Thanks.

Guess we may end up on having the car hauled back into town to some shop that knows how to check it... we are going in circles and getting nowhere with it. I was afraid of this.

Down for the count... car still broken. We have tried everything everyone has said. The MB mechanic (20 miles away) was called and he cant even come and check it until the 26th and its $50 just to come and look at it - then another $50 if he has to go back to his place for parts, etc - then who knows how much more to actually repair. We may go that route unless we just end up putting it out to pasture. This whole ordeal has been frustrating, not having anyone really local that knows about Mercedes. I have been thinking of giving her my car and buying me another and junking this one out (I am going to discuss this with her - too bad the CFC is over ). Dont know what its worth (I know I gave a pretty penny for it 4 years ago when I bought it)... everything works, NO rust, no dents, nice paint, very nice interior, cold a/c, and it ran perfectly until I filled it with gas then it would not start - now its very hard to start and missed and then stalls again. I just think we are tired of dealing with the no-start/poor running issue. Also dont smoke or leak. No head gasket issues, etc.

here is a pic...

If you engine has no big mechanical failure, it either has no good ignition or no fuel.

1 Ignition.
The best way to check the ignition is with a stroboscope lamp (oscilloscope is even better, but very expensive).

The second way is;
- find about 5 feet of metal wire
- take all plug out
- Put the caps back on
- fix one end of the wire to the engine
- wrap the wire around the metal part of the plugs (upside down)
- Make a string of all six plugs with the wire and fix the other end
to the other side of the engine.
- Pull the fuel relay
- Have someone crank the engine and watch the sparks. They
should all fire (powerful spark)

Do not stand to close to the engine, some fuel/air mixture may come out and ignite!!

Put the plugs back in and reinsert the fuel relay.

2 Fuel delivery.
- Take two open end wrenches and loosen the fuel lines from the
injector (just a little bit loose).
- Have someone crank the engine and see if fuel seeps out of the
lines.


Rob

Recommend having your 300SEL flatbedded to the MB tech. With the car at his shop he will be able to properly diagnose the problem, and you won't be paying for his roundtrips to get more parts.

Your car looks far too nice to even consider parting it out. I suspect it's a relatively minor problem that an experienced MB-trained tech familiar with your vintage automobile can pinpoint quickly. You want to avoid selling your car in desperation, and have someone else spend $100 to repair the problem.

__________________
Fred Hoelzle

Hes working on a 300SEL.

__________________
91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

Been a couple of months... to update, the car has still been setting, collecting dust and spiders.

My dads nephew is a general mechanic and he brought a neighbor who is also a mechanic, but specializes in Volvos to look at the car this evening. Can you believe they turned the key and the car started right up? It ran smooth for 10 minutes, but when they would up the rpms, the car had a bad lifter peck. I am guessing all of the gas we had "pumped" up in there when we have been getting it to start.

Anyway, they told me to place it in gear and I did... again, it was smooth, but when I gave it some acceleration, it stalled. Started back up, this time even in park when I would rev it up, it would sputter and miss and run poorly. They both said to first give it a general tune up. New fuel filter, new plugs, new plug wires, etc....

I am wondering, what are the BEST lowest price spark plugs for the M103? It has platinum plugs and one MB tech told my dad these are not good for this engine. They also said to replace the entire distributor cap.

Also, I priced plug wires... $100 for the Bosch or $70 for the Duralast... is it worth the extra $30 to go with the Bosch?

OH, I did a search on the plugs for the M103 and WOW, what a bunch of mixed responses! I hear use Bosch H9DCO, or NGK BP5EFS, TR5 NGK, etc.

these... http://www.autozone.com/autozone/parts/Ngk-Gp-Platinum-Spark-Plug/1988-Mercedes-Benz-300SEL/_/N-ii3phZ9n80x?counter=12&itemIdentifier=441315_0_0_

or these

http://www.autozone.com/autozone/parts/Bosch-Platinum-Plus-Spark-Plug/1988-Mercedes-Benz-300SEL/_/N-ii3phZ9n80x?counter=10&itemIdentifier=870942_0_0_

should platinum plugs be used in the M103? I am so confused.

The best plugs for the M103 are of the copper non-resistor type. Platinum plugs are not recommended. For plugs wires I recommend Beru.

__________________
1989 300CE

Thanks. I will look for the non-platinum plugs... seem to not be any listed at Autozone for this car. How much are the Beru plug wires? The Bosch ones are pricey enough... $102.

Ew, I found this... Beru wires are $132. @ this place. Kinda $ for something we dont know is the problem.
http://www.thepartsbin.com/catalog/?N=4294952487+1073&Vi=1668%2011149%204294963357&mk=Mercedes%20Benz&md=300SEL&y=1988&Nr=OR(AND(make:Mercedes%20Benz,model:300SEL,year:1988),AND(universal:1))

I wonder if these plugs are the ones that would be best... Bosch (I think these are non-platinum)

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Super-Plus-Spark-Plug-Bosch_15650376-P_960_R%7CGRPTUNEAMS_940831381___

All of those plugs shown at the parts store links are resistor plugs. Not the way to go for the M103 motor. Bosch H9DC0 or NGK BP5EFS (or BP6EFS) are the right plugs and are available either through MB dealers or the Classic Center in Irvine, and maybe even from Fastlane Phil. At one time, Phil told me they were not stocking these, but that may have changed. Agree that Beru ignition wires are the best.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

UPDATE!!!

Car is repaired! It was the coil! A MB mechanic told my dad to check the coil. He put one off of my old station wagon on it just to see if it would start and it did and ran perfectly.... then he went and bought a brand new one for that car and the car has ran all day.... no problems. The other day some mechanic came to inspect and it idled fine for 20 minutes, but then when given acceleration, it would miss and stall. Not anymore. Strange, I never dreamed it was the coil.

Someone had been helping themselves to the gas though... I had filled it up the day it broke down... then today when dad was working on it, the fuel gauge was down on "R" and the low fuel warning light was illuminated! We live in a rural neighborhood, mostly older folk, but apparently some hooligans or some grandkids of these people needed gas. Dad drove it to the filling station and it held about 20 gallons. Can you imagine?

Oh well, still need to get those plugs replaced since apparently the ones on there are not the correct ones (resister plugs are in there now).

Thanks for all of the replies!

These are the only ones I found on the site here... not sure if these are resistor plugs or not... the part # is slightly different.

http://catalog.peachparts.com/ShopByVehicle.epc?q=1988-Mercedes--Benz-300sel-Engine--Electrical&yearid=1988%40%401988&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6220%3AED%7C10000012%3AMBC%7C1515%40%40300SEL&catid=240798%40%40Engine+Electrical&subcatid=240800@@Spark+Plug&mode=PD

most likely it will turn out to be the fuel pump relay if its still the original old one.
For testing i had replaced mine ,a 9 pin with a !0 pin one .it worked perfectly except it will have a lower cut off point of 4500 RPM ;4 & 6 cylinder variations
mak
300se

Thanks. They had tested that and apparently it was OK. They "jumped" it somehow and the car still would not start. It was funny... some days it would not start at all... some days it would idle rough, some days it would idle fine for 20 minutes, but when you gave it some gas it would start missing, then stall out, etc. New coil and its ran fine... he drove it all over today, then I drove it about 45 miles this evening when I got off of work. I dont know, I hope that was the problem... no one knew, could not find any good mechanics to check it, closest MB mechanic was 30 miles away (and would probably have charged $600), etc. LOL, one mechanic told my dad that it probably had broken the timing BELT. I told my dad that car didnt have a timing belt. Only thing now is that there is a gas smell coming from the gas tank cap area... I guess the cap seal is bad... so bad that fumes come in the car... none under the hood, so it has to be blowing back in. Guess a new one is in order. Just wondering if an aftermarket one would be OK, of if I should purchase an OEM one here for $18.00.