77 dodge rv problems

[damien191]

first post - sorry if it is in the wrong spot

i have a 77 dodge rv - model mbh 400 on the title - i'm ahving some trubles with it electrically - we jsut bought it and it seems like everything is shorting out - we drove it three hours home and earlier today when i was trying to back it up to work on it it lost power completely and cut off

there is a long list so far but it seems to have started with a short in the tail light cabling and moved up from there

about 2/3 of the way in our three hour drive the headlights and running lights went out and both fusable links were gone - i replaced them but then only the lights on the left side came on and when on the right turn signal lamp on the dash is dim but on

my most major question is this - if i do some shady wiring can i get it started to get it to a shop to have it looked at - it has a lot of wiring so i'm not terribly sure i could isolate the alt - charge controll - ignition controll - and bat (fuel pump if electric) and start it because i don't know what else electrically is absolutely required for a quick and dirty fix - i plan on only connecting those and unhooking the positive from the rest because of this nasty short going on, so if there's anything else that would keep it from running at all or damage by not connecting it i need to know now

i've done a lot of googleing this morning and it seems like that combo will at least get it started if nothing else to get it moved around - but i wanted to double check to be positive

i planned on starting it straight from the starter if you're wondering why i left parts out...

it is tempting to just wire it that way and get blinkers and tail lights going if that works and is all i need to do - id rather it work and i know how to fix it than it break down again - but this time half way to nowhere - and still be having problems

[toedtoes]

MrWizard wrote:
"flood the battery" ?

do you mean flood the carburetor ?

Yes, that's what I meant. Brain farts happen. 🙂

[MrWizard]

"flood the battery" ?

do you mean flood the carburetor ?

[damien191]

toedtoes wrote:
OK. Here is the ignition mod. It basically replaces the Mopar ignition module with a GM HEI module AND bypasses the ballast resistor. This means you don't get the drop down in the spark. Since I did it, I can actually start it even if I flood the battery.

Ignition Mod

This resolved a whole lot of starting issues I had where I would randomly be unable to start the engine and it would take anywhere from 20 minutes to 4 days for everything to kick back in. I didn't change to an HEI coil because it wouldn't fit in the doghouse, but it hasn't made a difference operational wise.

o.k. - i think that looks super do-able - we had someone out today and discussed just having the distributor swapped for one with points - they're going to look into if there's one that will fit it - i know it's old school but i feel more comfortable with a mechanical system that i can see and feel what's going on

[damien191]

MEXICOWANDERER wrote:
Biggest pass-through-firewall socket. Find two largest wires. The need to be cut on both sides. Drill 2 small holes close by through steel firewall.

Extend each wire. Pass each through their new hole and join other wire. A bypass. This is what happens if you do not bypass...

egad - that looks bad - on a side note we had someone actually come by and they said the best option was to re-wire - so i'm going to pull the harness out and wire up what all i need - and just leave the rest unhooked - there's no ac or computers so it seems like less of a big deal to us just to go that route

[MEXICOWANDERER]

Biggest pass-through-firewall socket. Find two largest wires. The need to be cut on both sides. Drill 2 small holes close by through steel firewall.

Extend each wire. Pass each through their new hole and join other wire. A bypass. This is what happens if you do not bypass...

[damien191]

MEXICOWANDERER wrote:
No Delco Packard .250 terminal can take that high of amperqge, Period. Remember they are BRASS not copper. A genuine MoPar design FUBAR I must have fixed 8 dozen of them.

Clean the remainder with D100.

i'm sorry - I'm not entirely sure what this bit is about

[MEXICOWANDERER]

No Delco Packard .250 terminal can take that high of amperqge, Period. Remember they are BRASS not copper. A genuine MoPar design FUBAR I must have fixed 8 dozen of them.

Clean the remainder with D100.

[landyacht318]

I recommend opening up the bulkhead connector and looking for corrosion and signs of excessive heating.

Also the Ignition switch is at the base of the steering column. Look for burnt/ scorched wires going into it.

Also, Add a ground cable from frame to engine and double check the ground from engine battery to engine, and to firewall.

I'd start by eliminating the grounds as culprits, and this cannot be done visually without having removed the bolt/nut/screw holding ring terminal to surface

[toedtoes]

OK. Here is the ignition mod. It basically replaces the Mopar ignition module with a GM HEI module AND bypasses the ballast resistor. This means you don't get the drop down in the spark. Since I did it, I can actually start it even if I flood the battery.

Ignition Mod

This resolved a whole lot of starting issues I had where I would randomly be unable to start the engine and it would take anywhere from 20 minutes to 4 days for everything to kick back in. I didn't change to an HEI coil because it wouldn't fit in the doghouse, but it hasn't made a difference operational wise.

[MEXICOWANDERER]

Here Are The TWO BIGGIES...

Eliminate the pass through the firewall alternator charge lead wire. Wire direct to battery isolation device and use a voltmeter not an ammeter for the chassis.

Chrysler took LSD when they designed the voltage regulator circuit. Learn how to install a Bosch style RELAY and use it to power BOTH the alternator field ignition feed wire and the termnal that feeds the top of the connector at the voltage regulator.

The 1980's REVISED SQUAREBACK MoPar alternator is a plug n play for your 60 amp. Choose the 78 amp model.

Use 6 wire TRAILER wire cable under the chassis to the rear. eBay truck 7 way connector junction box for distribution ease. Get a 1/8" POP RIVET GUN to redo junk clearance lights don't try to use screws. LED markers and tail lights are the way to go. Expensive but a bottle of DeOxit D100 cleaner works miracles on bad connections. anything else is a bad joke.

[j-d]

By 1977, the block would be a "two part" resistor. In other words it had two resistors for two different purposes, but in the same ceramic housing. We had a 1971, and it was a single resistor block. Good thing, it had a metal mounting band around it, and the mounting screw tightened that band against the firewall. The two part has a simple mounting hole in the center and uses a long screw.

The two part resistor will last longer if you do NOT tighten that long mounting screw! Apparently tight leads to the resistor cracking when it heats up in normal operation.

I installed electronic ignition on our 1971 (along with replacing the 318 engine with a 360) and didn't have trouble with resistor or module. Nor with the distributor, but I heard the magnet in the distributor weakens over time and the engine won't start unless it's cranking good and fast. Good Starter, Good Battery, Good Cables (OEM was too small), Good Connections!

[damien191]

toedtoes wrote:
Regarding the balast resistor, there is an easy fix for that - basically bypassing it and using a GM ignition module. I will post a link to the instructions when I have access to my computer.

Having the wiring done professionally will be very expensive and you'll be hard pressed to find a shop willing to take it on.

Also, go to the Class C forum and look at the Dodge motorhome thread. It's huge with hundreds of pages, but a ton of great information and lots of folks who understand these old Dodges. Ask questions there, and you'll get some extremely helpful advice.

does the gm module bypass the whole ignition module or just the resistor?

http://www.junkyardgenius.com/ignition/jeep/HEI01.html - i found this and i would be more than happy to replace the whole ignition system with one - my only question is if the hall effect sensor will need to be changed or if the original will be sufficient

[damien191]

kerrlakeroo wrote:
I had forgotten about that stinkin resistor block, when I was in the CG we towed a boat with a 79 Ramcharger that we used to blow those things constantly. If her solution on a different replacement is viable to you, look at it. those things were a pain.

i'm still at a loss as to why an ignition module was better than a mechanical distributor with points

[kerrlakeRoo]

I had forgotten about that stinkin resistor block, when I was in the CG we towed a boat with a 79 Ramcharger that we used to blow those things constantly. If her solution on a different replacement is viable to you, look at it. those things were a pain.