Page 2 of 3 FirstFirst 123 LastLast
Results 21 to 40 of 49

Thread: How to tune for return fuel system.

  1. #21
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    ok, I updated the first two, they're easy,

    but the"offset vs volts vs vac" table ---first, its my understanding that as long as that's what's selected in the first bar, I don't need to address the "...vs map" table at all... correct?

    then, in order to get correct values into that table --I don't actually have the correct info. I have the Omega spreadsheet that gives me 80's and 58 psi, where I'm at 89lb at 43.5psi -- so am I stuck using my current values and the -39kpa column, and then tuning as suggested?

    currently my "short pulse limit" is 0.00 -- should I have a value there?
    I read alot about zeroing the "short pulse adder" table -- about the first half of my table has values, the second half is zeros. Should I zero that table ?
    my "min pulse width" is at .102 -- is that ok ?

  2. #22
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    yes the drop down tab with map and vac option will select one or the other. so only 1 table needs adjusting.
    i would put the recommended short pulse from omega in there. if you have problems halve it then set it to zero if it happens again.

    ok here is the cells you need... courtesy one of omegas spreadsheets. Injector Offsets.png
    2000 Ford Mustang - Top Sportsman

  3. #23
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    you must me younger than me :-)
    I can't read your screen shot.

    I put 1.6 as the modifier in the omega spreadsheet and then copy and pasted the values from the -39kpa column all the way across

    the "pulse corrections" and "limits" match the Omega spreadsheet

    am I ready to go for a spin? :-)

  4. #24
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    if you click on the screen shot it expands...did you do that?
    in your file of omegas work with a higher base pressure it would be a different cell you copy from than mine.

    attach your version of omegas work to a post and i can tell you which cell you would need if you still have trouble seeing my data shot.
    2000 Ford Mustang - Top Sportsman

  5. #25
    Quote Originally Posted by wayfarer View Post
    ok, I updated the first two, they're easy,

    but the"offset vs volts vs vac" table ---first, its my understanding that as long as that's what's selected in the first bar, I don't need to address the "...vs map" table at all... correct?

    then, in order to get correct values into that table --I don't actually have the correct info. I have the Omega spreadsheet that gives me 80's and 58 psi, where I'm at 89lb at 43.5psi -- so am I stuck using my current values and the -39kpa column, and then tuning as suggested?

    currently my "short pulse limit" is 0.00 -- should I have a value there?
    I read alot about zeroing the "short pulse adder" table -- about the first half of my table has values, the second half is zeros. Should I zero that table ?
    my "min pulse width" is at .102 -- is that ok ?

    Reading this; you have 43.5psi @idle, but is this with everything connected up? With a boost referenced system you will measure your Fuel Base Pressure minus the idle vacuum... You must disconnect the regulator boost tube to measure your fuel base pressure, or swich on the pump without the engine running.

  6. #26
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    Quote Originally Posted by Speedytec View Post
    Reading this; you have 43.5psi @idle, but is this with everything connected up? With a boost referenced system you will measure your Fuel Base Pressure minus the idle vacuum... You must disconnect the regulator boost tube to measure your fuel base pressure, or swich on the pump without the engine running.
    no, I have 38psi @idle, but that IS with vac hooked up and engine running. I will remove vac and check again, and report back. I actually have two gauges, one Autometer electric with sending unit in the end of the rail, and a small mechanical at the tee for my fuel pressure cutoff for the nitrous. I will check both.

  7. #27
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    Quote Originally Posted by cobaltssoverbooster View Post
    if you click on the screen shot it expands...did you do that?
    in your file of omegas work with a higher base pressure it would be a different cell you copy from than mine.

    attach your version of omegas work to a post and i can tell you which cell you would need if you still have trouble seeing my data shot.
    yeah, I clicked the thumbnail and it expanded, but I couln't read it. I tried to figure out how to zoom it from there, to no avail. I saved it to my pictures and opened it, and....VOILA, I can read it !

  8. #28
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    Quote Originally Posted by wayfarer View Post
    no, I have 38psi @idle, but that IS with vac hooked up and engine running. I will remove vac and check again, and report back. I actually have two gauges, one Autometer electric with sending unit in the end of the rail, and a small mechanical at the tee for my fuel pressure cutoff for the nitrous. I will check both.
    went out and checked -- key on, engine off, the mechanical underhood reads approx 42-43, and the electric autometer about 10psi less (kinda scary !). For one more verification I will hook up a fuel pressure tester to the service port on the rail tomorrow.

  9. #29
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    It should be read at the injectors to be most accurate

  10. #30
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    Quote Originally Posted by cobaltssoverbooster View Post
    if you click on the screen shot it expands...did you do that?
    in your file of omegas work with a higher base pressure it would be a different cell you copy from than mine.

    attach your version of omegas work to a post and i can tell you which cell you would need if you still have trouble seeing my data shot.
    injector 42,60,80.xls

  11. #31
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    so the rail pressure you have chosen now is off the chart so for ease of tuning and operation reset the rail pressure to 42 psi at the rail with the reference port disconnected as mentioned before.
    with this pressure change you will need to change the injector flow rate to 50 lb/hr and multiplier to 1.572. Now you can use the -120 kpa column from your data chart received by omega. i miss-read my supplied information from before and it is also set to a rail pressure of 58 psi instead of the 43.5 i thought i had. for that my apologies.
    2000 Ford Mustang - Top Sportsman

  12. #32
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    no apologies needed! this all helping me.

    However, I have gone over and over this in my head and on the calculator, and I'm still plenty confused.

    1) the IFR and modifier that I plug into the tune -- should they be based on the factory 58 psi that the Cobalt originally had, or on the the new rail pressure that the car will actually see now ?

    I.E. --my injectors are rated at 89lb @ 43.5 psi --- so do I use 102.77 @ 58 psi, or 87.45 @ 42psi ?

    2) the Omega spreadsheet isn't for the same injectors, (his sheet shows 80lb @ 43.5psi) so I can't for the life of me wrap my head around how to plug in a conversion factor to figure out which line to use out of the offset table, to get me reasonably close
    Last edited by wayfarer; 03-11-2014 at 08:23 PM.

  13. #33
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    ifr is based on the new fuel rail pressure. ecu injector parameters are for the data that is to match what the injectors will be running at. so if your ifr was for the factory 58 psi and you moved to 42 psi dont leave the 58 psi data there. the injectors aren't flowing that psi anymore.
    87.45 for 42 psi is your answer. flow for the actual.

    the zzp are the same injectors...89 lb @ 58 psi and 80 lb @ 43.5 psi ... the omega sheet is for these injectors but set for a 58 psi rail pressure as noted (because that's oem pressure so most will use that again)
    i will talk to another friend and see if i can get some more data for these injectors.
    2000 Ford Mustang - Top Sportsman

  14. #34
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    thank you for clarifying. The ZZP website is where I got the 89lb @ 43.5psi -- must be a typo. Frustrating!

    ok then, so I can plug in 54.66 as my IFR, 1.6 as my modifier in my tune (54.66 x 1.6 = 87.456)

    then plug 1.6 into the Omega sheet

    set my regulator to 42psi

    difference between 42 psi and 58 psi is -16

    -16psi = -110.32kpa

    copy and paste the -108kpa column from the Omega sheet to my offset vs volts vs vac table (in my tune) all the way across

    shut off MAF

    tune VE.

  15. #35
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    thank lwrs

    set to 43 psi rail with no reference
    Attached Files Attached Files
    2000 Ford Mustang - Top Sportsman

  16. #36
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    k. so --

    80's at 43.5psi --- (81.1 in the spreadsheet above)

    regulator to 43psi
    50.68 across the IFR table
    1.6 across the modifier table
    copy and paste the -101 column out of the spreadsheet across the offset table

    that work ?

    EDIT: copy and pasted the short pulse limit, short pulse adder, and min pw from the spreadsheet. Also copied the -101 column from the spreadsheet and noticed that the values are around 1/2 what they were before. I remember reading something about that, but just wanted to verify.

    03-12-14 no timing tables.hpt
    Last edited by wayfarer; 03-12-2014 at 01:39 PM.

  17. #37
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    That last sheet I posted was a direct copy and paste.

  18. #38
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    Quote Originally Posted by cobaltssoverbooster View Post
    That last sheet I posted was a direct copy and paste.
    cant directly copy 81.1 IFR with 1.0 multiplier. IFR max is 63.5. Everything else i copied exactly (I did do it the hard way, but then I'm kinda a dumbass like that )

  19. #39
    Senior Tuner cobaltssoverbooster's Avatar
    Join Date
    Dec 2008
    Location
    Nevada
    Posts
    4,452
    good eye didn't catch that. just pick a divider like 1.6 and then the result will be your ifr and use the divider you picked to be your multiplier. as long as ifr goes under 63 you can pick whatever combo you want.
    2000 Ford Mustang - Top Sportsman

  20. #40
    Tuner in Training
    Join Date
    Oct 2013
    Posts
    15
    it's been quite some time -- closing in on a year ! since I did all this, and I'm still running into issues, so I thought I'd drag this one back from the dead, being that it's in the "LSJ helpful threads"

    so, I used the info above -- 80 / 81 lb injectors, and chased my tail trying to get my VE to come into submission. It just wasn't happening. I got another tuner to help me along, and he backed up my thoughts that the injector data was still wrong. He plugged in values close to 103 lb/hr and we dug a GIANT hole in the middle of the VE table.
    The car was at least moderately driveable, but still not without its issues.

    I actually kind of quit driving it much during the summer in favor of 2 wheels, but as it got cold I tried to drive it more. Of course, that brought its own issues, e85 vs cold weather and all.

    I gotta get this thing straight.

    So, since all of the threads last winter and spring, a few people have said that the IFR modifier just DOES NOT WORK for the P12 pcm, so the best route to go is to cut your IFR in half, put 1.0 in the modifier table, and scale the VE and MAF tables by 50% as well. In my case this would certainly seem to bear fruit, especially if the giant hole and the values in my VE table mean anything.

    so I guess besides just updating this thread, does anybody have any helpful advice for working a P12 in a 50% scaled way ?