Electrically Shorted Throttle Cable?

[Gray86Lxi]

1st post; been lurking for some time...

My son and I had a major electrical event with my 86 LXi last Friday night. While making a right turn out of Wal-Mart's parking lot, everything (dash, lights) went dark for a few seconds. I pulled off to the right, and then suddenly everything lit back up! Then I noticed all the smoke coming out from under the hood near the battery. We popped the hood, but not having a flashlight, nothing was immediately obvious (later I kicked myself for not disconnecting the battery then). My son and I then pushed it back into the parking lot (uphill, of course), and started to investigate. When we got the hood open again, this time there were flames on the firewall where the throttle cable goes through, and the cable itself was red-hot. We managed to get the flames out and disconnect the battery (glad I had my Leatherman…).

Long story short, after getting it home it became clear that the initial event was a short between the primary positive and negative battery cables.

The positive had been replaced - before my time - and a small amount of excess length had been looped forward so that it was resting on the negative cable, with the obvious inevitable outcome. For all the time I've spent under the hood of this thing, I'm surprised I didn't notice it until after it was too late. The battery shorting part I understand, but what I don't get is how the throttle cable became energized afterward; I mean that thing was glowing! The plastic over the metal sheathing was gone on both ends of the cable, and the plastic guide that twists into the firewall was completely gone - a molten, flaming, plastic mess.

While researching this issue here I came across one other thread that looks like the guy might have had a similar problem, as he referenced melting of parts of the cable assembly. Other than shorting this cable, I can't see any other way of causing the plastic stuff to melt - it just isn't that close to the really hot stuff.

I'm just hoping someone here can tell me how that cable got shorted in the first place so I can take some precautions to make sure it doesn't happen again. Thanks in advance for your help. This site has been invaluable to me (and the LXi).

Stan

[cygnus x-1]

Check all the ground connections to the engine itself. If all of those connections are broken or corroded the throttle cable could become a conducting path back to ground.

C|

[A18A]

^^yup^^ i had that happen to me on another car, but with the clutch cable.

[LX-incredible]

Holy cow! Never would have expected that to happen, makes sense though.

[AccordB20A]

pretty shitty stuff when wires do that. Glad u didnt burn ur car out

[Gray86Lxi]

I just finished putting it all back together, and everything seems to be working fine, with the exception of some unexpected adjustments I had to make on the throttle cable. Apparently not all 86-89 FI Accord throttle cables are alike. The one I got at the junkyard came from a FI Accord, but probably not the same year as mine. Based on a few measurements I took, it should have worked just fine but I ended up having to use nearly all the adjustment to snug up the cable. Taking a closer look after installation, there is a 1" difference in the distance between a crimped ring (near the firewall) and the end of the sheath by the throttle body between the original cable and the junkyard one. This forced me to position the jam nuts so that the threadless portion of the adjustment is right under the slot in the bracket that allows it to be removed; not an ideal situation.

Have I screwed this up somehow? I figure I either need a different cable, or there is some trick to adjusting it that eludes me. Those of you who have done this before probably already know where I messed up. Perhaps you could take a moment and enlighten me. Once again, thanks for all the help and replies. You guys are great!

[LX-incredible]

The cables are different between 86-87 and 88-89. The part numbers are also different between auto and manual models. Personally, I would just get a new one, as they are prone to binding and breaking at the firewall. They go for like $20 on http://www.hondaautomotiveparts.com, $33 after shipping and handling.

[AccordB20A]

Im gunna agreee that the cables are different because when i put my blacktop b20a intake on the cable woodnt fit on the bracket on the TB so i had to modify it.

[Gray86Lxi]

The cables are different between 86-87 and 88-89. The part numbers are also different between auto and manual models. Personally, I would just get a new one, as they are prone to binding and breaking at the firewall. They go for like $20 on http://www.hondaautomotiveparts.com, $33 after shipping and handling.

I just ordered the cable from http://www.hondaautomotiveparts.com, plus the little sealing gasket I forgot to pull off the junker. Thanks for pointing me to them. Aside from getting the right cable, all that's left is to get a new relay for the turn signal/hazard; neither work at this point and no fuses are blown. I checked them all - both in the dash and under the hood.

Check all the ground connections to the engine itself. If all of those connections are broken or corroded the throttle cable could become a conducting path back to ground.

This is a great suggestion. I did this but I want to do more. Since I'm on a pretty tight budget, this guy's approach looks pretty appealing: http://s95014253.onlinehome.us/63104/44704.html. For about 10 bucks and a little sweat equity, this should get me pretty well grounded, so to speak .

Thanks again everyone!

[turabaka]

This is a great suggestion. I did this but I want to do more. Since I'm on a pretty tight budget, this guy's approach looks pretty appealing: http://s95014253.onlinehome.us/63104/44704.html. For about 10 bucks and a little sweat equity, this should get me pretty well grounded, so to speak .

Thanks again everyone!

I did that to my car actually, using the guide in the how too section. It helped my car with starting up in cold weather. I would definitely recommend it.

[cygnus x-1]

I did that to my car actually, using the guide in the how too section. It helped my car with starting up in cold weather. I would definitely recommend it.

Absolutely. Over time the wires get corroded and don't conduct as well, causing excessive voltage drop and in severe cases lots of heat. The fix is easy too. Some heavy gauge wire, a few crimp connectors, and a pair of pliers or a vise is all you need.

C|

[Gray86Lxi]

I'm bumping this thread to add pics of the grounding kit I built/installed about a month ago. I hadn't seen Alex's DIY grounding kit until turabaka mentioned it, so using that as a starting point, and combining some ideas from the thread I mentioned earlier, I created cables that are connected in series (mostly). This (according to the other guy's web page) is based on dyno data from Sun Auto's Hyper Ground System, which is also serially connected, but I unfortunately don't have the data so I'll have to take the guy's word for it...

Anyway, I managed to hit all the points mentioned in Alex's graphic in his How To, but any suggestions as to better connection points are welcome. I was hoping to tack this onto the end of Alex's thread, but since it's closed, they are here.

Battery to firewall:


Firewall to Alternator (well, really alternator bracket): Cable follows firewall, turns around air filter box, and down to the alternator bracket. I really need to get some nylon cable standoffs to secure that cable better.


Alternator to Cylinder Head (short stubby cable): Actually connects to a bolt that holds the lifting bracket, but it screws into the head.


Head to Distributor: Runs along back of valve cover, bends forward and then down to distributor bolt. The cable that continues from there goes down under the distributor and back to the body ground by the battery, as seen in next picture.


This pic is pretty congested. It shows 3 cables:
1) Distributor to Body Ground next to battery (Cable is in a loom to protect it. This is near where all the trouble started )
2) Cable from negative battery post to starter ground.
3) Cable from starter ground to body ground.
The original negative battery cable accomplishes 2 and 3, but I didn't have all the materials I needed to splice in a mid-cable connection on the 4 gage wire...


A reverse, one-handed, back-handed, and no lookie photo of the body ground connection that amazingly turned out very good...


And last but not least, the replacement ground connection from the body to the valve cover bolt:


Seems to work pretty good, but I'm not in a position to give quantitative proof. Cold starts are a snap, even in single digit temperatures, though the power steering pump wasn't as happy and squealed a little until whatever had thickened up in the lines cleared (or melted; Gotta fix that too). And the annoying whining on the radio that matched the engines rpms was reduced significantly (then replacing the radio capacitor got rid of it completely). I can't say if its helped gas mileage yet as I haven't run a full tank through it since the mod. Come to think of it, I'll probably never know since I changed the O2 sensor at the same time. At least I'm not throwing codes anymore .

Now I've got to start fixing all the small (and not so small) leaks...

Stan

[Demon1024]

good deal! Where'd you pick up a new capacitor?

[Gray86Lxi]

Off the 89 junker I was pulling dogbone hardware from. Spotted it and figured I'd give it a shot. It worked!