Community Forums

Scot2scot · 06-23-2021, 06:58 AM

Hi All - looking for any help on why I am not able to get our 1992 pacearrow , p30 chasis with a 454 to start . I have replaced the starter and alternator and in the processed thoroughly cleaned connections to ensure good contact. I have inspected the engine ground wire and other grounds and removed to clean connections and all is good there . I have replaced the two continuous duty selenoids by the two 6v aux batteries, along with the battery isolator and relay delay . I have been through fuses as well making sure non were blown especially for the ignition . All that said - the only way I have found to get coach started is if I bypass the negative engine battery cable and connect it to the frame, usually the negative engine cable connects into the negative of the aux battery - anyway- even when I bypass the negative ground, the volt meter surges which I’m not sure what to make of but the motor runs fine otherwise . I am also not able to get it running with using the aux button in the dash- there again there’s nothing - appreciate any thoughts on this as we are days away from a trip out west and without this figured out we clearly won’t be able to go.😫

Diesel-Lover · 06-24-2021, 05:08 PM

Well what are your thoughts on the following:

if you ground the engine battery and also ground your aux batteries to the chassis independently, because negative is the ground correct.

When I moved my engine battery out from under the stairs into the engine compartment, I ran its ground to the frame there, while the house battery complex was grounded under the stairs.

Greatly improved the cranking, and reducing the cable length as well as the convection air flow (battery was about a foot off the bottom with about 2 feet of headroom. Lots of convection there when stopped and cooling air while driving. I did enclose the top of the battery with a splash proof shroud.

Scot2scot · 06-25-2021, 06:26 AM

I had been going down that very path but discovered that independent operation of the batteries is not how the rig is set up to run, in part , as I got major sparks when going from the aux neg post to the frame, in my experience you should not get sparks to fly when coming off a negative post-

Diesel-Lover · 06-25-2021, 08:18 AM

Is you rig set up as a two 6V battery?

Ours came with 2 12V for house, perhaps that is the difference.

The other thought is that the switch/relay mechanism that melds the house and engine battery together for startup may be loosing its functionality or got wired wrong.

I think something got rewired incorrectly, the negative ground could spark to complete a circuit that was on however. As in say you have a high wattage gizmo on a circuit that is not grounded, then you attach the ground after you have attached the pos side already.

Or alternately, the current is coming from the engine battery to the house battery when you tried to ground the house circuit?!

While you are doing all the grounds, also ground the engine block to the frame with your own cable. An old codger told me to do that, and move the battery closer to the starter and alternator!

I also moved the engine management unit off the hot spot into a cooler location to let it work without losing its mind! While shielding it adequately from engine heat while running down the road and or parked after a trip.

When I had the P30 unit, I created a "vented floor" stamped metal to allow the air coming through the front grill to go through the radiator instead of being lost directly! but the flooring piece had vents to when parked cool air could drift upward a bit, though most of it would be coming off the engine from around it which had no floor air panel.

Also if you don't like the engine robbing you of critical power while you are trying to get up hill mount a couple of electric fans in front of the radiator which you can either thermostatically set to come on early or manually operate when needed. When my cooling fan went into high speed mode, I swear it was robbing me of like 3-5 mpg off the speed uphill! The mechanical fan was two speed, with the addition of the electric fans (a twin set), it never kicked that second stage harrier liftoff hover noise!

I tend to do that with most of my rigs now or run the dash air provided radiator fans in newer models, turning on the electric fans on the radiator! if so designed.

Scot2scot · 06-26-2021, 12:24 PM

Yes - the rv is set up with two 6 volt aux batteries - I have replaced the battery aux isolator selenoid. In doing some further checking it seems I’m getting some parasitic power as I only have 6 volt at the generator and am actually reading 6 volts on the frame itself …???

Scot2scot · 06-26-2021, 08:50 PM

Tested the 2 latching battery disconnect relays and both open and close fine , so think I can rule those out as the issue , unless does anyone know if they can still be bad even though they are opening and closing ? Have a trip coming on Wednesday and would appreciate any thoughts…

BA-in-Mich · 06-27-2021, 01:14 PM

Have you looked at the engine to frame ground? Try using your jumper cables from the negative of the start battery to the frame.

Scot2scot · 06-28-2021, 07:26 AM

So , happy to report the mystery is solved - come to find out in load testing the batteries- the new aux battery was bad and wasn’t providing the needed ground - new battery and everything is bad in order !

Diesel-Lover · 06-28-2021, 07:43 AM

Congratulations you are a regular RV battery electrical prime care doctor.
Must feel great to resolve the issues. Have an extra helping of icecream with some Cointreau or Irish Cream or Kahlua on top!