powerstroke glow plugs

[tesla4210]

to get a good smoke free cold start I have to turn the glow plugs on twice. does this indicate a couple of bad glow plugs or that they aren't staying on long enough? (although the on-time seems sufficiently long enough) is there any way to check each glow plug without removing the valve covers?

thanks for your time

[4500]

you have to remove the cover

[ModMech]

Yes there is. The glow plugs are the outermost two of the five connectors. Remove the connectors, and using either test light or an ohm-meter check the outermost two terminals for good ground. Any that are open are bad (or the undervalve-cover harness is).