened is you've put the shaft of the SOV in the wrong place and it is messing with the throttle. The proper way to get the old valve out is to push the stop lever all the way down (in the stop position) and then gently pull and wiggle the SOV out at the angle shown in the pic below - ie leaning backwards. It will then slide out of the connector to the stop lever. Have a look in there when you've got it out and you'll see what I mean. The new valve shaft then will slide in at the same angle and mate with the stop lever.

When I put the SOV in the wrong way, the stop lever moved with the throttle. So if that happens to you, you know you've got it in wrong.

So ignore the bits below about removing the circlip (if you don't see them then it is becuase I have deleted them).

Now you can wiggle the SOV out of the IP. Note that the thumb twist ring thing that held the idle solenoid electrical connector in place, might get in the way a bit. Sort of push it out the way with a screw driver (that's what I did - gently) to get the lip of the SOV past it. Leaning the SOV backwards and pushing the stop lever down, will allow the SOV to disconnect from the stop lever.

All done. Rinse and Repeat. Um... I mean..... installation is the reverse of removal. Be sure to look down inside the IP and see where the stop lever goes to. Move the stop lever and see the piece of metal with a strip cut out of it move up and down. That cut out strip is where the nib at the end of the SOV fits into. NOt above, or below, but right into it. If you put it above or below, you risk a car that doesn't run, or a runaway diesel. See below

VERY IMPORTANT: I'm not sure if it can happen with the 602/3 but with other's such as the 616/7, if you install the SOV wrong you can end up with a 'run away' diesel. If you don't know what that is, look it up. Basically, bad. Very bad. Mucho bad.
To avoid a run away diesel, test the SOV you just installed by applying vacuum to it. The shutoff lever should go all the way down to horizontal. Check it is all the way down and that you can't press it down anymore by hand. If that is the case, you are probably OK. Just to be 100% safe, I took the cross over tube off and got a piece of wood ready to put over the intake in case it did the runaway thing. It didn't, but better safe than sorry (my mother taught me that).

Hope that helped.

Paul

KEYWORDS (for poor beggars searching for this stuff): Vacuum Shutoff valve, vacuum shut off valve, engine stop unit, 603, 602 W124 300D 2.5, won't shut off.

Bio300TDTdriver · #2 06-09-2007, 05:22 PM

I had my indie do mine on my 603. He pulled the intake off to get at it. What I thought was going to be $150 job turned out to be $350 one.

Next time I will do it my self.

Chris

pdrayton · #3 06-09-2007, 07:02 PM

Yeah, actually I read that taking off the intake was the way to go. But me and things to do with the head (even if it is just undoing and redoing bolts into it) don't go well together. So I tried to figure a way round it.

2.5Turbo · #4 06-09-2007, 09:02 PM

I did the job exactly the same as you, but I didn't take the stop lever off. I couldn't see very well down into the IP with the intake on, but I just pulled the old one out and unhooked the little nub from the mechanism inside the IP. Then I just hooked the new one back onto the mechanism and it worked fine. I got a chunk of 2x4 just in case and disconnected the flex tube before starting. Had my brother start the car while I stood by with the block. Fortunately everything was in order and shut off perfectly.

The only pain in the butt for me was the removal of the ALDA. I had to remove the windshield washer tank and cruise actuator to get enough wrench clearance for my channel locks.

This might be good in the DIY section where there is only a 61x specific article.

Bio300TDTdriver · #5 06-09-2007, 11:03 PM

It should definitely go into the DIY section. If both of yours failed and mine failed, there must be others out there that it is happening to.

Chris

pdrayton · #6 06-10-2007, 09:26 AM

Well, my car now shuts off.... but there's no turbo! Also the idle was acting funky for a while - would drop to below 500rpm and then catch back up to 700.
I'm wondering if I screwed up the ALDA by adjusting it. Maybe it's not happy and is cutting the boost..... AARGH! Annoying.

2.5Turbo - maybe I didn't have to remove the stop lever, I'm not sure. If it worked for you that way, then obviously it is not necessary. my stop lever moves up and down with throttle now though. Is that normal?

I could just fit a 12inch crescent wrench in around the ALDA lock nut by removing the cruise control piece only. It's a tight fit, but can be done.

pdrayton · #7 06-10-2007, 11:30 AM

Yes, the dreaded no boost in the W124. I just changed out the engine shut off valve, and now there is no boost. There is EDS error 3 (meaning the air sensor b2/1 - which I didn't touch BTW). Somehow the EDS thinks there is a problem with air flow.

I've checked with a pressure meter at the intake port - there is no boost, maybe 2 or 3 psi at WOT. So I put my mityvac on the wastegate and gave it 13 mmHG while driving to close the wastegate and make turbo. Boost rose to 7 psi for a short time and then dropped down again. Does that mean a leak?

Also, when I apply vacuum to the ALDA only, it leaks slowly - about 10 seconds for 10 mmHg.

So where the hell is my boost gone? The ARV and EGR seem to be working fine. How do I tell if the turbo is actually spinning up or not?

Any help appreciated. Got to get this thing going properly by tomorrow, or the wife will have my head on a stick.

EDIT: I did adjust the ALDA - turned the screw 3 turns out from fully in. I've also tried without the ALDA on and the vacuum line plugged. I've tried it with the screw all the way out, and all the way in. Same results, which makes sense since the ALDA is only reacting to what the boost is doing. So my conclusion so far is that the ALDA is not the cause of the boost problem. The real cause is something thinking there is a problem with the air sensor. And I don't know how to test it without the hook up box.

2.5Turbo · #8 06-10-2007, 11:12 PM

Check the connection to the airflow sensor (on the airbox). If it's OK, then clear the codes and drive it again. That sensor is pretty big bucks, so you won't want to just throw one at it and hope it works. A few other things might be tripping the airflow meter sensor code. Check the vacuum transducers/switchover valves for the EGR and intake butterfly flap and make sure they're good. They won't necessarily throw a code if they're bad, but they'll definitely throw an airflow code if the EGR isn't working at all, or if the intake flap isn't closing when it is told.

Briefly connect straight vacuum to the turbo wastegate, and check your boost gauge. You should get a good amount of boost. Make sure to not overboost too much...I wouldn't trust your engine and turbo to the overboost protection circuit. If you have good performance with straight vacuum to the turbo, your fuel system (including ALDA) is OK.

If everything else tests OK, you're probably going to have to get a new airflow sensor.

pmari · #9 06-11-2007, 12:03 AM

pdrayton
Registered User Join Date: May 2005
Location: Fernandina Beach, Florida
Posts: 312

Gsxr is a smart chappie, even with Hobbes as his mascot.

Turns out even with full boost I got no acceleration (gerry rigged the wastegate open), so I figured out that has to be no fuel being supplied.

DUH, turns out Stupid here (that's me) screwed up putting the shut off valve in - it was causing the IP to give almost no fuel, no matter what.

Took the shut off valve off and put it back properly and voila - back to the good ol' days! Turbo working great, power back, etc. Geez, what a dork!

Thanks for the help Gsxr.

I'm going back to my corner now. No more car crunching for me this weekend.....

Ah, but one good question - what is spec 0-60 for the 2.5? I'm at about 16 sec. Should I be messing with things?
__________________
1983 240D Silver/Blue "Sadie", unknown miles. WVO single tank, FPHE, Injector Heaters, Aux Fuel pump. Alcohol/Water injection. Frantz oil bypass filter
1992 300D 2.5 Turbo Green/Tan "Jade" 206K

pdrayton · #10 06-11-2007, 11:54 AM

Thanks Pmari. I was going to post here earlier, but today my computer was buggered, so it's taken a bit longer than expected. I'll be updating the how to as well! Ouch, spent most of the day on this stupid thing (that's a transfered epithet - I asked my english teacher) and wouldn't want anyone else doing that....

pdrayton · #11 06-11-2007, 12:10 PM

I corrected the procedure above to reflect the proper way to do it. Proper means not spending almost the whole next day trying to figure out why your car doesn't run worth a dam. Basically, you should do as 2.5Turbo did - don't remove the stop lever. (I updated the first post to reflect that, so if you follow those instructions, you should be fine)

compress ignite · #12 03-02-2008, 01:01 AM

Excellent tutorial!
Sharp , Clear pictures!

Brian Carlton · #13 02-26-2009, 04:44 PM

Added to the DIY library:

http://www.peachparts.com/Wikka/OM602ShutOffValve

pdrayton · #14 02-26-2009, 05:51 PM

Whooo hooo, I'm famous!

stevekc84 · #15 06-18-2009, 10:25 PM

To all who helped, I owe you a big thanks, ( if you were here in Dixon IL, I would have you over for a steak dinner). I ended up taking off the intake manifold and the 3 rear fuel lines and then out she came. I used the mitivac to position the plunge rod and had no trouble (other than dropping a manifold bolt and having to take off the dirt shield under the car). Everything went back together real well and the car runs fine. Evidently that leak was also causing the car to not start in Park. I was having to shift into neutral to start, thinking it was an electric relay. Need to do some more research on this one to know what I am talking about. I didn't know so many things on the car were operated on vacuum. Again, thanks for your help.

By the way. I have been running WVO for the past year and a half with great results. I have been using the "Diesel Secret blend" and simply mix it in with the diesel. I found that running more than 70% WVO clogs up my fuel filter. Best results and performance is 60% WVO and 40% diesel.

I have also treated my engine and transmission with a Ceramic Treatment and on my last road trip I got 29 MPG driving 80 mph (3100) rpm for 1300 miles. The best to date before the treatment was 26 keeping it around 2300 - 2500 rpm. Mileage really dropped over 2500 rpm. This is on a 1991 350SD with 150,000 miles.