Everything You Need to START a Chevy Performance Connect & Cruise System (LS and LT Engines)

wiring a Chevy Performance Connect and Cruise system for its first start

Wiring is scary. But wiring a Chevrolet Performance Connect & Cruise system is not. Here’s what you need to start up your build the first time.

Hey, folks! It’s been a minute, but we’re still cranking away on our CARB Legal LS3 Wagon Swap project. When we last chatted, I had just pulled the engine and was preparing to install the LS3 E-ROD Connect & Cruise powertrain system — acquired from California’s #1 Chevy Performance dealer, Guaranty Chevrolet — along with a smattering of Holley components and Dakota Digital gauges.

Click HERE to join in on the
official Wagon Swap build thread!!!

After a few delays (some my fault, some not), I decided to finish the build so I could release content more consistently. As I type this, I just did a 500-mile second oil change and have a few things to sort. But it’s coming along well and you’ll see more very soon. In the meantime, I thought it’d be fun to walk everyone through everything you need to wire to get a Chevrolet Performance Connect & Cruise system started for the very first time.

But first, a big, fat DISCLAIMER: this article, which assumes all major powertrain components are safely in place, is a mild overview for wiring and starting an LS or LT engine with Chevrolet Performance components. It’s not a shop manual. I’m not a mechanic. Read and re-read the instructions. Proceed at your own risk.

Fuel, Spark, Air & Everything Else You Need

CARB Legal LS3 Wagon Swap Project

Great news. You managed to tuck, grind, fab, mount and squeeze your LS or LT powertrain into position. And now you’re itching to fire up your beast for the first time. Here’s everything the Connect & Cruise system requires —

  • Wiring harnesses & computers
  • Proper grounds
  • Constant and switched 12V Ppower
  • Accelerator pedal
  • Air intake, Mass Air Sensor, and O2 sensors
  • Fuel & EVAP* systems (*for E-ROD)
  • Starter
  • Electric fan(s)
  • Fluids

Chevy Performance Connect & Cruise

Chevy Performance Connect & Cruise powertrain systems include an Engine Control Modele (ECM), a Transmission Control Module (TCM), a universal engine harness with fuse/relay center, a transmission harness, a mass-air sensor and air filter, O2 sensors, headers, and, for E-ROD systems, EVAP components and catalytic converters. (#CARBLegal)

As you can see, it’s not everything you need. But it’s a big fat chunk of it.

Along those lines, you will also need to acquire —

  • Engine accessories (we used a Holley Mid-Mount Accessory Drive kit ) and brackets
  • Air intake
  • Fuel pump, hoses, fittings, and a filter/regulator
  • Radiator and misc. hoses (transmission and oil coolers are a good idea too)
  • Starter and starter bolts
  • Accelerator pedal mounting bracket
  • Good working battery and properly gauged wire
  • Misc. fasteners, nuts, and firewall grommets
  • Exhaust piping for your O2 sensors (for non E-ROD)

Wiring Is Scary (But Also Not)

wiring a connect & cruise system

Chevrolet Performance Connect & Cruise systems want to roar. You just need to give them fuel, power, ground, air, and ignition. Which means wiring. And I know, I know. Wiring is terrifying. Or it was for me. But these kits make the process shockingly approachable.

To begin, first lay out and route your engine and transmission harnesses (it may be best to do this prior to installation if you don’t have room behind your engine and/or above your transmission). During this mock-up phase, figure out where you’re going to mount the fuse box, ECM, and TCM. Chevy recommends flat surfaces.

This may seem daunting at first, like wrangling a plastic octopus, so just take your time. Also, because the harnesses are universal, you’ll most likely end up with a few long strands that need to be looped and tucked away. For this reason, some of you may prefer a custom harness (or you could shorten the included harnesses).

With the harnesses in place and various modules mounted, connect as many of the plugs as you can, but leave the ECM and TCM disconnected until priming the engine with oil. This is really easy because everything’s labeled.

TIP 1: Not all connections are mandatory for operation, so check your instructions. For example, alternators/generators don’t need to be plugged into the harness. And, you may not have every transmission feature available on the harness, like manual shifting paddles for an automatic. (Manual transmission don’t have ECMs.)

TIP 2: Be on the lookout for a few harness jumpers, multiple transmission speed sensors (use the engine harness), and the bulkhead connector for uniting the engine and transmission harnesses.

Unlike Your Teenage Self, You WANT to be Grounded

negative grounds

If you don’t ground your engine, it won’t start. (I think my parents had a similar philosophy.)

Chevrolet Performance wiring harnesses include ground straps that need to be secured to the back of the cylinder heads. For my kit, it was three. Also, don’t forget to run a negative cable from the front of the engine to the negative terminal of your battery.

TIP: Chevy doesn’t include bolts for the grounds, so you’ll need to buy three or four short bolts (M10 x 1.5 for the LS3).

B-BODY TIP: Roadmasters also ground the battery’s negative terminal to the front fender. (Pictured above.)

Constant & Switched 12V Power

Connect & Cruse fuse/relay panel

Chevy Performance Connect & Cruise harnesses need two types of positive 12V power to operate and complete a successful startup procedure — Constant & Switched (aka, power that is only on when the key is in the ON position).

For Constant Power, run (at least) an 8-gauge wire from your battery to the single side-post terminal on the Connect & Cruise fuse box. No nut is included, so you’ll need to buy one M7 x 1.0 nut. (The other two terminals, downward-facing, are fused and relayed optional accessory outputs and require M8 x 1.25 nuts.)

For Switched or Key On, Power, the harness includes a wire marked Ignition. This branch of the harness features other connections for the accelerator pedal, the MIL wire (for a Check Engine light), and your OBII port, so you’ll most likely run this Ignition wire into the cabin with those. You’ll need to find a wire that becomes hot when the key is on (or in the start position).

57 Corvette Ignition Wire

1957 Corvette ignition wires from CorvetteForum.

GM typically uses a thick PINK ignition wire under the steering column so we tapped it for our Connect & Cruise harness as well as the control box for the Dakota Digital VHX 1023 gauges.

TIP 1: Consider grabbing a new battery prior to your first start because, as you start and break-in your project, it’s a pain to worry about jumping an old battery.

TIP 2: don’t forget an alternator. You don’t need this to start your CnC system, but you need one to drive. In our case, the Holly mid-mount system includes a Holley 197-303 150amp high-performance alternator. The plug fits the Chevy Performance harness. And GM recommends running a high-quality wire directly to your positive battery terminal. (Guage depends on length, so read Holley’s instructions.)

Earl's firewall grommet

B-BODY TIP:  The OEM throttle cable hole is a great place to run your harness into the cabin. I enlarged mine and used an Earl’s firewall grommet to seal it up.

B-BODY TIP 2: 91-93 models have a junction box that sends 12v power to the rest of the vehicle (anything that’s not on the engine harness, like your interior fuse box). Make sure you run a wire to this from your battery. You can see that red box next to the GM harness fuse box in the pick above.

Accelerator Pedal

If you’re running an LS3 (or newer) engine, you’ll need a drive-by-wire accelerator pedal, which is basically a throttle position sensor that looks like a gas pedal. The one in our kit appears to be out of a second-gen CTS-V. To mount this in place, you’ll need to either fab up a bracket or purchase one on eBay.

B-BODY TIP: Pedal bracket designed for C10 trucks (78-87?) fit the firewall bolt pattern of B-Bodies, but you’ll need to add spacers to align the accelerator pedal away from the transmission tunnel.

Air Intake, Mass Air Sensor, and 02 Sensors

Chevy Performance Universal LS Air Intake

Chevy Performance Connect & Cruise Systems include a Mass Air Sensor and an air filter, but not the air intake itself, which needs to be 4-inches in diameter. I initially ordered a SIKKY intake designed for the LS3, but it lacked an extra port for the PCV systems’ Fresh Air Tube. So I snagged a Chevy Performance intake from Guaranty Chevrolet. It’s expensive (too expensive), but looks nice, has a built-in Mass Air Sensor bung, Fresh Air Tube port, and fits the included filter.

Likewise, Chevy Performance includes 02 sensors that need to be connected for proper operation. E-ROD kits include catted downpipes, so, once the pipes are in place (fitment can be a challenge — I suggest teaming with an exhaust shop) it’s pretty easy to install the sensors and connect them to the harness.

The kit also includes bungs if you’re mounting the sensors into your own pipe(s).

Starter

Not included in the kit, but very easy to find thanks to the popularity of LS engines. LS3s, as you probably know, were in fifth-generation Camaros and sixth-generation Corvettes. And don’t forget the bolts (I did); ICT billet sells a set that I grabbed on Amazon. For the positive connection, run a wire from your battery terminal to the larger stud on the starter.

For the solenoid (negative) connection, save the starter wire from your vehicle’s original harness.

TIP 1: Depending on your starter, the solenoid connection might not be a stud. So you may need pick up a pigtail connector.

TIP 2: I ended up wrapping my starter in DEI heat shielding because the positive stud started arcing on the (also shielded) transmission cooler lines. Just keep an eye out that things aren’t too close.

B-BODY TIP: The solenoid (negative) wire is the THICK PURPLE wire in the passenger side engine harness.

Fuel System & Fuel Pump Wiring

Earl's Performance Vapor Guard fuel system

This may vary depending on your crate engine, so read the instructions. The LS3, for example, needs 60 PSI of constant fuel pressure. So we installed Earl’s Performance Vapor Guard fuel line, AN fittings, and a C5 Corvette fuel filter regulator. (Here’s the AC Delco GF822 mentioned in the instructions.)

Chevy Performance actually recommends this filter/regulator over adjustable regulators, but beware there are some poorly made units out there that don’t last. (#NewDoesn’tGuarantyGood)

With fuel lines plumbed to the engine, you need to power your fuel pump. There’s a fused and relayed GREY wire coming out of the Connect & Cruise fuse box. This wire supplies (positive) 12v power to the fuel pump. Find a wiring diagram for your vehicle and send power to that pump!

Connect & Cruise fuel pump 12v power grey wire

TIP: While not required to start the vehicle, consider integrating an INERTIA SWITCH. These simple switches cut power to the fuel pump in the case of a rollover or any type of high-g activity (like a crash).

TIP 2: Chevy doesn’t allow the fuel pump to run very long when an engine isn’t firing. So you may want to manualy prime the fuel system prior to first startup (OIL PRESSURE is also vital!!!)

B-BODY TIP: Funny enough, in my 92 Roadmaster, the main fuel pump wire is also a thick grey one. It runs all the way from the passenger side front relay to the in-tank sending unit (which we upgraded in part 5 with a drop-in Walbro 255 pump). To make the Connect & Cruise system work, I deleted everything from the fuel circuit save for the tick grey wire and connected it to the CnC harness.

EVAP System (E-ROD Only)

EVAP purge solenoid

In addition to the included catalytic converters and 50-state legal engine tune, the E-ROD kits include an EVAP system, which collects gas tank fumes, runs them through a charcoal canister, and back into the engine via a purge solenoid. All with GM factory parts.

You just need to plumb it all up with gasoline-rated lines and make sure that purge solenoid is connected to your harness.

Fan(s)

impala ss fans

Chevy Performance Harnesses require a connected fan connected or it illuminates a Check Engine light. The fan control wire is thick and blue, and it too is fused and relayed. The ECM will trigger the fan at 207 degrees (measured at the coolant temp sensor).

For the Roadmaster, I used a set of 94-96 dual electric fans from an Impala and wired both to the single blue wire. They’re relatively low amperage and move a lot of air despite their age. (#OEMengineering)

After a recommendation from my A/C installer, I added a secondary fan controller, the Dakota Digital PAC-2800bt. This controller allows you to control up to two fans based on custom coolant temp(s), vehicle speed, and air conditioning, which is what I needed. To oversimply, A/C systems are most efficient with the fans running, which improves cooling as well as system longevity.

The end result? If my A/C is on, the fans kick on. If it’s off, the ECM runs the fans. Redundant. Simple. And no sign of overheating in the first 500 miles (knocking on my wooden head), all with chilly a/c.

B-BODY TIP: GM did a really nice job with B-Body cooling systems. If you have a 94-96 B-Body with dual fans, you can probably run the radiator and fans as they are if you aren’t building a racecar. If you have a mechanical fan, you could upgrade to the 94-96 fans and shroud, or add something aftermarket.

Fluids

fluids

This may seem obvious, but for the love all things holy, double-triple-QUADRUPLE-check-ask-yourself, do you have proper amounts of —

  • oil
  • coolant
  • gasoline
  • transmission fluid
  • power steering fluid
  • brake fluid
  • rear differential gear oil
  • blinker fluid (just kidding)

–in your project? Make sure everything’s topped off, clean, and not leaking before you turn that key. Leaks may also present themself the moment you turn said key, so be on the lookout and keep fire suppression in mind.

Final Thoughts (READ THE INSTRUCTIONS)

LS3

At the end of the day, you’ll probably spend hours mocking things up, routing wires, searching for nuts and bolts and hoses, and making all of these parts find a new home in places they were never meant to be. It’s a bit of a time suck… But, outside of some odd fitment and loom length, Connect & Cruise harnesses are about as simple as they come.

Just be careful.

Be mindful of live wires. Disconnect the battery every time you’re wiring. Keep wires and hoses away from headers and/or your catalytic converters. And please, please, please read and re-read your Chevy Performance instructions. They aren’t very detailed, sadly. You’ll probably need to look in the forums for context.

But those instructions are vital (like making sure you prime your engine with oil).

Most of all, dear reader, I hope this article helped a little. And good luck!

 

Be the first to comment

Leave a Reply

Your email address will not be published.


*


I agree to receive emails from RacingJunk.com. I understand that I can unsubscribe at any time. Privacy Policy
Copyright © 2005-2022 MH Sub I, LLC dba Internet Brands
All Rights Reserved.

Internet Brands