Grid Heaters and the Virtual Voltmeter
03-19-2004, 01:32 PM
#16
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...so I'm a little confused about the grid heaters (and the "cold start").
I suspect my problem is that I spoke to a young kid salesman a few months ago who probably was speaking out his... ummm... neck...
I know the Cummins doesn't have glow-plugs and does have grid heaters. Ignoring any issues with plugging in the block heater - when you turn the ignition key on a chilly morning, is there a light on the dash that says something like "wait to start"? ...and is that the grid-heaters "warming up"?
The sales-goober told me that this "new cold start" feature meant you can climb in, turn the key and go... in fact, that's what he did. Climbed in and fired it up without any wait at all. This was long enough ago that it was probably not a new 600, but was the "old" SO Cummins.
It doesn't matter much to me either way - I'm sold on the Cummins - but I'd like to be fully/correctly informed.
I suspect my problem is that I spoke to a young kid salesman a few months ago who probably was speaking out his... ummm... neck...
I know the Cummins doesn't have glow-plugs and does have grid heaters. Ignoring any issues with plugging in the block heater - when you turn the ignition key on a chilly morning, is there a light on the dash that says something like "wait to start"? ...and is that the grid-heaters "warming up"?
The sales-goober told me that this "new cold start" feature meant you can climb in, turn the key and go... in fact, that's what he did. Climbed in and fired it up without any wait at all. This was long enough ago that it was probably not a new 600, but was the "old" SO Cummins.
It doesn't matter much to me either way - I'm sold on the Cummins - but I'd like to be fully/correctly informed.
03-19-2004, 02:06 PM
#17
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BensBud, correctomundo on the W.T.S. light. Additionally after starting and until you reach 15mph, if the temperature is X degrees (cold), the grids will cycle on and off. After reaching 15mph, the grids will not come on again until you shut it off and re-start it. Cold starts? I've jumped in and forgotten to wait, especially in the beginning of the cold season. It will start, but usually smokes a little more. I've done it once or twice when the temps are in the teens............it doesn't like it. 
03-20-2004, 01:39 PM
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The voltmeter seems heavily damped (whether it's the gauge or the firmware), so it does not respond quickly.
Regardless - the reason the it reads low until the grid heaters finish cycliing is that until that is done, the alternator is inactive and you are just running off battery. Even if you disconnect the grid heaters the ecu/pcm expects them to be on and the alternator stays off.
I don't have the manual handy on this PC - but am 99% sure I am remembering that correctly.
Leonard
Regardless - the reason the it reads low until the grid heaters finish cycliing is that until that is done, the alternator is inactive and you are just running off battery. Even if you disconnect the grid heaters the ecu/pcm expects them to be on and the alternator stays off.
I don't have the manual handy on this PC - but am 99% sure I am remembering that correctly.
Leonard
03-20-2004, 03:11 PM
#19
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I'm not so sure about the voltmeter not reading the correct voltage situation. The fuel filter has a heater in it also. Grid heater, fan, A/C compressor, defroster, they all cause the electrical system to cycle on and off.
05-22-2006, 03:30 PM
#20
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Firmware????
I love all the references to "firmware" in this thread. It cracks me up. When stuff doesn't work right around here, us hardware guys immediately say "it is the FIRMWARE! Call the software guys! 
I love it! It is always a software problem!
I love it! It is always a software problem!
05-24-2006, 10:06 PM
#21
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Maybe next we'll find out the headlights really aren't dimming because of load but because the ECM is dimming them to look like a load. How far does this go? It would really scare me if I found out the temp gauge operated this way. I wonder if the ECM is making sounds we'll recognize as a running Cummins? Maybe it's projecting scenery on the windshield and I really haven't left the dealership yet. Does the ECM control the dead bug dispenser? HELP! Maybe this is all virtual, there really is no such thing as Dodge trucks.
Wetspirit
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05-25-2006, 07:46 AM
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I don't have the service manual with me to verify this - but I think most of you are chasing this from the wrong direction.
From what I remember reading - the ECU disables the charging circuit while the grid heaters are on. Or - if you've disconnected the grid heaters - the ECU disables the charging circuit when it *thinks* the grid heaters are on.
You start truck with disabled grid heaters, ECU thinks they are on anyways and does not enable charging circuit. At this point you are essentially running the truck of battery power and voltage should be below 12v nominal. Once you've gon over 20mph (or whatever the time or temp check is?) the ECU enables the charging circuit and voltage comes up to 14-ish - and the gauge responds too.
The gauge is definitely highly damped though I don't know if that is due to software or the actual gauge/indicator assembly.
Anyone have the service manual handy to check the above? I'm sure that's where I read this.
Leonard
From what I remember reading - the ECU disables the charging circuit while the grid heaters are on. Or - if you've disconnected the grid heaters - the ECU disables the charging circuit when it *thinks* the grid heaters are on.
You start truck with disabled grid heaters, ECU thinks they are on anyways and does not enable charging circuit. At this point you are essentially running the truck of battery power and voltage should be below 12v nominal. Once you've gon over 20mph (or whatever the time or temp check is?) the ECU enables the charging circuit and voltage comes up to 14-ish - and the gauge responds too.
The gauge is definitely highly damped though I don't know if that is due to software or the actual gauge/indicator assembly.
Anyone have the service manual handy to check the above? I'm sure that's where I read this.
Leonard
05-25-2006, 09:49 AM
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I wonder if Marco can incorporate a software fix via the smarty.
You know add a sensor, run the CaTcher and you have real gauges.
This stuff is so lame, DC should pay to retrofit all these trucks with real instruments....
You know add a sensor, run the CaTcher and you have real gauges.
This stuff is so lame, DC should pay to retrofit all these trucks with real instruments....
11-14-2007, 07:53 AM
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Fellas,
Since the cold weather has set in I am getting a higher than normal charge indication on my voltmeter. The needle is staying to the right of the "4" on the gauge all of the time as temps have been between 20 & 55 degrees outside. I have isolated the batts & load tested them & they check out OK. I tested voltage with truck off & I get 12.6v. With truck running acc. on or off I get 14.7v. The acc. on or off have no impact on the gauge reading. So is the reserve power in my batts questionable??? Is after 4 years of plowing snow & 100k miles weakened my batts & causing the Alternator to charge harder? Or is this normal & the gauges kinda an Idiot light??? My freinds 05 voltmeter show almost dead center.
I also have just updated my Predator to the newest download... did that effect anything??
Thanks
Since the cold weather has set in I am getting a higher than normal charge indication on my voltmeter. The needle is staying to the right of the "4" on the gauge all of the time as temps have been between 20 & 55 degrees outside. I have isolated the batts & load tested them & they check out OK. I tested voltage with truck off & I get 12.6v. With truck running acc. on or off I get 14.7v. The acc. on or off have no impact on the gauge reading. So is the reserve power in my batts questionable??? Is after 4 years of plowing snow & 100k miles weakened my batts & causing the Alternator to charge harder? Or is this normal & the gauges kinda an Idiot light??? My freinds 05 voltmeter show almost dead center.
I also have just updated my Predator to the newest download... did that effect anything??
Thanks
11-14-2007, 09:43 AM
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I haven't done extensive testing on the OEM voltmeter, neither have I disconnected the grid heaters; however, I do have a digital in-cab volt-meter that is active all the time (even with ignition off). The digital meter does seem to track the OEM pretty well.
When the grids start cycling, it will pull down to about 11.2 volts, and then swing back up. Normal running down the interstate is around 15.1 - 15.3. I'd nearly convinced myself the OEM unit was a real gauge, but I may have to do some further investigation...
Interesting stuff for sure.
--Eric
When the grids start cycling, it will pull down to about 11.2 volts, and then swing back up. Normal running down the interstate is around 15.1 - 15.3. I'd nearly convinced myself the OEM unit was a real gauge, but I may have to do some further investigation...
Interesting stuff for sure.
--Eric
11-14-2007, 03:49 PM
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Interesting thread... One thing I didn't see mentioned that I notice:
Start the truck on a cold morning, grid heaters cycling, voltmeter stuck at the fake 11v, headlights dim bright dim bright, blah blah blah. At this point seems only running off the batteries.
THEN, after about a minute or so of idling I think is when the charging system is finally loading and unloading with the cycling of the grid heaters (especially at fast idle I notice the RPM wanting to dip and rise slightly and the ECM quickly compensating to keep it at the preset RPM)
I sure hope the guage is only fake for the first couple minutes, I'm not really bothered by it if thats how it is.
Start the truck on a cold morning, grid heaters cycling, voltmeter stuck at the fake 11v, headlights dim bright dim bright, blah blah blah. At this point seems only running off the batteries.
THEN, after about a minute or so of idling I think is when the charging system is finally loading and unloading with the cycling of the grid heaters (especially at fast idle I notice the RPM wanting to dip and rise slightly and the ECM quickly compensating to keep it at the preset RPM)
I sure hope the guage is only fake for the first couple minutes, I'm not really bothered by it if thats how it is.
11-14-2007, 04:04 PM
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What I find interesting about all these PLACEBO gauges is that WE owners CATCH a great big load of WARRANTY ISSUES out of them when we install the REAL THINGS for REAL INFORMATION. Maybe when we install real gauges it worries them that we might find out something we should not know??? The real things lead to GOOD/EXCELLENT diagnostics in solving problems and knowing about your operational conditions. Gauges are the first thing I installed regarding boost, egt's and fuel pressure. I guess I now need to also install a oil pressure gauge and maybe even a voltmeter. I suppose the water temp is just a glorified linear idiot light too?? I have also considered installing an hours meter, just to be able to compare it to the stock one.
CD
CD
11-15-2007, 06:42 AM
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Mikey,
Do you still have original batteries??? Last night I cranked the heat in my garage & this AM the needle was more toward the center. Half mile from home temps in hi 30's needle went back to right of the 4 again. I am really concerned that I am having an early battery problem.
Do you still have original batteries??? Last night I cranked the heat in my garage & this AM the needle was more toward the center. Half mile from home temps in hi 30's needle went back to right of the 4 again. I am really concerned that I am having an early battery problem.
11-15-2007, 07:18 AM
#30
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I'm still on the original batteries.
Go to Walmart and pickup one of those digital voltmeters that plugs into the cigarette lighter. Can find them in the automotive section where the inverters/chargers are located. Will give a better indication for what's going on.
MikeyB
Go to Walmart and pickup one of those digital voltmeters that plugs into the cigarette lighter. Can find them in the automotive section where the inverters/chargers are located. Will give a better indication for what's going on.
MikeyB