Well, i see many many threads on people asking for injector dead times for variouse injectors all the time, well being from an erra of when i learned Stand alone programming "dead times" weren't even there (or called dead times anyway)
The "dead time" is just the amount of time from closed to opened that a certain sized injector takes to open under a certain, voltage and fuel pressure, and to be honest is NOT THAT IMPORTANT in reality, it's one of those "fine tuning" things tht keeps a steady idle at night or when there's a load on the electrical system... don't believe me set them all to zero and watch yourself remap the egnine to run just fine, but also watch how you'll nver get consistant AFR's at idle when electrical loads fluctuate. And at WOT it's not even relevant in the least..
If you're having some tuning/fueling issues under load or cruising RPM's and think they are due to the dead times you're looking in the wrong area
What i intend to do with this short article is teach you how to establish your own DT's for YOUR setup and injectors as each vehicle will vary from things such as injector wiring, ECU ground and power quality and other simple little things (and are mainly only important at all during light cruise and idle)
Instead of getting too deep into explaining them i'll just make a simple step by step on setting them up for yourself and your car.. any issues after this in your tune are a result of something wrong else where in the tune it's self
I'm starting this with the steps assuming your car is assembled, will start and run and has a working electrical system
** All you're going to need is a wideband, a way to plug the vac line to the afpr, and a laptop or whatever you tune your ECU with
1.) GEt into your "dead time" or battery volt compensation map and zero all values, and make sure you're at "normaloperating temps" and zero out any air temp or coolant temp trims in thiese ranges while setting dead times (for me i disconnect then IAT and coolant temp sensors and set the values at teh extreme ends where the ECU will go to at zero compensation
2.) get the car up and running to where you have the best voltage you can normally get (for me that's between 13.6 warm and 14.4v cold at idle and above) the voltage drops as the engine and alt head up (this mens turn off all accessories/extra electronics you have, radio ncluded and especially a power inverter you might use for laptop, just use an extension cord fromthe house to power it)
3.) Get the engine timing locked to a value of somewhere between 10 and 20 degrees (what ever gives you the steadiest idle you can obtain) **disconnect the vac line from the AFPR and plug the leak/hose*** need to keep FP constant to do this
4.) set theAFR at this idle to somethng like 14.7 and adjust the pulse width for all the cells around the idle's current cell to the exact same value so if it changes cells for some reason you won't be thrown off and confused - at this idle, your volts should be at their best/highest average value, make sure the radio, lights and all electronics are OFF (or all thatyou can turn off that isn't needed in daily idle.driving situations)
5.)Set the dead time (volt comp) in this area at a nice low even number like say .200ms and take note of the AFR (you can tune the AFR for 14.7 or whatever you want, it's just a baseline for now to use as refference
6.)turn on enough accesories/lights to move the volt comp/dead time cell to it's next cell over (usally in a stand alone it will be a graph ov volts from 16 down to 6 or 8 volts in small increments) We are aiming for 13.6 or whatever your operating temp highest volts are - if 13.6 was our average peak, load the electrics enough to bring it to say 12.8/13.0 whatever is the next lowest volt cell
7.) Now, increase the dead time at this lower voltage untill you get the exact same stable AFR you had in step 5
8.) Load the electrics MORE to get to the NEXT lowest cell (say 12.0 - 11.8 volts, and repeat the process by raising dead times untill your AFR is again the same as step 5
9.) take note of the amount of pulsewidth/ms changed in the 2 cells you adjusted, average these out (say the first one took you fro .200 to .350 and the third took you to .486 (add them and divide by 2) .350+.486 = .836 ... Then .836 /2 = .418
10.) now make the new value .418 your initial full voltage dead time, and add the amoung of values you got from steps7 and 8 to fill in the next two cells
it would be like so...the initial .200 took .150ms to get AFR's back in check so now you'd add the .150 to the new value of .418 which is our actual base top voltage dead time
example now you're table will read 14v = .418ms / 12.8v = .568 /11.8v ill now = .704 (the difference between the values you came up with in steps 7 and 8 added to the new dead time for the 12.8v range)
So now the dead times table volt comp table will read
.418 then .568 then .704
Repeat this loading down the rest of the voltage cells/dead time cells with as much draw as you can put on via amps, lights, wipers, heater etc.. there's no need to reset the initial first value again after getting a baseline from the setting of the first two as the times will increase in a linear fashion, if your table is graphical just follow the shape of the rising curve, or if it's numeric based just figure out the average amount you're raising the dead time per volt dropped or each cell whatever it's range may be (some may be 1 volt per cell, some may be 1.3 v per cell) i'm sur eyou get iut by now
Then as you near the lowest end of the scale (say 8 volts) raise the values a bit more, say we were adding .150 per volt and did that from 12.8 volts down to 10 volts, well at anything below 10, make the value you add by increase by say 50% so .150 * .50 = .075... Then .150 + .075 = .225ms, and there you have it, no need to ask, post, use other's numbers to only have it still not be right etc..
what dead times really only do is make sure the injectors are opening enough to get the amount of fuel needed to keep the AFR's in check when the volts drop since they will taek longer to open with less volts... now hook your fuel pressure vac line back up and enjoy. As for the values when FP rises wtih boost, no worries, that's what your pulsewidth takes care of, like i siad, most older systems and some newer ones don't even call it dead time, it's just voltage compensation mapping and in boost you have higher bolts at higher RPM's (at least your regulated peak of say 13.6) and dead times don't make a difference, you just change the open tiem on the injector overall.. this is really as i said a way to keep things operating and the egnienr unning at ngiht with lights on, or to keep the engine from stalling out due to lack of fuel should there be a sudden drop in vots from an electrical draw on the system at night at idle and low RPM cruise
HOpe this helps some of you, i've never posted tjhis up before because on tunters i know some one who's never tuned anything but an AFC would hve some reason to prove i'm wrong adn that my theory is flawed
so i hope you enjoy
The "dead time" is just the amount of time from closed to opened that a certain sized injector takes to open under a certain, voltage and fuel pressure, and to be honest is NOT THAT IMPORTANT in reality, it's one of those "fine tuning" things tht keeps a steady idle at night or when there's a load on the electrical system... don't believe me set them all to zero and watch yourself remap the egnine to run just fine, but also watch how you'll nver get consistant AFR's at idle when electrical loads fluctuate. And at WOT it's not even relevant in the least..
If you're having some tuning/fueling issues under load or cruising RPM's and think they are due to the dead times you're looking in the wrong area
What i intend to do with this short article is teach you how to establish your own DT's for YOUR setup and injectors as each vehicle will vary from things such as injector wiring, ECU ground and power quality and other simple little things (and are mainly only important at all during light cruise and idle)
Instead of getting too deep into explaining them i'll just make a simple step by step on setting them up for yourself and your car.. any issues after this in your tune are a result of something wrong else where in the tune it's self
I'm starting this with the steps assuming your car is assembled, will start and run and has a working electrical system
** All you're going to need is a wideband, a way to plug the vac line to the afpr, and a laptop or whatever you tune your ECU with
1.) GEt into your "dead time" or battery volt compensation map and zero all values, and make sure you're at "normaloperating temps" and zero out any air temp or coolant temp trims in thiese ranges while setting dead times (for me i disconnect then IAT and coolant temp sensors and set the values at teh extreme ends where the ECU will go to at zero compensation
2.) get the car up and running to where you have the best voltage you can normally get (for me that's between 13.6 warm and 14.4v cold at idle and above) the voltage drops as the engine and alt head up (this mens turn off all accessories/extra electronics you have, radio ncluded and especially a power inverter you might use for laptop, just use an extension cord fromthe house to power it)
3.) Get the engine timing locked to a value of somewhere between 10 and 20 degrees (what ever gives you the steadiest idle you can obtain) **disconnect the vac line from the AFPR and plug the leak/hose*** need to keep FP constant to do this
4.) set theAFR at this idle to somethng like 14.7 and adjust the pulse width for all the cells around the idle's current cell to the exact same value so if it changes cells for some reason you won't be thrown off and confused - at this idle, your volts should be at their best/highest average value, make sure the radio, lights and all electronics are OFF (or all thatyou can turn off that isn't needed in daily idle.driving situations)
5.)Set the dead time (volt comp) in this area at a nice low even number like say .200ms and take note of the AFR (you can tune the AFR for 14.7 or whatever you want, it's just a baseline for now to use as refference
6.)turn on enough accesories/lights to move the volt comp/dead time cell to it's next cell over (usally in a stand alone it will be a graph ov volts from 16 down to 6 or 8 volts in small increments) We are aiming for 13.6 or whatever your operating temp highest volts are - if 13.6 was our average peak, load the electrics enough to bring it to say 12.8/13.0 whatever is the next lowest volt cell
7.) Now, increase the dead time at this lower voltage untill you get the exact same stable AFR you had in step 5
8.) Load the electrics MORE to get to the NEXT lowest cell (say 12.0 - 11.8 volts, and repeat the process by raising dead times untill your AFR is again the same as step 5
9.) take note of the amount of pulsewidth/ms changed in the 2 cells you adjusted, average these out (say the first one took you fro .200 to .350 and the third took you to .486 (add them and divide by 2) .350+.486 = .836 ... Then .836 /2 = .418
10.) now make the new value .418 your initial full voltage dead time, and add the amoung of values you got from steps7 and 8 to fill in the next two cells
it would be like so...the initial .200 took .150ms to get AFR's back in check so now you'd add the .150 to the new value of .418 which is our actual base top voltage dead time
example now you're table will read 14v = .418ms / 12.8v = .568 /11.8v ill now = .704 (the difference between the values you came up with in steps 7 and 8 added to the new dead time for the 12.8v range)
So now the dead times table volt comp table will read
.418 then .568 then .704
Repeat this loading down the rest of the voltage cells/dead time cells with as much draw as you can put on via amps, lights, wipers, heater etc.. there's no need to reset the initial first value again after getting a baseline from the setting of the first two as the times will increase in a linear fashion, if your table is graphical just follow the shape of the rising curve, or if it's numeric based just figure out the average amount you're raising the dead time per volt dropped or each cell whatever it's range may be (some may be 1 volt per cell, some may be 1.3 v per cell) i'm sur eyou get iut by now
Then as you near the lowest end of the scale (say 8 volts) raise the values a bit more, say we were adding .150 per volt and did that from 12.8 volts down to 10 volts, well at anything below 10, make the value you add by increase by say 50% so .150 * .50 = .075... Then .150 + .075 = .225ms, and there you have it, no need to ask, post, use other's numbers to only have it still not be right etc..
what dead times really only do is make sure the injectors are opening enough to get the amount of fuel needed to keep the AFR's in check when the volts drop since they will taek longer to open with less volts... now hook your fuel pressure vac line back up and enjoy. As for the values when FP rises wtih boost, no worries, that's what your pulsewidth takes care of, like i siad, most older systems and some newer ones don't even call it dead time, it's just voltage compensation mapping and in boost you have higher bolts at higher RPM's (at least your regulated peak of say 13.6) and dead times don't make a difference, you just change the open tiem on the injector overall.. this is really as i said a way to keep things operating and the egnienr unning at ngiht with lights on, or to keep the engine from stalling out due to lack of fuel should there be a sudden drop in vots from an electrical draw on the system at night at idle and low RPM cruise
HOpe this helps some of you, i've never posted tjhis up before because on tunters i know some one who's never tuned anything but an AFC would hve some reason to prove i'm wrong adn that my theory is flawed
so i hope you enjoy
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