Re: better glow plugs for 96 7.3 powerstroke
Your son should be able to get it to start at or below 0F assuming he has:
Good glowplugs: Most of us would recommend only using OEM Motorcraft/Beru ZD-11 plugs. There are too many horror stories using others.
Good Glowplug Relay. The stock relay is notoriously lousy. I would recommend using a White-Rodgers (formerly Stancor) 586-902 relay (about $50) or a Western Plow 56131K-1 (about $16). I've used both with excellent results (W-R on the 94 and a WP currently on the 97). He should also test the plugs and relay per the below details.
For checking the injector/glowplug wiring: From each valvecover gasket connection's outermost pins (2 per connector) to ground you should get 0.1 to 2 ohms (indicates good plug and wiring). From each valvecover gasket connection's center pin to each immediately adjacent pin, you should get around 3 ohms (indicates good injector solenoid and wiring). You should not get any continuity from any of the outer pins to the 3 inner pins (indicates no shorts between injector and glowplug wiring). You should also get 0 to 1 ohms from each of the external harness connectors outer pins back to the Glowplug Relay's large terminal on the GP side (indicates good wiring from external connections back to the relay).
To check the glowplug relay (GPR), measure the voltage drop across the GPR's large terminals. While the GPR is active (up to 1.5 to 2 minutes after the key is turned to Wait-to-Start) put your meter leads on the large terminals (one lead on one large terminal and the other lead on the other large terminal). The measures how much voltage is being "lost" across the relay. A reading of 0.3V or more indicates a bad relay. Also, check the relay’s control wires (smaller wires) disconnected from the relay for battery voltage at the Red/Light Green striped wire and ground at the Purple/Orange striped wire (check both when the key is turned to Wait-to-Start).
97 F250 SC 4x4, E4OD, 4.10 LS, Basically Stock, Relocated Block Heater Plug, Ext Trans Filter, Tru-Cool Max, I/C Mounted but not Plumbed
SOLD: 94 F350 CC DRW PSD, 5 Speed, 4.10 LS, SBC Con-O, Baldwin Filter, Tymar HPX Hose, 3” DP, Bilsteins, $12 AIC, Coolant Filter, Explorer O/H Console, Trans Temp, Boost, and Pyro, Pedestal Mod, Gutted EBPV