That's a 25W loss, per glowplug, somewhere in the wiring. You'll only need 100 milliohms of resistance to get that much loss @ 16A, so it could be spread out across too-thin wiring and corroded contacts. Take every connection between the battery posts and the glowplugs apart, clean till shiney and reassemble and I bet the loss will be greatly reduced.

Don't know if that 25W loss will make much of a difference though -- 9.4V@16A is only 150W to begin with -- 25 more watts probably won't tip the scales and make it start.

Chances are, there's something else wrong too.. like the starter isn't turning over fast enough or the diesel spray can't contact anything hot enough to ignite in the cylinder. Maybe it's as simple as the glow plug really isn't going off when you crank so the starter doesn't get enough juice to turn her over fast enough to start.. or perhaps the plugs are so coated with soot that the diesel spray can't contact the hot metal.

Check to see that the voltage on the plugs drops to 0 when you crank. You could also pull the plugs and check to see if they literally get glowing during a glow cycle. No glow, no ignition. It would also give you a chance to ream the holes so the diesel spray can better get to the plugs.

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'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

When compared against the available battery voltage, the voltage drop is rather significant.

>> (1.6/10.4)*100

ans =

15.3846


Some 15%

However, as the power in the glow plugs can be written as V^2 / R

>> 100*(1-((10.4-1.6)^2)/(10.4^2))

ans =

28.4024

Compared with a system with no voltage drop, there's 28% less power available to heat the prechamber. (subject to the assumption that R doesn't change)

Obviously, you'll never get a voltage drop of zero, 1.6 volts is excessive. 0.3 volts would be good.