another glow plug question

My 79 300D is still very difficult to start. I replaced all the glow plugs, adjusted the valves, and changed both fuel filters. It's 32 F. outside and she's plugged in, but still no go. It's my understanding that the glow plugs turn off when the starter is engaged. Would it make sense to start over after every five cranks or so to heat the plugs up again? Also are the preformed solid wires between the glow plugs supposed to get so hot that they can burn you real good? Even though all my plugs are new, I've got this feeling they're not working properly. Does anyone know a proper test procedure? Thank you, CJ.

[psfred]

Chris:

Yes, the zigzag link will get red hot (it's a resistor link).

Most likely, you have a stretched chain or a weak starter. Engine MUST rotate at leat 100 rpm to start, slower and it will take forever if it starts at all.

A stretched chain will give both late valve timing and late injection, and it won't start below freezing. Will run fine if you ever get it going, but starting will be problematic.

Check the chain -- align the marks on the cam and front cam tower and read the number off the crank pulley. More than 8 degrees and you need a new chain.

It's also possible you have low compression. You will need to do a compression test to find out.

Peter

[P.E.Haiges]

That GP system is screwy and I can't figure why MB ever used it. The GP are actually 1.2 Volts as if they were designed for a 6 volt system. The wires between the GP are resistance wires to drop 6 volts or so. They are supposed to get hot, so don't replace them with copper wire.

Does you GP indicator glow orange hot? That is a good test of the GP system. The GP are not turned off when the starter is engaged. When you pull the starter handle to the start position, the dash indicator is shunted out (the glow disappears) to give a slightly higher voltage to the GP which remain energized when the starter is cranking the engine.

How fast does the starter crank the engine? A few fast cranks are better than a lot of slow cranks. It could be you starter or battery are getting weak. Or it could be a poor connection in the cables (either end) from and to the battery and starter or ground.
See if you can feel a hot spot in these cable connections or measure the voltage drop across the connections, it should be almost zero.

The next test for hard starting would be a compression test.

P E H