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RMurwin · 01-19-2013, 04:09 PM

My wife and I purchased a 1995 Dynasty '38. The previous owner had put an 8D-XHD engine starting battery in for the coach battery; it was dead as a door nail and will only be good as a core in the future. I replaced it with 4 Trojan T-105 6-volts, but when I connected the coach leads to the bank I accidentally reversed them for just an instant; I connected the ground to the positive post and when I touched the hot lead to the negative post it made sparks so I stopped doing that. I recognized what I had done and corrected it. Now everything on the coach seems to work correctly except the engine won't turn over. The solenoid engages and voltage is going out from it to somewhere (towards the back of the coach, at a plug it changes from a white wire to one of several black wires and I wasn't able to trace it out). I used a screwdriver directly on the starter terminals to start the engine so I could move it. So here is the question; any ideas on what I killed?

nightriderrv · 01-19-2013, 06:22 PM

From what you are saying sounds blew a fuse someware because it will start anything else not running or turning on

RMurwin · 01-19-2013, 06:29 PM

Everything else seems to be working. I thought the inverter wasn't charging the coach batteries, but there was a little over 14 volts at the batteries and they slowly took a charge.

nightriderrv · 01-20-2013, 08:42 AM

I would run through the fuses there should be some big main ones at the battery bank mounted to the wall

RMurwin · 01-20-2013, 09:22 AM

What do you think the fuses would be powering? There are none in the battery bay, and the cable literally runs straight from the battery to the starter and it has power there. There aren't any fuses marked on the engine bay electrical diagram, but then again there is a lot of stuff that is missing from that thing. If I knew where the wire that comes from the solenoid went before it got to the starter it would help; guess I'll have to take things apart to trace it back. I guess I was just hoping that someone else had a Dynasty from this era that had perhaps done a bone-headed maneuver like me and wasn't afraid to admit it.

distaff · 01-20-2013, 09:59 AM

Reversing the polarity by itself should not cause excessive sparking, even if the polarity is correct you will see some sparking. You will have certain circuits open since the coach is always drawing some power for some things, and you may have damaged some of them if they are sensitive to polarity (lots of things aren't, but motors and electronics tend to be). You can create some serious fireworks if you mis-wire and cause a short between the batteries (big one) or if you wire the the two batteries in series and get 24v (smaller but more than you expect with 12v) because it is voltage that causes current over a gap, so the higher the voltage the bigger the spark.

It is highly unlikely that you damaged the starter as it was not engaged at the time, and the same is true of the starter solenoid as the circuit was open when you changed the battery. The same should be true of the engine computers but I can't say as I don't know what is powered on your coach when the ignition circuit is open (i.e. off).

To shorten your diagnostic process you can check if there is voltage present at the starter solenoid with the ignition held to start. If you don't have one, there are fairly affordable multi-meters that will hold (remember) the high voltage they have seen so you can do this single handed. You can also do the same test coming off the ignition solenoids.

Last comment - don't think the starter is controlled by the engine computer, I think it is a direct path from the ignition solenoid to the starter solenoid.

distaff · 01-20-2013, 10:06 AM

Went back over your post again, I see it was the coach batteries you cross wired, not the chassis, depending on how the coach and chassis cross wire you may have run a very interesting dead short between the coach and chassis circuits. If you have a good mult-meter you will be busy.

Sorry for your troubles, I know from experience how stupid you feel after making a simple mistake that has ugly consequences. At least no one was hurt.

Papa_Jim · 01-20-2013, 11:04 AM

If I understand correctly, the starter worked using a screwdriver across the solenoid posts. So the starter itself is OK, and everything runs OK. It just won't start using the key.

Did you try this? Turn key to on. Then go back outside to the engine compartment, and see if you can start the engine at the panel there. There's two gauges in that panel, and a start button. Let's you start and stop the engine when you're servicing the engine, as long as the key is in the on position.

I guess what I'm getting at is this. Up at the dash, there can be some interesting connections involving coach and chassis batteries. For instance, the headlight switch is fed from the coach batteries. However, that same switch feeds the overhead dash lights from the chassis batteries. Did you check in the front run bay (outside underneath the driver's window) for a blown fuse in there? I think there's a fuse there for the ignition switch.

RMurwin · 01-20-2013, 11:57 AM

I tried the rear panel; it or the ignition switch will both engage the starting solenoid. The wire that comes off of the solenoid is getting powered, but it isn't getting over to the starter. It runs toward the back of the coach an might be going into a box that I haven't identified yet. I think it runs to the starter from there, but I haven't been able to trace it out yet. I used the screwdriver technique directly on the starter, not the solenoid. The solenoid is working like its supposed to, the voltage is getting lost somewhere on the way to the starter.

William Willard · 01-20-2013, 12:29 PM

Double check to make sure you have connected all the wires going to the battery -- I had the same problem once, & I found a small wire that had slipped behind the battery box -- Connected it & all was well -- Bill Willard

Dr4Film · 01-20-2013, 07:17 PM

Quote:

Originally Posted by RMurwin

o here is the question; any ideas on what I killed?

I know of just the person that could help you but he is NOT a iRV2.com member.

Send me a PM with your email and I will have him contact you with the resolution.

He owns a 1994 Dynasty and is also a diesel mechanic.

Dr4Film ----- Richard

Mike Canter · 01-21-2013, 05:06 AM

RMURWIN, did you successfully move it after you started it with the screwdriver? Was everything else working ok?

RMurwin · 01-21-2013, 05:14 AM

Yes, I was able to move it. The transmission shifted into forward and reverse. Everything else seems to work okay.

Mike Canter · 01-21-2013, 05:24 AM

Did you disconnect the chassis battery anytime while changing the house batteries? When you turn the key to start is there any clicking sound of is it just dead?