Went to the dyno today...fuel issue FML. need assistance
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
I have a small machine shop (mini-lathe and mill) to make one-off custom parts, and an electronics lab (I buy up, repair, and resell test equipment). I hope these will let me earn some play money when I get fully retired in just a bit less than 5 years.
5th Gear Member
Joined: Feb 2010
Posts: 2,758
From: PA
I am a semi-retired mechanical engineer (BSME, MIT '71) that has done a little bit of everything since then. I got involved with micro-computers in the mid-70s and have built. programmed, and used them ever since.
I have a small machine shop (mini-lathe and mill) to make one-off custom parts, and an electronics lab (I buy up, repair, and resell test equipment). I hope these will let me earn some play money when I get fully retired in just a bit less than 5 years.
I have a small machine shop (mini-lathe and mill) to make one-off custom parts, and an electronics lab (I buy up, repair, and resell test equipment). I hope these will let me earn some play money when I get fully retired in just a bit less than 5 years.
5th Gear Member
Joined: Nov 2006
Posts: 2,402
From: MA
Are you still running the stock returnless fuel system? If so then 30psi at idle is normal
Monitoring the rail pressure under load at the higher revs will tell you a lot--if the pumps and BAP can't supply enough fuel the pressure will drop as the mix goes lean.
MAFs are not really calibrated to any specific injector capacity, but rather to a specific injector and tune, usually a stock tune, its a kludge left over from the days when tunes could not be changed.
However since you have the transfer function (entered into the tune I assume) that doesn't matter.
I don't know what "opened the injectors to full" means, do you mean that he played with the low and high injector slope scalar values? Making them smaller will richen the mix, as the PCM's thinking they are smaller than they really are will cause it to calculate a longer pulse width to get the amount of fuel it wants--which will be more than it wants as the injectors are really larger than it believes.
One other possibility is that the stock PCM can only read airflow values of less than 1740kg/h (3830lb/h) unless the standard air charge, MAF transfer, and injector slopes are scaled.
This is around 560fwHP, 475 or so at the wheels--you may have hit that limit?
Can you post or send me the MAF sheet?
Monitoring the rail pressure under load at the higher revs will tell you a lot--if the pumps and BAP can't supply enough fuel the pressure will drop as the mix goes lean.
MAFs are not really calibrated to any specific injector capacity, but rather to a specific injector and tune, usually a stock tune, its a kludge left over from the days when tunes could not be changed.
However since you have the transfer function (entered into the tune I assume) that doesn't matter.
I don't know what "opened the injectors to full" means, do you mean that he played with the low and high injector slope scalar values? Making them smaller will richen the mix, as the PCM's thinking they are smaller than they really are will cause it to calculate a longer pulse width to get the amount of fuel it wants--which will be more than it wants as the injectors are really larger than it believes.
One other possibility is that the stock PCM can only read airflow values of less than 1740kg/h (3830lb/h) unless the standard air charge, MAF transfer, and injector slopes are scaled.
This is around 560fwHP, 475 or so at the wheels--you may have hit that limit?
Can you post or send me the MAF sheet?
I would love for you to look at my tune. Keith from Plymouth MASS.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
Cliffy - you are amazing. I have same PRO-M meter calibrated to my 60 injectors and with my Delta Force tune from my dyno shop my car maxed out at 470 rwhp at 6100 rpms. My tuner did not change injector slopes, he does NOT have sniper experience you have.
I would love for you to look at my tune. Keith from Plymouth MASS.
I would love for you to look at my tune. Keith from Plymouth MASS.
In 1992 we brought Mayflower down here to Saint Augustine, I liked it and ended up moving here in August of 1993. I miss crisp clean air (though we are on the Intracoastal Waterway so that helps), real seasons (we only have 2-1/2)--however I do not miss scraping and shoveling one damned bit.
Send me a PM and I will give you my email address.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
Just out of school I worked as Plant Engineer for a couple of textile companies in Maine, and then for 18 years for a rope making company. Loved it, that's why I have had had to have my own lathe and mill ever since.
Engineering is a discipline, a way of logically meeting challenges, best defined as:
"Making what you need, from what you can get."
Also, an engineer does not consider a partially filled glass as half-full or half-empty--it is simply larger than it needs to be...
5th Gear Member
Joined: Feb 2010
Posts: 2,758
From: PA
Hey, watch that "were a mechanical engineer" crap! Still am...
Just out of school I worked as Plant Engineer for a couple of textile companies in Maine, and then for 18 years for a rope making company. Loved it, that's why I have had had to have my own lathe and mill ever since.
Engineering is a discipline, a way of logically meeting challenges, best defined as:
"Making what you need, from what you can get."
Also, an engineer does not consider a partially filled glass as half-full or half-empty--it is simply larger than it needs to be...
Just out of school I worked as Plant Engineer for a couple of textile companies in Maine, and then for 18 years for a rope making company. Loved it, that's why I have had had to have my own lathe and mill ever since.
Engineering is a discipline, a way of logically meeting challenges, best defined as:
"Making what you need, from what you can get."
Also, an engineer does not consider a partially filled glass as half-full or half-empty--it is simply larger than it needs to be...
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
Didnt mean to offend you man haha. But i am going over CAD drawings, as well as hand drawing now. I am getting more into design next semester. I was told next semester we get to design our own cam and actually get to have it ground out so we can keep it. Should be a really fun project.
Due to budgetary constraints I use TurboCAD...
Thread Starter
4th Gear Member
Joined: Apr 2008
Posts: 1,086
From: mi
Cliffy - you are amazing. I have same PRO-M meter calibrated to my 60 injectors and with my Delta Force tune from my dyno shop my car maxed out at 470 rwhp at 6100 rpms. My tuner did not change injector slopes, he does NOT have sniper experience you have.
I would love for you to look at my tune. Keith from Plymouth MASS.
I would love for you to look at my tune. Keith from Plymouth MASS.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
[/quote]Wat r u thinking it is? Do u think its in the tune or my fuel system?[/QUOTE]
Need those fuel rail numbers, or data logged fuel pressures, to tell...