Proper Jump-Start Procedure for a C4

[Ken]

I don't know how many of you are already aware of this fact, but I just came across it in my Electrical Diagnosis Service Manual Supplement manual, so I figured eh... Why not share it?

I don't know if the "jump start junction block" (located LH rear engine compartment, behind battery) applies to the other generations. Therefore, I just posted it here.

PROPER JUMP START PROCEDURES

With the use of electronic components (such as solid-state radios, electronic control modules, and others) becoming more wide-spread each model year, the potential for damage caused by improper jump-starts increases. The following guidelines are presented to reduce the likelihood of such damage.

JUMP START ONLY IF BUILT-IN HYDOMETER "EYE" ON BATTERY IS DARK. If the "eye" is clear or yellow, do not attempt to jump start. If the "eye" is green, the battery is charged and does not require a jump start. Both the booster and the discharged battery should be treated carefully when using jumper cables.

CAUTION: DO NOT EXPOSE THE BATTERY TO OPEN FLAME OR SPARKS. SERIOUS PERSONAL INJURY, PARTICULARLY TO THE EYES, MAY RESULT FROM A BATTERY EXPLOSION, BATTERY ACID, OR ELECTRICAL BURNS.

• The ignition switch must be in OFF when connecting or disconnecting the jumper cables.
• All accessories, including the radio, should be turned off before jump starting.
• Cable polarity must be correct. Component damage can occur if the polarity is reversed, even if only briefly.
• Connect the positive jumper cable first, then connect the negative cable to the engine ground (not the negative terminal of the dead battery).

Something is left to be desired as far as being a little more definitive in describing proper jump-start procedures, I just copied from the book, but my point is that there is a "jump start junction block" on our cars. Learn something new each day.

 

[trrgod]

Ken- You are right. I never knew of this before. I'm going to check for this on my 89.
Tom

 

[JonM]

There is the little bugger in the lower left...I think they started putting them in the cars in 1987...my 84 doesn't have one.

 

[jwn4854]

would this also apply to a dead battery that you now have to connect a trickle charger too? where are the points of connection under the hood?

 

[flier32]

Ken,

I do not mean to challenge your post on jump-starting, but if you have a dead battery and turn off the ignition after the car is started to disconnect the jump cables, I can’t see how the car will restart. The battery is still weak/dead. Maybe I’m missing something.
:confused

 

[Ken]

Something is left to be desired as far as being a little more definitive in describing proper jump-start procedures, I just copied from the book, but my point is that there is a "jump start junction block" on our cars. (I) Learn something new each day.

_ken

 

[BigRed]

Assuming that magic battery eye actually works....Ive only ever seen ONE that did! Lol

:L

 

[jeepie]

I have seen a jump start block before and I always wondered why they called it that since it is buried behind the battery. Not a very easy place to get to.

 

[Ken]

No it isn't very accessible, is it Al? I ain't gonna say a thing about engineers. :eyerole :L

_ken

 

[WhalePirot]

'it isn't very accessible'

Neither are the battery terminals.

My '84 had no junction block, but, ala BMW, I made one for the + side when I relocated the battery inside. I used a large bolt, through the plastic fenderwell, passenger side. It is great, but so far, unused. The battery is the sealed type, now behind the passenger.

A totally dead battery may not allow a jump from another car. It may not even take a charge, either, and will lose something like 30% of its life after being allowed to go dead.

The operative NEW thing here is, ensure the ignition key is off, to isolate the sensitive electronics on ANY new car, from a probable voltage spike when connecting the jumper cables. I always connect the positives first; connect the negative to the boosting car's FRAME, last. That keeps any spark away from either battery, especially the 'dead' one, which may be emitting explosive hydrogen gas as it takes a charge.

 

[Ken]

Re: 'it isn't very accessible'

The battery is the sealed type, now behind the passenger.

Mike, do you have any pictures of that installation? How'd you go about running the cables? Funny, but I was just lately thinking of relocating the battery.

_ken

 

[geekinavette]

I ain't gonna say a thing about engineers. :eyerole :L

Ouch!

:L

Bill

 

[Ken]

Hey, some of my best friends are engineers, I just ain't gonna say anything about them. :L My mother always told me that if I couldn't say anything nice... :L

_ken

 

[WhalePirot]

pictures of that installation << No but I could take some.

I decided to trim the stock battery mount, after looking and rejecting a box I ordered from Summit. There are long 'tangs' on it which would not fit or seat properly in the well behind the passenger. I drilled holes for (and sealed) the bolts through the floor, using large washers to spread the load. Same for the cables.

The black ground wire is very short and its eyelet bolted to a convenient bolt on the frame near the left rear wheel.

The red #2 cable fits in a channel behind the rocker, just below the sill, and runs forward to the engine compartment, just fwd, of the pax footwell. Very cool! Only 3" or so is exposed in case of a major tire failure. Even that part is out of the line-of-fire.

The cable attaches to a large bolt thru the plastic well. Cable ends are easily obtained. I soldered and shrink-tubed mine for a clean and troublefree job. The other cable runs across the (tight) rear of the engine compartment. It is the smaller, hot feed, now from the large lug on the starter solenoid, not the battery post. This wire had to be lengthened to reach across to the 'stock' locale.

All in all, the hardest part was mounting the holder. I use an Optima, vaporless battery, inside the car's non-vented box. A strap secures it.

Ken, you gotta see this sometime. And I, yours.

 

[Ken]

Oh yeah, I wanna see your Corvette too!

Tell me, did you run an on/off switch at the rear to be legal at the dragstrip (if you relocate the battery to the rear you must equip it with a kill switch).

_ken

 

[scorp508]

If you actually carry the torx bits and 10mm socket & driver to get the battery gill panel off to GET to that junction box, you are a better man than I. I have no idea why that thing is called that.

 

[vigman]

The Jump block is USELESS!

As far as I'm concerned, the only way to jump is with cables. The newer style cables have little fork tines to grab around the raised circle behind the 7mm nut of the cables on the battery.

DO NOT BUY CHEEPO JUMPER CABLES.

Feel how BIG the wire is.. not how big the insulation is.

My Big BLUES are "8" gauge wire.. bulky cumbersome but never let me down!They were 45 bucks.. ( 5 years ago ).

Make sure when you jump.... hook the dead car up first. While you are doing this .. smell for fuel... cracked battery case ( Acid ) and do a visual inspection of the terminals.

Negative to a good point (CLEAN BARE METAL) on the block.

Positive on the batt terminal.


Then on the RUNNING car
Negative to the negative batt terminal..

Then positive to the positive terminal.

Keep a eye on the cable connections ( looking for smoke) and keep a hand on the cables as your charging to make sure there not getting HOT!

Have somebody keep the car that is running just above idle ( 1500 rpm ) to let the ALT do it's thing for a few minutes.

If your jumping a Vette.. turn the ign on ( Before hook up) and look @ your batt voltage... make a note. then key off, hook up.. and while your "charging/jumping" look at the batt voltage again... do not try a start unless your over ...11 volts or better.

You should see the voltage climb after a few minutes.. IF THE BATT IS TAKING A CHARGE!

Then try to start!


Vig!

 

[Ken]

I don't know how many of you are already aware of this fact, but I just came across it in my Electrical Diagnosis Service Manual Supplement manual, so I figured eh... Why not share it?

I wasn't suggesting actually using it, just the fact that it was there.

_ken

 

[vigman]

Oh I know that Ken

It's probably a factory temp power up terminal for assy line testing... you COULDN'T use that terminal for actual starting... the wires are not beefy enough... this is all secondary power distribution.



Vig!