Trying to get old truck running again. It was running fine when parked about 6 mo ago. Batteries were dead so I charged them several times and it wouldn't quite spin the starter. Replaced the batteries with new ones and brought truck into heated shop. Thought it would fire right up, but it cranks and still no start. Replaced fuel filter and filled it with fuel, cracked line going to IP coming out of filter housing until I had fuel so probably no more air in filter. Checked and I have 8 volts at one of the glow plugs, have 11 volts at fuel shutoff harness. The glow plug relay clicks after 3 -5 sec. I replaced it in 02. I also replaced in the past the EEC relay. Not sure how to test to see if it's gone bad??
I will check all the fuses in fuse box, but unless I blew one in the recharging and trying to start with crap batteries, they should be ok.
Any other ideas, something I am missing?

 

If the glow plug relay is clicking after just 3-5 seconds,then with the '87-'94 system,it means you have at least one bad glow plug.You can test for completely dead ones with a test light.The light doesn't turn with they are totally shot.To test for poor ones,it takes an ohm meter.
With the key on,you should have a good distinct loud click when you disconnect and reconnect the fuel shut off solenoid on the injection pump.

 

Ohm out each glow plug.
might need to crack the lines at each injector to get the air out as well