Fuel issues, please help a newbie!

[RobParkerMB]

Skipping most of the story, I have no fuel coming out of a couple of IP outlets. Can you see in this picture a stuck plunger, or do I have to remove more parts?

Out of the two with their fittings off, the left one was producing fuel, the one on the right was not. Yet both looks the same. And nothing moves when turning the engine by hand.

I'm a decent home mechanic but haven't worked on one of these before so I don't fully understand which bits are meant to move and not.

Any help greatly appreciated.

[rwmastel]

I'm sure you'll get some good advice.

I'll say that I've been in this group since before we started a website 23 years ago. I'm a basic DIY mechanic who's brave enough to try new things.  I wouldn't touch the inside of the fuel injection pump without multiple experience people agreeing on the same advice and instructions. Tread lightly.

[RobParkerMB]

Well it already doesn't work so I have little to loose before forking out 3k for a refurbished one

[Lori]

There is more than 1 type of injection  pump in these cars so it would be helpful to get more information. 
Here is one thread that has a lot of info

https://www.sl113.org/forums/index.php?topic=886.0

[rwmastel]

And, once you join as a full member:

https://www.sl113.org/wiki/Fuel/Injection

[ja17]

Your looking down on the check-valve assembly. It  threaded on the outside. Find a fitting to scew onto it so you can pull it out. Below you will fine a cylinder and plunger (piston). The pistons get stuck in the up position and then do not pump fuel and cause the rack to stick also. Use penetrant and a blunt soft metal or hardwood drift to knock the pistons downward. Turn the engine and repeat until the pistons return down on their own. Eventually you may be able to free them up. When the pistons become free the rack will move freely also! Re-install the check valves. Torgue the fittings in place to 21 ft/lbs. (important)

[RobParkerMB]

Really helpful advice from everyone, thank you.
I have ordered what I think is the right thread to pull out the check valves, so will give that all a go.

I've just replaced all the fuel lines, electric pump and the tank itself, so I'm really hoping this will now get it going.

[BobH]

Hello Rob, there are a couple of helpful links on here

https://www.sl113.org/forums/index.php?topic=39147.msg285761#msg285761

[RobParkerMB]

Hello Rob, there are a couple of helpful links on here

https://www.sl113.org/forums/index.php?topic=39147.msg285761#msg285761

Thank you

[rwmastel]

The pistons get stuck in the up position and then do not pump fuel and cause the rack to stick also. Use penetrant and a blunt soft metal or hardwood drift to knock the pistons downward. Turn the engine and repeat until the pistons return down on their own.

How do these pistons normally return down?  Spring?  Vacuum below?  Fuel pressure above?

[ja17]

They return back down from a spring below.

[RobParkerMB]

Update. Made a crude little tool to pull the next part out (forget the name), and the piston is stuck in the up position. Good news for me (hopefully). Since it's only been stuck for 6 weeks I'm hoping it won't be too difficult to free up.

[rwmastel]

Just to cover all bases, are you aware that the 230SL injection pumps have their own oil reservoir and dip stick?

[RobParkerMB]

No I'm not aware of that.. will that be obvious when I look?

[rwmastel]

Just do a quick forums search.  Many discussion threads on it.  It's something new owners never know about.  Also, do a search for water pump lubrication, which is another 230SL thing.

[RobParkerMB]

Just incase anyone is interested, after getting the 2 stuck plungers free, checking the rack was now free- which it was, bleeding, and then finishing off some ignition stuff, she fired back up again and ran really nicely. I made a little YouTube video on the IP which might help other people, as I personally find it much easier working from a video than written instructions. That said, without the writers instructions from this group, I wouldn't have taken the pump to bits and been able to fix it. So, thank you