I'm a newby and just bought a November 1989 300E sedan

[Waynebro]

Hello All.

I just bought my first Benz. A November 1989 300E W124 sedan (not a 24V). Its in almost showroom condition with 134,000km. Incredibly straight with almost unmarked paint. Even the front air dam under the bumper is only very lightly marked, same with the area behind the wheels - almost unmarked from stone spray. Interior almost showroom as well.

There are a couple of downsides as always. It does have a cracked windscreen from what looks like a surprisingly small stone chip. I'm hoping this wont be an expensive problem to replace.

Second problem is its stopped running. When it ran the couple of times it ran beautifully except cold start took a bit of cranking. Once warm started instantly. Plenty of fuel getting to the fuel injection unit. Fuel pumps hard out of the fuel injection unit to the warm-up injector but not through to the 6 injectors. Its got us stumped at the moment. We took off the Electro Hydraulic Actuator valve, but not sure if its the problem. Fuel is certainly getting to it and its not leaking.

I'm a bit of a car guy but mostly 1930's - 1950's stuff.

Always liked 124's though so thought I would give it a go.

So I'm in for a bit of a learning curve for sure.

Not sure though if I shouldn't have bought a slightly later model with the computerized fuel injection?....a couple of mates have warned me about the mechanical injection. Hopefully it wont end up biting me too hard.

What does everyone think of 1989 w124??? Do they live up to the quality and longevity hype?
Should I have gone for later one???
Will it likely serve me long and well if well maintained???

I will post some pics soon.

Regards to all

[T-Modell]

Hi Wayne (?) here,

welcome! The predictions regarding your car will be difficult, as they touch the future ... if the car is that good and you put a bit of effort in, it will give you a lot of you. I remember the 300E very well, my father had one around 1986. He got one for a test drive at the beginning of that year and he let me drive (surprise) ... first time in my life, that I clocked 230

I think if you have 5 posts or so, you can show us some pics ... general rule here: no pics -> doesn't exist

Regards and enjoy your car
Thomas

[John Green]

I just bought my first Benz. A November 1989 300E W124 sedan (not a 24V).

There are a couple of downsides as always. It does have a cracked windscreen from what looks like a surprisingly small stone chip. I'm hoping this wont be an expensive problem to replace.

Second problem is its stopped running. When it ran the couple of times it ran beautifully except cold start took a bit of cranking. Once warm started instantly. Plenty of fuel getting to the fuel injection unit. Fuel pumps hard out of the fuel injection unit to the warm-up injector but not through to the 6 injectors. Its got us stumped at the moment. We took off the Electro Hydraulic Actuator valve, but not sure if its the problem. Fuel is certainly getting to it and its not leaking.

Hello and welcome. Do some reading up on ke-jetronic, there is heaps of info out on the web. Essentially it is a mechanical system, but with electronic overrides. This is done via the EHA and the idle valve, providing you with a richer mixture when cold and under full load throttle. That said if you unplug the control module (it's behind the battery) it will still run, but not as nice.

The cold start injector only runs below about 20deg and even then it only runs for a VERY short period of time. From memory at 10deg it is something like 2 seconds.

Take one of the injector lines off the fuel divider, find the fuel pump relay (also behind the battery) and bridge terminals 5 and 6 (you had better look that up as I am typing this from home and guessing) so the pump runs all the time. Depress the dunny flap a few millimetres and see what you get. You should have a very small stream of fuel.

[CraigB]

It is a robust system when you get it right and usually there are only few main culprits that cause the problems. Agree with JG to do a bit of time researching the system because it does make sense. Not sure I follow you - cold start has fuel but not injectors? Perhaps with line off cold start you have pressure, and that's right with it held there by accumulator and tells you accumulator ok. But as John points out, fuel only comes out injector lines when flap down and engine running or has that accumulator pressure for a while.... or if you bypass the relay as JG suggests and keep the pumps running. Hot starts often a problem with accumulator gone - but I have only had the cold start problem once and that was to do with wiring and cold start valve (on a very old W116 but same basics in k jet)

I like the simplicity of the k jet with a bit of understanding. The only later system car I have has issues related to the wiring loom. I don't think it is a bad decision, just need to sort and then will no doubt be very reliable. But I do have to say that W124 quality of plastic trim bits that break, saggy sunvisor bits etc, it just doesn't seem quite the same quality of the W126 I am more familiar with, but then each car has had lots of history by now and shouldn't make sweeping statements.

And windscreen should be cheap.

[Waynebro]

Thanks heaps. I been doing lots of reading on Kjet and watching MMWA (a 124 guy from Perth) on Youtube but I still got a way to go on KJet. I got a couple of mates who came to my place to have a look who are also stumped.

The car will not start at all, so I will do the fuel pump relay bridge test Wednesday morning when mates come over and see what happens.

Car had been sitting for a "while", so maybe blockage somewhere. Maybe some injector cleaning in order?

There's some varnish (not huge amount though) around the inlet to the fuel distributor tower and the EHA.

We also noticed smoke coming from the first injector (nearest to radiator) and less smoke from the second injector while trying to start it. The other 4 had no smoke.

Thanks again to all

[John Green]

terminals 7 and 8

[Waynebro]

Mates came over today to look at non-running 300E.

New eyes heard and saw start - up attempts.

Smoke came from injectors as always. Slight backfiring noises as well as engine wanted to start but couldnt. Mates concluded straight away that the smoke is petrol smoke and that the problem is most definitely Camshaft position (angle) sensor.

They thought that the fact that car on rare occasion suddenly started and ran beautifully was further evidence of ok fuel supply and bad camshaft position sensor

They were convinced fuel supply not the issue so we didnt do the bridge test as suggested.

So I guess I will pull radiator out and to have a look at sensor. Not sure of part availability.

Any comments most welcome.

Thanks as always

[Waynebro]

woops. I meant crankshaft position sensor

[Bartman4800]

https://www.benzworld.org/threads/1987- ... 57&slide=7

Hope this helps

[Waynebro]

Yikes. Sounds like there's both a front and rear crank position sensor.

Mates thought it was just the thing tucked down quite low behind the radiator.

Didn't know about the rear one. It looks tricky to say the least.

Quite a baptism for this newby.

[John Green]

Mates came over today to look at non-running 300E.
New eyes heard and saw start - up attempts.
Smoke came from injectors as always.

Smoke from injectors? As in smoke from where the injectors go into the inlet manifold? If so this must mean that the rubber seals that seal the injector to the manifold are way past there use by date and allowing excess air in to the inlet system (when they are not letting smoke out). I would start by replacing them, they are only a few $$$ each. One of the first rules of diagnosing problems is that if you find a known issue you fix it. I suspect this is not the only problem here, but it is still a problem and resolving it now remove it from the equation.

Google how to test a crank angle sensor, its easy.

[John Green]

Yikes. Sounds like there's both a front and rear crank position sensor.

The one at the front is for the diagnostic plug, has nothing to do with the injection system.