1972 280SEL 4.5L won't start.

1972merc280sel · #1 07-12-2012, 01:36 AM

I have a 1972 Mercedes 280 SEL that I have not been able to get running. I had it running well but took it for a car wash and i must have sprayed something under the hood that caused it to not start. I was able to use a jumper and by pass the si,oniod on the starter to get it home but after that i cant get it to start. Replaced the starter and the ingnition switch does crank the carso i put in a push button to crank it. I can get it cranking but the .4 ohm ballast resistor burned and smoked on me. Will this cause it to not start and is this the reason for my problem from the get go, did I spray it and it was hot causesing it to malfnction? Would Like Help Please!!!!!!

I got the car to start but the engines runs rough and then after a bit it dies and wont start again, I bypassed the ballast resistor, is this causeing the problems?

bwostosh · #2 07-12-2012, 09:45 AM

In general, are ALL the motor functions correct?
When correct the car can be driven into a rainfall at any speed and water blown throughout the engine compartment.

There is supposed to be a black cover over the distributor cap to prevent water around there from getting in. The trigger points chamberr must be sealed. those can and will get wet.then cause these symtoms.

Electric components are susceptible to water intrusion.
WD-40 after a engine wash is a possibility to fix this.

smiffy6four · #3 07-12-2012, 10:13 AM

Bypassing the ballast resistor will cause the ignition points to burn out. The resistor is bypassed while cranking( to give full battery voltage to the coil). When the key returns to the run position, the resistor is back in the coil circuit to limit voltage to about 9v to prolong point life.

meltedpanda · #4 07-12-2012, 10:34 AM

I'm with Brian, sounds like water intrusion into electronics , bypassing any of the ignition components is not a good idea on an MB. They are there for a reason. Unless you go to optical ( and in some cases even then ) keep the resistors in the circuit

gingerkid · #5 07-12-2012, 12:55 PM

maybe some water got in the dist cap?

1972merc280sel · #6 08-03-2012, 08:27 PM

Well all, good news it started and I ran. I was able to drive it around the block. Was scared the whole way. Haha. Any way. Does anyone have a picture of what the ballast resistors look like connected and with the wires hooked up ? Also arethe ballast resistors suppose to get hot? Also does anyone know te easiest and cheapest way to get the windows to rolls up properly. The motors work but it sounds as if the gear of something is worn. I have to help the window up to close because it sounds like slipping. Thanks again for all your help everyone.

meltedpanda · #7 08-03-2012, 08:35 PM

take the door panel off, clean and lube, unless the mechanism is broken it will be obvious what needs to be done, the resisters do get hot.
Are you running original point set up or pertronix?

1972merc280sel · #8 08-04-2012, 02:44 AM

Quote:

Originally Posted by meltedpanda

take the door panel off, clean and lube, unless the mechanism is broken it will be obvious what needs to be done, the resisters do get hot.
Are you running original point set up or pertronix?

I don't know what you mean by "running original point or pertronix" ? Ok I was just making sure. Do you happen to have a picture of them hooked up. I want to make sure I have them connected properly.

meltedpanda · #9 08-04-2012, 08:56 AM

original point and condensor set up or pertronix electronic ( retrofit) ..my picture wont help. I do believe there is a picture on this forum somewhere . PM Graham, I think he sent me one some time ago or made the post

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