For the '95 truck in the sig:

I had an issue a while back with some poor workmanship at a local dealership, an I just found something else that they did not put back right.

What is the purpose of the braided ground wire that connects from the passenger side firewall to the intake manifold? They just left it on the wheel well and put a regular bolt in the air pump hose bracket.

Thanks for the input,

 

On the other cars I've owned, you'd lose ground to a bunch of items in the car without this particular braided wire.

the negative terminal on the battery ran right to the block, and that was the ground for the whole chassis of the car.

So it's good to have it hooked up.

on an 82 volvo I had, it was broken, and the car worked. I guess somewhere there was a motormount worn through enough that I was contacting the chassis

Check the wiring in your vehicle. (I'm inside, or I'd look at my truck and tell you)

Follow the negative wire from the battery and see where it goes.

that should tell you if its important or not.

 

billman,

Did you notice if the starter turned any better after you hooked it back up?

I'm not sure it has a specific purpose other than to aid in grounding the entire block to the chassis, then to the battery. There may be another ground cable, and there may not be.

But with computer management systems, and that your truck's computer may actually be grounded to the same firewall, it might be a good idea to maintain that engine electrical-ground there.

Actually, I've found that the more grounds, the better - especially on older vehicles where the other ground wires have started corroding.

I added a second negative battery cable from a secondary negative post (aftermarket battery), and realized a nice gain in starter peformance, plus perhaps a tiny increase in engine smoothness (not a very objective term, huh?).

All my stock cables are in place, and none seem very corroded at all, yet my starter certainly turns faster and stronger with the additional cable. Obviously I am not putting any more volts to the system - it is still a standard ~12.6 volt battery and alternator - so this tells me there are negative/ground bottlenecks with the original system. That was my initial theory about these trucks, and once I added a MSD ignition to mine I added the second ground (from battery to head) to compensate for the additional energy. It works nicely.

Best,

 

Thanks for all the input.

I am going to hook it back up tonight- there has not been any starting problems at all; however, right after the last job from the dealership (they replaced a cracked exhaust manifold and left this cable like this) I noticed the truck had a slightly shaky idle, rich smelling exhaust, and poorer gas mileage. Don't know if they are related though- I think they introduced a vacuum leak somewhere and am just starting to chase it.

 

Mine started just fine without the second ground, too.

I'm just saying the starter turns the engine faster now.

If you get this before you play with it, try a few starts and listen closely to the starter.

Hook it up and listen again. It may turn faster.

Plus a rich smelling exhaust could point toward the fact that you really don't have a proper ground, thus you may be getting a really underpowered spark across the sparkplugs. That ground to the intake is the engine's upper ground (the one where your spark current would want to follow).

But if they were that ham-fisted, I'd check for vacuum leaks as well.

Best of luck,

 

Back together now, no immediate changes as far as I can tell. Starts and idles the same.