Hello again all! Got cold again here in the Mid-Atlantic and my 1982 Mercedes 300d has presented me with and interesting problem.

Today I went outside at about 11 am (~31 degrees F got down to 25 that night) and checked my battery voltage (12.87 V) let the glow plugs go until I heard the relay click off (about 30 seconds) and then try to start the car, engine cranks slowly and does not start. Get out and open the hood (so my car knows I mean serious business!) and try again (full glow) same thing. I then get out and look longingly at the engine remembering all the times it hasn't given me trouble for about 3 minutes. I get into the car and start the glow cycle and about halfway through (10-15 seconds) I turn the key and the starter whirls at full speed and the car starts right away.

Some of you may recognize me I have posted earlier and thought I found my problem as corroded ground wires but obviously if that was a problem it was only one of several.

My original post is here:
http://www.peachparts.com/shopforum/showthread.php?t=269490

I posted a new thread since most of that information doesn't seem relevant anymore, but I posted the link for any who are interested or if I am just wrong.

What would cause my starter to be so slow 1 minute then so fast 5 minutes later? A bad starter, solenoid, or ignition switch? How do I go about testing an intermittent failure like this?

Thank you all for your help and ideas.

If the '82 is equipped with the terminal box on the passenger side wheel-well, you can jump the two outside terminals and pretty much eliminate the "ignition" and neutral safety switches. Both of these items can be the cause of slow engine rotation or none at all when attempting a start. However the terminal box bypasses both. For this test you probably wouldn't even need to do a glow, as you are not really caring if the engine starts this one time.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

Why not pull the starter and have it tested on a bench?

My SD had an OLD starter on it when purchased (potentially since new) and would barely crank the car in the cold, to the point where I was stranded by it a few times.

You will be very surprised what a new starter does...

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Soooooooooo hard to get out. But may end up having to do this anyways.


@ Lycoming-8: Do I only have to jump the positive terminal? And I assume I would just be jumping the solenoid so I wouldn't need wires capable of hadling the starters inrush current?

I wouldn't pull the starter either unless I had to. Slow crank usually means not enough electricity as in weak battery or corroded connections. Corroded connections can be tested by measuring voltage drop. ie measure battery voltage across the posts. Next move 1 probe out to the cable terminal. Next move the other probe to the other terminal. Next move to one of the cable ends. Measured voltage should be = battery voltage across the terminal. An additional option is to drive to a parts store. They have a tester that can measure required voltage to turn starter. I think they can also measure amps.

I'm trying to find an intermittent no crank situation on a gasser. Most of the time all is well. Sometimes key to start & no crank. It has always started with a jump. Wife wants it fixed. I want to be sure before installing a part.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Hard to pull? I had mine out in about 30 minutes... you want hard, go change one on an early EFI M30 BMW (the M30B34).

Mine was a slow crank and the starter was dying, replaced it and problem was solved.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Homeboy,

I believe that you are correct about the amperage level going thru the terminal jumper as mentioned above. However some have advocated just using the two legs of an old pliers for the procedure. Just be sure the car is in park!!

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150

I was told this is unsafe due to the amperage involved while cranking . Maybe if the pliers or wire are insulated . Were talking 80 amps on a good starter so who knows how many on a bad one . Less than one amp can kill you . So if it gets a hold of you

Please correct me if I'm wrong

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Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

Correction: The terminal block does not carry the starter amperage. The terminal block just activates the solenoid then starter amperage passes thru the main cable directly to the starter.

The starter can be tested with an inductive ammeter placed on the positive cable going to the starter. It will tell you how much amperage the starter is drawing. I don't know how much amperage a good starter draws vs a bad starter but a comparison between a functioning starter on another car and a slow one on yours would probably tell you if your starter is bad or not without removing it.
By the way, the difficulty of starter removal is overrated in my opinion. I've replaced starters in about an hour.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

yeah 99.999% sure you are wrong. we are not talking about adding a jumper from the battery to the starter directly just from the battery to the electrical soliniod that then pulls in the contacts for the starter.
though you are right about the 1 amp thing, just hard to get 1 amp across your chest with only 12-14 V pushing on your skin.

went out this morning and it slow cranked the first time. then fast cranked but i didnt crank long enough for the engine to actually start (oops) then a third time it cranked slow again.

so i went and got a length of wire and jumped it. Seemed very fast and started up good. going to try starting the car like this the next couple of days to see if the intermittent problem presents it's self any.
if it starts fine for the next couple of days i guess i'll look at the cost of a new ignition switch/neutral saftey switch, and possible shunting them out of the circuit to test which is messed up.

@ hit man X: good for you. from what i've read here and on several other forums, and from my own experience it is not easy or a 30 min job for a guy like me.

There's a thread on here which describes how to clean the contacts inside the ignition switch if it turns out your ignition switch is not providing enough power to the solenoid to get a good connection to the main cable.
I think the NSS is typically a go/nogo type of failure as opposed to causing low voltage or amperage. The NSS can be jumped at a wire junction above the driver's footwell. Thread on here somewhere about that too. I think it says purple wires.
Alternatively, there's a picture in here of someone who wired a starter switch directly to the terminal block in front of the battery with a button in the cabin.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Sorry guys read the post wrong. Thought we were jumping the complete solenoid.

__________________


Experience : what you receive 3 seconds after you really needed it !!



86 300SDL 387,000? Motor committed suicide
81 300SD 214,000 "new" 132,000 motor
83 300SD 212,000 parts car
83 300SD 147,000

91 F700 5.9 cummins 5spd eaton 298,000
66 AMC rambler American 2dr auto 108,000
95 Chevy 3/4 ton auto 160,000
03 Toyota 4runner 180,000 wifes

Another area to check are the grounds Batt-Chassis and especially the Chassis-Engine. A loose chassis-engine ground caused mine to have an intermittent slow starter.

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Sam

84 300SD 350K+ miles ( Blue Belle )

['Will not fix "Bad" Wiring (and Grounds) or the Electrical Portion of the Ignition Switch]

It Takes the "Load" off your Ignition Switch(and ,Etc.)
'Ask Phil if he's got one.
Or if not,"Froogle" "Bosch WR1"

"Installing a Hard Start Relay, such as Bosch’s WR-1, can definitely enhance the starting action. Essentially, it “shortens” the
current flow from the Ignition/Start Switch from the Battery to the Starter Solenoid"

"OK, here's what you did. Picture the flow of the electricity now: You've taken the wire from the ignition switch that used to trip the solenoid off the solenoid and are now using that 12v signal to trip the relay. Even if there is a voltage drop you are still likely to have enough juice to trip the relay. Then you hooked up a wire to the big post on the starter, which is power directly from the battery about a foot away. Then you hooked another wire from the relay to the ignition switch terminal on the solenoid. Now instead of getting your power to the solenoid by way of Outer Mongolia, it's going directly from the battery to the solenoid, enabling you to get all the juice you need right to the solenoid. Now the ignition switch current only acts as a signal to tell the relay to send the power to the solenoid. As a side bonus this may help your ignition switch last longer as there will be much less electrical load on it."

Install DIY instructions:
(Oops,These are for VWs BUT a Bosch Starter is still a Bosch Starter)
http://www.type2.com/bartnik/relay.htm

Attached Thumbnails

     

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'84 300SD sold
124.128

I spent far too long on my SD starter when I did the R&R on the transmission. The starter had been replaced at one time and the mechanic was lazy and didn't use the supplemental bracket that attaches the starter to the engine block. Well, overtime the threads on the two bolts that attach the starter had wiggled a tad loose. Anyhow, when reinstalling this starter I couldn't get the bolts in straight. Struggled for the better part of a Saturday until I just let the starter win. The internal threads on the starter were stripped. I'm amazed it held in place until I removed it.

Anyhow, a locally sourced OEM starter and bolts including the "phantom" bracket set me back $50.

This silly issue was the most time consuming part of the entire transmission R&R.

Now that I know my way around the starter, I would agree that on an SD this would be approximately a 30 minute job, if on ramps and tackled from underneath. This would require no removal of other parts. You'll need a big of creative wiggling to get the starter through suspension parts.

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This area is typically used to brag about one's current or former automobiles.