starting/electrical issues

[allencr]

Jezza_hr Wrote:I have been having an intermittent starting issue...

There is nothing intermittent about wire size/gauge!
There is often something intermittent about bad connectors/terminals/crimps and their contact! This includes battery terminals!!!!!!

Feel all the cabling & connectors, if its hot it's telling you that it is either undersize or has resistance from bad contact.

[Jezza_hr]

jondee86 Wrote:To be fair, throwing bigger cable at it is not the best way to solve this
problem. The important thing is the total resistance for the circuits...
battery positive to starter, and engine block to battery negative. That
plus the cranking amps will determine the voltage drop while cranking.

As you have stated, there are plenty of 4Ga installs that work fine. So
if your starter is in good condition and your battery is fully charged,
check the voltage at the starter while cranking. If you have 10V or
better, the 4Ga is not the problem.

Then you need to check that you are getting a full 12V at the COR
while cranking. If there is a bad (high resistance) connection on the
keyswitch power supply, or a high resistance ground, the voltage may
drop low enough during cranking to prevent starting.

Cheers... jondee86

I'll check the resistance through both connections. I've ordered up a Digital voltage meter, since the analogue one I have is a pain to read.

The only other idea I have had, is if the 4G wire is the culprit, is to create a bigger ground at the back of the car and double up on the 4G wire to the positive terminal to reduce the overall resistance. Not the neatest way to do it, but if it works it shows that investing in 0 gauge isn't such a bad idea.

[Jezza_hr]

Okay, I've had an opportunity to check this today.

When going out to look at the readings across everything the battery was reading as little as 11.3v, which is a little low. I decided to test the voltage at the junction box and at the starter. The readings were a little odd, since they were .1v higher than the battery itself I'm guessing this could be down to environmental conditions or just how good the connectivity was on the probes themselves.

I attempted to start the car and as I expected it was reluctant to get the starter motor running, so I had to swap for my fresh battery reading 12.6v from the garage. Whilst I had the old battery out, I decided to do some changes by creating a new ground from the block with a nice clean connection to bare metal on the chassis and I doubled up on my 4 gauge wire to reduce any resistance that may be found at the junction box. I also decided to re-solder some ignition wires in the off chance these could be causing an issue.

When I put in the battery it sprung to life quicker than it ever has done before, I'm thinking the change in ground and doubling up the wire may have helped with this. Reading the battery whilst the ignition was on, I could see it was getting a steady 14.4v, but would drop down to the region of 13.5v with all the lights on, stereo, blower etc. but when revving up to 1500 rpm, it all leveled out to 14.4v again.

I thought everything seemed fine, but to check any other irregularities, I wanted to check that nothing is draining the battery while the car isn't in use. I understand that 0.2 mah is the most you want to see being drained from your battery, however mine measured at 0.1 mah so, I don't think there's an issue here.

I'm hoping that my tinkering around has sorted my issues, I'll soon find out I guess if the problem occurs again. When I can next get behind the dash, I will be swapping the power lead for the tachometer though, as there still seems to be the odd bit of movement when using things such as the indicators, so I may route this to a constant 12v feed instead of an ignition feed.

[jondee86]

All starters love a fully charged battery It seems as so you may have
had a high resistance ground. Testing voltages with the engine running or
off lets you know that you have continuity. But to test the performance of
the circuit, you need to do a voltage drop test. In the case of problems
with the starter, you need to check what the voltage drops to while the
starter is cranking i.e. with max current flowing in the starter circuit.

Test between the starter positive and ground....


This will tell you the voltage that is being applied to the starter during
cranking. You should be looking for a minimum of 10 - 11V and if it is low
(say 5 or 6V), then you need to check the voltage drop in the starter
supply circuit...


... and in the ground return circuit while cranking.


Ideally, you are looking for a voltage drop of not more than 0.25 - 0.5V
in these circuits... lower is better. Not trying to be a smarta$$ as all this
information is readily available on the interweb, and you have already
solved your problem. But there may be others who will find the diagrams
helpful when they are trouble shooting their own starting problems.

Cheers... jondee86

[Apsogos]

This eternaly 4age 16v problem...the starter
Once upon a time i have metalic hose on the back seat and when the starter not cranking then i was kicking her ass with hose
Jondee has right for the volts....mine had problem it was 6v when try to crank the engine....i replace some cables and the contacts, i relocate the starter on the intake side, get a rebuild 4afe starter , my electrician made some kind of ampilifier to help the starter with a relay... and finally i use lightweight flywheel from the blacktop. I have ae92 4age16v.
the Starter problem dissapeared for ever, now i that the starter will never stuck again,i feel that she has more power ....