Is correcting the base pulse width the same for every ECU?
Or are there different equations for different computers?
I understandthat the pw needs to be corrected for higher fuel pressure but where in the bin file do you do this?

 

Some ECU's have a BPW constant, others an injector constant. For starters, what ECM and code mask are you using?

-- Joe

 

Ecu is 7747 mask 42

 

That has a base pulse constant. You will have to do the math (based on the current value) to indicate the percentage of reduction. Even still, it will probably require some fine tuning.

But anyway, it's in the constants menu.

-- Joe

 

Aahh.. I seeee... no. Lol I keep reading about a constants menu, but nothing in tuner pro do I see about constants. Haha are these constants scalars? Flags? In the tables? A drop down menu like the data monitors?

 

Can someone direct me to a source where I can all I need to know about the values that need to be changed in the ecu mask 42, for increased fuel pressure, and what exactly needs to be fined tuned so I can at least start tuning for idle....

 

The engine will make somewhere between 350-400ish horsepower. At this point I have no idea.to many others saying different things. Which equation do I use for the constant value for fuel pressure? I have no idea what fuel pressure to use either. My system can go up until 43psi.

 

I'm not a TBI guy, but If you increased fuel pressure by 10% I'd probably decrease the base pulse constant by 10%..

I use Tunercat, so I don't know what the layout is like for $42 in tunerpro.

You should probably read some of the stickys on tuning before you dive in. Basically, you are going to set your base pulse and then adjust your VE table(s) until your BLM's are in check, and then adjust your PE fuel until your WOT gives a good AFR, then you can play with timing.

-- Joe

 

Okay so basically, tune the ve based on what I see from the blm data at certain cells. But does spark effect how fuel is being read? I've also read that you can force open loop for idle, but no idea how to do that. Or even sync vs async fueling. What do those follow under??

 

There might be a minimum RPM for closed loop constant, I'm not sure.

Spark and fuel go hand in hand, but the stock advance curve should be fine. Dial in your fuel map and then work on spark.

Don't worry about sync vs async fueling.

-- Joe

 

Well I am worried about those different types of fueling. Since I'm going to be running such an insane about of fuel pressure. Also with my first datalog.... the spark advance was reading waaaaaayyyyyyy high, like 80+ at idle, what could cause this???

 

Another thing is that my pw is reading 200-800% at IDLE. I'm going to need to tune the VE extreme well for this bigger cam,ZZ4. Im getting around 17 in hg on my mechanical gauge.

 

I did have to fix a vacuum leak on both intake gaskets. Using an air gap with vortec style procomp heads ports are different sizes a hahaha butchery! So I replaced the gaskets and the walls are thin but I think they are doing the job, I used a bit of gasket maker to seal them in this time....

 

That's not right. Either the datalog has bad data, or something crazy is going on.


If this is a hot-rod, have you considered an aftermarket system? I've heard a lot of good things about the newer Holley stuff, and the learning curve isn't too much.

-- Joe

 

I haaave, only problem. I'm 23 freshly fired from walmart for attendance. So no more money right now. Hahaha

 

I do have the Holley 502-6 670cfm projection though. Still a little unsure of the injector size, do to Holley not picking up the phone and difference of opinions on the Net. Either 65lbs at 12psi or 85lb at 12psi. No. Idea.

 

I did fail to mention that I had like it around 6 degrees advanced at the dizzy, with no accommodation in the chip, so that could have something to do with it..

 

Just got off the phone with Holley. They are 65lbs at 12psi. And they said can not run then safely over 25psi. Well that sucks, cause I needed them to run at 43psi hahaha. Anyone want to buy all my tuning gear and TBI??

 

Have you considered the military? They will pay for your college, and pay for you to go to school (if you are deployed). There is nothing more rewarding than service to your country.

As far as your spark advance, 80 is just crazy. I don't know why it would be reporting that. Nothing in the calibration, even the steepest decel burn off is that high. Something is not right.

-- Joe

 

Yeah I've tried the military, I have a long history of asthma, so that is that......

As for tuning this now.... Idk Holley just said I can't safely run their injectors at 43psi. Over 25psi. I don't have a 4 brrl tbi. So I think I'm just going to have to sell all this stuff I purchased. $1045. For this. My sweet luck. And lack of know how.

 

I think Ronnie has done a lot with TBI on this forum, maybe he can chime in. I"ve never tried TBI on something that wasn't stock, and if I did I'd probably go with a 4bbl TBI and an aftermarket ECU simply to have access to more fuel.

I suspect your reason for wanting higher fuel pressure is because the injectors are too small for the application? In theory the 65# injectors only support about 250hp.

There is a lot of little off the shelf, self-tuning TBI units on the market now, many under $2,000. You won't find much info on this forum, but if you hang out in Corvette forum where a lot of guys do EFI swaps on older vehicles, or Yellowbullet you will find the information you need.

-- Joe