Engine starts once I let go of the starter switch..

[compunerdy]

I have of course messed with my wiring quite a bit but I did not think I did anything to the starting circuit but for some reason lately I can crank and crank and the engine does not start until right as I let go of the switch. Anyone see this before?

[berger]

Could it be the button switch itself?


Sent from my Mobile

[Stekay]

Not that uncommon. I've never found a definitive answer but, it certainly points to a low voltage situation I believe. Could be the starter, starter connections, batteries, coil connections, ballast connections, etc. You need to do the diagnostic work in a logical order measuring the voltage at the coil and work your way to the batteries. I've seen cars work like this for years when the owner didn't want to invest in finding the solution. BTW, Petronix or points?

[compunerdy]

Petronix.. I will be changing my battery setup soon so I will check everything then.. It does seem like the starter is not leaving enough juice for the coil. It has been turning over slower as well so definitely could be the issue.

[edzz]

Check the battery voltages.

[Jim LaGuardia]

First make sure you have 24-26v at batteries. Second, use a test light at the white wire on the noise suppressor before the coil, it should light up with key on and stay on while cranking.
If it goes off during cranking look at the following in order. (1)There is a small wire that jumps the power from the button to the ballast resistor circuit, (2) if power is still gone while cranking check ballast resistor outputs.
If it is on while cranking make sure the coil spark jumps at least 1/2".
Coil failure is common on some Pertonix ignition coils. You can use a 12v Bosch Blue VW Beetle coil (must be more than 3.0 ohms)most are around 3.6-4.1 ohms
Coil gets 24v while cranking, 15-19v while running(ballast resistor).

[Jimm391730]

It's the key switch. Try jiggling and try starting again; if it starts, you'll know! Happens occasionally on my truck.

[compunerdy]

It is a new ignition switch.. I think the batteries are low and since the positive goes from the batteries to the starter and then out to everything else it might be the starter drawing all the juice so there is not enough to feed the coil until I let go of the switch. Installing new batteries and redoing the wiring in the next few days so if that fixes it then I will know..

[Stekay]

I ALWAYS disassemble and clean the connections first and here's an illustration of why.

A Few Milliohms Go a Long Way by Bob Nuckolls
A pretty decent flooded (wet), lead-acid battery will have
an internal resistance of about 10 milliohms. It's difficult
to make a joint between any two conductors that's much
better than 0.5 milliohms per joint without welding.
Consider 2AWG wire with a resistance of .156 milliohms
per foot. In a Long-Ez the path from nose to tail can be
about 20 feet round trip so 20 x .156 = 3.22 milliohms
resistance in the wire alone. How about the contactors?
Hmmmmm . . . two contacts in series held together by an
energized electromagnet might be 1 milliohm per contact
so there's another 4 milliohms total. Add 'em up . . .
Battery resistance . . . . . . . . . . . 10.0 milliohms
2 Contactors . . . . . . . . . . . . . . . 4.0 milliohms
15' of 2AWG wire . . . . . . . . . . . 3.2 milliohms
Bolted Joints (4 wire
segments with 2 joints
at 0.5 milliohms each) . . . . . 8.0 milliohms
____________
Total resistance . . . . . . . . . . . . . 25.2 milliohms
It is difficult to imagine how so small a resistance can
make any difference. Consider that for all but the smallest
engines, a starter can easily draw over 200 amps!
Ohm's law says that for every ampere of current pushed
through 1 ohm of resistance, there will be 1 volt of drop
across the resistor or Volts = Amps x Ohms. 25.2 Milliohms
time 200 Amps equal 5040 Millivolts or 5.04 volts of
drop. If we started with a 12.5 volt battery, we'll now see
about 12.5 minus 5.04 or 7.46 volts at the starter terminals.
We've lost over 1/3 of our cranking energy in the trip from
battery to motor! On a cold morning, the engine is stiffer
and battery resistance goes up. Just when the engine would
benefit from more cranking energy, the battery's ability to
deliver it lessens.
The resistance of wire, contactors and battery are fixed, we
have no control over them and they are never zero. Also
note that bolted joints make up a significant percentage of
total drop. Even minimizing wire length has a rather small
effect compared to reduction in number of bolted joints.
Numbers in real life may vary quite a bit from those I’ve
used in the example. The point to be made is that while the
resistance values we’re discussing are tiny; pushing
electrons through the system at 200+ amps makes every
milliohm count. Some care in selection and assembly of
parts can reduce the over all resistance numbers.
In Figure 1, I've illustrated the most important wires in the
airplane. The first wire I install is from battery minus to a
firewall ground block thru-bolt.. The second wire runs from
ground block thrubolt to crankcase. For canard-pushers
with forward batteries, a instrument panel ground block is
wired to battery minus lead in the nose as shown. Ground
points for equipment in the rear are provided with a second
ground block mounted on one or both sides of the firewall.
Some of the worst performing starters are found on metal
airplanes where battery ground lead is bonded locally to
airframe. Engine is bonded to mount by jumpers around the
vibration isolators and the mount is "grounded" to airframe
through its mounting bolts. New airframes and other
structures holding engines on are pretty good substitutes for
wires when new. A few decades of age and improper
maintenance can drive ground path resistance up dramatically
from that which left the factory.