So I switched my ‘88 e250 over to manual GP’s. I have tested the 6 rear GP’s (the ones I can get at from inside the van) and they all test good. I will be testing the front 2 as well.

My question is, how long do people usually glow their plugs at different temps?

My van has been sitting in 20* temps for 4 days. Yesterday morning I did an 8 second glow and it didn’t start. I did another 8 seconds glow and it kinda acted like it wanted to start. I did a 10 second glow and it fired of and ran.

This morning the temps were high 20's. I did a 10-12 second glow and the van started after a minimal amount of cranking, but I wouldn't say that it fired off immediately.

All I did was remove the white wire from the relay on my GP controller and add a push button ground to the post. With this setup my WTS light just give a quick blink when the key is turned to the on position. I am thinking that this is the expected behavior since I can hear the relay close and see the voltage drop on my meter when I push my button.

Also, the clicking Afterglow helps keep the GP hot/warm during cranking to help heat the air coming in. Is it suggested that that behavior is somewhat simulated when manually glowing the plugs?

 

20 degrees.. About

Hold 10s
Off 5
Hold 5
Off 5

Start..

0 degrees.. About

Hold 10
Off 5
Hold 5
Off 5
Hold 5
Off 5

Start

.. Let em cool 5s before start and if needed press while turning over for the last hurrah..

Always make the first cycle longest because it's cold and takes a little longer to warm, don't hold longer than 10 seconds after initial cycle.. Give it a break between 5 seconds or slightly longer bursts till it's hot to go.
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with a properly working controller, my 88 glows around 10 seconds over 40 degrees. 15 seconds 30 degrees and under, and 20 seconds 20 degrees and under.
then it will after glow for 1-2 seconds every 4-5 seconds for about 1 minute to keep the engine idling.

 

Plus I always figured my controller is more in tune with the glow plug system as far as seconds on, than my thumb. At least on the later 7.3 systems. They've always been pretty bulletproof IMO.