sweet70oldz

I bought a new alternator for my 70 Supreme which is stock w/ an original external type regulator. Been battling an intermittent failure to start condition for some time now. The negative battery cable is fully intact on both ends and terminates to the block. But there is a small ground wire (it appears) which runs from the negative batt cable to the outside of the radiator housing. Not sure if ths is stock or not and if this could be the issue as the previous, original alternator (it appeared) never had a ground wire hooked up to it. It may not had one either. Just had the two wire plug and the cable which routed to the postive batt cable. Should I remove the small ground cable from neg battery and buy a new longer one and route to the alternator instead? Where should the grd for the alternator be located? Would like to shake this no start deal and at least move the car back to stock. Of course, there is a short which seems to be draining the battery. The previous alternator was tested good by Autozone but was looking past its prime. Thanks in advance / you guys are the best!

oldcutlass

Your alternator is grounded through the housing to the block, it's referred to as chassis ground. The ground straps to the radiator support is for extra insurance, as is the multiple straps to the rear of the engine block and elsewhere.

Your starting issue is probably your positive cable or starter related if it fails to engage the starter and crank the engine. If the engine cranks but will not start, it will be ignition related.

What we really need is a better description of what happens when it fails to start.

sweet70oldz

When the no start condition occurs the the starter never cranks at all or sometimes gives a clicking noise if the battery has some charge left. Last time the battery was almost completely discharged. Charged back up and put back in and comes back alive again. If the alternator grd wire isnt it. I heard in old posts could be a faulty horn relay or vavle cover grounds straps have been removed. I guess I could always get a battery switch device. I would assume this put on the neg battery cable. I would like like to figure this out w/o taking the last route.

oldcutlass

So what your saying is your battery has a parasitic draw draining it dead, or it's not holding a full charge by itself. After a period of time it's too low to start your car. COrrect?

The other issue may be your starter solenoid or loose/ bad connection at the starter.

ah64pilot

How old is the batry? If it's not new it could be the problem itself. Doesn't sound like a starter solenoid as it's "trying" to click over...just doesn't have the juice to do it.

sweet70oldz

Oldcutlass has it right there is a draw somewhere which is draining the battery too low to start it after it sits for a few nights in the garage. The battery is brand new. I restate on fully charged battery starts right up.

oldcutlass

What have you added to your car recently that would maybe cause this problem. A tach, any gauges, radio, lights, recent electrical repairs?

sweet70oldz

Electrically speaking the only additions I have made were a new stereo that that is grounded and using properly switched fuse, new alternator (old one tested fine) and a few new bulbs inside car (all but rear view map light and trunk bulb work). Any chance this could be a horn relay issue. If i disconnect I will lose the horn but will still be able to start the car, right?

Sugar Bear

As previously stated the alternator will be grounded as you bolt it to the block.

The small black wire at the battery cable is a chassis ground and is actually quite important but probably is not related to the starting problem you are encountering. A previous poster stated that the small wire is extra insurance, this is accurate. It prevents the ground for anything grounded to the chassis from finding a ground connection through places it should not, preventing peculiar hard to find ground related electrical problems. In particular it prevents grounds from being conducted through transmissions/drivelines and having stray DC current/electrolysis consume internal bushings.

When really odd electrical symptoms occur it is usually a high resistance/poor ground connection.

1970cs

Easiest way to check for a battery drain is to take a test light or multimeter set to the lowest setting possible for volts, you need to remove the negative cable from negative terminal on the battery and hook the tester in series or one leed to the cable end and the other to the negative terminal on the battery, if you have a drain it will show with a dim or strong light or small reading or large reading on the voltmeter!

If it does this then you need to unhook every electrical component one by one till the meter reads zero or light goes out! BIGGIE HERE MAKE SURE EVERYTHING IS IN THE OFF POSITION i.e. ignition, radio and the dome lights (door closed)

Pat

sweet70oldz

1970Cs- I like your idea and would like to try but may need more explanation. Unfortunately I am bit of an electrical dunderhead. When you say unhook each component are you refer to the fuses.

MDchanic

Or just do it the right way, and use an ammeter, which may give you a hint where to look, by telling exactly how much the drain current is.

... And, in terms of unhooking each component, it may be better to remove ALL the fuses, then re-check the drain current, then, if it is zero, replace the fuses one at a time, checking the current again after each one.
If you still have a drain with all fuses disconnected, then you need to consult the wiring schematic and go after the remaining non-fused circuits.

- Eric

1970cs

Yes you could do it that way but your just narrowing it down to a circuit, not to a component! Do the test as per my post, but I say this with slight apprehension, unhook your horn relay and see if the light goes out, also get a trusted buddy or family memeber and go into the trunk and have them shut it, you said you had a trunk light if you can still see

By unhooking components unhook radio, alternator I know you replaced it but it could the external voltage regulator might have stuck points! so and so fourth.

Pat

Rickman48

A while back, I had all kinds of problems with my '69 442.
As you said, intermittent starting problems, battery going dead, and even dim lights at night.
Did as you did - checked the alternator, regulator, etc. - even replaced the cable ends.
Noticed the positive cable seemed 'green' inside - didn't worry about it until the problem continued.
Just for the halibut, stripped a little of the positive cable near the starter, and found the green corrosion a little thicker.
Replaced both cables, and never had a problem again!
Also cleaned the negative straps to the valve covers real well.
For the maybe $30-40, was well worth it!

sweet70oldz

Rickman- I have not checked the positive cable entirely yet. The end near the battery is good and has been investigated. I have a 350 where would the ground straps attach on the valve covers?Assume they terminate to the firewall.

MDchanic

One strap (you could install 2) goes from the back of the head (same screw holes that the front brackets would attach to) to the firewall.
Strap is about ½" x 6".

- Eric

Rickman48

My '69 had one to each valve cover - Maybe '70 only had one??

oldcutlass

Did it give you problems before you did the last few items? Does your stereo have an external amp that may not be turning off when the main unit or the key is turned off. What I've found in most of these cases, is it's usually related to one of the most recent repairs or mods. So think back to what you've done and when this problem started.

sweet70oldz

Since I got the car about a year ago its been doing this and was was noticed after about two weeks during some mild interior work. I did notice quite early on it needed to be started about once a week to keep it starting normally. A new battery was purchased because the old one about 1.5 yrs old developed a small leak. Since then the drain has become faster.The radio uses stock wiring and draws power only when the key is on or accessory position which i checked when it was installed. If the trunk light shows no power with an idiot light and a new bulb could this be the source of my draw and possible short?

1970cs

Lets go back to step one, It appears that you have a draw? use your test light in series with battery and neg. cable, we need to confirm draw! If this part is true then go to next step.

Than take yours and Erics application by pulling fuses to isolate the circuit which is giving you the issue and after that reinstall fuse and start upluging each component on that circuit one at a time till you find the draw! Pic posted is a good draw scenerio.

Do you have a CSM, you really need to have one!
Also shorts will blow fuses.

hookem horns

A modern stereo will draw a tiny amount of power all the time, so disconnect that first. After the simple test light check (may be very dim) get an ammeter and check each circuit at the fuse box. It will be tedious. Maybe focus on the dome/courtesy lights first since you mentioned changing a couple of bulbs. They have + power all the time and work by completing the ground with the door switch. A tiny gound fault at one of the sockets could be the culprit.

oldcutlass

As mentioned above, your problem is always a pain in da butt! First check the simple stuff like lights on all the time and stereo. If you have an aftermarket set of guages and tach, make sure the voltmeter is off with the key, same with the tach.

Then after checking the obvious, you probably need to hook an ammeter in series with the positive battery cable and start pulling fuses 1 at a time until the meter read "0" amps.

Good luck, and let us know what you find!

sweet70oldz

I hooked my old (AC Delco) voltage regulator, disconenct the horn relay and the car is starting normally. So should test the horn further before buying another?

75cutty455

I have a Question. Not sure if its a dumb or or not but I dont know so I'll ask anyway. I am having this same issue.

If I take all the fuses out then put them back in and my tester light comes back on what would the next step be. Replace the wires and/or check the ground for whatever the fuse is for.

Or

If i disconnect all my wires at the relay on my firewall then replace them one by one and the light comes back on after placing a partricular wire back on what to do there? Replace the wires and/or check the ground?

1970cs

In a few of the prior post, remove fuses then plug each one in and if the light lights then you have found the faulity circuit. You then can unplug each componenet on that circuit one at a time till the light goes out.

Pat

75cutty455

Thanks Pat,

I found my issue. It turns out one of my horn wires inside the steering wheel cover was broken and was touching the metal causing the drain. Repaired and working fine.

1970cs

Super! and thank you for telling us what you found, It helps all of us when you post the results.

I might post a thread about REPLYING WITH THE CURE! seems like about one out 8 memebers give feedback on the fix.

Pat