Tuning question: injector flow rate table
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St. Jude Donor '03-'04-'05-'06-'07-'08
Tuning question: injector flow rate table
Hi,
I got HP tuner and using Jer's tuning file since I got exactly the same setup as Jer got.
However, Jer's injector flow rate table is set at 72.48 and when I use that number, my car runs super lean (20.2 or something like that) and my car is not responsive at all.
When I set my table to 54.01 it run richer but still a bit lean (15.2 at around 2500 rpm and 13.6 at WOT)
When I set my table lower to 49.98 and then to 45.02, it runs much better (14 at around 2500 rpm and 12.8 at WOT)
I got 60 lbs mototron injectors just like Jer.
Any idea?
Thanks,
-Mike
***BTW, I read the AFR thru LC1- XD1 gauge and both of our C5's are 98's
I got HP tuner and using Jer's tuning file since I got exactly the same setup as Jer got.
However, Jer's injector flow rate table is set at 72.48 and when I use that number, my car runs super lean (20.2 or something like that) and my car is not responsive at all.
When I set my table to 54.01 it run richer but still a bit lean (15.2 at around 2500 rpm and 13.6 at WOT)
When I set my table lower to 49.98 and then to 45.02, it runs much better (14 at around 2500 rpm and 12.8 at WOT)
I got 60 lbs mototron injectors just like Jer.
Any idea?
Thanks,
-Mike
***BTW, I read the AFR thru LC1- XD1 gauge and both of our C5's are 98's
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I have a spread sheat for that..
http://www.marcintology.com/tuning/injectors.xls
save it, and change the top inputs only..I.E, injector size, FP, ect.....
But for the sheet to work you have to get everything else in sync... MAF table, VE table, ect...
This sheet ASSUMES that youre IFR table is matched to youre injectors... If that makes anysense to you???
anymore questions post up and happy tuning...youre on the right track, just dont butcher the IFR table to correct fueling...
http://www.marcintology.com/tuning/injectors.xls
save it, and change the top inputs only..I.E, injector size, FP, ect.....
But for the sheet to work you have to get everything else in sync... MAF table, VE table, ect...
This sheet ASSUMES that youre IFR table is matched to youre injectors... If that makes anysense to you???
anymore questions post up and happy tuning...youre on the right track, just dont butcher the IFR table to correct fueling...
Last edited by 01c5z; Jul 21, 2007 at 04:29 PM.
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From: http://www.mphparts.com 800-364-1975
Injector flow rate is one of the tables "where it all starts". Much of the rest of the tune is relative to that table, and if you alter that relativity by changing the IFR table incorrectly your tune will be off.
Just to use simple numbers, if your car runs perfectly on 50# injectors and upgrade to 100# injectors your IFR table needs to double, assuming both injectors were rated at the same pressure.
When tuning anew, I would start with the data that comes out of the popular spreadsheet IFR calculators since they are somewhat standardized and accurate. But when tweaking an existing tune -- watch out. Your tuner may not have used the same spreadsheet and if you just go by what a calculator tells you, your tune will be off. If this is the case, tweak your IFR relatively (e.g., figure out by what percentage your new injectors are larger, and increase IFR by that percentage).
Finally, don't forget to reset your fuel trims before making any judgment as to the accuracy of your new IFR values.
Just to use simple numbers, if your car runs perfectly on 50# injectors and upgrade to 100# injectors your IFR table needs to double, assuming both injectors were rated at the same pressure.
When tuning anew, I would start with the data that comes out of the popular spreadsheet IFR calculators since they are somewhat standardized and accurate. But when tweaking an existing tune -- watch out. Your tuner may not have used the same spreadsheet and if you just go by what a calculator tells you, your tune will be off. If this is the case, tweak your IFR relatively (e.g., figure out by what percentage your new injectors are larger, and increase IFR by that percentage).
Finally, don't forget to reset your fuel trims before making any judgment as to the accuracy of your new IFR values.
Thread Starter
Former Vendor
Joined: Feb 2002
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From: DFW, TX www.vettestripes.com
St. Jude Donor '03-'04-'05-'06-'07-'08
Hi,
My fuel rail pressure is 58
I got Mototron 60 lbs so the "Injector rated flow rate" would be 60?
What is "Injectors rated fuel pressure"?
Thanks,
-Mike
My fuel rail pressure is 58
I got Mototron 60 lbs so the "Injector rated flow rate" would be 60?
What is "Injectors rated fuel pressure"?
Thanks,
-Mike
I have a spread sheat for that..
http://www.marcintology.com/tuning/injectors.xls
save it, and change the top inputs only..I.E, injector size, FP, ect.....
But for the sheet to work you have to get everything else in sync... MAF table, VE table, ect...
This sheet ASSUMES that youre IFR table is matched to youre injectors... If that makes anysense to you???
anymore questions post up and happy tuning...youre on the right track, just dont butcher the IFR table to correct fueling...
http://www.marcintology.com/tuning/injectors.xls
save it, and change the top inputs only..I.E, injector size, FP, ect.....
But for the sheet to work you have to get everything else in sync... MAF table, VE table, ect...
This sheet ASSUMES that youre IFR table is matched to youre injectors... If that makes anysense to you???
anymore questions post up and happy tuning...youre on the right track, just dont butcher the IFR table to correct fueling...
Thread Starter
Former Vendor
Joined: Feb 2002
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From: DFW, TX www.vettestripes.com
St. Jude Donor '03-'04-'05-'06-'07-'08
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Thread Starter
Former Vendor
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From: DFW, TX www.vettestripes.com
St. Jude Donor '03-'04-'05-'06-'07-'08
I will ask about "Injector rated fuel pressue" in another post.
For now, I am kindda happy because the new tuning has fixed my idle issue because the amount of air coming into the engine is greater than what the LTIT can compensate before.
-Mike
***BTW, I am just like my wife when she's first in medical school
all new terminologies and I don't get anything at all 
Melting Slicks
Joined: Nov 2004
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From: Tinker till it blows... then back it off a notch, maybe!!
St. Jude Donor '08
Hi,
I got HP tuner and using Jer's tuning file since I got exactly the same setup as Jer got.
However, Jer's injector flow rate table is set at 72.48 and when I use that number, my car runs super lean (20.2 or something like that) and my car is not responsive at all.
When I set my table to 54.01 it run richer but still a bit lean (15.2 at around 2500 rpm and 13.6 at WOT)
When I set my table lower to 49.98 and then to 45.02, it runs much better (14 at around 2500 rpm and 12.8 at WOT)
I got 60 lbs mototron injectors just like Jer.
Any idea?
Thanks,
-Mike
***BTW, I read the AFR thru LC1- XD1 gauge and both of our C5's are 98's
I got HP tuner and using Jer's tuning file since I got exactly the same setup as Jer got.
However, Jer's injector flow rate table is set at 72.48 and when I use that number, my car runs super lean (20.2 or something like that) and my car is not responsive at all.
When I set my table to 54.01 it run richer but still a bit lean (15.2 at around 2500 rpm and 13.6 at WOT)
When I set my table lower to 49.98 and then to 45.02, it runs much better (14 at around 2500 rpm and 12.8 at WOT)
I got 60 lbs mototron injectors just like Jer.
Any idea?
Thanks,
-Mike
***BTW, I read the AFR thru LC1- XD1 gauge and both of our C5's are 98's
2) Depending how old your 60's are, values across the IFR table should be hovering around 60's
3) Using the scanner, vcm controls, reset fuel trims and let them relearn before going WOT.
What can happen is that the fuel trims lock in when going into open loop, so if they are way off, then PE will not be even close.
45 to 54 is way too low unless you have LOW fuel pressure.
All this is assuming that the tune your using is worth more than a dime.
If the tune was decent, you can also go into open loop from scanner, vcm and cruise while checking afr's. better to get the IFR dialed in at cruise rather than wot.
Better take it easy until you figure out what is going on...if you were FI, you'd probably be toast by now...
Last edited by RJW; Jul 21, 2007 at 06:59 PM.
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Thanks so much!!!
I will ask about "Injector rated fuel pressue" in another post.
For now, I am kindda happy because the new tuning has fixed my idle issue because the amount of air coming into the engine is greater than what the LTIT can compensate before.
-Mike
***BTW, I am just like my wife when she's first in medical school all new terminologies and I don't get anything at all
I will ask about "Injector rated fuel pressue" in another post.
For now, I am kindda happy because the new tuning has fixed my idle issue because the amount of air coming into the engine is greater than what the LTIT can compensate before.
-Mike
***BTW, I am just like my wife when she's first in medical school
all new terminologies and I don't get anything at all Good luck...its new to me as well, learning as i go...
Thread Starter
Former Vendor
Joined: Feb 2002
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From: DFW, TX www.vettestripes.com
St. Jude Donor '03-'04-'05-'06-'07-'08
1) Better MAKE SURE that your wideband is reading correctly before doing anything.
2) Depending how old your 60's are, values across the IFR table should be hovering around 60's
3) Using the scanner, vcm controls, reset fuel trims and let them relearn before going WOT.
What can happen is that the fuel trims lock in when going into open loop, so if they are way off, then PE will not be even close.
45 to 54 is way too low unless you have LOW fuel pressure.
All this is assuming that the tune your using is worth more than a dime.
If the tune was decent, you can also go into open loop from scanner, vcm and cruise while checking afr's. better to get the IFR dialed in at cruise rather than wot.
Better take it easy until you figure out what is going on...if you were FI, you'd probably be toast by now...
2) Depending how old your 60's are, values across the IFR table should be hovering around 60's
3) Using the scanner, vcm controls, reset fuel trims and let them relearn before going WOT.
What can happen is that the fuel trims lock in when going into open loop, so if they are way off, then PE will not be even close.
45 to 54 is way too low unless you have LOW fuel pressure.
All this is assuming that the tune your using is worth more than a dime.
If the tune was decent, you can also go into open loop from scanner, vcm and cruise while checking afr's. better to get the IFR dialed in at cruise rather than wot.
Better take it easy until you figure out what is going on...if you were FI, you'd probably be toast by now...
My fuel pressure is at 58 so I think it is normal ... for the injectors, they are just about 1000 miles.
So when you increase the IFR, you allow more fuel?
Thanks,
-Mike
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From: Vancouver WA
It shouldn't be the same number across unless you are running a boost reference regulator. The number should increase as the manifold vacuum increases.
Melting Slicks
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From: Tinker till it blows... then back it off a notch, maybe!!
St. Jude Donor '08
Increasing IFR will lean things out ...the pcm will turn them on for less time because it thinks that they flow more.
That is why things got better when you lowered the IFR numbers.
You have your old tune saved? and outside of your idle issues, the car ran fine?
You or someone with some know how should simply compare tune files and mod your old tune.
I like to start with the OEM tune and work from there, personally
That is why things got better when you lowered the IFR numbers.
You have your old tune saved? and outside of your idle issues, the car ran fine?
You or someone with some know how should simply compare tune files and mod your old tune.
I like to start with the OEM tune and work from there, personally
Last edited by RJW; Jul 21, 2007 at 09:38 PM.
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From: http://www.mphparts.com 800-364-1975
I may think my wideband reading is correct becuase when I put it at 74.2 for IFR, it was super lean and my car cannot be driven as well.
My fuel pressure is at 58 so I think it is normal ... for the injectors, they are just about 1000 miles.
So when you increase the IFR, you allow more fuel?
Thanks,
-Mike
My fuel pressure is at 58 so I think it is normal ... for the injectors, they are just about 1000 miles.
So when you increase the IFR, you allow more fuel?
Thanks,
-Mike
If you do not have a vacuum and boost referenced regulator (either in a 97/98 car or aftermarket regulator) your IFR table should not be flat. Note, some regulators are only boost referenced and not vac referenced.
Did you reset your fuel trims yet like I mentioned in my post?
Thread Starter
Former Vendor
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From: DFW, TX www.vettestripes.com
St. Jude Donor '03-'04-'05-'06-'07-'08
Melting Slicks
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From: Tinker till it blows... then back it off a notch, maybe!!
St. Jude Donor '08
At the top middle portion of the screen, look for vcm controls (just under help in the menu) and start vcm controls
In vcm controls click on the fuel and spark tab and then click on reset fuel trims...
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St. Jude Donor '08
Melting Slicks
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From: Tinker till it blows... then back it off a notch, maybe!!
St. Jude Donor '08
Personally I'm still fairly damp....
Besides...he has all those NICE stripey thingys that he sells....so we gotta be nice, just in case ya get the urge...