PROBLEMS!!!

[Hump]

Well I had my first major problem with the J-20 yesterday. I was picking up a trailer that I am using to get Marc's truck in MA, and everything was going well. I had changed oil and filter, air filter, air breather gasket, oil filler cap, pcv valve, and tightened loose oil pan bolts in the morning. There was a three foot snow drift in the drive that I thought I would test my e-drive. So I reached into the glove box and turned it away from me...it didn't seem to do anything so I turned it towards me...and again it didn't do anything. So I put it back where it was (heard some hissing, but the truck didn't drive different, and the light didn't come on)

After I had the trailer hooked up w/lights and everything I started on my way home. I pulled out onto a main road and traffic was coming pretty fast, so I accelerated hard. All of the sudden there was a small pop heard and the truck died instantly. It has two gas tanks so I thought that it might be out of gas. I switched the tanks, put the tranny in neutral (I was going probably 40 mph) and got ready to hit the starter. That is when I hesitated and smelled a little smoke. Then to my horror smoke started pouring from the dash.

Long story short, it never really flamed, but now there is nothing when I turn the key, and the e-drive light is on all the time no matter what I do with the switch. I'm going to tear the dash all apart and see if I can find anything. Any ideas?

Secondly I thought I had found my oil leak when I put on the new oil filler cap, and tightened the oil pan bolts. Then I noticed the nice clean intake manifold that I had cleaned, was once again full of oil on the drivers side. There was also oil dripping off the very front of the tranny behind the oil pan. I couldn't tell if it was coming from in between that thin cover and the tranny, or if was just running off the intake manifold down the back of the engine. There isn't any oil on the pass. side of the intake manifold, so the only thing that I can think of is a bad valve cover gasket, but why would the oil go up instead of down?

Thirdly, when I replaced the pcv valve, I couldn't get it out of the cold manifold, so I tried with it warm and it came out. The old one seemed fine, but I replaced it anyways. I did think it was kind of strange that the hole was filled with the "stuff". Hard to describe, but it was pretty solid when cold, but kind of rubbery when warm. Is it supposed to be like that, or is that a PO job?

[Don S]

Sorry to hear 'bout the prob's...HUMP..one time I grabbed the e-switch and the whole thing rotated. This could have moved some wires and caused a short. The hiss may have been the man.vac. hose feeding the e-switch. all my hoses are "factory" but had to trim 3/8ths" off the bottom ones. There are some strange air currants under the hood... :eek: ......good luck.....ds..

[Bob Barry]

Sounds like a fried dash wiring harness. Only way to find out definitively is to pull the instrument cluster and start poking around to see what melted to what. Like Don said, it could have been a wire that shorted when the whole E-drive switch just turned. Or you could have just gotten unlucky and it was time for your ammeter to give up its ghost.

I was able to fix mine in two days; just remove and replace the burnt wiring, and you should be good to go.

[Crazy_Jeepman]

Your oil leak problems sound like two separate leaks. Rear main be the leak between engine and trany, and as you suspect a bad valve cover gasket for the oil leak on your intake manifold. Another thing I have noticed a lot of is the end gaskets under the intake manifold after time get pushed out, this will leak a tremendous amount of oil. I notice this to be very common when someone replaces the intake, and use the end gaskets along with RTV, if this was done it is not a matter if it will leak it is more the question WHEN! If these are the cause, you will need a new intake gasket set. When I install them I throw the end gaskets away, CLEAN the surface of the block and intake like you plan on serving your mother dinner on it. Then I lay a THICK bead of BLACK RTV (only RTV that is heat and oil resistant) let sit about an hour and then just set intake down and start bolts but do not tighten for another hour or so (LONGER the BETTER). I have done this a number of times with great results. Hey at least its one less oil leak! ;) Good luck on the wiring

[Hump]

Bob, are you psychic or something? I pulled the radio out, checked all over the wiring, jerked all the speakers out, then finally the instrument cluster. Sure enough, the red wire going into the ammeter was without any coating. The yellow wire was fairly melted, but just from the red one. This caused a couple of the wires back to the main bundle to be melted slightly, and some of the wrap is melted up to where the light switch comes into the main wire wrap. This blew the ignition fuse and was why I couldn't start it.

Could this have been caused by plugging into that trailer? I noticed that the ammeter was moving, and never before had, and I also noticed that the oil gauge went up to like 80 for a while then back to zero. I had never seen either of them move, but they both did for a while.

My question is...was the problem caused by something else, so if I fix it it will happen again, or was it just caused by the ammeter? I had thought about replacing the whole cluster anyways. Any recommendations on how to fix those few wires? Do I just cut the wrap on the main bundle and check it out? Then just splice in new wires where they have been burned? Electrical stuff scares me!

Pete, thanks for the oil leak advice! Sounds like i've got some work to do. I guess I need to read up on how to do a rear main. On a side note, i'm working hard to catch up to you. I'm picking up my second J-truck in two weeks. :D To bad that none of my spare parts match my truck. :D shhhh don't tell my wife that I am just stockpiling! :D

[DrChop]

Hump...

If you're smart, you won't even CONSIDER hooking the stock ampmeter back up. Those things are an accident waiting to happen, as you just found out.

Shortly after getting my '76 J-10 truck drivable, I had exactly the same kind of wiring meltdown that you just experienced. Mine cooked thru a bunch of stuff under the dash, and totally wasted the dash wiring harness.

I do not trust the stock ampmeters in any truck that has them, I had similar problems about 5-6 years ago with Dodge trucks, and a nice Plymouth RoadRunner with a swapped-in 440.

Do yourself a BIG favor and get rid of the ampmeter wiring in the dash. Find the big red and the big yellow wires on the firewall side of the harness, cut them off right at the plug, and splice them together with either an inline solder connection (preferred) insulated with heat-shrink tubing, or use a large yellow inline crimp fitting and some good crimping pliers.

You can easily monitor the electrical system with a voltmeter, and it's much safer for the vehicle. All you need is a switched 12 volt source (ACC) to the + terminal, a good ground to the - terminal, and hook up your existing dash indicator light wire to the gauge's bulb.

Reading one is simplicity itself. With the key on, and the engine off, the voltmeter should read about 12-12.6 volts with a fully-charged battery. It should go up to around 13.5-14.5 volts with the engine running, this shows the alternator is charging the battery. If it goes down with the engine on, you could have a loose/thrown belt, and a discharging battery.

PLEASE, install a good voltmeter. I'm sure if you value your FSJ, you will do it just for the peace of mind that it won't let the truck melt down again...

Doc

[Bob Barry]

<blockquote>quote:</font><hr>Originally posted by DrChop:
Do yourself a BIG favor and get rid of the ampmeter wiring in the dash. Find the big red and the big yellow wires on the firewall side of the harness, cut them off right at the plug, and splice them together with either an inline solder connection (preferred) insulated with heat-shrink tubing, or use a large yellow inline crimp fitting and some good crimping pliers.<hr></blockquote>

WAIT!!!

Good advice from Dr. Chop, but that big red wire supplies 12V(+) to the "Big Splice", from which everything else is fed. If you are going to cut the ammeter wiring, you want to cut the lead from that "big splice" to the ammeter ring. You'll have the opportunity to do this when you rewire the dash harness.

The best way is to remove the harness entirely from behind the dash, including the fuse-box and bulkhead connector. A bit of tedious work, but worth it, since you'll have to separate those wires and check each one for melting.

And no, I'm not psychic; I'm just an FSJ owner who has done this when MY dash harness melted due to a failed ammeter.

So, please, for the love of all that is mechanical and electrical, ALL you '73-'85 FSJ owners with that demonic fire-breathing ammeter! Switch one ring terminal over to join the other wire on the same stud, so all that charging juice isn't feeding that ticking time-bomb of an ammeter that Jeep chose to install on our beloved trucks (no, it is NOT run through a shunt like any safe and sensible system would be).

[DrChop]

Thanks Bob, it's been awhile since I last saw the FSJ dash harness.

FWIW, when I put the '28 Ford body on the J-10 chassis almost 5 years ago, I rewired everything with all brand-new wire, fuse panel, etc. I forgot about the Jeep using the 'big splice' in the red wire...

I forgot the big red wire also feeds battery power to the fuse panel and the ignition switch, among other things...

Doc

[chrisnsarah]

This may be a dumb ?, but is the fusible link supposed to go out in case there's a short, or is the ammeter the fusible link? :confused:
On the quadratrac light, sounds like the switch at the transfercase isn't working, or the diaphram isn't sliding, or the wire is loose or dirty, The light could be on because hte lead could be melted and touching metal. The light completes the circuit by grounding at the transfercase.

[jeepbob]

The amp meter is a good way to burn up a truck, do use a volt meter instead. That rubbery goo thing is prolly the original PCV grommet that has been broken down by engine oil.
BTW the extra load put on by the triler lighting and (if applicable)braking system may have helped the ampmeter go out but they can and will do it with out any help.

[Hump]

Thanks for all the advice guys, really appreciate it!!!

jeepbob, where can I get a replacement grommet for the pcv?

chrisnsarah, the ignition fuse did blow...maybe others, but that's what I saw off hand. Probably the only thing that kept the whole thing from burning up. To my surprise there isn't actually that much damage, just a couple of wires.

[PAJEEPER]

Thats a good thing it didnt burn up all of your wiring. I've read the horror stories of flaming ammeters. So I've done the conversion long before my Jeeps hits the road again. What I plan on doing somedy is replace the whole harness with an aftermarket one. That way all the AMC oddball wiring will be eliminated.

[Bob Barry]

<blockquote>quote:</font><hr>Originally posted by chrisnsarah:
This may be a dumb ?, but is the fusible link supposed to go out in case there's a short, or is the ammeter the fusible link? :confused: <hr></blockquote>

There is SUPPOSED to be a fusible link that, IN THEORY, would melt before the killer ammeter took out the whole wiring harness. In actual fact, fusible links have often been replaced with straight wire, or the fusible link doesn't blow quick enough (that was my problem).

I now run a separate 10-ga charging wire right from the alternator to the (+) stud on the starter relay (protected by a 14-ga fusible link), along with the stock circuitry through the ammeter (which reads nothing, since that charging wire takes all the load), also protected by some fusible link. That way, if I ever see the ammeter working, I KNOW I've got problems.

Michael Baxter pointed out one drawback with this setup; the alternator will still sense current if the fusible link on one of those charging circuits melted, so it would still crank out the charging amps (whereas in a single-charging circuit system, the fusible link blowing would cut off voltage to the alternator, causing it to stop producing a charge, cutting off the source of a short). That's probably the safer way to go.