d11gnccer
4 year old Carrier unit with a 2.5 liter ford 1800 rpm R100 controller. Customer has been without power for 2 days. Upon arrival I hear "Generator has never ran since installed last fall. It was bought second hand and the tech was here yesterday for 9 hours."

A new board was tried by previous tech from another company. I tried 2 new batteries also just to be sure. When the unit is placed in manual it will engage crank relay for half a second and latch out on low battery.

Measured 12.2 volts on 15e and 0 at board. Disconnected starter contactor, voltage regulator, fuel solenoid, battery charger, coil pack, and tried switched crank and run relays. Same problem. ohmed from board back to battery terminal. 0.3 ohms. Generac had no other ideas except "it must be wiring".

Any tips? The starter will crank the engine when you go directly to the battery terminal and drops to 10.5 volts during cranking.
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Scotty306134
I dont think a fully charged battery woul drop to 10.5 volts during simple cranking. How many amps is the starter drawing? I would try hooking it up to a larger battery that could maintain voltage and see if it still 'unlatches'.
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d11gnccer
But with wire 56 disconnected at the start contactor it takes the starter out of the equation. It should then lock out on a different fault, shouldn't it?
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ohmslaw
There is a thread here about this happening on 22kw units .
Search for that it may help you.
Tim
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ohmslaw
[url]http://zillerelectric.com/forums/showthread.php?t=850[/url]
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ohmslaw
[url]http://zillerelectric.com/forums/showthread.php?t=697[/url]
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ohmslaw
I found one with a loose connection from the battery to the starter relay. That fixed the problem.
Tim
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Ira
ohmslaw;8368 wrote:
[url]http://zillerelectric.com/forums/showthread.php?t=850[/url]


My problem (the one in the link above) seems to have been fixed with the installation of a redesigned wiring harness. I guess I should update the thread. It was installed about six months ago, and has worked flawlessly since then for exercising and a few multi-hour outages, until...

...a few days ago, Texas had rolling blackouts due to the cold weather -- 10 minutes with power, 45 minutes without -- and my genset failed to start on the first outage. When I checked it, the overspeed led was on. Tried starting it manually. Cranked for a few seconds, never tried to fire, then latched with the overspeed fault. It had exercised normally a couple of days earlier.

Dealer came out within two hours of getting the call (good response time given that they were probably very busy), and determined that it was a bad cam sensor. Genset is under extended warranty, so no cost to me, but I had to go thru about eight hours of rolling blackouts without the genset. Also, the dealer didn't have the cam sensor on the shelf, so it will take five to seven business days to get it here, and probably a few more days to get it installed.

How expensive is a cam sensor? Do they fail very often? Maybe I should get one for my "shelf". Are they typically affected by cold weather, or was this just a coincidence? It doesn't get down to 25*F here (and stay there for a few hours) very often.

Sorry for hijacking the thread.
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ohmslaw
Cam sensor or Mag pick-up?
Tim
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Ira
The service tech specifically said cam sensor. I forgot to mention in my previous post that the overspeed led was flashing red, not steady red.

I assumed it was similar to this... [url]http://zillerelectric.com/forums/showthread.php?t=733&highlight=overspeed[/url]

I don't know what led him to believe cam sensor over mag pick-up. He just said "everything pointed to a bad cam sensor".
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ohmslaw
I think the cam sensor controls engine function. The mag pick-up senses RPM.
Tim
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d11gnccer
They use the cam sensor to control engine timing and spark. If a signal is not recieved it will flash the overspeed indicating an rpm error. I went through a control board and a couple phone calls to learn this. I had a good reading at the circuit board for the mag pickup. Has to be a circuit board sensing error, and generac support tech agreed. New board with the same problem. It should shut down within 4 seconds of cranking if it is the mag pickup. If it is the cam sensor you shouldn't get any spark.
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