97 black box

[rocko350]

To start, I tune with Tunercat2. I will probably make the jump to EFI live in the future, but for right now I dont have the option of doing the 0411 swap on this truck, the owner wont agree to it. I know its the right way and even showed him the software differences and explianed why we should do it. I even showed him the 2000MY vin number in the 1997 pcm. He has it in his mind that he wont be able to sell the RV if he modifies it passed where it is now.

Anyhow, I have literally, over the last few days, read trough this sction of this forum and some others to find and answer. It is possible that i have not searched with the correct terms. The fuel injector flow correction vs fuel pump voltge and the injector timing vs coolant temps are the only tables I have seen that relate to the flow rating of the injectors. I have a motor tht runs real rich at startup in an RV. What makes this a real issue is this is an RV with a battery cutoff switch. Obviously it loses its saved fuel trim data and starts and runs real hard. I have an inclination that the fast switching points are just simply too rich and make the trims and other functions moving targets. We already replaced the injectors with ones from injector connection (bosch3 upgraded ones), and a new fuel pressure regulator. Both replaced pieces make definitive drivability improvements, however, there is a calibration issue with this truck thats very clear. I understand how to VE tune, MAF tune and make the load changes for timing and such, but for this ecm, I need help with the specific settings for fuel injector voltage offsets,that dont seem to exist. I will be changing the o2 swing point table to reflect a targeted 14.7 AFR ans setting the PE to act more like a firebird since this vehicle has a 4.56 gear and a 4l80e and runs 2500 rpms down the highway at 70 mph.

If anyone had had sucess making these adjustments in this ECU for the gen3 injectors your input would be greatly appreciated. I wont be going much futher until i can reslove these issues.

Thanks guys,

Chris

[EagleMark]

I'm guessing a 7.4L since you changed injectors? If you have the voltage offsets for the injectors you already listed where they go. "flow correction vs fuel pump voltge"

That may fix the cold start issue, or a power wire to PCM around battery cut off? If not the "Open Loop fuel Multiplier Vs Vacuum Vs Coolant" will help.

Don't think the cold start has anything to do with O2 swing points... since it's open loop at that time.

[rocko350]

The cold start issue I'm sure is an injector control table or trimming adjustment along with the poor factory calibration. I fully understand how the ecm works, just not familiar with this ECMs table layout.

So on this pcm, the open loop fuel multiplier vs vacuum vs coolant is the open loop table that were used to seeing on other ecu's? The table for flow vs fuel pump voltage isn't nearly what you'd expect to see for a voltage offset table. I switched from the original multec to the Bosch 3 design. In an LT1 that table gets set to ".100" in just about every cell within normal voltage range. The flow table looks to me like a larger scaling multiplier, not the finer trim adjustment that I know I need when changing injector styles. In this case the injectors aren't any larger, they just flow differently and react electrically different.

I mentioned the o2 swing points as being similar in function as the commanded stoich table we use in the gen 3/4 pcm's.I'm sure gm was trying hard to get them right, but it makes trims a moving target. Getting them straightened out and then reducing the PE delay was only mentioned to share my plan of attack so to speak.

Chris

[EagleMark]

I don't think the open loop fuel multiplier vs vacuum vs coolant is the open loop table is the Open Loop table but more the choke/cold start? I agree the flow vs fuel pump voltage is not what your used to, but it works. Don't get fooled by titles of some of this stuff. I don't have a 7.4L .cal to look at but 5.7L is fairly flat at normal voltages.

I think the reason the bin editors are so unrefined from like 0411 stuff is 96 Vortec ECM was one year, 97 one year, 98 to 00 was not looked at hard because of the 0411 development since it came out that year. But there's usually enough there to tune a motor if it was built knowing limitations of intake and injectors, easy to get 350 to 400 HP and stay under the RPM limit. But the standard answer is... swap in a 0411!

Since Monodax has seemed to die we started a new TunerCat OBDII forum, most likely it will be for 97-97 vortec and preserving .cal files. Also doing data logging with Scan XL Pro and new TunerPro ADX files.
http://www.gearhead-efi.com/Fuel-Inj...TunerCat-OBDII

But it's a hard route compared to using EFI Live!

[rocko350]

Went to the Junk Yard and grabbed 2 0411's with harness connectors. Not gonna go that route yet since i have to "sell" that job to the customer. Anyway, i figured out that the table listed as open loop multiplier vs vacuum vs temp is the open loop table, just expressed in the lambda equiv ratio. Just wanted to pass that on. Still looking for the adress and table for the injector voltage offset. Its in a 98 def file i have but it doesnt correspond in the 97 file. Must be in a very different place.

Chris

[hog]

I use TC2 as well, are you sure that you have the correct IFR settings? Also these Vortec FPR's can allow for up to 66 psi of fuel pressure at WOT.
I installed different fuel injectors on my 97 Vortec 350, I went from teh stock poppets to marine EV6 stainless tipped injectors which flow 28.? at 66 psi.

Maybe your math is off for you IFR(injector flow rate) calulations? I dont know of any LS1` or LS6 injectors that are 100% the same flow rate as the original Vortec 454 L29/21 injectors.

EagleMark, Monodax is still down, but should be up in a bit. Thanks for the link to yor site. I'm a Mod. over at Monodax.

peace
Hog

[rocko350]

I got a set of injectors from injector connection and asked for a drop in set so I wouldn't have to calibrate for them. I suspect now that they might be 22 lber's instead of the 19's like stock. Problem is I will need to pull the upper intake again to check for the part number to be absolutely sure. I need to call down there and ask what he sent me. Our parts deptartment has already recycled the invoice and closed the ticket for end of year. I will post back my findings. I did run a test on another car I own with regards the o2 milivolt swing points. At this point, the vehicle tries to get the milivolts back down to .450 to relfect stoich. Whatever that might be. On cars like the LT1 and this 454, the numbers reflect the air column speed/volume. I would venture to say that if you have a vehicle or calibration that isnt commented out with a table or scalar for fuel trim gain/response, then this table might be manipulated to help with the corrections to make them faster or slower. Thats all I have on this for now.

Chris

[EagleMark]

I still think your right about fuel injector flow correction vs fuel pump voltge for the new injector offset. There may be more but I have not found it yet in dissasembly...

air column speed/volume table if this paremter has to do with O2 sensor volts? As air flow increases the offset for Rich/Lean O2 sensor volts is differant. But again all the paremeters are not there.

I made a mask for 4k bin from the late 80's that has 10+ times paremeters then any Vortec 512k mask. It has all these settings for Idle and Off idle.