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Thomas Ford 85-16
Top Member
USA
4177 Posts |
 Posted - 01/11/2012 : 07:12:13 AM
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What triggers the alternator warning on an '06 All American FE with a CAT C7? The lights on the ammeter or voltmeter do not turn on. What happens is the "everything beeper" turns on and the LCD display says "Alternator" below the odometer. The volt gauge stays steady at 14.0V and the ammeter, when not up near 120 when first started (for the intake heater grid), is usually at 1 or 2 amps. I have verified these numbers through the "read parameters" function the LCD display. I cannot see any malfunction from my perspective. It does it a lot more when the weather is in the mid 30s, like it has been lately. When the weather is cooler, the alarm does not sound as often.
I have brought this in to my mechanics before but they could not find the problem; the bus was returned to me and I was told to wear ear plugs. I have grown tired of listening to that beeper so I have returned the bus to them and hope maybe you can give me some pointers to pass along. |
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slippert
Top Member
USA
630 Posts |
Posted - 01/11/2012 : 11:58:51 AM
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Is it plugged in when the temp is in the mid thirty's? and then if it is plugged in when colder maybe the oil and water temps are actually getting to 120 combine deg's sooner.
I have some 08 visions with cummins engines, The everything buzzer and dash displays a big STOP sign and flashes low voltage every time the heaters cycle on, Not quite the same as yours; I know(lol), but the grid heaters on mine seem to cycle or come on and off for longer periods when the outside air temp is between 30-50 degrees as our power to block heaters is not turned on until temps fall below 30. given that I had assumed possibly that when the block heaters were on, the water temp being warmer from heating for a few hours, that it might be taking less time to get to the 120 deg that the ECM is looking for to stop grid heater function.
Normally the everything buzzer and warning on dash display only come on once or twice and sometimes not at all, if these buses have been plugged in for a few hours. If between 30 to 50 deg and no block heat they will cycle more times and cause the annoying buzzer and warnings to happen longer.
thats what I see with mine |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 01/11/2012 : 12:12:07 PM
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| Bluebird always instructed me to pull a relay out of the panel behind the left wiper door. I believe it says ALT lamp or something like that. Usually when the alternator is upgraded the wire to the relay is not connected, then the lamp is on. |
“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 01/11/2012 : 2:37:03 PM
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slippert, the bus never gets plugged in. Overnight, it stays in a heated garage so the coolant starts off at room temperature. During the day it does stay outside (unless it's really cold) and one could assume the coolant gets to near ambient temperature. Either way, this alternator warning comes on during the route. With outisde temps in the 20s, the warning seemed to come on when the engine was in the range between 170 and 190 degrees. With this week being in the 30s, and the alarm problem having gotten worse, it seems to only occur when the engine is at operating temperature (180 or more). I seem to think the alternator still powers the intake heater correctly. Like I said, when the engine is cold, the ammeter goes on up to 120 A or whatever its max is. Sometimes when we're underway, the ammeter will be around 30 A. I figured this was maybe a middle setting, where the intake heater is on "low" so to speak, but I do not know for sure. (And maybe this middle setting is where something is wrong?) Usually when the alarm is sounding though, the ammeter is at 1 or 2 amps, when the bus is all warmed up and only asked to sustain its accesories.
The Wait To Start light on this and its sister buses seem to have been disabled, so I cannot know what the bus's intentions are for that intake heater.
Wolf0r, I know that this bus has had its alternator upgraded. It was delivered with a Leece-Neville but I think it now has a Delco. So is the relay in the front panel (I know which one you are talking about) only meant for one style of alternator? If I remove that relay, will there be any ill affects? Is the non-OEM alternator the reason why the Wait To Start light does not operate anymore?
Lastly, for what it's worth, quickly cycling the key (so as to keep the engine running but reset the electronics) does not help, nor does fully shutting down the engine and restarted. The blasted alarm picks right up where it left off.
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Edited by - Thomas Ford 85-16 on 01/11/2012 2:37:28 PM |
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Mechan1c
Top Member
USA
853 Posts |
Posted - 01/11/2012 : 3:56:18 PM
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The intake heater is both a starting aid, and an emission device. Changing our Thomas CAT powered buses from LN JB's to Bosch and Delco-Remy has not changed the operation of our intake heaters. Our buses do not have a medium or low setting on the intake heater circuit. It's either on or off. Cat used to make an optional switch (7E-9425) that had different assending and decending temp settings; That was for a 3116 however, and I'm not sure if it worked with the 3126 and C7?
I wonder if your problem is more related to the alt being affected by engine temp and not the intake circuit at all? When the alarm is going you could check the intake system at the grid heater relay to see if it's even active. |
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Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 01/11/2012 : 4:42:12 PM
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Mechanic1c, you could be very right. The main reason I bring up the intake heater is because 1) it's been an indicator that the bus still works as I THINK it should and 2) it is a significant load on the alternator that could affect operation.
I often set the digital display on the Blue Bird dash to read out the intake manifold temperature. When the alarm was sounding today, I observed IMTs of anywhere from 66 to 112 degrees, and those temperature readings made sense for the type of pulling I was doing at the moment.
I think Wolf0r may be on to something with the relay he mentions. I looked up the schematics for my body number and it appears the "Alt Failure" relay at the front of the bus uses a high signal (purple wire 1198) from the alternator to activate the "Alt Failure" relay, which grounds out yellow wire 1460, thus creating a low signal for the dashboard. I cannot find the mate to the connector that 1460 runs into, but I have to assume it goes straight to the cluster. From reading the digital inputs on the LCD, I know the cluster looks for a low signal to sound the alternator alarm; it is high otherwise.
Tomorrow morning, if I can get the darned panel open, I will pull that relay. It may not be a real fix, but at least the "everything buzzer" will no longer be able to mask actual problems that might occur. I'll also look for a loose purple wire in the engine compartment.
Thanks guys! |
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jfbiscarner
Active Member
19 Posts |
Posted - 01/11/2012 : 5:39:54 PM
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| I will follow up in the morning we have had this exact issue a couple of months ago. It was not my assigned bus but I'll check with the tec who's bus it was and post what we found |
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Thomas Ford 85-16
Top Member
USA
4177 Posts |
Posted - 01/12/2012 : 10:05:59 AM
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jfbiscarner,
Thanks, I'll look forward to reading what you have found!
All,
I pulled that relay today, and it stopped my alternator alarm. But get this... The relay was HOT when I pulled it out. Sticking it back in, it would click on and off as it made contact, so something is powering that purple wire that triggers the relay, and it was probably powering it all night long (I pulled the relay before my morning pretrip). I think my issues have suddenly gotten way more complicated. |
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Wolf0r
Top Member
USA
2181 Posts |
Posted - 01/12/2012 : 12:15:44 PM
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| Follow that purple wire down and you'll find it either taped in the harness disconnected, or someone has hooked it to a terminal on the alternator. You CAN do this but a diode must be installed to keep current from feeding back to the relay when the key is off. Good diagnostics on your part on the heater grid operation. If your tech has CAT ET there is a test for turning on/off the heater grid. All you have to do then is point your thermometer at it and see a temperature increase. |
“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson |
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jfbiscarner
Active Member
19 Posts |
Posted - 01/12/2012 : 4:15:49 PM
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| Unfortunately, I had forgotten to talk to the tec that had that issue I had made myself a note to remind to talk and pull his paper work on that bus sorry and look for my post Friday morning thanks |
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jfbiscarner
Active Member
19 Posts |
Posted - 01/13/2012 : 11:02:14 AM
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| Our issues was that the display said gauge missing sorry for misleading you thinking I has the same issue but this bus had a alternator put on it at 61,000 was was replaced with LN self ignitor maybe urs is not ? |
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Topic |
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'06 AAFE : Alternator warning
