injector and injection pump test pressures

[GGR]

Mu cousin is restoring a Pagoda W113 280SL. He sent me an email asking for these pressures as they would like to test them to see if that's preventing the car from running properly. My worksop manual gives test values only for the feed pump. Could someone get me the test pressures for the injectors and the injection pump?

Thanks!

[jackson101]

DO these units have the Bosch CIS injection systems? Sorry, my son just bought his (our) first vintage Mercedes and I don't know much about them. I do know about Bosch mechanical injection though.

[GGR]

No, this is a six plunger injection pump, no distributor.

[bwostosh]

Over 200 PSI, A cheap test is to remove the pipes to the injectors, and spark plugs, crank the motor WITH THE SPARK GROUNDED and observe the squirt. Sleazy but I've done this. otherwise send the pump out for the $$ 600-800 $$ service on a test bench.
The test bench will do the same thing in a controlled way and measure the output volume balance.

[ctaylor738]

Pressure is not going to tell him anything because even a worn or out-of- adjustment pump will have good pressure. The key to a good-running engine is good seals in the pump, and the proper adjustment of the mixture for temperature, load, and throttle. This needs to be done on a flow bench. I would recommend sending the pump and injectors out for a rebuild. The places usually mentioned are H&R in New York, Pacific Fuel Injection in California, and Black Forest in PA. Then the pump will be good for another 100K miles.

A lot of people, myself included, have wasted time farting around with worn-out pumps. They usually end up sending them out and it's a "why didn't I do this sooner" thing.

[GGR]

Thanks Chuck.

I sent you a PM.

[bwostosh]

Chuck is correct, or if you have spares, do a parts substitution to a known unit.