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Thread: injector pulse width

  1. #1
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    Default injector pulse width

    i am in the process of tuning my vz ss it is ls1 with 60lb injectors the problem i was having is on light throttle cruise it was going rich and no matter how much i trimmed down the ve table it made no difference the lowest pulse width i could get was 1.7ms. i have now changed b4003 and b4004 to .85ms and now able to get just below 1.5ms and has fixed my problem. my question is these 2 injector tables called minimum pulse width are they actually the pulse width or are they dead time.

    also what is the best way to reduce the rich spike on deccel after giving it a boot

  2. #2
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    Have a search on here for CAX files and B9021. I'm running an LS1 on COS3 and adjusted the pulse width down accordingly (in terms that I understand B9021 removes a hidden "mimimum" PW that you run into), I'm also running SD60's and had the same problem.

    Jim
    2000 LS1 M6, No EGR/Air/PS/CATs. TR230 Cam, COS3, OLSD, LC1 Wideband fitted, Procharger P1SC, 2 Bar MAP, Siemans Dekka 60Lb Injectors.
    All wrapped up in a 2000Lb AC Cobra Replica

  3. #3
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    Those tables are for the fuelling portion of the pulsewidth. So if you are showing a minimum pulsewidth in the scanner of 1.5ms with B4003 & B4004 set to 0.85ms you have 0.65ms of offsets added.This 0.65ms would be made up from the battery voltage/manvac offset table and short pulse adder.
    see here:https://forum.efilive.com/showthread...01-correlation
    Last edited by 5.7ute; January 24th, 2017 at 01:43 PM. Reason: added link
    The Tremor at AIR

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    Quote Originally Posted by 5.7ute View Post
    Those tables are for the fuelling portion of the pulsewidth. So if you are showing a minimum pulsewidth in the scanner of 1.5ms with B4003 & B4004 set to 0.85ms you have 0.65ms of offsets added.This 0.65ms would be made up from the battery voltage/manvac offset table and short pulse adder.
    see here:https://forum.efilive.com/showthread...01-correlation
    I had a feeling this may be the case. What do you think is the best way to go about this? It seems to be working well the map is blending well cold start is good mixtures are very stable. Should I put in the correct values into b4003 & b4004 then adjust using the voltage offset table or leave it.
    I had a read of one of your threads while searching this did not see the one in the link I will have a read tomorrow when I'm at a computer

  5. #5
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    The best way IMHO is to get the correct injector data and start again from scratch with the Ve table etc.
    from memory the 60lbers have a large offset so using the B9021 cax will be necessary to get idle and decel fuelling into line.
    I no longer have the data for the 60lbers as my old computer crashed, but on the "other" forum, Dsteck has posted a spreadsheet with the data in HPT format. You will just need to transpose the tables to get them in Efilive format.
    The Tremor at AIR

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    Quote Originally Posted by 5.7ute View Post
    The best way IMHO is to get the correct injector data and start again from scratch with the Ve table etc.
    from memory the 60lbers have a large offset so using the B9021 cax will be necessary to get idle and decel fuelling into line.
    I no longer have the data for the 60lbers as my old computer crashed, but on the "other" forum, Dsteck has posted a spreadsheet with the data in HPT format. You will just need to transpose the tables to get them in Efilive format.
    i know the spreadsheet you speak of i have seen it before but when i went looking for it i could not find it. if you have a link please pm me. atm im thinking about just getting a set of id's but that wont be for a while as money is a problem atm

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    Quote Originally Posted by h41ry View Post
    i am in the process of tuning my vz ss it is ls1 with 60lb injectors the problem i was having is on light throttle cruise it was going rich and no matter how much i trimmed down the ve table it made no difference the lowest pulse width i could get was 1.7ms. i have now changed b4003 and b4004 to .85ms and now able to get just below 1.5ms and has fixed my problem. my question is these 2 injector tables called minimum pulse width are they actually the pulse width or are they dead time.

    also what is the best way to reduce the rich spike on deccel after giving it a boot
    I'm Having this same problem!!!!!!! Its killing me!! I have FIC 1000cc Bosch injectors, FIC gives data spreadsheets along with the injectors. All the data is in there correctly. B4003/B4004 are both set at .125ms, but the computer will not command anything less than 2.4ms IDC. Car idles and light throttle cuises between 10-12 AFR, Ive even tried setting injectors upto 150 LB/HR, no difference, tried commanding 20:1 AFR, no difference.

    BUT if i turn fuel trims on, it'll pull fuel and idle/cruise 14.6 AFR...

    SOOOOO FRUSTRATING!!!!!

    Ive been tuning Gen3 LS' stuff for over 10 years, never had this problem before. In fact, Ive tuned multiple cars with these same FIC 95's and never had this problem. The first car that was doing this to me, i figured there must be an underlying issue, but now my brothers car is doing the exact same thing... I'm honestly to the point of thinking that its the updated version of EFILive that i have, cuz ive never had this problem before i updated it, i think in March sometime.
    -John

    1991 RCSB 2WD Sierra LQ4 swap, 220/224 112 cam, FI Billet s476/96 turbo
    4L80e w/shift kit, PY 3400, and 3.73 gears.
    19 PSI and E85, 4300# with driver. 9.60@141.8, 1.43 sixty

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    why do my deka 60 idle just fine without cax or anything? b4003/4 around 1.3 ms. (ls1b)

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    Quote Originally Posted by dian View Post
    why do my deka 60 idle just fine without cax or anything? b4003/4 around 1.3 ms. (ls1b)
    60# injectors will idle just fine... but you'll probably end up with a really rich decel without the cax.

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