Key Ignition has lost it's springback ability?
 

First off: we are dealing with a mb 1985 300D. Ok so after many hours searching for answers now I must ask a few questions.. I am having ignition problems... I have narrowed it down to either the ignition switch, the neutral safety switch, a worn key, or the engine grounding cable.

the problem started with my key not being able to turn correctly.. after a while of jiggling i was able to get the key to turn... it will turn without resistance into all key positions.. even the starting position which i believe is position 3. The interesting thing is when it goes into 3, the glowplugs do engage as I can easily start the car by jumping the starter solenoid on the passenger side under the hood, yet the key goes into this position without any kind of resistance and without the springback feature that is normal (like when you go to start your car you move the key from the "on" position into the "start" position and it automatically springs back into the "on" position) for me, I am able to move the key to the start position, and I get no response, no starter, no springback, nothing.. this leads me to believe my problem lies with the ignition switch and not the tumbler the grounding wires or anything else, is this a safe assumption to make?

some more background.. related to this issue and arising on the same day.. when i take my key out of the ignition, my dash lights for my battery, my brakes, and the emergency brake stay illuminated as if they key is in, which is frustrating and will drain my battery (over a few days) if I do not disconnect it, also as I said I am able to start the car (only by jumping the starter, as long as the battery isn't drained and I get the key into the right position for the glow plugs to turn on), but the tachometer isn't working right now either..

is this problem likely with the ignition switch, and if so can I remove it without drilling the steering wheel lock out that other have mentioned doing to get the ignition assembly out on other threads here (as i said my key will turn with jiggling and i am able to remove the ignition cylinder tumbler if I need to), or are these problems something with the electric or vacuum system of the car? OR something else completely? the neutral safety switch perhaps? (edit: just remembered, one of the things that initially made me think this could be nss related is that about a month before this my reverse lights had gone out.. I figured it was a fuse but never could figure it out.. some people related that to the NSS, though this problem along with some of the newer problems i'm having could all be unrelated from one another.. one thing i know is that the problems with the key not engaging the starter and the dash lights staying on when i remove the key all happened at the same time.) ... (I am having trouble finding both the engine's grounding cable and the neutral safety switch) sorry I am a complete newbie, both to auto work and this forum, so I might not understand everything completely but I'm trying :D


hoping to be able to fix the problem myself or at least be able to narrow down the possibilities before taking it to a mechanic. thank you very much!

Check out this link
 

I think your seeing a different manifestation of the same problem. The tumbler itself does not contain the "spring back mech". It has to be the lock. This has to be the first time I've heard of the steering lock mech. free wheeling, instead of siezed up. :confused: :eek:


http://dieselgiant.com/repairignitionlock.htm

The link you posted I have already read, and while it is enlightening, I don't think my problem is with the part that he needed replaced.. I can already turn the key enough and remove the tumbler in place with a paperclip without removing any other parts of the assembly if there is a thread about fixing, cleaning or replacing the lock switch that would be really helpful. I already thought that it wasn't the tumbler.. I did think that it was possible because of the necessary jiggling, i have since narrowed it past the tumbler.. but maybe I'm using the wrong words.. the part out of the ignition lock assembly that I suspect is possibly the root of my problems is labeled number 7 in this diagram:
http://home.comcast.net/%7Ephantoms/...k_assembly.jpg
when I say ignition switch I only mean the starter switch which I believe is the electronic part of the ignition? is this what you mean by it has to be the "lock"? should I remove the cylinder tumbler, and attempt to turn the switch with something else? (I have no idea how it would be any different from the cylinder turning it but who knows?? someone else has posted about having a key not work but removing the cylinder and using pliers on the starter switch or "lock" which apparently worked great..) Can the "lock" or "switch" be taken out and cleaned or maintained in anyway or is the only solution a replacement? and as to my question.. if i do end up removing the starter switch, am I going to have to somehow drill out the steering wheel lock as others have mentioned doing on here like in the thread you posted?? (my steering wheel isn't locked up abnormally or anything, and I can easily turn the key and remove the tumbler.. is the drilling on the part connecting to the steering column necessary even if they key can turn the ignition? as a theft prevention its hard built in and needs to be drilled out or only when the car's ignition is locked?)


even though I don't think this is a problem with the actual tumbler cylinder (mainly because the key doesn't spring back when moved to the start position, which ive been told that the spring is located in the "starter switch"), I already have ordered a new key from my dealer using my VIN# (hopefully my ignition assembly is still the factory original :laugh3: .. so if the problem is from a worn out key.. I guess I will find out on monday.. (unlikely but i figured its worth a shot and to have a backup key for the $10 it cost)


edit: ALSO: I also have vacuum problems such as only being able to see the autolock on doors while the car is running.. and i notice there are vacuum lines (i think) going to the lock assembly.. is it possible that a vacuum problem is making the lock malfunction, or that the lock is somehow impairing the vacuum's functioning?

Afaik
 

Most people replace the entire steering lock mech. That would include 1, 7 & 10.

5 & 6 are the tumbler assembly.

2 is the threaded black cover.

I think 11 is part of the lock assy' (vac ports).

8 is the connector for the "key in" alarm, I believe that is also part of the steering lock mech.

EDIT: yours would be the "2nd version"

I have the same problem. Haven't had the time to fix it, but I know what the problem is.

Part 7, the starting switch, worked itself loose. With that part loose, there was play at the back of part 5, the locking cylinder, which caused the tang on the back of the cylinder to break off.

With luck, your switch is loose and tightening will fix it. If you are unlucky, the cylinder will have to be replaced using the paperclip method.

yes, I know all this.. I'm not sure if this is my first choice though as I have other issues that seem like they may be related.. also is there any way to clean the #7 piece?

are you sure this is my exact and only problem? I will try checking if it is loose in the morning.. and if one of the tangs broke off the cylinder... how do i tighten the switch if it happens to be loose? do I need a special tool?

I am the one who used the needle nose pliers to start my car. I have not repaired my problem yet, but will be looking into it further today. I believe that the switch, part 7, is what you need, if it cannot be tightened. I will be disassembling the entire locking/starting mechanism today and will post later what I find.

how do you tighten it? is there any way to clean it or re-grease it or anything?

Okay, here is what I found. I was having the same problem with the key turning but no resistance when turning to start and starter not turning over either. In part #1, the steering lock housing, there is a part that connects the cylinder to the switch. If you look at the bottom of the key cylinder there are 2 tangs that line up inside the locking mechanism. The steering wheel locking mechanism runs through the lock housing. On the other end of the locking mechanism are 2 tangs that connect to the switch, part #7. They are not as large and beefy as those on the back of the lock cylinder. Both of the tangs on my assembly are broken. Therefore, when I turn the key nothing happens. After removing entire assembly (pay attention to key positions mentioned in Diesel Giants write up, very important), I removed part #7, the switch. Basically it is contacts that open and close by a cam. The springback action is actually not a spring at all but a stiff piece of metal that "springs" back into position when released. As far as your other issues, if the cam is in the right position the contacts for dash lights and glow plugs will be closed and therefore activated. I ordered a new ignition lock housing. It comes with a new switch, although I don't believe there is anything wrong with the switch itself. I intend to use my original lock cylinder. Naturally, the lock housing is the most expensive part. Hope this helps.

at the dealer they told me that the actual mechanism that gives the key the spring back is located in the switch, not the cylinder, not the housing.. was he mistaken and the spring is actually located in the housing?? I can get the switch part for about $40... would much rather replace this than buy the housing as well for $200 if it is unnecessary.. have you seen the physical piece of metal that springs the key back? are you sure its in the housing?

btw i tried using the pliers trick and it wont start my car.. the part inside just can turn around and around.. it does click into certain positions but i believe it somehow can turn past the start position.. very weird..

can the spring piece of metal be replaced independently somehow, or how about the switch (because its not just that the key doesn't spring back the key doesnt start it as well).. how is the switch removed? when i unplug the wires from the back will i be able to access the screws?

Also in the mean time I am unplugging my battery's positive cable when I park my car so that it doesn't get run down from the dash lights staying on... it has been fine a few times but other times it seems like it doesn't have enough juice to start it up and I run it down completely while trying to jump the starter.. should I remove the negative cable from the battery when I'm not using the car as well, is it possible that the negative being attached could somehow drain the battery? or was this a symptom of my battery just never getting fully charged... I drove it around for a good 40 minutes...after it had died.:dizzy2:

The dealer is correct. The "spring" is in the switch. However, I do not think this is your problem. As stated earlier, this is basically a 3 part system. There is the lock cylinder, the steering lock mechanism(which runs through the housing), and the switch. When you turn the key, the lock cylinder turns the steering lock mechanism which turns the switch. There are tabs on the back of the lock cylinder and also on the end of the steering lock mechanism. These tabs go into slots that connect the parts. My problem was the tabs on the steering lock mechanism were broken off, therefore no contact with switch. That is why with the pliers it just goes round and round. It is not connected to the switch. To remove the switch, I believe you will have to remove the entire assembly. Once removed, the switch is held on by 3 screws. They are under the wiring harness. I got my new housing today, installed it and car is starting fine.

Damn I think that makes sense.. I currently can't afford the $200 for about a week for the new housing.. do you suggest I go to a junkyard??

also.. you said you were able to start yours with a pair of pliers? where did you put them so that the actual ignition switch could turn?? this would be much easier than jumping the starter everytime I need to start my car.

now my car wont even start by jumping the solenoid... even with someone charging my battery it will catch for a second and then seize up... :(

My memory is failing me, but if you do a search on my name and "ignition lock" you should find my post where I overcame my problem with a tip from another member.

Once I removed the cylinder I could look inside of the tube that was still in the dash. There were two ears that would spring into place and lock the steering wheel. I was able to keep those ears apart by wedging in a piece of hard plastic I cut to fit. By doing that I completely resolved my sticking key/ignition problems. That was about a year ago and it's been fine ever since, although I do not have the benefit of a steering wheel lock.

Its the tumbler, replace it before it breaks. If it fails and you cannot move it its a monster job that requires you remove the steering column. On the W126 you can pop it right out with a paper clip if you can still turn it. The W123 should be similer.

You can get a vin cut one from the dealer, or for a little less a generic one from Worldpac.

I honestly don't think that its the tumbler...

now I'm having problems starting the car no matter what I do. time to replace the ground wire and spark plug wires...

I think I got lucky with the pliers. I also think this is what finished off the tabs on the steering lock mechanism. You could take out the key lock cylinder, and then use needle nose pliers to remove the steering lock mechanism. Then you should be able to put a screwdriver to the switch itself. I may take a while to catch the slot in the switch right. I started mine like this a couple of times. If you do this, and are going to drive it, you will need to insert something in the lock housing to keep the steering wheel from locking. I used a 13mm wrench. You have to insert it in the housing so that it holds the lock open. Also you will have to shut it off by removing vacumn from the shutoff valve or by pressing the lever down on the shut off valve. I don't really recommend driving it like this, but it beat having to pay the tow bill to get it home.

Well if you can't turn the key the tumbler is failing. However after reading the post again, it sounds like the ignition switch is dieing.

You probably need 1, 7 & 10.

delayed starter engagement
 

I just replaced my tumbler on Saturday. My key wasn't stuck, so I didn't have to do any grinding. The spring hasn't lost it's springback, but it isn't great.

Aside from the spring, my starter wouldn't kick in until a 1/2 second or so after turning to the start position. It was also slow to disengage. After taking the Ignition switch apart, I found my problem. The switch is generously greased, and over time my switch contacts have become loaded w/ dust, grime & grease. I will be installing a new switch as soon as time allows.

Mark