Onan 4.0 BFA generator problem

Water Dog said:

You shouldn't have 12 volts at the "S" terminal (small one) at the solenoid until you hit the start button....same as a car. If you do, the voltage is either coming through a faulty start button, it is wired wrong, or in the case of a circuit board mounted start button (which you probably don't have) could be bridged there. Does your solenoid look like the picture below?

The other important thing on Onan generator solenoids, is be sure you only use one that is Onan...don't try using a Ford solenoid as Onans have an additional wire connection built inside....but that shouldn't have anything to do with your particular problem.

Click to expand...

Bring everyone up to date: generator - 4.0 BFA - 1R/16004A Gen Set
First off, bought a new solenoid and yes watch dog, it looks like the one in the picture. Had to get a couple of new batteries, old ones shot. I unplugged the remote starter switch and the clicking stopped. Still can't get it to start with the switch on the generator. Used a volt meter to check a few things, this is what I found:
ref. pictured solenoid - big post on right has 12volt constant
little post on right has 12volt constant
little post on left has 12 volt constant
big post on left has nothing
using the switch on the generator changes nothing to any of the posts. Checked the switch on generator, has three spades on back with four wires. Looking from the top, one wire on left that has 12volt constant, one in the middle with no reading, and two wires on the one spade on the right which should be start has no reading. When actuating switch to start or stop, readings don't change. I would keep pushing the start and a couple of times something started clicking but I don't think it was the solenoid.
Question: when actuating switch to start, the right spade should have 12volts to it?
Greatly appreciate all the advice given. I am at a loss right now. My inclination is to get a new starter switch on the generator but I don't want to keep throwing money at it hoping I'm guessing right. Thanks!
John

According to the schematic on page 28 of the manual that Seilerbird posted, grounding the "S" terminal on the start solenoid should engage the solenoid and provide 12 volts across to the other large post (which in turn provides voltage to the generator to run as an electric motor to start the engine). That is why you have 12 volts at one leg of the start switch....it's the same wire that comes from the solenoid. You should be able to ground the hot side of the switch and accomplish the same thing. If it turns over, then you know it is either a bad switch or a bad ground on the downstream side of the switch. If it doesn't turn over, there may be something wrong with the generator itself. Read the text and take a look at the schematic on page 28 of this manual.

Thanks water dog. I skipped through everything and missed his post.
I will have to take a closer look at it, but I grounded out the "s" terminal like the guy at cummins told me to do (which as I mentioned before, has 12volt constant to it) there started a clicking sound that I don't think was coming from the solenoid.
I will take a closer look at the manual.
John

by the way, i put in another post that my coach won't switch power from the shore line to the batteries. could it be related?

I would say yes. Does it come from the generator area or elsewhere?

clicking comes from the generator area.

About your shoreline issue, did you get both positive cables hooked up to your batteries? There should be one that supplies your genset, and another that supplies the coach.

ditrranch said:

by the way, i put in another post that my coach won't switch power from the shore line to the batteries. could it be related?

Click to expand...

Not sure what you mean. Are you saying you have no 12volt service without shore power? If you are, maybe you just don't have the amps to turn the generator over. I think I would take a known charged good battery and hook it up directly to the generator with jumper cables and see if the generator turns over.

His other post is located at http://www.rvforum.net/SMF_forum/index.php?topic=45673.0. He has 12v service when the unit is plugged in, but loses 12v when unplugged. Apparantly the batteries do not provide power to the coach. Possibly a disconnect or a bad connection.

Brother Bill said:

His other post is located at http://www.rvforum.net/SMF_forum/index.php?topic=45673.0. He has 12v service when the unit is plugged in, but loses 12v when unplugged. Apparantly the batteries do not provide power to the coach. Possibly a disconnect or a bad connection.

Click to expand...

If this is the case, then it sounds like he's trying to start the generator from the converter power (if it uses the house battery) without the benefit of batteries. Maybe there isn't sufficient amperage from the converter, especially if it is original to the coach.

I greatly appreciate all the comments.
I have two brand new dual-purpose with 550cca/105 amp hrs.  a piece hooked together. I put in the "spare" fuse board the guy had left in the rv, but it worked worse than the other board. I don't think it's the fuse board, suspecting it is a symptom of the problem. What I'm referring to is the charging light on the fuse board doesn't light up at all. You all think it's a bad converter? It won't switch to battery power once the shore line is unplugged? Without shore line plugged in, I have no power, not even the lights work.
Again, GREATLY appreciate all comments. New to having a rv. Had a Hi-Lo camper previously.
John

I would simply forget about this problem until the other one is resolved. It seems to me that the two are connected but the no 12V in the coach problem has to be resolved first.

I'd start with the Battery cut off switch; are you sure its on/working (should energize a solenoid).

The converter almost certainly won't put out enough to start the generator. It normally uses the batteries as a filter while simultaneously charging them. e.g. they are supposed to be connected when in operation.

Do the lights, etc. work off the batteries (w/o ac in); if not see first sentence.

Ernie

ditrranch said:

. You all think it's a bad converter? It won't switch to battery power once the shore line is unplugged? Without shore line plugged in, I have no power, not even the lights work.

Click to expand...

John, I don't think it's a bad converter. When you are plugged in to shore power, the converter takes the 120 Volts and converts it to 12 volts. That sounds like it is happening. Only when you unplug do you not have 12 volts you said. When you unplug you no longer have converter power, so apparently somewhere the batteries are not connected either a bad connection or perhaps a main switch. What I was thinking was that if your generator is wired to start off your house batteries, but the house batteries are somewhere not connected, then it would be depending on the converter 12 volts to try and start the generator which may not produce enough amperage. Fix your battery problem and you MAY fix the generator problem.

Thanks guys, will do.
For starters, if I was a battery cutoff switch, where would I be?
There is a solenoid coming off the coach batteries that looks like the generator starter solenoid. How would I test that to see if it is working correctly?
John

ditrranch said:

Thanks guys, will do.
For starters, if I was a battery cutoff switch, where would I be?

Click to expand...

Not sure on your "79" Ours is right above the entry door on one side mounted in the end (outside) of a cabinet. Our disconnect switch operates a solenoid like you described.

ditrranch said:

There is a solenoid coming off the coach batteries that looks like the generator starter solenoid. How would I test that to see if it is working correctly?

Click to expand...

You should have 12 volts on both big posts if it has your batteries connected. If there is no power on the big post opposite the battery side, you should find the switch that operates it.

There should be one or more smaller guage wires connected to the solenoid. Can you follow them?

Solenoid by the batteries, power on both big posts, no power on two small posts. There is one smaller wire coming off the solenoid by the batteries. I traced it, I believe, to some switches on the dash. (4 switches together, looks like they are for checking status of batteries, lp gas, fresh water and something else, can't remember) What does the battery cutoff switch look like?
Found something interesting. I disconnect the coach batteries and the shore line. I checked the solenoid by the batteries, no power on the big post coming off the batteries (which I expected) no power on the small posts but there was still power on the big post away from the batteries. Should that be happening?
Thanks,
John

John, if you unplugged from shore power and disconnected your house battery(s), the only other 12 volt source that remains is your 12 volt chassis battery. That would indicate to me that maybe the solenoid you are playing with is the one that ties the two systems together for auxillary starting power when holding the aux switch down on the dash. On one post you were  probably reading house voltage, and the other post you were probably reading chassis voltage. Since you disconnected house, you are left with chassis. Find your house 12 volt fuse panel (possibly in with the 120 volt circuit breakers), unplug from shore power, and hook up your house batterys, then see if you have 12 volts at the fuse panel.

Not sure how much it will help, but I found an owner's manual for an '83. On page 31 is a basic wiring schematic. I couldn't find anything that might help, but someone else might. Save it in your favorites, it's only downloadable to members.

http://www.scribd.com/doc/36019061/Pace-Arrow-Owners-Manual-0001

Also found an operator's manual for an Onan BFA Genset and if you'll look down the right side of the page, there are the installation and parts manuals there as well. Again, they're for an '83, but it might be better than nothing.

http://1983fleetwoodpacearrowownersmanuals.blogspot.com/2010/08/onan-40-kw-bfa-genset-operators-manual.html

John, I was just looking at the schematic that Brother Bill posted and it doesn't show a shut off switch, but it does show a 40 amp 12 volt main fuse between your house battery and the fuse box...you might want to check that. It also shows that the solenoid is in fact an auxillary emergency start solenoid.