Ultimate LS Systems 700xx information
As I’ve installed the Fitech EFI Ultimate LS 70051 system on my car, I’d like to add some useful info here.
These systems come in a variety of builds, from simple harnesses and ECM to everything including an intake, throttle body and injectors. They all have the same basic main harness and ECM.
It comes with ProCal tuning software, which is in the touch screen. Unplug it from the ECM and connect it to your laptop and it's there for you to install on the laptop
They are designed to work with all factory stock GM sensors for the genIII and genIV LS engines.
This system is speed density, there is no MAF sensor.
This system is a drive by cable system, in other words, the gas pedal needs to have a cable to the throttle body. This system will NOT support drive by wire in any way.
These systems do NOT support Nitrous systems nor do they have any user programable unused inputs or outputs. They DO support superchargers or turbo chargers-it’s all in the touch pad settings.
This system will NOT work or provide signals for any type of gauges, stock or aftermarket. Dakota Digital may be working on something but I’d think it’s best to not interwire these systems, keep them separate.
This system works with a 24x OR 58x crank sensor and a 1x OR 4x cam sensor. Any cam sensor will work with any crank sensor EG: My setup uses a 58x crank sensor (LS2/genIV) and 1x cam sensor (LS1/genIII). An adapter harness is included to change from a rear mounted 1x cam sensor to a front mounted 4x cam sensor.
These kits come with two wideband Bosch o2 sensors. Some kits come with a plug-in adder harness for a GM automatic transmission, 4L60e and 4L80e and their variations. Different kit numbers correlate to the different features.
They come with a pair of fuel injector harnesses, you can choose a kit for your injector style. Some have reported kits coming with BOTH injector style harnesses. These injector plugs are NOT marked so assume the injector plug nearest to the harness plug is the rear injector, seven or eight, depending on which bank you’re working on.
Ignition coils and harnesses are NOT included. The harness accepts the same plug GM uses so it’s convenient to purchase a set off eBay with harnesses. I’ve seen full sets on brackets with harnesses between $50 and $100. The round body LS2 truck coils, 585, are pretty much the most powerful coils GM offered. If you don’t mount the coils in the stock valve cover locations, add an extra 12 gauge ground wire between the coils and the block. If your coils are all together on one bracket you made up, one 12 gauge wire will suffice.
Fuel, ignition and o2 plugs are marked “D” for drivers side and “P” for passenger side.
Some systems have been reported as coming with the needed MAP sensor. If not, you need a 3 bar sensor, GM number 12592525. The ECM is calibrated for THIS 3 bar sensor so don’t think a 1 bar or 2 bar will work. Where does it go? The ECM doesn’t care so long as you get manifold vacuum to it. Pop it into the manifold or remotely mount it and run a hose between it and the manifold.
The throttle bodies have been reported to whistle.
The intake manifolds look nice. They’re apparently made in China. It’s reported that they’re not great performers so if every bit of HP is your goal, don’t order the kit with the Fitech EFI intake manifold.
The instructions are pretty clear about the fuel pump relay being PWM controlled and that you can adjust the power to the fuel pump. THIS IS INCORRECT. Unless Fitech EFI makes changes, the supplied fuel pump relay is a regular contact relay and is either on or off.
The fuel pump relay is triggered by a ground provided by the ECM. It and the harness wiring should not be relied upon for any kind of a big fuel pump. They say 15 amps but I’d put it at less. It would be wise to dig out the ground trigger wire and use it to trigger a relay of your own powered from a better source with better wiring. Or you can retain the original relay and use it’s positive output to trigger your better relay.
Just like a stock system, upon key on, the fuel pump relay will close and power up the fuel pump. If the ECM does not see crank rotation via the crank sensor, it will power down the fuel pump relay after a few seconds.
The fan 1 & fan 2 wires emulate how GM’s LS fans operate for F-body cars. They’re grounded when a fan is called for. You’ll need to provide switched power to the coil and the ECM grounds the other side of the coil to close the contacts when the fan is called for. Fan 1 & 2 on & off times are user programable. If using dual fans, GM had a slightly complicated series/parallel control via three relays. Fan 1 put them in series at half speed, fan 2 put them in parallel at full speed.
Alternator: The harness has an alternator plug that allows the ECM to control the voltage output, just like the GM LS system. It connects to any CS130D or AD244 alternator with the four pin oval connector. If you’re using another alternator without this connector, just bury and abandon the plug from the ECM.
The A/C REQ (requested) wire goes to the hot feed of your A/C compressor clutch. This tells the ECM when the compressor is engaged and it steps up the idle RPM a bit.
Transmission speed sensor: You’d think it’s only needed for using a GM auto transmission but it helps the ECM control deceleration fuel if it knows the vehicle is still moving. The aftermarket offers speed sensors for a variety of non-electronic transmissions. You can get away without using this feature.
The brake switch wire (yellow TCC wire in the flying leads bunch) is required when using the system to control an automatic transmission. This wire needs to have 12v when the brake is NOT applied, and zero voltage when the brake IS applied. This will enable the TCC to operate correctly. Also, apparently, the brake switch wire changes the deceleration parameters when the ECM knows you're braking so it should be connected regardless of which transmission you're using.
The tach wire will drive a variety of stock and aftermarket tachometers and is user set up via the touch pad.
The system requires a good positive and negative feed, Fitech wisely recommends going directly to the battery for this. Fuse it at the battery to protect the wire from there to the system. Any good and heavy power source can be used such as: a power distribution block with a heavy feed from the battery.
The red wire (#4 “KEY”) needs to go to a power source in your car that has positive power when the ignition key is in the ON AND CRANK position. This tells the ECM you want to run the engine. There is no specific “crank” wire because when the “KEY” wire is powered and the ECM sees crank rotation from the crank sensor, it know’s the engine is being cranked to start and it adjusts the fuel and ignition to get the engine started. This #4 “KEY” wire must lose power when you turn the key off, this shuts everything down.
Fuel pressure should be 55 PSI. Despite conversations with Fitech EFI, I can’t determine if the system wants a constant fuel pressure or manifold vacuum modified fuel pressure. I believe a steady 55 PSI is more preferred.
Fuel systems: Early on, Fitech EFI had many problems with their fuel systems. Although they’ve improved, there’s plenty better components on the market. Installer’s choice.
Most users will need to call Fitech EFI and be walked through the initial programing setup to get things going. I did, some people are more lucky and their first key attempt works.
In the supplied fuse block, the right relay is the main power. Ignition on closes this relay and all fuses are powered up. One of these fuses is powered all the time.
The left relay is the fuel pump relay.
When shutting down the system, the ECM does an auto-save of the last running conditions learned and the settings. It will retain all this even if you remove ALL power (as in having a battery disconnect) but if you (like me) leave your car with the battery disconnected, I would suggest you just give it a minute to store everything before killing the battery power.
Other engine usage? YES! So long as you provide the needed inputs sensors (crank, cam, MAP, intake air, coolant, etc.) and a throttle body with GM style IAC and TPS, this system will function. The ECM doesn’t know or care if it’s running an LS engine or some crazy big block (like I am).
This is the fuse block and you can see the relays are identical.
Also shown is what a PWM relay would look like.
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Aftermarket electric cooling fans have some wildly advertised CFM ratings. The truth is the powerful ones that move more air draw plenty current, some as much as 25 amps, with a start inrush current as high as 40 amps.
If you're brave and skilled enough to do the fan series/parallel control via three relays, here it is. Each fused feed should support one fan's startup and run current. Use wiring for 30 amps and relays rated at 40 amps.
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For those of you even braver to delve into the harness itself, here's the diagram:
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Wow Paul. That is awesome!!!! As you know I haven't had my hands on an LS system yet. This will help a lot. You may teach the Fitech guys a thing or two. (Just joking, they are great guys)
When I was at SEMA we talked about using the LS system on a Sbc or a BBC. They said the same thing. The ecu doesn't care what engine is running as long as it has the sensors.
Thanks again....
What did you use to adapt the 700r's TV cable to the TB. I assume you have a longer cable also. Thanks!
Assuming you're using the LS kit that included the throttle body, they have a cable stud that would accommodate a kick down cable.
Fitech EFI also offers separately a throttle body cable bracket. https://fitechefi.com/product-category/accessories-components/ls-throttle-body/
You'll need to figure out on your own what cable to use.
Good stuff. I have the 750 HP kit on my 403 stroker with good-sized cam, 4L80E; my son has the 500 HP kit on his LS1 with MS3 cam, TH400.
I'd add a couple of corrections.
Brake wire - This needs to have 12v when the brake is NOT applied, and zero voltage when the brake IS applied. This will enable the TCC to operate correctly. I used a relay with a NC terminal ("normally closed" - not all relays have that function), the activating circuit is connected to the brake light switch. I drove most of the summer with the wire connected directly to the brake light switch, and the TCC did not operate correctly. I finally called tech support, they identified the problem in less than a minute. The installation instructions really need to be updated to correct this.
Only the 750 HP kits come with 2 O2 sensors. The 500 HP kits have a single O2 sensor, but a connector for a 2nd.
Five7kid, thanks for the clarification on the brake wire use. I've corrected the text I've posted.
I purchased the 70051 kit which is the standalone ECU with trans control (harness) kit. It came with two o2 sensors.
As these LS systems have bank-to-bank fuel and timing control (actually per cylinder, just like a GM LS system does) I think it's foolish to use it with one o2 sensor.
I agree, Fitech needs to improve their instructions and it would be helpful to people considering this system if they were to create a chart on their website showing what each kit contains.
They have so many configurations, it would be helpful to have such a chart on their website.