When I turn my key to start, the power cuts out - PeachParts Mercedes-Benz Forum

studjuice · #1 11-10-2012, 03:39 PM

I'm having a problem that at least I think is weird. When I turn my key to the on position the lights and radio will come on, then if I turn it to start the power cuts out (the starter doesn't turn on but I hear a click like usual). If I take the key out and put it back in and turn to the ON position there still won't be any power. But about 15 seconds later the power will come back on.

-Prior to this, since I bought it in July, the car has had trouble starting. Specifically it has had trouble making the starter 'start'. I replaced the ignition switch because thats what we determined here and at first it worked pretty well. But I think that because the shut off valve sucks (the last ignition switch was flooded with oil) it ruined this ignition switch. (now don't get me wrong, i wasn't planning on having it connected but after 2 days I forgot and shut it off with the key, since then has been acting like the old ignition switch) It will still start the car but it takes many tries before it will actually turn the starter.

-- on a side note, there is also a problem with the ignition switch and the glow plugs, the first time i turn the key to on they will click off after about 7-8 seconds. each subsequent times after that it will be even shorter, till it gets to about ~3 seconds before clicking off.

Not sure where to go with this. I'm thinking maybe the battery doesn't have enough juice to do it's job, but it has enough to turn on the lights and radio. Also that the oil in the ignition switch has raised the resistance(?) so the battery would need even more voltage(?) to get the starter to turn. I'm wanting to make a push button start, i got 10 gauge wire to do it and had them connected to the terminal in front of the battery to do it but now I have this problem....

vstech · #2 11-10-2012, 03:47 PM

this sounds like classic bad battery terminal or body ground terminal problems.
check the terminals on the battery, disconnect and clean them, then reassemble. also check the ground connection at the body mount, and the body to engine connection. also check the positive cable that connects to the starter.

vstech · #3 11-10-2012, 03:49 PM

of course, if the battery itself is bad it will do this also... get a meter, digital, and get an exact reading of the battery. it should read 12.75 or better if it's good, then try the starter, and see if the battery voltage drops. report back with all numbers.

Diesel911 · #4 11-10-2012, 03:52 PM

Disconnect square Connector that is on is on the Glow Plug Relay and see if you Starter will Crank.

X2 on the Wires, Cables and Grounds.

Is it possible more Oil Got into the new Ignition Switch?

kerry · #5 11-10-2012, 04:24 PM

Sounds like bad connections to me, or a bad battery. When's the last time you cleaned the battery connections?

studjuice · #6 11-10-2012, 06:29 PM

I cleaned the connections and tried to start it... and it started first turn. I think it was luck though.

After that I shut it off, and tried to start it but it was the old way where you have to turn the key many times. So I figured it was 'fixed' back to it's old way and was satisfied so I went to getting the push button started wired back up. When I tried it though it fried it again and my problems returned. After much trouble shooting I didn't figure anything out. for about 30 mins when I would turn the key the gpr would make a sick rattling growl instead of the usual silence -> click. then that stopped and went back to normal. Obviously I gave up on ever trying to get a push button start to work and just tried to get the car to not suck.
Eventually after trying to start the car, losing electricity, unplugging ground and positive from the battery, reconnecting, and repeating that for about an hour my car started and is back to the old way. I totally don't understand it, so can anyone shed light on this?

Quote:

Originally Posted by Diesel911

Disconnect square Connector that is on is on the Glow Plug Relay and see if you Starter will Crank.

X2 on the Wires, Cables and Grounds.

Is it possible more Oil Got into the new Ignition Switch?

I tried this while the car was messed up, and it didn't make a difference. But now I'm wondering what would happen if I did that with it 'working'

Quote:

Originally Posted by vstech

this sounds like classic bad battery terminal or body ground terminal problems.
check the terminals on the battery, disconnect and clean them, then reassemble. also check the ground connection at the body mount, and the body to engine connection. also check the positive cable that connects to the starter.

I cleaned them up and but now I notice there is corrosion on the positive wire parts under the plastic coating, the copper has varnished to a green just like a penny does. (can't think of what that's called).
Where is the body to engine connection?

vstech · #7 11-10-2012, 10:54 PM

on the 83 300D, it should be under the driver's side of the car, a braided wire bolted to the body of the car on one end, and the bellhousing bolt of the transmission on the other end.
corrosion in the battery cables is not a good thing. do you have a voltage measurement during cranking at the battery? if the battery voltage stays up around 12.6 during cranking failure, then it's the terminals/connection/cables. if battery voltage drops during cranking failure, then the battery is at fault.

layback40 · #8 11-11-2012, 04:33 AM

Quote:

Originally Posted by studjuice

I cleaned them up and but now I notice there is corrosion on the positive wire parts under the plastic coating, the copper has varnished to a green just like a penny does. (can't think of what that's called).
Where is the body to engine connection?

The best thing to clean them with is boiling water. It will take that green stuff off. As the water is so hot the connections dry out. A good coating of your favorite terminal protector is then needed. I use grease.

vstech · #9 11-11-2012, 10:04 AM

Quote:

Originally Posted by layback40

The best thing to clean them with is boiling water. It will take that green stuff off. As the water is so hot the connections dry out. A good coating of your favorite terminal protector is then needed. I use grease.

hot water makes sense from the drying out standard, but the best thing to clean corrosion from battery cables and terminals is baking soda, to neutralize the acid on them.
actually, the BEST way to clean up the battery cables is to replace them and the battery that is leaking sulfur vapors...

, but baking soda will safely clean up the acid, from the cable, and from the car itself. (using hot water with the soda sounds smart to me!

kerry · #10 11-11-2012, 10:27 AM

I always mix baking soda in hot water and pour it on my battery cables/posts to clean them. Coke works too from what I hear.

4x4_Welder · #11 11-11-2012, 02:23 PM

Battery cables are cheap, replace them if there is any corrosion around where the terminal and copper wire meet (green or whitish powder). Use a battery terminal cleaning tool to clean the battery posts, and wire brush any connection points like at the starter and bell housing. Put in the new cables, and once it's all tightened up solidly spray with a terminal protector.

studjuice · #12 11-25-2012, 03:10 PM

Replaced the battery terminals and that fixed it. The old ones were awful and weren't very tight. Also replaced the ground wire while I was at it since that was simple.

Now I got my push button start working successfully

next thing to fix is the oil leak.

Junkman · #13 11-25-2012, 03:39 PM

Quote:

Originally Posted by studjuice

Replaced the battery terminals and that fixed it. The old ones were awful and weren't very tight. Also replaced the ground wire while I was at it since that was simple.

Now I got my push button start working successfully

next thing to fix is the oil leak.

Bad terminals indicate neglect. Cleaning all connections including those on the starter, alternator, passenger fender and also the fuse box is a good idea. Disconnect the battery so you don't short anything.

I have never seen much of a need to rig these cars. Having to install a push button is unnecessary if the key switch is working. Key to start and starter engages engine and cranks. Fuel squirt into cylinders, compression then boom. You're driving.

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