Hi all,
I am new to this forum, and although I don't own a third gen Camaro, I do own a third gen (C3) vette It has a big block that I have done some nice mods to (larger valves, ported/polished heads, decent cam). I am having problems getting the VE tables right. I always seem to run lean around 1600 to 2400 RPM. I am using winALDL, and wrote a VB program to update my VE1 table. I then verify it in TunerCAT, and burn the gin file into an EEPROM and go for a drive. The values in VE table 1 keep going up in those ranges till they hit 100%. Then I lower the whole VE1 table and raise the VE2 table, and do it again. I've had to do this twice, and it is still lean. So my question: Can the sum of the value at an RPM in VE2 plus a value at the same RPM in VE1 add up to more than 100%? I've heard both yes and no to this, which is it? I have also raised my BPW a couple of times. It should be 63 (I am using a 4 barrel holley TBI with 85 lb/hr injectors), and I now have it at about 73.

I do have an injector driver board that I built to drive the other two (low impedance) injectors, and they seem to flow just fine, for instance, when I go into PE mode the car doesn't run lean and I get pretty good power in PE mode. I think my pressure (about 18 psi) is staying up, since it runs pretty good at WOT, but haven't verified this.

Any help would be greatly appreciated.

Thanks.

 

The BPC of 63 is the same I calc for a 454, so that should be correct. As for the VE tables the sum of the two tables can not exceed 100%. Or 255 if using the raw bin values. The ECM adds the tables together and if > 100% set it to 100%.

If not running the EGR have you disabled it within the code? If not then upon it activating the ECM will also lean the mixture.

For my own curiosity what intake manifold are you using (single or dual plane)?

RBob.

 

I'm running the stock (but slightly hogged out and port matched) 454 manifold that came on that vintage vette. I think I have EGR turned off, what is the best way to do so so I can make sure it is really off?

Is it possible that with larger valves and ported intake I really do have that much higher of a VE in those RPM ranges?

I can keep raising the BPW I guess, but it just doesn't seem right, especially when I have ranges of VE from around 20 to around 99 in my VE1 table now. It seems that something is wrong -- I wonder what?

 

Best way to turn off EGR is to set the EGR enable temperature to the maximum value. At $1B3 set the value to 0 (it is an inverse term). TunerCAT would probably have that as an actual temperature value.

As for the high VE it may be not enough acceleration enrichment. That RPM area is a common driving area. Not enough AE will show as having the INT/BLM will climb in that area. This makes it look like the engine VE is higher then it really is. If you can hold the MAP & RPM steady long enough (hard w/BBC) the AFR will start to go rich. This points to not enough AE.

RBob.

 

I'll try that.

At 60MPH, I only have to have the throttle at about 8%-9% to maintain speed, so the MAP is pretty low there. I need a real real real long hill I guess.

How do you adjust the AE? It is in microseconds I think. Do I tweak the differential TPS one or the differential MAP one or both if I need to tweak it?

 

There are several tables that affect the AE. Lag filter coef's for both TPS & MAP, the amount of added PW, then the coolant multiplier table. If you started w/a BBC BCC then maybe try the coolant multiplier table first, then the TPS adder.

If you are not running EGR and don't have it disabled in the code do that before anything else.

RBob.

 

RBob,

I just discarded my bin file and went back to the ANTZ.bin file, adjusted my BPW to 63, and then set the BPW offset at 2D4 to 25 instead of 18 and it ran pretty good, except at WOT. I need to adjust the PE mode for that. I am getting BLM values all over though. For instance, at 800 RPM and 60 MAP I get BLM of 122 and at 2400 RPM and 40 MAP I get 154. That is from a 20 minute drive. I think I will increase the BLM offset a little higher, adjust my PE up some and try again. I guess I should expect this engine to flow better at mid tohigh RPM than the truck engine that the BIN file came from. It seems that the AE might be OK though. I'll keep you posted.

I thought I had EGR disabled, but it looks like I was setting 1B4 to 0 instead of 1B3. I'll fix that and try it again.

 

This all sounds good. Especially the EGR part w/1B4 and 1B3. Changing 1B4 to 0 didn't disable the EGR, whereas doing that to 1B3 will. That in itself will make a big change (less SA & more fuel).

Yes, please let us know how it turns out.

RBob.

 

Well, it's different. I still had quite a wide span between BLM values, some as high as 153 and others as low as 122. I am going to raise my BPW a little now. I am also going to put it into closed loop idle so I can get my low RPM values better. I am also raising the 100 MAP portion of the table to see if it will hep WOT. It does play better now, doesn't backfire (out the exhaust) as much as it did before.

Will try driving again tomorrow morning.

 

Now, it is so rich at idle that it won't idle worth a darn. I will have to lower the VE table there. I also installed a knock sensor amplifier today. I will install a knock sensor soon.

The rain has started again, and I don't like driving this thing on wet streets, so I may not get much more done till April or May Thanks for all the help, and I will probably ask for more before long.