'85 300SD CRAWLS on initial take-off
 

My '85 SD is abnormally slow after first start-up and will only crawl off the line when I leave the drive everyday. The outside temps are in the 80's and it has new filters, cleaned banjo bolt, boost line, but will not hardly move until the engine reaches operating temp or 2500 rpms (turbo kicks in). After the car is warm then it functions normally. If you let it sit and cool for 6 0r 8 hours then you have the same problem again. Am I just being paranoid? :confused:

Kevin

Mine used to do that too, but I'm sure you want a simpler solution than rebuilding. Check that the throttle linkage moves all the way to full throttle stop by depressing the petal. Pulling on the linkage by hand doesn't always give the same results due to lost motion in older, worn linkages. Also, check glowplugs - engine can sound OK, but not burning well when cold. Bosch offers a kit with new glowplugs and a glowplug relay/controller which runs up to 3 minutes to address such issues. Available through Fastlane

.... Tune the ALDA..... I'd bet 1/2 CCW will do the trick....

THanks!
 

The engine starts smoothly in all temps and doesn't use any oil in between changes and it gets great fuel mileage so I am hopefully not going to need to rebuild it anytime soon. I will try to address the linkage issue. Maybe it's just the linkage.

Kevin

Check the linkage first, just for grins. But I almost guarantee the cure will be about 1.0-1.5 turns (gently!) CCW on the ALDA... this is a VERY common problem and the ALDA tweak is the cure in almost every case. You should never feel the turbo "kick in", the car should pull strongly off idle and smoothly build power as boost pressure increases. What you are feeling is low fuel delivery and the ALDA tweak is *usually* the cure. (The proper cure is to yank the IP and have it calibrated on a Bosch test bench, but I haven't met one person willing to do that on a 617...! ;) )


:cool: :cool:

Oh yeah - one last thing. When was the last valve adjustment? You're supposed to do that every 15kmi. :eek: If it hasn't been done in a LONG time, you could have the valves waaay out of spec, which can create a pretty significant power loss!

:o

mine is kind of like that too
 

Mine starts slightly rough, after a couple minutes it goes pretty well. It actually goes a lot better than it did when I first got it. But- I can hear and feel the turbo wind up and it's not a smooth progressive offline delivery of boost from what I can tell. It spools up kind of late and hits all at once. It's very audible also. I really have no complaint with the way it accelerates now but I'd like to have it running as properly as I can anyways. I don't want to mess with the ALDA, the sealed cap has been broken anyway so obviously it's already been messed with. I adjusted the valves about a thousand miles ago. I think maybe I need a purge or some new injectors, but I'm a cheapskate and just had to have 2 new rear axles put in so I'll just do a purge and hope for the best.
This is definitely the coolest car I've ever had. I just wish the doors didn't bounce back when you try to shut 'em. All four of them do that and it gets on your nerves when you have to open and slam them five times in a row before they shut properly.

The ALDA is not as mysterious as you might think. If the capsules inside have not cracked, the ALDA can be rebuilt by replacing the shaft seal (which seems to wear out & leak after 15+ years, causing part-throttle power loss.) Photos of the ALDA internals are here:

http://www.meimann.com/images/mercedes/OM603_injection/

Just don't force the setscrew when adjusting... a couple of fingers tension is all that should be required to turn the screw after loosening the locknut. BTW, your door latches either need cleaning & lubricating, and/or adjustment...!

:eek:

Boy, I hear ya. I spent two and one half hours and $70. to get the driver's door on the SDL to operate just about perfectly. It is at the end of its available hinge travel and it still sits low by about 1/8 of and inch, but, it closes with just the effort of your pinky.

It's a long and tedious process, but, it's worth it in the end. PM me if you want more specific details.

Don't know if I want to try...
 

and adjust the ALDA. The factory cap is still there and I am just not comfortable with tampering with it.

Kevin

Kevin,

If you don't want to touch the ALDA, you have two choices:

1) remove the injection pump and have it calibrated at a Bosch shop

2) Get used to having a sluggish car that is not how Mercedes engineers intended it to operate. ;)


FYI, if for some freak reason you damage the ALDA, you can usually find one at a salvage yard cheap. They're all the same on 617, 602, and 603 turbo engines through at least 1987. Also, another option is to remove the ALDA and insert an extra shim underneath... this is a PITA, as you will need to fine-tune the shim thickness by filing it, etc to simulate turning the ALDA shaft screw. I long ago gave up on trying to leave the ALDA tamper seal in place! Just not worth the hassle...

:p :p

if I could I would, but I don't know how
 

how does one adjust a door latch?

There should be a section in the factory service manual about the door striker (latch). More likely they just need some cleaning and lubrication. Try that first. I know of very few MB's that require multiple tries to close the doors...!

:eek:

Hijaking threads again?
 

Hello everyone.
Where the heck did door handles come into a performance problem?? :confused: LOL

Too the main event!
STOP:
Do not mess with the ALDA yet.
Try cleaning the ALDA air feed banjo and line first.
http://www.peachparts.com/shopforum/diesel-discussion/102259-om617-turbo-alda-boost-pressure-signal-banjo-bolt-fitting-post707523.html?posted=1#post707523

If it is partly or fully plugged, the power loss is terrible.

Other thoughts:
Don't waste your time with this section, until you address the first section.
Remove the CCV tube from air filter housing and test drive, did the smoke go away?
Is it possible that you have too tight of valve lash?
Have you checked for broken or disconnected vacuum lines?
Did you replace the O rings on your filter housing oil return tube, upper and lower?
If you removed the fuel injector lines to adjust the valves, they are full of air, take it out for an Italian tune-up, 50 - 60 miles. :D

Not to keep hijacking this into a door thread, but one on my '85 300D was doing that, and it was the strap mechanism that holds the door open. It had broken out the ball bearing that locks into the detents and wouldn't close right, and the reaped slammings of the P.O. had misaligned the door. Interestingly, one of the ones out of a parts cart I am gouging, a'80 300d, had the same failure

Sounds like the same problem I had.......EGR was not fully closing. Please check that if your's has one. I've been out of the loop for a while (many trouble free miles (fingers crossed), so I hope you're car has one.

Gadzooks
 

Yours was not blocked off? :SHOCK:
You make a very good point, it is possible. :(
The EGR is a breakdown waiting to happen. :eek:

Whunter,

I have a brand new line from the Banjo bolt to the Crossover on the firewall. The line from the Crossover to the ALDA looks clean.

The top of the Crossover valve has some kind of rubber goo on it. I don't want to peal it off, just in case it's covering a hole or something.

Would it be a good test to run direct from the Intake manifold to the ALDA to see how the performance is affected?

I just don't want to do anything that will mess up the car.

So, would it be a good idea, performance wise and for off road use only ;) ;) ;) to block off the EGR tube? At least as a test...say using some heavy aluminum plating?

1) The valve has three ports. The top one is normally capped off - you can leave it alone.

2) Yes, you can temporarily bypass the valve and see if there's any change. Also you want to try to blow through the valve - if you can't, it's plugged, and needs to be cleaned or replaced!


:cool:

That's a roger, Roger. I did this on my 603's and my 617 as well. Photos of before & after are at this URL:

http://www.meimann.com/images/mercedes/OM603_intake/



Here's what a 603 looks like with the, uh, 'heavy aluminum plating' installed:

http://www.meimann.com/images/merced...EGR_after2.jpg

the top is a vent cap!!!!!!!
 

:eek: If someone put goop in it, the crossover valve can NOT work. :eek:
Picture attached showing cap.

Minor correction. The cap can be sealed, or not - it doesn't matter. When properly connected (manifold to bottom port, ALDA to center, cap on top port), and the overboost switch triggers, the center port switches from default position (connected to the bottom, manifold pressure) to the top position (capped off). My 617 refuses to build over 15psi even with the wastegate disabled, so I bypassed my valve permanently (although I don't recommend this unless you understand the risks involved.)

;)

I recommend using caution bypassing the over pressure switch. I had an issue with my '85 300D where right before it shifted and at high speed runs it would "cut out". I did some troubleshooting and found the hose that signals the wastegate had a hole in it and it was pressurizing enough to trip the over pressure switch. I can see where some engine damage could be done if the hose at the wastegate leaks badly enough to prevent it from opening up.

My mistake
 

Thank you for the correction. :)

Back to the subject...
 

Since I started this thread I figured that I would nudge it back into the direction it was intended to go before it flew out one of those open "doors" :p .

I tweaked the ALDA and it did help. The problem is really a morning problem so I will have to see if the ALDA tweak really helps the real problem in the morning when I start out of the drive.

Thanks for the input. BTW, would any of you be interested in a 1984 380SEL? It is complete but has no title. My friend wants $300 for it. It supposedly has a bad fuel distributor.

Hey, I hijacked my own thread! :confused: :p :rolleyes:

Kevin

Please see my post about Fuel Pump replacement/rebuilding
 

I was in this identical position once and the Forum convinced me my engine was dead. The good thing was I got a new 87 300D out of it, because thats what I bought instead of a new engine!
Later on, I found out that the Fuel Pump was toast. They do that sometimes because of incosiistent fuel quality and low sulfur in today's modern diesel....3 ou of 5 barrels were dead, the ALDA had a BAD leak, other parst were dead
...

Forgive me for a minor hijack of the thread, Jim, but was this on the black '85 I'm driving? I'm a little embarassed, but for the life of me, I've been unable to locate the "overboost protection" valve on this car. I wasn't troubleshooting anything, just trying to get acquainted with everything under the hood. Am I missing something obvious?


-- eskimo