Starting problems: Electrical

[The_Handier_Man1]

From: nvdesertrat0775  (Original Message)
Sent: 6/8/2002 4:35 PM

My 73' Brave twisted the speedometer cable off, and when I replaced it I replaced the entire unit, gauges and all, from a RV wrecking yard near me.  On the next trip, I noticed the gas gauge was way off, and after filling the tank the needle stayed at 'full', so I put the 'original' gauge back in. Now it too showed 'full', and the alternator gauge showed a constant, unmoving slight discharge.  Racing the motor or turning on the headlights didn't effect the reading.
    I cleaned & tested the sending unit and hand-checked every fuse, terminal and connection. The RV will actually start, as long as I'm turning the key~ running off the battery~~but as soon as I release the key it dies.  I put my back-up alternator in, without any change.  I've tried both manual and electric fuel pumps.

I suspect the problem is somehow connected to the dash panel, because that's where the problems all seemed to begin, but I compared the alternator and gas gauge connections with a different unit and they seem right. I've installed another grounding wire from the panel, just to be sure, but it didn't help either.  I suspected a dead short somewhere, but I can't find any. If all else fails, I'll probably tear the wiring harness apart, check every wire and determine, as well as I can, if they all go where they're supposed to. But I still feel like it's in the instrument panel, and I just can't see it.  Any ideas
      Da Rat 



From: nvdesertrat0775
 
The only thing is, the fuel gauge and the alternator gauge are connected with a small metal bar, and the alternator never moves.  Can I have max volts thru one of them and nothing thru the other??  When I say 'never moves', I mean with the key turned on.  With the key off the fuel gauge does drop to nothing and the alt gauge centers.  I've tried disconnecting the OTHER wires to the fuel gauge, and it still shows 'full'.  I'm off to Pep boys to get a ballast resistor......



From: nvdesertrat0775
 
     With the new ballast R in place, and a fully charged battery, and all wires checked, now it won't even try to start.  The electronic fuel pump cuts out, when I turn the key.  Still sounds like a dead short, but , where?  It's well-grounded.  I was careful to connect the new BR exactly as the old one had been connected, I charged the ignition battery off the vehicle, and...nothing.
    For my own check list, I see the possibilities as:  Ignition switch; Electronic starter itself; some undefined short in wiring; (slight change of:  starter failure).  I've already swapped batteries without effect, so I can eliminate 'battery'.  I've also swapped alternators, so that is (probably) eliminated. (very slight chance both might be bad).
  Tomorrow, I will begin by making sure the new BR is correctly installed, and then determine if I have 12 v to starter. I may short across the terminals to see if it will start that way. I may disengage all the fuses and re-engage them one at a time while trying starter, to see what effect that has.
   Am I over-looking anything?
   The only thing I can think of that might be a great help, would be if someone with another 73 or maybe 72 Brave was willing to pull their instrument panel off and tell me exactly how it's wired, I would sure appreciate it!  I know the ground wire to the fuel gauge is a dark blue wire flat slide-on connection, with a light blue wire round connector next to it, then a double flat male connector with one black wire on one end of a small bar reaching over to the alternator. (One of the panels I looked at also has a red wire connected to the other terminal of that double flat male connector, but mine doesn't.  problem?) The alternator end of this small bar has eight unused male terminals, two rows of four each. The alternator has a heavy black wire on one terminal and a heavy red one on the other, both 'nut-and-bolt' connections. I will trace them down tomorrow...I suspect this area the most.



From: varmitexpress 

It won't even start at all now? Does it make any kind of noise ( clicking, starter drag anything)? What size motor did you say it is?



From: melyash 

If replacing the Ballast resistor degraded the situation, perhaps something in the wires to it or associated with the Ignition are the culprit.



From: nvdesertrat0775
 
  As for noises when I turn the key~~ nope.  As I said, it even shuts down the rattle of the electric fuel pump.  Dead silence, dead results.  I have the Dodge 318.



From: nvdesertrat0775
 
I crawled under the RV, shorted out the starter terminals, and it tried to start, so it's most likely not the starter itself.  I found that I was now back to "Starts-when-the-key-is-turned-but-dies-when-key is-released", so I guess that's progress. I put the old ignition coil in, but nothing changed.  I hooked a meter to the high tension coil wire (to the distrib cap) and turned the key.  The voltage shifted all over the place, from 2.something to 12 or 13v, moving so fast I couldn't really read it, but certainly not a steady 12v.
   I tested the coil itself, both from neg terminal to positive terminal, and from positive terminal to an outside ground.  Negative to positive terminals read about 4.6v; but positive term to outside ground read 6.7v. I don't understand that...seems to me it should be higher within the coil.  Anyone know for sure?   Oh...disconnecting the newly connected headlight dimmer didn't seem to help



From 

   I might have an idea that no one else thought of.  I had a similar problem earlier this year.  Stopped at a grocery store and when i came out and tried to start my rig, nuttin'.  I purchased a starter, starter relay box, regrounded my MSD ignition, and still nuttin'.  Baffled I returned to the auto parts store where the gentelman behind the counter suggested that it may be my ignition switch.  I swapped the part that the key goes into and put it in the dash.  BINGO!!!  I don't know if this would help but its worth a try.  The part was only $12.00.



From: nvdesertrat0775
 
It is starting and running now, and I only found two relatively minor problems.  It wouldn't even try to start, because when I was holding the key 'on', trying to get it to run, apparently the Bendix spring hung up.  I crawled underneath and shorted across the terminals and it gave a healthy snort.  When I tried it, the starter tried to work.  Then I noticed the two wires going to the automatic choke control had broken off.  After trying all day to find a replacement, I soldered the flat connectors back on, reconnected the terminals, and started the RV w/o a hesitation.  It ran just fine, which is great even if overly frustrating.  It simply COULDN'T have been those two wires!  But I didn't fix anything else, so...
   The two gauges, fuel and alternator, are still not right, but Varmint Express is sending me a wiring diagram of the panel, so hopefully I'll figure out what the hang-up is there.



From: nvdesertrat0775
 
Wait!!  I DID do something else!  I replaced the Ballast Resistor!  Because the starter wasn't working right afterward, I don't know if that was the initial problem or not, but it sure seems more likely than just those two wires...
   Let's all say that was it, ok???




From: Alaska gal

I had this with a truck of mine took me and several mechanics to find problem. I would start and when put in gear it died. Come to find out it was the coil and the ingnition modular. Just a thought.. ak. gal P.S, replaced coil and modular no more problems..