Normal glow plug relay operation.

[w123suv]

Yesterday I replaced auto lite glow plugs from PO with motorcraft. Two were burned out so lots of smoke when starting.

Before I put the new plugs in the plugs would cycle with clicking sound and gauge jumping after the wait to start light went out. After the new plugs were in the wait to start light went out it started great but no further cycling. I did have the block heart pugged in. Also new was that just after the wait to start light went out it flashed back on for just a second.

I should probably just be happy with the fact that it started up and ran great without smoke but I am just curios wether this is normal?

 

[ToughOldFord]

You don't say what year your truck is so if it's a '83-'86 then the block heater's probably has it warm enough to where the controller doesn't cycle the 'after-burn'.

If it's '87-'94 it should cycle the after-burn regardless and so your controller may have devolved an issue, but since after-burn isn't necessary I'd just leave it be as long as the initial cycle is as it should be.