Brand new instant swell glow plugs

[steelheadguy]

Since that plug is the old style (has the spade connector) isn't that a 6v plug?

I thought maybe this was the problem. When I put 2 glow plugs in series the 12v battery barely got them hot.

 

[dgr]

Steelhead, do you have a 7.3 controller on your truck? If it is still the 6.9, there is no purpose designed current limiter (nor a voltage regulator). On the 7.3 controller, there is a folded steel strap (z-bar) that adds resistance on the feed to the glow plugs.

On the 6.9 if you run a manual switch it will trigger the relay just as the thermo timing switch in the rear of the head. If you run a manual switch to the 7.3, the power feed is still current limited but you bypass the short cycle feature that detects a burned out glow plug. So you're sending the same total current to fewer glow plugs.

 

[steelheadguy]

I have the 6.9 controller with a manual switch.

 

[dgr]

Short of a complete rewiring of the feed side to larger wires, you are supplying the same current to the glow plugs. Your finger is just a substitute for the temp sensor.

 

[OLDBULL8]

Here is the 6.9 early GPC, the one that screws into the pass side head.