Starting problem on my 230sl - Any suggestions?

[sam choong]

Good evening and greetings from Malaysia!

I have a favour to ask.

I restored the engine and injector pump of my 230sl over 10 years ago. It runs very well once started. However, even after restoration my mechanic was never able to sort out the starting issue. The engine had to be cranked for a long time before igniting from a cold start. Pushing down on the pedal helped. Once the engine was warmed up, starting was a bit easier.

I recently put in a new CSV, thermostat, diaphragm. The cold start issue was sorted for the 1st week after coming out of the garage. The car started quickly from a cold start. After more driving, the cold start problem started coming back. After a few weeks, it's now a lot worse than before. It now takes a lot longer to start the car from cold. I recently took the car for a 30 minute drive, turned off the engine and couldn't start the car after cranking the engine for a long time. I let the car cool down for about 30 minutes then tried again. After cranking for a long time, I managed to get the car started.

My garage reckons it's the fuel injector pump which needs to be looked at. Before I send the injector pump for a check up/overhaul, I wanted to see if anyone has any ideas? I'm happy to send the injector pump for an overhaul if this was indeed the fix. I've read some forums where the problem wasn't solved after the injector pump was overhauled.

My car is in Malaysia and I'm also wondering whether any of you could recommend a specialist for checking/overhauling this injector pump?

Much thanks!
Sam

[ja17]

Hello Sam,

First of all make sure your fuel system has correct fuel pressure and volume. The fuel filter and tank screen must also be clean. Most cars have a fine screen in the intake fitting of the electric fuel pump also. Next with the engine running, energize the intake starting valve on the intake manifold and the starting solenoid on the injection pump one at a time. The engine should falter and stop as you energize each device. This will confirm that they are able to function. Next after the engine cools hook a 12 volt test light or volt meter to each starting device (intake manifold cold start valve CSV and the injection pump starting solenoid. Each device should activate during cold starting. Get back to us with results or questions.

[rjgricius1]

Sam
Joe Alexander's post is spot on. If his advice does not solve your problem you may want to check the O ring for the CSV. My car had a similar problem that stumped my mechanic. It turned out that the O ring had a slit that was not apparent. This allowed gas to flood the engine, it world start after a lot of cranking and coaxing.

[sam choong]

Thanks so much for the pointers! Much appreciated.