Hey guys, after 7 years in storage, my Fiero is ready to get running stronger. It is a 1988 Formula bored and stroked to 3.2l with 61cc/min. injectors, a GT30R turbo and Saab intercooler. I am using TunerPro with my stock ECM and have been using the fuel and spark tables from Greg Wagoner's High Performance Fieros. It is running pretty good at 10psi boost, but I had to revise the Base Pulse width to 176 versus Gregs 208. I have been messing with several things, but wondered if anyone has been through the process and has some more tips on what to tweak?
Yes, I have that already. But what values in the PROM do I adjust besides the VEtable and Spark table and what is the best methodology to make progress?
I wish I could but I'm in the same boat! I just got an Ostrich emulator to do my own tuning and haven't a clue where to start. Plus, I'm running a 7730 ecm...I don't know how similar they'd be.
LOT, DarthFiero or phonedawgz can definitely help you, but they are in the tuning business so I don't want to speak for them on how much they're willing to give out free help, which I understand and agree with.
Unfortunately my research on tuning hasn't yielded much info...I wish I knew how to begin learning the basics. Everything I've found is either too specific or too general. If you come across any good resources for learning I'd much appreciate the info!
I kind of cheated using code59 and Autotune. Datalogging will tell you the same stuff but you have to dig out all the numbers yourself. If you are good at setting up Excel you can automate the process of dialing in your fuel table.
From what I've learned you set your base pulse and leave it alone. 170, 180, 200 whatever. Set it and move to the main fuel table. If you run out of injector pulse width then go back and up the base, then correct all the cells. Tune in open loop by raising the coolant temp needed to go closed loop to 255. Also disable DFCO so that your datalogging is not influenced incorrectly with cells showing totally lean readings. Smooth adjacent cells so you don't have really big spikes and valleys next to each other. Go slow and watch for KR. Make changes slowly and to one table at a time.
You said it runs good at 10 psi. Are you wanting more?
No, I just upped it from 7 psi to 10 psi. I would like to keep it at 10 psi because it seems to have a nice power level above 3500 rpm. I just want to optimize it and smooth out any sags or erratic performance at normal temps. What table or value do I change to raise the coolant temp for closed loop? When you are modifyint tables, are you trying to run constant MAP accels or otherwise trying to hold something constant?
Everyone probably has their own way so take what I say with a grain of salt. I lock blm's at 128 and tune using integrator values shooting for about 120 to keep the computer pulling fuel. I prefer to keep it safe and tune a little on the rich side and let the o2 do the rest. Also make sure your idle and main tables are similar. A little leaner on the idle table but similar, it will keep things smoother when the computer switches between tables. Also keep in mind there is the main VE table and the adder table. If these values total over 100 you need to go back and adjust your bpc. Don't forget to unlock blm's when you're done tuning and don't beat on it real hard until you have things close,the computer won't be able to compensate very far with it locked.
Depending on which code you are using there will be either a value for closed loop or maybe a flag.
What you are looking for is the air/fuel ratio for best power with no knock. Part throttle cruising with no boost it's 14.7:1. As you start into boost bring it richer, 14, 13, 12, 11.5. You do this by adding pulse width to your VE table cells. You have to datalog to see the effects on each cell. After correcting the VE then look for big peaks and valleys in adjacent VE cells. Add or subtract all around to lessen the spike. Then datalog again and repeat.
I would highly recommend some type of knock sensor with a light or gauge to warn you. I'm running a 7730 ECM and have the knock count and knock retard pulled up on the TunerPro dashboard.
[This message has been edited by Hudini (edited 08-18-2013).]
Unfortunately my research on tuning hasn't yielded much info...I wish I knew how to begin learning the basics. Everything I've found is either too specific or too general. If you come across any good resources for learning I'd much appreciate the info! I agree that it is hard to get started. I understand that I am adjusting AF ratio and Spark, but I am just running it on the street, not a dyno. What is the proper technique to try to get some data? Do I try to run constant MAPs through the RPM ranges?
I would advise relying on the narrow band O2 sensor to adjust fuel. It's range is only 0-1V and once the output goes high there is nothing further than the ECM can do. The O2 sensor is only used for idle, cruise and normal driving conditions. Once you go WOT the O2 sensor is ignored and means nothing. At WOT you are in open loop mode where only the fuel and timing tables are used. Calculate the base pulse constant based upon your injector size. Plug in that value and move on to the fueling (VE) and timing tables.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Maybe start with idle tuning. Get it up to temp and lock the blm's at 128. You can play around with either putting it in gear or riding the clutch a little to put some load on the engine while still being in the idle table. Watch the integrator or short term fuel trims and shoot for low 120's. then take those numbers and install them into the main VE table except add 2 to everything. It should get you into the lower rpm ranges with decent driveability. You can now start driving easy, no full throttle runs, and keep making adjustments as necessary. I've had good luck driving at say 3,000rpm and watching what it does, shoot for low 120's again and smooth out the transitions. You should have a decent running car now so you can set the blm's back to stock and now watch the wideband on the full throttle runs and make the adjustments as necessary making sure the VE and adder tables don't total over 100. If they do you have to raise the bpc and start over. Any funny areas you'll have to drive and make mental notes, does it hesitate when cold? There is a table for that. Does it hesitate when stabbing the throttle? Adjust the AE vs AE pulse table. Also dont make hasty decisions. The computer could be in AE or PE and you dont want to use that data to adjust VE so i only make VE changes holding steady rpm's for a good length of time. There are also some knowledgable tuners on 60degreev6 that are pretty fast with responses to specific questions.
