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A couple of things I am hoping to gain some insight here.
First off, the glow plugs don't seem to stay on very long at all, perhaps three seconds or so after truck has been sitting overnight. Granted it is not cold here yet, but I am wondering......is the cycle preset a standard delay no matter what? I can't recall how the glow plugs acted before I had her tore down a few weeks ago. Is the cycle somehow based on engine or ambient temp?
The second part of my question is this. Before the boy took off for school this morning I took note on the Scangauge what the temp spread was between the EOT and the ECT, it was around 3.5 degrees, with the ECT the lower reading. This mornings example was an ECT of 83, and the EOT 86.5.
Is this spread normal? I would think they should be at parity after sitting all night, but that is the calibration side of me talking, and I realize there is a margin of error, taking into account the age of the truck.
At any rate, the thing pops right off with a smooth idle. Granted this morning it was a little chilly at 52 but not cold.
Once the trucks temp is above a certain temp, no plug required and mine skips the cycle. I think at that temp it would remain on for 90-120 seconds.
ECT EOT spread is ok when cold. Tells me that your oil cooler may show early signs of flow issues as the water temps and oil temps transfer that temp between themselves. If water can't flow well, transfer doesn't happen. What are your temps after the truck is fully warmed up? That may be a better indicator. Should be less that 15° spread.... if your not EGR deleted, after the trucks fully warm and you drive unloaded, no towing, level ground at 65mph for 15 minutes.
The cold soak temp you put up are really to see if the sensors actually work, are close together and give you a starting point. They are already 3.5° apart.
Need a cold soak of 24 hours to truly test the equalization of the sensors. Shutting the engine down at 10:00 pm and restarting at 6:00am there is still latent heat in both systems effecting the sensors.
Need a cold soak of 24 hours to truly test the equalization of the sensors. Shutting the engine down at 10:00 pm and restarting at 6:00am there is still latent heat in both systems effecting the sensors.
Josh
Thanks Josh, I was not aware of that. That explains why it was reading the temp it was reading when the ambient this morning was around 52.
Once the trucks temp is above a certain temp, no plug required and mine skips the cycle. I think at that temp it would remain on for 90-120 seconds.
ECT EOT spread is ok when cold. Tells me that your oil cooler may show early signs of flow issues as the water temps and oil temps transfer that temp between themselves. If water can't flow well, transfer doesn't happen. What are your temps after the truck is fully warmed up? That may be a better indicator. Should be less that 15° spread.... if your not EGR deleted, after the trucks fully warm and you drive unloaded, no towing, level ground at 65mph for 15 minutes.
The cold soak temp you put up are really to see if the sensors actually work, are close together and give you a starting point. They are already 3.5° apart.
EGR is deleted on this one yes. The delta for the driving test is around 10 degrees so while it is only a matter of time I didn't replace it when I did the HPOP. I don't mind the fact I might have to do that down the road.
As for the glow plugs, it was never stayed on that long.
Is this a sign perhaps that the relay is going out? Or is it really just because of the fact it's basing it off of the trucks temp?
I'm sure someone out there knows the ins and outs of how the glow plug system works, any insight is appreciated.
If your basing the on time with the light on the dash... that goes off pretty fast in mine also... reality is, it stays active for about 90 seconds (even after the light goes off) and can be seen on the gauge (scan gauge for me) when system voltage jumps from 11.7v to 13.5v+ Once the cycle is complete, truck warms up to operating temps, mine (glow plugs) rarely come back on after the initial start of the day. Once the truck is above 80* ambient or so, the plugs really do nothing.
The light just indicates its ready to start, not that the plugs are off.
If your basing the on time with the light on the dash... that goes off pretty fast in mine also... reality is, it stays active for about 90 seconds (even after the light goes off) and can be seen on the gauge (scan gauge for me) when system voltage jumps from 11.7v to 13.5v+ Once the cycle is complete, truck warms up to operating temps, mine (glow plugs) rarely come back on after the initial start of the day. Once the truck is above 80* ambient or so, the plugs really do nothing.
The light just indicates its ready to start, not that the plugs are off.
Gotcha, yes I was basing it off of the little dash light. I'll check my SCII next time I start it cold. I was basing it off the time that the light was lit up. I think it was the older 6.9 or 7.3 where the light would stay on a long time, then go off and come back on when it was a cold start. I could be wrong about that but I drove a older diesel years ago that behaved this way so I just assumed that this truck was the same.
There is a SGII Xgauge that will show you the desired on time.
But yes that dash light is only there to tell you is OK to start.
Plugs will stay on longer if below the engine set point. I have it
in a book here somewhere and can look it up if you need me to.
There is a SGII Xgauge that will show you the desired on time.
But yes that dash light is only there to tell you is OK to start.
Plugs will stay on longer if below the engine set point. I have it
in a book here somewhere and can look it up if you need me to.
Thanks again Sean, if it's not too much trouble that info from the book would be great.
I can't find anything in the SGII book about that x gauge function. I did manage to get the x gauge for the ICP voltage done so am guessing this is one that is on youtube or elsewhere?
When you say it shows the desired time, does this just tell you how long the module actually wants the glow plugs on? Or does this show you something real time?
BTW the plug on time does not give a count down just a #
of the total time it will be on for. Then I think it goes to 0
when they turn off. Been a while,
