low limit of injector table?
04-19-2004, 09:42 PM
#1
low limit of injector table? I need to know what the lowest possible value is in the injector pulse width (IFR?) table. This is so I can get an idea of whether idle will still be OK with bigger injectors.
I don't have ability to read out my PCM tables yet, which is why I'm asking. I know that autotap shows mine are at 2 at idle, seems like injector control might get less accurate if pulse width went much lower.
Also pulse width is at 25 (even seen 27) at WOT, around 5K rpm - isn't this at 100% duty cycle? This is stock 2000 injectors.
I don't have ability to read out my PCM tables yet, which is why I'm asking. I know that autotap shows mine are at 2 at idle, seems like injector control might get less accurate if pulse width went much lower.
Also pulse width is at 25 (even seen 27) at WOT, around 5K rpm - isn't this at 100% duty cycle? This is stock 2000 injectors.
04-19-2004, 09:49 PM
#2
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Originally Posted by patSS/00
I need to know what the lowest possible value is in the injector pulse width (IFR?) table. This is so I can get an idea of whether idle will still be OK with bigger injectors.
I don't have ability to read out my PCM tables yet, which is why I'm asking. I know that autotap shows mine are at 2 at idle, seems like injector control might get less accurate if pulse width went much lower.
Also pulse width is at 25 (even seen 27) at WOT, around 5K rpm - isn't this at 100% duty cycle? This is stock 2000 injectors.
I don't have ability to read out my PCM tables yet, which is why I'm asking. I know that autotap shows mine are at 2 at idle, seems like injector control might get less accurate if pulse width went much lower.
Also pulse width is at 25 (even seen 27) at WOT, around 5K rpm - isn't this at 100% duty cycle? This is stock 2000 injectors.
Bigger injectors require larger IFR values no lower values. The minimum injector pulsewidth that is set in the pcm is not accessible by any of the editors. Its probably around 1.5 ms though. Depending on the setup of the car bigger injectors can cause some idleing issues.
Gary
04-19-2004, 10:12 PM
#3
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The minimum pulsewidth is 1.68 ms. I've seen it in EFILive. 
I'm running 57#(43.5psi rating) injectors and still haven't hit the lower pulsewidth limit yet. These idle with 1.9ms pulsewidths so in theory there is room for more injector than that. In reality bigger injectors than that may be a handful to get to work.
I've also ran 42# SVO injectors before with absolutely no problems.
I'm running 57#(43.5psi rating) injectors and still haven't hit the lower pulsewidth limit yet. These idle with 1.9ms pulsewidths so in theory there is room for more injector than that. In reality bigger injectors than that may be a handful to get to work.
I've also ran 42# SVO injectors before with absolutely no problems.
04-19-2004, 11:27 PM
#4
Originally Posted by XLR8NSS
The minimum pulsewidth is 1.68 ms. I've seen it in EFILive.
I'm running 57#(43.5psi rating) injectors and still haven't hit the lower pulsewidth limit yet. These idle with 1.9ms pulsewidths so in theory there is room for more injector than that. In reality bigger injectors than that may be a handful to get to work.
I've also ran 42# SVO injectors before with absolutely no problems.
I'm running 57#(43.5psi rating) injectors and still haven't hit the lower pulsewidth limit yet. These idle with 1.9ms pulsewidths so in theory there is room for more injector than that. In reality bigger injectors than that may be a handful to get to work.
I've also ran 42# SVO injectors before with absolutely no problems.
04-20-2004, 07:36 PM
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The only thing I did when I put the 57#ers in was adjust the IFR across the table to get the Ltrims in line. I didn't do anything special for the idle at all.
I have a in car wideband and these injectors(Siemens 57#) idle right at 14.5-14.6:1 no problem.
I doubt you need an injector that big(just assuming) but, I'm just letting you know that injectors that big will work fine. Much bigger and issues might start to arise.
PS - I'm running a truck and the fuel system is slightly different than the cars but, the low pulsewidth limits are all the same in the LS1 variants.
I have a in car wideband and these injectors(Siemens 57#) idle right at 14.5-14.6:1 no problem.
I doubt you need an injector that big(just assuming) but, I'm just letting you know that injectors that big will work fine. Much bigger and issues might start to arise.
PS - I'm running a truck and the fuel system is slightly different than the cars but, the low pulsewidth limits are all the same in the LS1 variants.
04-21-2004, 12:25 PM
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At 5000 RPM injectors will go static with a pulsewidth of 24ms. You are static
Unless you have a really low idle speed with high vacuum, you probably won't have a problem with any of the common high impedence injectors out there with the low pulse limit.
Unless you have a really low idle speed with high vacuum, you probably won't have a problem with any of the common high impedence injectors out there with the low pulse limit.
