Calling all m103 guru's - Cooling and starting issues
 

So I have a 89 m103 190e, Im having cold start issues where sometimes it just dies and every single time on cold starts i have to give it gas and it misfires and chugs until it get revs past 1500 then it seems fine. When stored in heated garage though it starts without gas and misfires minimally.
Then on warm starts it does the same misfiring and chugging until revved past 1500 then it seems fine.
It also does the same thing under heavy braking to a stop, it'll chug and misfire until revved from a red light to about 1500 then all is fine again

Now onto the cooling issue, when at speeds above 65km/h (40mph) the temp is at 80-85c then when brought to a stop the temp creeps up to over 100c and when idling or slow moving around downtown it gets to 110c, at this point it'll again misfire and sputter about until revved past 1500rpm.

I've changed the cap, rotor and spark plugs, put in a new voltage regulator, done front timing cover seal, cleaned the injectors with carb cleaner, new air filter, new fuel filter. I had a shop change the lamba or something along those lines and it didn't really help. The pass side aux fax is seized but the tech at the shop said it shouldnt really matter much

Should I be looking to change the spark plug wires and coil, put in new thermostat and water pump as well as fan clutch this summer ?

The chugging and hard start is usually leaking injectors. These are wear items, and should be changed.

The car typically will heat up in to the 100 ish degrees at which point your electric fans should kick in and bring you back down in to the 80's- 90's. You can (should) do a coolant flush, and new thermostat. Just keep in mind the temp fluctuations are somewhat normal.

Cooling is primarily a function of the mechanical fan, not the electrics. Especially when you have a problem at low speeds, that's where you start. The electrics are only a back up in case the system is on the edge of overheating. They should come on at around 105.

If the mechanical fan isn't engaging, then you have a problem with the fan clutch. I believe that by 89, all the 190's had viscous clutches. If this is the case, the only solution is to replace the clutch.

but when the car is stored in underground heated it starts 50% of the time no problem but when outside its just dying and misfiring, ill post a video of what im talking about

The situation is more complex than I can explain. Basically, 2 or 3 of your injectors leak, flooding the 3 cylinders. On the three, the valves may or may not be open, allowing the fuel to evaporate. Sometimes not. You hard start is basically intermittent. I had the same issue with my 300e years ago and the injectors completely cleared it up.

The m103 engine needs spark plugs every year or 16,000 miles
Cap and rotor every 2 years/ 32k
Wires every 4-5 years/ 50k

Only use genuine MB parts or Bosch.

If it's been a while since your last tune up, I would do that first.

I would check the cold start valve and see if it is operational, then go and check the coolant temp sensor, it might be fooling the ecu with a wrong ambient temp reading and not giving the proper cold start fuel mixture. Next look at the ovp relay it may be old and have the alternator output checked, these cars need a lot of amperage to run all the systems, the factory 65 amp alternator may not be enough. I had similar problem with a 300e and the alternator was this issue after checking all of the above.

Just an FYI, the only fan clutch that has been of good service to me is the Sachs brand. You will have to look to Arizona for it.

I suppose OEM would work well.

Rock Auto has a Hayden listed as the Sachs... some POS Made in China showed instead. :mad:

Yes. I am running the fan clutch for a Sprinter on my M103 cause I got a good deal on NOS OEM clutches, which are Sachs. I had a Behr clutch that did fine cooling the car, it just never disengaged, which sounded great on the interstate. I paid $50 each for two when I needed to replace the clutch on my dad's van.

And something i would do, is open the hood. And take the top of the fuse box , then turn all the fuses Change them for copper or brass type if they are the old silver ones. Check earth points on engine to bulkhead , gearbox to body , grease and refit. This is just maintenance .

Ragarding the starting issues, search for a thread started by me about a year ago, "fuel accumulator failure analysis", run the simple test, and go from there.

The viscous mechanical fan clutch should tighten at about 100C and if it does, you will hear a lot of "fan roar" at about 2000. If not the clutch is defective. Also, when very hot - say over 100C when you shut down the engine the fan should have a lot more resistance to hand rotation than when cold.

The two electric fans should engage at 105C. Test by letting the car idle to that temperature or a little above.

Duke

How often would you say for injectors? My 190E's motor probably has about 130K on it now. I've got some rough idle issues. Still trying to sort out.

I was putting some spreadsheets together on replacement parts.

Ah, I remember I had the same issue with the Behr I purchased new. It would NEVER unlock. :rolleyes: My city only econ dipped into the low teens in the 300SEL with that. 12-13 area. Comical.

Does the Sprinter have a higher flowing fan blade? Any pics?

I used the 9 blade fan off of a late M104. I think it's basically the same on the Sprinter 2500, but I think the 3500 or and OM606 uses 11 blades. Both of those are superior to the 10 blade M103 fan.

Hmmmmm, when I compared that fan blade on my SDL (which I think is the 606) the blade pitch was wrong.

I have always said the fan blade on the M103 is pathetic compared to the V8s and 603s

I had a similar problem caused by a defective coil. Ran great after I got it running but when coming to a stop sign, it started having idle problems. Put in a new OEM coil and it stopped.
Anziani
'97 CL600 55K