Working with a 92 camaro tbi 305, full exhaust, open element, VAFPR, timing set @ 4.

I am just alittle confused when i am tuning the VE's using the wide BLM average in Winaldl. I read through the tech article and decided to take the advice of someone and use the wide average to help me do my VE's. To start off, i set my injector constant to 115 in tunerpro (stock injectors at 15psi and hopefully someone will chime in here about the vacuum assistance i have on it and if its even a good idea), set base timing to 4. I took it for a drive and i notice at first my BLMS look good, but the longer i sat in a cell the lower the BLM drops. I am pretty confident that if i set in a cell long enough i could get it down to 108. I figured it would level out? I mean i dont think i am really running that rich, but is it possible? Initially i was watching o2 volts and sensor data while juta datalogging and the cells that are pinned around 109-110 have o2 volts that seemed lean to me? When i used to do my old 88 maf car i would mess with the injector constant until my blms were all kind of close to 128 and then fine tune from there. Can i still do this with speed density or am i totally missing the picture?

 

With your current setup I wouldn't recommend a VRFPR. A couple of reasons is that the '8746 code isn't set up for one. And that at 15 psi it will pull the fuel pressure too low at high vacuum. For now just disconnect the vacuum line to the FPR and leave it open. Although do plug the vacuum port on the intake/TBI unit.

What I don't quite understand about the low BLM, low BPC, and stock injectors at 15 psi and lower (due to VRFPR): why is the BLM so low? Seems to me that it should be higher then 128.

Lowering the BPC lowers the PW (gets leaner)
Lowering the fuel pressure (VRFPR) is less fuel (leaner)

Ah, EGR, what have you done with the EGR? There is a separate set of BPC tables for when the EGR is active.

And CCP, maybe pulling a lot of fumes through the system. I always pull the hose & plug the fitting on the TBI while working in the VE tables. I do re-connect it from time-to-time during VE table work. This is to keep the cannister from getting saturated. Although no VE work while connected.

Injector o-ring could also be seeping.

RBob.

 

RBob i was hoping you would chime in, i really appreciate it. Yea i dont know why the just continue to drop like that. I decided to just use the data i have and started doing my VEs and ill take it or another ride and see what i get. Anyway, EGR has been left alone, stock, never touched and nothing messed with it my prom. CCP? you mean the charcoal canister? disconnect it and plug it at the tb while logging?

I just redid my injector pod, new o rings, filter and gaskets. So i ASSUME thats out but i guess i cant be too sure. How do i post a copy of my table so you can take a look? But like i said, it starts off nice, the more i cruise the more it drops, it's wierd. I will take of the vacumm line as well.

 

hey man yanking the vacuum line from the fpr helped i assume, i put in my chip with the VE tables corrected and the blms did raise up. Most are in the 124-127 mark but i got mostly low rpm, low map values in the 116's range ( i accompany that by the fact that the vac line is now disconnected), so its porgress i assume ha..still get back to me on wat you meant the the egr and ccp thing

 

CCP is the Charcoal Cannister Purge. When it activates it can let additional fuel in, no additional fuel, or additional air. It all depends upon how much fuel is stored in the cannister and how long it has been purging.

Pulling the line and plugging the port on the TBI prevents the extra fuel/air from messing up the BLM learn.

The EGR needs to be deactivated during BLM VE table work. There is a separate routine and BPC table that needs to be tuned separately. This is done once the normal BLM/VE is OK.

The BPC value you changed was a single value? If so, this is the value that is used when the EGR is off. Once the EGR turns on the BPC is from the table at $2A2 ($2A1 has the table header).

RBob.

{edit: easiest way to disable EGR is to set the 2 temperature enables to 150 C. They are at: $20C, $20D). Then re-enable it once the VE table is good. Any change in the BLM will then require a change in the EGR BPC table at $2A2. }

 

Ok i will look into it tomorrow. I datalogged after the intial changes to the VE and no vacuum to the reg. and it did pull them up from being buried below 108, i did alittle more fine tuning and even tried out BSmontes spark advance table. The car sure woke up after all that, runs and drive great. It used to when first started and ran to redline it used to cough up top and fall on its face. I tested it out tonight leaving work and it ran great. I am very pleased with the results so far. I will disable egr and take a look tomorrow and see what i get. Thanks again Rbob!

 

stock those egr tables were 144 and 139...why does it disable it when you set them both to 150?

and I dont see the other table your mentioned about he BPC EGR one.

Also i decided to check my fuel pressure since i assume i had a stock replacement pump in there (previous owner said it had been replaced 3 times) Anyway, i had cranked my fuel pressure as high as it would go since i figured it would be 15psi. Well i checked it today and to my amazement it's at 20psi. So i think i found my rich condition. Looks i will be starting over with my VE tables now ha