M103 won’t start sat many years
 

Have an 87 300e that hasn’t run in 20-22 years. It ran when I bought it, but extremely poorly and misfired. Fuel starved, it would respond and run better with starting fluid.

Long story short:
New fuel pumps
New tank screen
Full tuneup with the correct plugs. Dist. Cap, rotor, wires
Old fuel drained, new fuel. Inspected the tank
Fresh fuel filter.

No improvements. Long cranks and won’t start without fluid and shortly dies right after.

I suspect the fuel distributor has went bad from sitting. I did get the car around the block for about a mile a few months ago but after that it went back to running like trash.

Anything else I should test? And how do you test these distributors?

Maybe you will get lucky with this:
Inside the fuel inlet fitting at the fuel distributor is a fine mesh screen.
Fish it out and clean it.

Hey Jake, I've had great luck with real strong injector cleaner for cars that had sat for 7 plus years. The few cars I did this with were running very poorly but that curred them after ideling for 20 minutes.

Convert it to full sequential EFI and u will have a car that will first time, start every time��

Thanks guys for the responses. I’ll give it a shot with the screen. I’m also gonna check the pump relay too

Do the fuel pumps run? With the key in the run position does any fuel spray from any injector if you push the round plate down under the air cleaner?

Good luck!!!

The metering piston in the fuel plate housing is probably stuck closed due to varnish, its a really irritating tear down but can be done.

I recently did a similar job but on a BMW, the metering piston needed to be soaked for a couple of days to let go.

After you go through the fuel system suggestions. Swap out the OVP ( next to engine "brain'-two fuses on top )relay with one from a known functioning car. Or get a used one from a junk yard or anything but a POC URO or other junk. Siemens is the best but often you can re work the solder joints in your unit.

Between my son and I we have had (and still have 3 124's) many MB's and this has fixed many !

I literally just went through this. Buy new injectors. Period.http://www.peachparts.com/shopforum/tech-help/415132-m103-fuel-distributor-fuel-pump.html

Thanks guys!!! I sprayed some starting fluid on one of the injectors and the idle came back and ran good. It must have an air leak through the o rings on injectors. I’m getting new injectors o rings distributor screen and main fuel filter. I removed two injectors to clean them with brake clean and put them back car wouldn’t start. I guess all the o rings are wasted. Some of the hard lines from the distributor are seized to the injectors. I soaked them in PB blaster. Any suggestion to remove them?

Clean the pipe/nut the best you can with a brass brush, then repeatedly soak it with penetrant over a few days if possible. Tap on each tube nut just after each soak.

Good luck!!!