I have a 1982 Mercedes W126 280se with the M110 motor. Brought it as a play car. Have been enjoying fixing little things on it. However went to use it and it wont start. Turns over fine, just wont start. Cracked the fuel pipe going into the injector body and had lots of fuel. Appears to be a ignition fault. These cars have a transistorised breakerless setup with a coil. While turning motor over checked coil and it had 12volts on battery side, and also 12 volts on side going to ignition module. Shouldn't the switched side have a on/off effect as the motor turns! Coil measures at about 2 ohms which I am told is good. Anybody able to help!
jmma,
Oct 22, 5:34am
Is there spark at the plugs !
matarautrader,
Oct 22, 5:44am
No spark at plugs.
carlz05,
Oct 22, 5:52am
Is the battery good!Car of this age can use the battery to turn the starter motor over, but doesn't provide enough to give spark to the plugs.Try jump starting it with another car.
matarautrader,
Oct 22, 5:58am
Tried putting jump starting, also a new battery to no avail. I suspect that the switching unit has failed but I'm no expert by any means.
intrade,
Oct 22, 6:00am
get a haynes manual if you keep the car .
matarautrader,
Oct 22, 6:08am
I have 2 manuals. Both have electrical diagrams which are very useful for lights, power windows etc. They show the ignition wiring but what I don't know is what readings I should see between the ignition module and the coil. The power to the coil is good and this car does not have ballast resistors so I measure battery voltage at the positive side of the coil. The coil is about 2 ohms so I would have thought that I would see something similar on the other side but flickering as the "points" open and close. But because this is a breakerless system I am not sure what I should see.
chebry,
Oct 22, 6:13am
That is the territory of a Merc workshop manual google is your friend
tmenz,
Oct 22, 7:33am
Yes, you're right - the switched side should be pulsing as the engine is turned over. If you have constant 12v there, it could be an open circuit wire or connection from the ignition module - or it could be an electronic fault in the module.
matarautrader,
Oct 22, 10:09am
Thanks for that tmenz. The cables all test OK and I can see about 200 ohms resistance in the cable from the distributor which is what it is supposed to be. But I dont want to test it whilst the motor is turning over as it may fry my meter! Failure of the ignition module is not that unusual either from what I googled today. It might be time to consult the experts. sigh .lots of dollars ( $US1200 for a genuine module)
intrade,
Oct 22, 7:59pm
plenty people who have parts for old mercs in this country just got to know where. some only wreck old mercs up to 91 and dont deal with anything after
Getmodule from merc wreckers, unfortunatelyno way to test them either work or they dont
matarautrader,
Oct 23, 3:34am
Saw auto electrician today. Took in electrical diagram, showed him what I had done and he said I had tested it correctly and the module was kaput. He has ordered a new one. $NZ200 for a aftermarket one. I can get one from the states for $NZ70 delivered, but I am happy to pay the extra, get a warranty, and also support the auto electricial who has been very good and given me better than good service over the past year.
kwkbrk . I have that site bookmarked and its a great resource all right.
electr70I am going to get the new module and also a second hand one as a back up.
dasfi,
Oct 23, 9:50am
A wise man once told me, A Mercedes, if ya cant afford a brand new one, ya cant afford a second hand one.
cowlover,
Oct 23, 10:08am
Good on you for supporting your local tradie.Just such a pity that so many would rather save the $130 and get a bit that then actually wasnt the problem etc.
kwkbrk,
Oct 23, 8:57pm
Got the same sort of message from a very experienced car sparkie not long after I bought mine . "That car was $305,000 in 1983. You are still maintaining a $300,000 car, except it is now 30 years old." I stopped complaining.
poppajn,
Oct 23, 10:36pm
This maybe different, but my daughter has a ML320 which kept cutting out, had it downloaded, was a faulty ignitition switch, new one fitted, had to be programmed into the injector pump and transmission. $535 all up
elect70,
Oct 24, 2:40am
Hope its not NZmade 1from same crowd that madecam angle sensors for VL coommomhores,went through 3 in 90 s@ $600 a pop . , so after last 1 boughtused dissy complete for$250& no more problems . Put me off buying any new NZ made electronicthings for cars .
00quattro00,
Oct 24, 4:14am
What a load of shit, i own a couple of old 80's turbo euro cars that were $160k when new and they hardly cost anything to keep going and they have done over 300,000km
matarautrader,
Oct 24, 6:14am
I brought this merc recently and paid less than $2000. Rated to do 130mph back in 1982. Think about the Ford falcon equivalent. XD Falcon 3.3 good for oh at least 90mph. After 30 yrs it still is tight, is in good nick and will give hours of pleasure. And hey its my toy. I looked around for a similar age car like a Valient or Ford and I paid less than a quarter of what people want for those. I enjoy tinkering with the car and I'm having fun, Isn't that what cars are all about!
carclan,
Oct 24, 6:55am
It sounds like it is the ignition module. Try a known good one and also primary and seconary resistance in the coil.
grangies,
Oct 24, 7:18am
Absolutely!
We own a W126 380SE.
We've had it for about 5 years, and only ever had minor niggly issues with it.
Way better than value for money ANY crappy old 1982 Falcon, Commodore etc.
The argument from the AussieHolden/Fordabout what the old Merc's may cost to maintain is laughable.
grangies,
Oct 24, 7:18am
Absolutely!
We own a W126 380SE.
We've had it for about 5 years, and only ever had minor niggly issues with it.
Way bettervalue for money ANY crappy old 1982 Falcon, Commodore etc.
The argument from the AussieHolden/Fordabout what the old Merc's may cost to maintain is laughable.
andrewph,
Oct 24, 7:22am
I used to work on them regularly and it will be either the dist. cap and rotor or the mixture adjustment on the fuel metering head or the 6! pin temp switch on the top of the head about half way along.
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