Hello Everyone,

I am helping a friend swap a 5.3 LS into his 3rd gen. We are going to be running a megasquirt ECU and a harness that I made. I aready have all the adapters for the engine mounts, torque converter pilot, and have opened up the torque converter bolt holes in the flexplate so the 700r4 converter will bolt up. I read through the swap guide on this forum and they suggest using a fuel tank from an LS1 car since they regulate at the tank and the EVAP is built into the tank already. Plus the LS engines run at a higher fuel pressure than the factory TPI motor. I have a question though. Is the Evap control system all local to the tank or does it need the factory ECU to read tank pressure and know when to open the solenoid to release the pressure? I am just wondering since we are not using the factory ECU and trying to plan ahead for what issues we may have. Can someone give me more insight as to how this works and what issues we will have with not using the factory ECU with the tank.

Thanks,

Shane

 

Retaining EVAP systems are for emissions friendly swaps, which your truck 5.3 never will be be. I wouldnt bother with the system

But to answer your question, the LSx EVAP system has 3 main parts: Vent and purge solenoids on the intake and canister mounted to the tank. You need all 3 for the system to work, plus the tank pressure sensor

Will megasquirt control all these? Doubtful. Its a barebones aftermarket ECM. Heck, it doesnt even have sequential injection or electronic transmission compatibility

Just wondering why MS over the stock PCM?

 

I wanted it more to help control tank pressure more than correctly circulating the fumes back into the intake etc.

No the meagsquirt will not control these thats why I was asking if it was a local system to the tank ex the pressure sensor and evap sensor worked together or if the ECU controlled them.

I would think the megasquirt is very far from a "barebones ecu" Maybe to someone that has never built or setup one but they are extremely customizable. The megasquirt does in fact have sequential injection. It has since the MS1 but it didn't support 8 Cylinders until the MS3x. They released this with the MS3x in the summer of 2010 and supports up to 12 cylinders. And they have a transmission controller as well.

Also I cannot even think about how much more I have learned by building the megasquirt, bench testing it, troubleshooting, and building the harness than I would have by using the factory ecu.

 

Use a vent instead or refitting EVAP for a different use

Perhaps the newer ms boards are more capable than the few I've wired in. I'm not sure. I do know the factory control systems for the LSx family is extremely capable, common and inexpensive. I don't see the benefit of ms over delphi

 

That sounds like a plan.

Yeah the MS lineup has come a long way in the past 5 years. I agree that they are not for everyone. In the case of most swaps the factory ECU is fine and great. I have a degree in Electrical Engineering and computer engineering which made the assembly and modification rather easy for me but again like I said I learned so much about ECUs and sensors and how everything works that I am more than glad I went that route.