Zombie

iTrader: (2)

I haven't heard of anyone doing this yet and decided to give it a crack. I've maxxed out my 60lb/hr injectors. I'm still on the stock fuel system line/rails and will continue to use it until I can no longer. My fuel pressure at idle with 1 pump on is 58psi but goes to 72psi with the second pump on due to over running the stock regulator. I'm out of injector at 16psi now in this cold weather and want to try using the megasquirt setup instead of going to speed density on the stock ecu. The reason for this is ease of making adjustments in the future (I don't own HP Tuners) and giving Mega Squirt control of timing will allow me to use it as a 2-step. I can also tune the cruise areas to a leaner ratio to improve milage and the MS opens up some other future possibilities as well.

I'm going to run this in parallel with my stock ECU so that I'm still able to pass emissions and I can also have the stock ECU report any knock events through my scan gage. The only downside to this setup is that knock events will not pull timing out which I don't think is a big deal since I know what safe timing is on my setup.

I'm going to run a seperate IAT and Coolant sensor for the MSII unit since I've been told that trying to piggyback off the ones connected to the stock ECU causes issues on the MS due to the way the stock ecu operates.

I'm going to start off fuel control only at first and then work on getting the spark control and IAC motor working until I'm completely weened off the factory ECU. Hopefully I'll be able to have the stock ECU thinking it's still in control of everything so emissions tests will not be an issue. Even if I can't get it to work properly in parallel I can just swap in some injectors, re-connect the stock injector harness and go pass emissions.

kbracing96

iTrader: (25)

That's pretty much what parish did on his truck, only he did use EFIlive to turn off some codes and stuff. Stock PCM still shifts the tranny and runs the ignition, Measquirt just does the fuel. He did a full write up on it thats around here some where.

Zombie

iTrader: (2)

I've read his threads and his success with doing fuel is motivater. I would like to give the squirt control over timing as well.

gametech

iTrader: (1)

You need to go ahead and invest in tuning software. While your ideas should work great, the stock PCM isn't going to like them. You will undoubtedly throw o2 and cat efficiency codes that will fubar emissions tests unless you tune them out. Other problems may arise, but those are the big two that I can think of offhand.

Zombie

iTrader: (2)

I've already handled those codes, I don't own my own software but I have access to it I've also got a cable on semi-permanent loan from a friend.

2001-WS6

Are you sure you wouldn't rather take one for the team and try the new Racetronix 79lbs\hr high impedence injectors? They should flow 91lbs\hr where we like them set at.

https://ls1tech.com/forums/fueling-injection/812140-new-racetronix-79lb-hr-high-impedance-flow-matched-injectors.html

I'm sure you'll earn the thanks for all the rest of us who are stuck in a 1' of snow right now.

Rick

Zombie

iTrader: (2)

Got the MSII installed into the car and monitoring all the sesnsors. Had a new bung welded in my i/c pipe for a 2nd IAT sensor. I set the Coolant sensor up in the TB bypass line, but it's too slow to come up to temp. I'm going to try and use a 3/8 NPT union and T fitting off the stock temp sensor location to run both sensors.

I'll hopefully have it taking control of my 60lb/hr injectors later this week. I want to get it working well on the high imp injectors before swapping to the low imp ones.

Zombie

iTrader: (2)

I'll try to keep updating this thread in case anyone else wants to go this route since it looks like several people have been at least reading it.

I upgraded to the MS2/Extra 1.0.2 firmware.
Had a problem where the RPM was only reading half of the actual value. The tach setup needs to be set to basic if you are doing fuel only as I am doing right now. You then need to tell it that you are running a 4 cyl engine instead of 8 so the RPM reads correctly. After you change the number of cylinders you need to power cycle the MSII unit for it to update.

Got a piece of 1.5" pipe with a 3/8 NPT bung in it. I'm going to splice it into the coolant hose for my coolant temp sensor.

For anyone who is looking for a source of power that is hot in run and cranking, look in the first fuse box of the engine bay at the empty ETC location. On F-bodies there is no ETC, but the fuse location is still there and labled.

Zombie

iTrader: (2)

Got it fired up tonight on the 96lb injectors. Fired up with a little bit of coaxing. Took 15 mins to get it to idle well at 14.5:1 a/f and have the ability to drive it around the block... kick ***!

I still have to install resistors in the old injector clips so that I don't get the p0200 code.

Frost

iTrader: (45)

congrats!! sweet diy.

why not just turn off the code; why dummy load the inj outputs?

Zombie

iTrader: (2)

not sure if I will pass emissions with the code turned off, i'll give it a shot, i have to work on getting the car ready for that anyways, can only have 2 not ready indicators.

Josh@KY-Turbo

iTrader: (120)

Subscribing.

shiftless

Any more updates on this? I was researching into doing the same thing myself. Emissions are not a problem here. I just want to make sure that the PCM doesn't freak out. Also are you using the stock LS1 crank/cam triggers, connected to both the stock PCM and the MS?

Zombie

iTrader: (2)

I still only using the MSII to control fuel and don't know if I'll give it control over spark or not. I'm using the factory tach signal at the PCM for my RPM pickup.

shiftless

Ah, very interesting, thanks for that info. I did not realize that the stock PCM outputs a "standard" type tach signal for the factory tach. Thank you, GM engineers. I was hoping it wasn't like the late model Ford setup, where the instrument cluster is one big computer in itself, and the PCM transmits the RPM data to it over a CAN-type network. I'll probably set mine up the same way as yours to begin with, then set it up for spark control later.

BB69

iTrader: (1)

Do you have any pictures of this setup? How are you connecting the MS to the engine sensors?

Thanks
Ken

Zombie

iTrader: (2)

No pics, but the only engine sensor i'm connected to is the throttle position sensor. It's not 100% accurate due to the way I hooked it up, but it serves it's purpose. It really should be run through an op amp buffer so it's more accurate.

For sensors I ran an seperate IAT and coolant sensors. IAT is in the intake pipe next to the factory one. Coolant sensor is in the heater core feed off the pump (LS1's use no heater valve so there is always flow). I also built my own seperate injector wiring harness so I didn't have to modify the stock one at all. Setup works great so far, even passes emissions thanks to the stock ECU and some editing

shiftless

I guess I should chime in, as I just installed a Megasquirt on my own car. I did things a bit differently than Zombie. On mine, I am getting my "tach" signal directly from the cam and crank sensors. I disconnected the stock IAT and CLT sensors from the stock PCM and connected them to the MS. I then connected some dummy resistors to the stock PCM to make it think the CLT is 140* and the IAT is 80*. This configuration works great. It would be better though to have a real CLT sensor connected to the PCM so that the dash temp gauge would read correctly. Plus the fans won't kick on so you need to control them with the MS. I just didn't have any spare temp sensors or pigtails.

I have it connected only to the fuel injectors at this moment but will be setting up spark control as well very soon.