strange starting issues

[jay-71]

Hello all,

Just bought a 71 240 and when the PO was getting it ready for the shipping truck it wouldn't start so now it's sitting on the side of the road in my neighborhood with it's pristine uncracked dash I managed to get it to attempt to crank twice last night during hours of tinkering. Got the battery tested and it shows 12.6 volts, or so the guy at auto zone said. With the ignition switch at the ON position all the lights come on with a little coaxing and when I try to start it all I hear is a click from the right side of the passenger floor board. I also did clean up some corroded wire splicing going from the starter into the cabin as well. I don't know anything about the voltage regulators on these cars and would've done a more in-depth search but I am at work and REALLY want to get this thing in my garage as soon as possible. Any help would be appreciated!

[SteveJ]

The click you heard was the accessory relay. That is normal.

Things to check:

1. Fusible link

2. Wiring in the steering column.

Unfortunately, the wiring has been hacked, as you noted. Who knows what was wrong before someone attacked the wiring with diagonal cutters?

The voltage regulator would not keep the car from starting. Don't worry about it right now.

Download the 1971 Chasis Supplement from Xenons30. It has the wiring diagram. The link is below.

Using a positive to negative convention for the circuit:

When you go to start your car, 12 VDC+ goes from the White/Red wire to the ignition switch. It goes out the Black/Yellow wire to the inhibtor switch (no function in the manual) and on to the solenoid. The switch also completes the contact for the Green/Blue wire. This wire joins the Green/White wire to provide 12VDC+ to the coil during starting. (This bypasses the ballast resistor.) If you don't have 12VDC at the coil and at the solenoid, the car won't start.

Where in North Alabama are you? Send me a PM if you're not comfortable answering in an open forum.

[240260280z]

If the starter is only clicking:

1. There is not enough power to turn it

2. It is faulty

For #1

a. you have to have a strong battery that is chargers. 12.6V should be OK

b. all contacts/connections from the battery to the starter should be cleanr. This includes the contacts at the starter.

c. The ground wires returning to the battery -Neg terminal and associated contacts/connections should be in good order.

d. All wires to/from battery and starter should be in good order (no corroded, frayed or white/green flakey stuff).

Once you get these minor issues resolved, you will have a fun ride.

[JLPurcell]

Did the Auto Zone do a draw test on the battery? PM sent

[jay-71]

Steve J - I am in the Huntsville area. And I plan on redoing a lot of wiring in a few months. Going to pull the motor to polish up oxidation on the motor and clean up some minimal battery tray rust.

The guy at Auto Zone did a load test I think. He kept mentioning only voltage, I never heard about amps which makes me think it just doesn't have enough draw left in it to really crank it. The PO would unhook the terminals and let it sit in his garage for long periods of time (it has 94K original miles to give an idea of durations). Even though it's only 2 years old, a mix of cold winters and long intervals of charging I would think would kill a battery.

I think I am going to just buy a new battery and then start tracking the suggested wires once I know I have proper draw. Does this sound like the right idea? I have never been the best electrical guy when it comes to automotive application.

[Gary in NJ]

A weak battery can show "normal" static voltage (~12.6VDC) but still drop below startable voltage which is around 10VDC. As Jerry mentioned, you need to make sure you do a dynamic voltage test.

[SteveJ]

The plates the in battery can become coated with lead sulfate, especially if the battery drains. So while the battery has 12 VDC potential, the plates are not exposed enough for electrons to flow. That limits current.

A way to measure this is to measure voltage at the battery after putting the key in the run position. (Notice that I didn't say, "start".) If the voltage at the battery drops significantly with no accessories going, it is gone. If you still have 12 VDC at the battery, then measure the voltage while having someone hit the starter. If the voltage at the battery drops below about 9 VDC or so, it is not strong enough to engage the solenoid or starter. If the battery still has good voltage, measure voltage at the solenoid and coil like I said in the first post. I know you have a Harbor Freight nearby, so it should be no problem for you to get a cheap multimeter.

As I mentioned in the previous reply, hacked wiring is usually a way of fixing a problem properly. Don't be surprised if other electrical gremlins appear.

By the way, I have family in Huntsville, so I get out that way from time-to-time.

[jay-71]

Thanks! I think I might have to cut out of work early today now that I know a quick way to be sure of the battery's condition. I am getting so ansy and worried knowing it's sitting on my curb, even though I'm in a cul-de-sac haha.

And SteveJ shoot me a message next time you're in town. Maybe we could try and meet up, I am always up for some Z stories and seeing other S30's (there are barely any around here that I have seen).

[240260280z]

Here are some photos showing the connections to refresh.

A new pos and neg battery cable from autozone would be a good replacement upgrade.

Note: The -neg terminal is on the battery tray and the +pos has fallen through it (see 2nd photo for this detail)

Edited June 3, 2011 by Blue

[240260280z]

Also, here is a tech tip on connector cleaning for a 77 EFI. Some of it is applicable to 71

http://atlanticz.ca/zclub/techtips/electricalconnections/index.html

[JohnnyO]

+1 for fusible link. Unplug, clean then replug and try to start.

[9teen7t240z]

The symptom that you described in your post was exactly the same as the problem that I recently encountered in my 1970 240z. A mechanic friend suggested that the problem could be the solenoid in the starter, and suggested that I try tapping the solenoid while attempting to start the engine. The engine fired up instantly when we did this, so I replaced the starter and have had no issues since.