Carb finally working...now melted wire...help!

[jode]

After some RIGHTEOUS ADVICE FROM PHIL (http://www.ifsja.org/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=2;t=017392#000000) (AKA oddfire), I was finally able to determine why my truck would not run after a new installation of a Edelbrock performer (#2131) intake and a Carter AFB carb. After checking everything we could think of and rebuilding the carb, Phil finally convinced me to check the timing and that was the problem! So for future info to those who are installing new intakes, the timing WILL be different after the install.

So as I was making the final adjustments, I was going through the process of:
- adjusting the timing to where it pulled a good vacuum (measured w/ a gauge)
- turning off the truck to see if it would start at that setting of the dizzy
- readjusting the timing
- turning it off again and restarting to see if it sounded right
- repeat

And all the sudden, the starter didn't have the power to turn the engine even once...so I get out to look and there is a huge cloud of smoke coming from under the hood. I thought I was majorly screwed (and I may still be), but it turned out that it was just a wire that comes off the (-) side of the battery. I have a digital image that I am trying to get hosted right now, but I'll try to describe it in the meantime.

This is a 12-14 gauge wire that joins into the (-) battery clamp right next to the heavy gauge, main (-) wire. It goes from the (-) battery clamp about 4-6" to the little box that is next to the ignition module and the starter solenoid. I have no clue what this wire does, why it fried, or what to do about it?
Does anybody have an idea of what may have happened here?

My best guess is that I had the timing either so far advanced, or so far retarded that the starter couldn't even turn the engine over so it jsut overheated and blew the wire....but why the (-) wire and not the (+) wire....my theory seems bad...but it is all I can think of right now....

Pics coming soon....hopefully

HELP!?

[ March 08, 2003, 06:24 PM: Message edited by: jode ]

[andy d]

uhhmn, how is the main ground connection at the block? if that is loose or broken the 10awg wire to the body will not handle the amps that the starter draws. that wire is there to handle all the body grounds, lights etc.

[oddfire]

Hey Jode,
I'm glad we're finely onto sumpin! However the vac reading still sounds a little low to me. Whats your alttitude in Boise? How many miles on the motor? Im at 6500 ft and I still pull 15 steady. Thats 21+ hg corrected for my alttitude. Try adjusting the timing and the idle mix screws at the same time to get the highest reading. Don't know about the fried wire, but as Andy said, good grounds are SO important in these rigs. For example, I have my batt grounded to the block the body and the frame. The block is grounded to the body and frame. and the body is grounded to the frame and that is just for 1 of my 2 batteries. Are you setting the timing with a light? Too far advanced and yes, it wont wanna crank. Keep us posted whats happening.....phil

[ March 08, 2003, 08:41 PM: Message edited by: oddfire ]

[porchpiggy]

I had a similar experience on a non fsj, only the smaller wire was just another ground to the body. The neg cable was not making good contact on the engine block that it was attached to, and the little wire could not handle all the load and fried. Make sure you have a good ground on the big cable.

[1BAD401]

Here is the pics for everyone!!!

http://www.fmtc.com/~wagenmann/Jeep/Joe/Fried01r.jpg

http://www.fmtc.com/~wagenmann/Jeep/Joe/Fried02r.jpg

[oddfire]

Cant tell from pict #2 but is the neg batt cable connected to the block.? Either its disconnected or its hooked to the body?.......phil

[porchpiggy]

Jode - That's exactly what my non fsj wire looked like, the big Neg was not making good contact with the engine block. I ran a whole different new neg cable to a spot on the alternator bracket. (it was a good connection plus I could reach it without having to crawl around on the cold ground).

[ March 08, 2003, 09:16 PM: Message edited by: porchpiggy ]

[okidoc]

Looking at your (-)cable it seems old and questionable. I can see what looks like a break in the insulation in the 2nd pic. That in itself is not a problem but could mean the wire is old, brittle and not condusive to good power flow. Replace with new cables, I'd go largest diameter you can find, check out car audio stores they have some trick wires that really push some volts.

It looks like what happened was the ground wire was not so good and the starter started pulling from wherever it could, hence the small black wire got a little hot. You can also use your side posts to mount body grounds etc. to, while using your top post as the main cable hook up.

Good luck.

[jode]

1BAD401 - thanks for hosting those so fast! :D

Originally posted by oddfire:
...the vac reading still sounds a little low to me. Whats your alttitude in Boise? How many miles on the motor? ....Are you setting the timing with a light? Too far advanced and yes, it wont wanna crank. I am at around 4000 feet. The vac was reading kinda low. It reads better when the engine is running good...like when there is a nice shot of starting fluid in the intake...then it reads around 18-20, then it drops down as the engine starts to not run so good...I'm sure it is more to do with the engine not being timed and the mix screws not being exactly right...I was still in the process of screwing around with it and getting things tuned when I popped the wire and was put out of commission.
Motor mileage is unknown...I bought it for $100 from a guy who said it had "recently" been rebuilt, but I have my doubts as to whether it has EVER been rebuilt....your guess is as good as mine, but I do know it does have some burnt (or brittle or something) valves (dollar bill exhaust trick).
Don't have a timing light, so I am going by vacuum and how the engine cranks when I try to start it....that's how I fried the wire...
Originally posted by oddfire:
Cant tell from pict #2 but is the neg batt cable connected to the block.? Either its disconnected or its hooked to the body?.......philYeah, it was connected...it is hard to see stuff like that with an image alone....that's why I tried to include two separate angles.

Originally posted by okidoc:
Looking at your (-)cable it seems old and questionable. I can see what looks like a break in the insulation in the 2nd picI think what you are seeing is dirt...but the cable is old enough that I had to use a screw driven in between the clamp and the post to get it to hold on there good....maybe it is time for some nice new cables... :rolleyes:

Here's the synopsis so far:

1) $30 for a rebuild kit for the MC4350 (still owe that $$ to 1BAD401)
2) $215 For intake and valley pan after failure in third attempt (two separate carbs) to rebuild MC4350
3) Free Carter AFB carb smile.gif
4) $33 misc. carb cleaner, gaskets, RTV, gasket shellac, antifreeze etc.
5) $25 vacuum gauge
6) $?? new battery ground wire

It isn't the total overall cost that is killing me....it is that every time I have to tell the wife that I have to go and spend "more" money...it is alot better when it all happens at once...then they (the wife) can forget it and get over it...but when the costs keep trickling in, it just keeps pissing them off and making them hate the Jeep. Ahhh Jeep ownership :cool:

Anyway, I guess what I'll do is replace all the ground wires and then just keep on truckin...this sounds better than I thought it was originally...I was nervous that the fried wire was symptomatic of a more serious and underlying problem...I always get nervous just replaceing wires that get fried without finding the source of the problem. I guess this time, the wires themselves are the problem. Looks like I'll be out getting new wires tomorrow so I can drive the beast to work on monday.
Thanks for all the help...I'll let you know what happens.

[dublt]

yea, thats the prob w/older rigs; nickel + dime! Glad u got the "carb" problem fixed. Now go buy some 1/0 welding lead and make the batt cables smile.gif

[jode]

1BAD401
I tried calling you today, but I must have the wrong number...I keep getting some spanish folk that no speak-ie english...shoot me an email or PM with your number
Thanks

[oddfire]

OK ... so your at 4000 ft, thats better. Add 1" of vacuum for every 1000ft above sea level, so that puts you between 19-21 hg which is fine..................glad things are coming together, finally!..................phil

[jode]

Yeah, I thought they were...till tonight I tried to start it cold with the dist. at the same setting as before and it won't start...so then I try adjusting dizzy (timing) and I still cant get it to run for more than a few seconds...it is starting to get old...then my wife happens by as I am starting it and notices a visible spark from under the vehicle as I start it...I get her to start it while I am under the truck and find that the starter is arcing over to the oil pan...I am sure that is what caused the fried wire.
I totally rewired the (-) from the battery to where it bolts to the block. I also replaced the fried little wire with 12 gauge wire.
Anyway, I am now afraid to go any further with the dizzy adjustment for fear of blowing the wires again.
My theory is that every time I hit the starter, it sounds (+) current through the oil pan and it is so high that it is exceeding the grounding capacity of the truck...so it blows that ground wire...I am surprised nothing else blew :rolleyes:
Anyway, I posted in a new topic about the battery. I'll update this thread after I figure out how to fix that so I can start the truck without fearing another blowout.
:(

[andy d]

there is another engine to body ground strap around the right motor mount. if the engine has been r/r'ed,and the body lifted, was this disturbed?

[jode]

Yes, it was distrubed...when I pulled the engine...I looked at it tonight and it apeared to be in good shape...is it related? I could always pull it off and clean up the contact points.