1989 190E Starting Failure
 

I have a 1989 190E I6 with over 300k miles on it (mileage gauge stopped about 8 years ago a bit under 250k). Up until about two years ago it ran fine, before beginning to have trouble starting. Since then I have put in a new cold start valve, crank position sensor, distributor cap, and over voltage relay, along with numerous spark plugs, with some relief of the problem for a few starts after each replacement. About half a year ago it developed into a problem idling, before it stopped starting altogether. After the latter few parts being replaced on it, I left it to sit since then. I'm coming back to it now and I am still lost as to what could be causing the current problem.

Coming back to it today, it cranks when turning the key, the plugs spark, and the engine refuses to turn over without the help of an unhealthy amount of starter fluid sprayed into the air intake.

Any ideas on places to start poking around?

Sounds like it is not getting fuel.

Check fuel pressure.

Agreed.

I've recently learnt that the injectors clog up and often refuse to work if the car has been sitting for a while.

Switch the ignition on so that the fuel pump will run - then crack each injector line to see if any fuel comes out. Check the starting injector too.

If the injectors are getting fuel remove the injectors to try and free them up.

I found a quick blast with my diesel pop tester cleared the problem with my dodgy injector.

Make sure you fit the injectors firmly in position

What should the fuel pressure be showing? I have the tools to check it, but the car didn't come with a manual and some Googling didn't turn up any numbers.

If you go to www.startekinfo.com

Click on workshop resources

Click on CD/DVD

You will get to see a free and legal version of the W201 factory service manual (FSM)

This has all of the correct data in it (whereas some other sources of information might not be so great)