Glow Plug Relay Question

[robthebuilder]

I thought mine was bad- the past two days it's been hard to start and when it does, out comes a big puff of white smoke. (As discussed in other threads) I checked it today and had 11 volts coming through. After that I started it up and it was ok- no poof of smoke. Is 11 volts normal or is it going bad? By the way, once it's running, it runs great, no problems at all. Any thoughts?

1999 Super Duty, 7.3 Powerstroke

[sikktruk01]

11 volts on both terminals ? should be at least batt voltage. how long is it staying engaged (closed) ?

[robthebuilder]

The battery voltage was a little over 12. The relay stayed closed for a seemingly normal amount of time, about 30 seconds i'd say. So, if the output terminal shows less voltage than the battery voltage, is it going bad?

[sikktruk01]

yes. if output is lower than input you have a problem within the GPR but check the voltage at the terminals on the GPR to eliminate a problem with supply voltage to the relay. it should put out whatever voltage it's getting.

if the relay is only getting 11 volts and the battery is reading 12 you have a problem in the supply wiring to the relay....did that make any sense ?

[robthebuilder]

yes, that makes sense. I have the suspicion that this solenoid is going to act like a starter going bad... works some of the time, have to hit it with a hammer to get it to go, then it will finally go out completely.

[SCUFFY828]

11.0 volts when ignition is engaged doesnt bother me that much considering all the other things on the truck that come on when switch is turned on , relay may be weak like said , but even a new one may only show 11.0 volts , its not necesarily voltage but amperage that i would be looking for

[robthebuilder]

Yeah, I was thinking that too. It worked fine again today- truck started right up with no smoke. I'm going to keep my eye on it, and my ear- to listen for it to click on with the key. I won't replace it until I know for sure it's bad. Thanks for the help guys.