Been putting this off a while, but for all you carbed LS guys that are trouble shooting, and those that are new to the carbed LS platform and want to know what your getting yourself into, this is the place many will be referred to.
Any other info i miss that is of great importance let me know, im not perfect and will miss several things since my mind will be spinning to get as much of this in as i can think of off the top. Im new, what do i do????
For starters, you new guys, with little or massive knowledge of the carb, need to know the primary things required to install a carbed setup on a LS.
1: Induction, the intake and carb of your choice. There are a couple large options and a couple high end that depending on budget and application, will fit any goals.
The intake will be 1 of 2, either the cathedral port heads from 97-2004 which are all the same and have a cathedral area at the top of the runner looking at the head and then there are cathedral port all the way to the present.
That is a Vic Jr and a Super Vic from edelbrock, just a couple of many options.
The second will be the square port variety, less selection but they all move tons of air for these big block style ports. The LS3, L92 and LY6 are the main engines/head castings for major power if a 4 inch or larger bore is being used, although there are ported stock and aftermarket cathedrals that will work very well for power.
Edelbrock, GMPP, MAST and some others will be the intake producers that you see us using.
On to the second part of the induction, the carb. Majority of us rock a Holley or holley platform of some variety. Some choose edelbrock and quadrajet with luck and are happy. I will get to the tuning aspect of that later.
Many options from Holley, pro form, demon, quick fuel, ect. Vacuum secondary and mechanical depend on the application as well as CFM rating. Refer to the build sections to grasp what CFM carbs we use on xxx cuic engines and you will see what works.
Expensive and for lots of power and efficiency, there is the single barrel setup from Pro Systems:
Moving massive amounts of air for massive power plants and some that are smaller cubes but spin lots of RPM. Not for the average street car. IGNITION
The next part of what you need to know if im new to carbs, is the ignition controller.
Edelbrock is NOT
the tunable model and many of us frown upon it. Not cost effective for those of us looking to get the most of our carbed mills. The 6010 and 6012 from edelbrock are the same in the fact that they both control the engines factory coils and have the same features. Heads up for EARLY LS2 design
The Early LS2 had the 24x reluctor with a front mount timing covr cam position sensor: msd 6010 Which one do i need???
Simple, the black crank position sensor(located behind the starter if there is one) is for the part number 6010. The gray sensor if there is one, will be the LS2 type requiring the part number 6012. My engine came with no sensor!?!?
Take a peek inside where the sensor will mount with a light and you will see either two stacked plates that are together, that is the older 24X requiring the 6010 and a black crank sensor or a single plate with gear looking teeth that is a 58x reluctor indicating the 6012 and a gray sensor:
This picture has both, one on top of the other, the top is the single that is a 58X, the bottom that is mounted on the crank is 2 plates together that is a 24X:
Right side 58X, left 24X: The connector wont connect!!!
MSD has had this issue before, some times some connectors get switched and some times wires can get crossed: http://ls1tech.com/forums/carbureted...wont-plug.html
That is it. Carb, intake and ignition controller.Lets move on... What harness do i need for the ignition controller???
You do not NEED any harness other than that provided by MSD with two exceptions:
1: The coil harnesses are needed
2: The front crank position sensor extension harness for the 6012.
The 6012 if used without the GM extension harness will need to have the two outside wires swapped. The GM harness corrects this, but is not needed. If you do not use the GM harness that mounts to the timing cover and you do not splice the wires and swap them, your car will run and pop and miss fire. Do i need to hook up a MAP sensor???
No, many of us do not. I dont but will be soon. The gains are in the fuel economy department at part throttle cruise and is surely a good thing considering as well as the read out can help tuning: MAP Timing with Speedtigger :p
And for the creative, there are other ways to mount a MAP sensor: mounted my map sensor My car wont start!!!!
Calm down, this is common. i have never had it happen to me with the many builds i have done, but that is my experience. I have fixed others and the main reason that we will sweat you to death over it because it is usually the issue: CHECK YOUR GROUNDS!!!
Grounds grounds grounds. I have seen many just not start, start some times and start but run like garbage.
You will need a solid ground for the ignition. I ground mine to the intake since the connector that comes with it is just long enough to do so. BUT, i also have a ground from the battery negative to the engine. A ground from the battery negative to the chassis. And usually 2 grounds from the engine to the chassis.
Want to ground it to the battery negative? Great! It will be fine.
Another issue for "My engine wont run!!!"
Some use the factory 12 volts from the ignition source that was originally on the car. Guess what? Not all cars are equal. Some only put out a little over half the volts required for the MSD system. This was usually called "points" ignitions back before i was born. Check it with a volt meter. Have a friend watch the lap top(or yourself if you trust them to drive your ride) while driving if it will run, if you see voltage drop, it is usually a bad ground, but if grounds are good, there may be a issue with your factory 12 volt supply. Nothing a relay wont fix.
The MSD software will also throw a bad cam sensor code if the sensor is usually bad. Not common but does happen.
If those two things are fine and you still cannot get fire, and you know its fire and just not getting FUEL, then contact MSD or see if we can help.
Beware, the TBI and other facotry EFI setups merely prime the fuel pump, so if you get fuel and run out, you need a hot wire that stays 12 volts when the car is running.
Another issue, be sure you are not dropping 12v when the key is turned. Most systems kill 12 volts from accessory output when in the starting position on the ignition cylinder. It HAS happened.
There is also the "180* out" of putting coil plug marked 1,3,5,7 to pack 2,4,6,8 and visa versa. Pay attention as there is no designated connector for one bank to the other, but MSD does wire them so you know 1,3,5,7 goes to the driver side coils. 2,4,6,8 to the passenger.
Im sure there is more but thats the main "problems" that happen.