So I had a v6 firebird, as for specs: built a 5.3 iron block gen III for it, bored it out to a 5.7, 3.898 bore, eagle rods an pistons, stock valves, stock crank under 0.10, ls2 timing chain, g5x3 112lsa cam, stock 28# injectors, heads are milled .010, corvette fuel filter so I could use the v6 fuel lines that has a main feed plus a return, ls6 intake, comp cams hydrologic roller lifters, ngk55 spark plugs gapped 30 was gapped 55 till we changed the gap. Stock ls1 maf, egr has been deleted from the tune at first the person who tuned it put a stock 5.7 tune in it an they have changed a few things (not sure what) but the car just won't idle an I still have some trouble getting it to start some times, basically it will start an sounds good if you keep your foot down on the gas but then sometimes it will start, idle for about 10-20 seconds an then surge to 500rpm then back up to 1000rpm then back to 500rpm then lose itself an die it seems to like to do the surging thing a lot, we are using efi live, I have no idea how to tune but I'm not the one doing the tuning. From what I understand they have forced the car to stay into open loop mode and at one point had It running to rich by opening the idle air control all the way, removing the maf plug does nothing, they have the idle set to idle at 1000rpm then It was supposed to drop down to 800 but then they changed It 900 to idle at, an now I think they changed It to idle 1000rpm, but it seems to always go back to that surging situation then die an I still have trouble starting it sometimes , so any advice would be appreciated. I can relay whatever needs to be relayed back to the person who is tuning the car if need be. Also as far as I know all vacuums are plugged off or hooked up an everything is new except intake an injectors also during all of this the transmission isn't hooked up an I am running headers no exhaust yet but also running corvette o2 sensors for the longer wiring there's probably a good 6 inches from the open headers to where the o2 sensors sit in the headers.

 

Also wanted to ask, does the transmission and exhaust have to be on in order to tune this properly? Just curious on that.

 

Complete the install, find a new "tuner"...………..

 

You need oxygen sensors connected and running properly in your exhaust system. And not just headers without pipes because the O2 sensors are probably too close to open air to read and react properly. My 5.3 liter LM7-equipped El Camino has two, three foot lengths of exhaust pipe at the header collectors to keep the O2 sensors completely bathed in exhaust gases and heat. I'm also running completely closed loop with only EGR and EVAP deleted - Mass Air Flow is still connected. And yes, my transmission is connected and fully installed with the Vehicle Speed Sensor attached to the wire harness.

All of these things play together for proper operation. I stayed with the original 5.3 tune (motor is not bored out to a 5.7) and it is working well with only the following changes:

Startup and at temp Idle Raised 100rpm
PE Delay set to zero
Cat Overtemp Disabled
All EVAP, EGR, Fuel Sender, and Rear O2 codes deleted
Speedo and shift points corrected for current tire/gear
Max line psi disabled in case of MAF failure
VATS turned off
Fans Activated

I'd go back to your factory tune with these kinds of changes made and see if it runs better. I'm certainly no expert but I'd hope that your engine and PCM could adapt and learn that it is now 5.7 liters and not a 5.3 liter.

Rick

 

So turns out all it was was a set of bad coils I bought problem solved.

Here she is running.