LS engines come in a lot of different flavors, today we are going to talk about some of the
differences that you may find in 24X1X applications.
In 2005-2006 GM mixed it up a little bit with the LS2.
They took a 24X1X engine that conventionally had the cam sensor located at the back of
the engine and they moved it to the front of the engine and the timing cover like a
58X engine, some of the later model LS2 as well as LS3 and later applications.
The problem that you will find with this is that if you have a 2005-2006 LS2, it may have
been a take-out engine from a trailblazer or GTO or some Corvette or some of the early
LSX applications with the cam sensor mounted in the front with a 1X cam and a 24X crank
sensor is a conventional 24X harness isn't really going to work out for you because the
cam connector and the harness is short and it's not going to be long enough to reach
up to the front.
I've seen people take these harnesses, cut them apart, extend out about 24 inches on
the cam sensor wiring to reach the front of the engine, try to keep the shielding intact,
then they also find out that the knock sensors on those engines aren't in the lifter valley
like in the 24X1X engines, they are down in the block.
What you could possibly do is take a 58X harness which will dress out properly on the engine.
But there is another difference, just because the sensor between a 24X and a 58X engine
may look the same other than the color, there is another difference between them and that
is the actual operating voltages.
24X warning sensors are engineered and designed to work with 12 volts, they have a battery
ground and battery 12-volt power feed.
58X4X sensor are designed to work on a sensor 5-volt reference and a specific sensor ground.
So they are not really going to be interchangeable.
I've seen some folks take a 58X harness and cut it apart and take the 5-volt reference
and the sensor ground and wire and splice those back into battery ground and battery
voltage, but I'm going to tell you that you really don't need to do that.
If you have a Holley system, whether you have a Dominator, an HP, a Terminator, LS, or one
of the new Terminator X or Terminator X MAX systems and you have one of the odd 24X1X
applications with the cam sensor in the front or you may have an engine that has an odd
mix, you may have a 24X crank but a 4X sensor in the front or visa versa, one of the things
that can help you out is make a simple modification to this harness.
You don't need to cut it apart like a lot of people do and try to maybe change the voltages
on it to 12 volts.
What I happen to know is that if you have one of the Holley systems, if you supply it
with a five-volt square wave reference that you would generate with this harness, it will
function fine because the internal switching threshold is three and a half volts.
So as long as your signal going into the ECU on the cam or the crank exceeds three and
a half volts, it's going to function fine.
The problem, however, is that the sensors are not wired the same, you are going to need
to make simple modifications by just swapping pin A and C, switching those two wires around.
You don't need a lot of special tools, but I would recommend getting a proper metripack
150 de-pinning tool.
You can get a Holley part number 567-101 or an equivalent.
You'll need a small screwdriver, possibly a pocket knife and a little bit of electrical
tape, so if you guys want to zoom in over here, we'll look at this a little bit closer
and we'll show you how to do it.
The first thing that you'll need to do is to look at your harness and find the connector
that is labeled cam.
Now you can work with this harness and try to modify it without removing the tape but
if you remove the tape it's going to give you a little extra wiggle room with the wires
so I would normally just take a knife and carefully remove the tape and you want to
be careful that you don't cut into the wires or the loom.
The next thing that you're going to want to do is to remove what they refer to as the
TPA or terminal position assurance, and you can usually pull this loose with your fingers
or a small screwdriver.
Remove that and set that off to the side because we will be reinstalling that later.
Now you need to get the appropriate tools.
So you can get a Holley 567-101 or equivalent and when you go to remove the pins when you
look at the connector, you'll see up at the top side of it there's a little depression
on the AB and C. You want to take your pin tool and carefully, this shouldn't require
a lot of force, but you'll want to insert it above that pin and you'll feel it when
it engages and just carefully release the D10.
Now when we look at the connector, it will be labeled A, B, and C and what you need to
do is remove the A pin and the C pin and you need to switch them but now since we have
depressed the D10 lock, you are going to need to carefully pick that back up.
And you don't want to get carried away with it you just want to bring it up just a little
bit so that it will be able to re-engage in the connector, you don't want to bend it too
far and you definitely don't want to break it off.
If you do accidentally damage the connector or the pins, they are available from Holley
or your local Holley dealer so you would be able to get those and switch them out.
You would then just carefully re-insert the connector, line up and push it in gently until
you hear it click and do the same thing on the second wire.
Once you get those installed, you can re-install the TPA.
Be careful, make sure that you get the wires separated.
Lock that back in, I would take a little bit of electrical tape, I use good quality harness
tape, it's worth a little extra expense to buy quality materials and you're good to go,
now depending on the application you may need to modify the settings on the software and
we will cover that next.
Now that you have your harness modified, you'll need to go in and set up the software.
If you are not dealing with a what I call a "Franken-motor" where you are dealing with
a 24X crank in the engine with a 4X or a 58X crank with a 1X cam, you could simply go on
in and program in the 58X, 4X, or the 24X1X settings that are in the immediate drop down
menu.
But if you have an engine that's kind of got a mashup of mixed cam and crank sensors, you'll
need to go in through the custom ignition settings to set that up.
I'm going to go ahead and show you how to do it now.
To program the proper ignition type in the software you go to ignition parameters.
The layout of the software between conventional Holley EFI systems and Terminator X is slightly
different but the overall setup will be the same.
In the ignition type drop-down, you want to look for 58X or 24X LS.
These options would be used if you have a factory cam and crank sensor combination.
If you have a combination that requires custom configurations, for example, 58X1X, you would
go to custom and then select Configure.
In this case, we are showing a factory 58X crank with 4X cam.
We may have a 58X crank sensor with a 1X cam, in which case we would select single pulse
and then our sensor type.
You want to make sure with the LS 1X cam sensor that the sensor type I set for digital rising.
It could be that 24X crank with a 4X cam and you would set it up accordingly, below that
you'll find the output setup.
You would want to make sure that your output type is always going to be set for a DIS coil
on plug and the dwell time will need to be programmed based on the coil manufacturer's
specifications.
Different coils and different manufacturers are going to have different dwell times and
it's going to be important to make sure that you follow their recommendations.
When you are programming the dwell time for factory LS coils, most factory 58X LS coils
use a dwell time of 3.5 milliseconds.
Yet a factory 24X coil, they were generally programmed for 4.5 milliseconds.
Now that you have your ignition types set up, you would simply go ahead and send that
to the ECU and then cycle the ignition key.
Now that you have your global file properly configured for the correct ignition type for
your application, you can go ahead and send that file to the ECU.
Just remember that if you haven't already done it, it's a new installation so perform
a TPS auto-set before you try to start the engine.
For more helpful Holley tech tips and videos, go to Holley.com