I think I got it dialed in but I have lots of questions- Inj Pulse width

[chadtunes]

This has been a 3yr journey. Back in Dec 2020 I bought this truck DOA from a Copart auction. The last diesel I worked on was more than 20yrs ago in the Marines. So all this is totally new, the engine & the electronics, mind boggling stuff... It's been a really steep learning curve. I still feel lost. The only thing that's saving me is you guys going back and forth about stuff here. I had a lot of issues getting the idle to settle down after installing 155/30's. Adjusting the FICM did it.. Took me a year to figure it out.

Should l stop here? 750Ft Lbs & 276hp @ 2000 RPM @ 50% throttle.

Can you look the log over and let me know what you see? I just don't have enough time in to know what exactly to look for. I don't necessarily care about peak #'s.. Over all the truck drives great but I think there's room for improvement.

Another question.. What does the pulse width mean in relation to the rest of the log? Are you just reading it as a indication of how much duty cycle of the injector is usiing and if it's high you're running out of injector?? What's a max #?

Log attached.

Back to normal!!! Logged from hot to cold runs and idles like a champ..hpl



Screenshot 2023-05-21 135922.png

[Powerstrokecustoms]

you can make the truck run smooth with just a good pcm tune. ficm is only going to tune pulse width. with bigger injectors you need to adjust icp, timing and other stuff to make it run smooth. if you dont then your going to run out of oil pressure for the extra 35cc of fuel your trying to add.

[JaegerWrenching]

I recommend anyone wanting to understand HEUI injectors a little more watch this video if you haven't already. https://www.youtube.com/watch?v=cw7a-D7gTIA Injector PW on a 7.3 or 6.0 is exactly how long the injector is opening the spool valve which is letting in High pressure oil that then pushes onto the top side of the intensifier piston which then pushes onto the smaller fuel side of the piston in the injector which then pushes on the fuel in the injector reservoir which pushes fuel into the injector nozzle which atomizes the fuel on it's way into the cylinder. The intensifier piston has a ratio of 7:1, so take your high pressure oil pressure, multiply it by 7, and this is what your fuel pressure entering the injector nozzle will be. As for making changes in the injector PW map it's a great place to start IMO. You now have an injector that flows more than stock at the same PW because of the bigger nozzles being less restrictive so more fuel flows into the cylinder with the same PW or injector on time. Therefore if you want to accurately delivery fuel and have fuel milage readouts be accurate you need the injector PW map to be accurate. But remember the PW map doesn't need to be accurate for your truck to run well it just needs to be close enough in the idle/light throttle area, anything past 40% throttle doesn't really matter except if you care about accurate mileage readout.... You can also drop ICP if you want to try and lengthen out the injector on time or PW, as it'll drop some naturally from the bigger nozzle delivering more fuel volume with equivalent injector on time. Your truck will require 0.5 to 0.6ms of injector on time at 1000PSI to idle, now you can increase ICP and get it down to around 0.4 maybe even 0.3ms on time, but the actual fuel amount delivered in mg or mm3 would be identical. If it were actually less then the idle would drop if it were more it'd increase in idle. But idle is a full time closed loop parameter so the truck would automatically ask for more or less mg/stroke to get the target idle in check... It also doesn't care if it takes 5mg or 18mg to idle, but a stock truck takes about 10-15mg to idle the closer you get yours to read that at idle the better it'll idle. 6.0's seem to like around 0.4 to 1.2 PW for idle Stock is 1.3ish and 0.8-1.5ms of PW/on time in the cruse range Stock is about 1-1.3pw on flat ground steady state 25% throttle input going 55mph. You change PW by adjusting ICP until you have your desired PW. Your log seems very close in those areas so that is good. You will need to increase the ICP flow map 3662 in HPT. I will say back pressure also needs to be set right, this is the most sensitive part when tuning these trucks. Also drop your gas tuning thinking, port injection gas has essentially fixed fuel pressure so when your PW is high you have no more fuel. Diesel's vary fuel pressure greatly so flow through the injector at equivalent PW will also very greatly. Pressure varies from 3000PSI to 27000psi, that's like a gas car going from 42psi to 378psi. Therefore PW is not a good way of looking at total fuel amount delivered like in a gas car. MG or mm3 per stroke is what you really want to look at, but then again if your PW map is wildly inaccurate then your actual mg or mm3 per stroke will also be wildly inaccurate... and your truck will run wildly inaccurate....

[chadtunes]

you can make the truck run smooth with just a good pcm tune. ficm is only going to tune pulse width. with bigger injectors you need to adjust icp, timing and other stuff to make it run smooth. if you dont then your going to run out of oil pressure for the extra 35cc of fuel your trying to add.

you can make the truck run smooth with just a good pcm tune. ficm is only going to tune pulse width. with bigger injectors you need to adjust icp, timing and other stuff to make it run smooth. if you don't then your going to run out of oil pressure for the extra 35cc of fuel your trying to add.

You know what was hunting me? This idle problem followed me from this tuning I paid. I think I gave them enough time to figure it out. It would idle fine cold but once it warms up it'll start to idle high and skip/roll and slowly idle down. And even through all the advise you've given to the guys here.. I forget which thread it was but it all clicked one day and here we are. I have a great running truck. Less pulse width duration in the ficm settled the idle down.

I still want to know how you do it without the ficm but I think there's good clues in the thread below because I'm still grasping this concept.

Anyways, I can't thank you enough for all your advise you've given, I couldn't have done this without you guys. I finally have a base line I can work with.

Ok one more question.. What do you mean run out of oil pressure.. what does that look like, what do you look for in the logs? Does that mean the engine just needs more revs to produce the same power?

C

[chadtunes]

I recommend anyone wanting to understand HEUI injectors a little more watch this video if you haven't already. https://www.youtube.com/watch?v=cw7a-D7gTIA Injector PW on a 7.3 or 6.0 is exactly how long the injector is opening the spool valve which is letting in High pressure oil that then pushes onto the top side of the intensifier piston which then pushes onto the smaller fuel side of the piston in the injector which then pushes on the fuel in the injector reservoir which pushes fuel into the injector nozzle which atomizes the fuel on it's way into the cylinder. The intensifier piston has a ratio of 7:1, so take your high pressure oil pressure, multiply it by 7, and this is what your fuel pressure entering the injector nozzle will be. As for making changes in the injector PW map it's a great place to start IMO. You now have an injector that flows more than stock at the same PW because of the bigger nozzles being less restrictive so more fuel flows into the cylinder with the same PW or injector on time. Therefore if you want to accurately delivery fuel and have fuel milage readouts be accurate you need the injector PW map to be accurate. But remember the PW map doesn't need to be accurate for your truck to run well it just needs to be close enough in the idle/light throttle area, anything past 40% throttle doesn't really matter except if you care about accurate mileage readout.... You can also drop ICP if you want to try and lengthen out the injector on time or PW, as it'll drop some naturally from the bigger nozzle delivering more fuel volume with equivalent injector on time. Your truck will require 0.5 to 0.6ms of injector on time at 1000PSI to idle, now you can increase ICP and get it down to around 0.4 maybe even 0.3ms on time, but the actual fuel amount delivered in mg or mm3 would be identical. If it were actually less then the idle would drop if it were more it'd increase in idle. But idle is a full time closed loop parameter so the truck would automatically ask for more or less mg/stroke to get the target idle in check... It also doesn't care if it takes 5mg or 18mg to idle, but a stock truck takes about 10-15mg to idle the closer you get yours to read that at idle the better it'll idle. 6.0's seem to like around 0.4 to 1.2 PW for idle Stock is 1.3ish and 0.8-1.5ms of PW/on time in the cruse range Stock is about 1-1.3pw on flat ground steady state 25% throttle input going 55mph. You change PW by adjusting ICP until you have your desired PW. Your log seems very close in those areas so that is good. You will need to increase the ICP flow map 3662 in HPT. I will say back pressure also needs to be set right, this is the most sensitive part when tuning these trucks. Also drop your gas tuning thinking, port injection gas has essentially fixed fuel pressure so when your PW is high you have no more fuel. Diesel's vary fuel pressure greatly so flow through the injector at equivalent PW will also very greatly. Pressure varies from 3000PSI to 27000psi, that's like a gas car going from 42psi to 378psi. Therefore PW is not a good way of looking at total fuel amount delivered like in a gas car. MG or mm3 per stroke is what you really want to look at, but then again if your PW map is wildly inaccurate then your actual mg or mm3 per stroke will also be wildly inaccurate... and your truck will run wildly inaccurate....

OK. Wow.. thanks.. I'm going to need time to digest this.. Couple questions that come to mind:

Can you share some more of your math equations to help with my logging? What do I log to see the relation of what back pressure does? Back pressure increases boost right? Back pressure to boost and timing? Or fuel mass desired? Increasing ICP flow in table 3662, what do I look for in the logs? What are the symptoms? Peaky power generation? Lugging in a tall gear under low boost?

C

[Powerstrokecustoms]

i change my icp maps and transfer functions so its adding more icp without the truck thinking it has more icp. just like i do with the map transfer function. if the truck says it has 600 psi reading off the factory icp sensor and i connect another sensor to the truck, it will read different. i can make more icp pressure out of the pump but i can only get so much. when you run 190-205 and up injectors you need to run a pump that will produce more icp. your trying to push more fuel out of a nozzle which means you need more pressure to do so.

[chadtunes]

I don't understand which way the #'s change things, hoping you can explain because I'm not grasping the concept. Previously you had posted something about the map transfer function with the first pic there with normal looking #'s. And then there's mine.. with the #'s in the 300's.. And you keep mentioning leavign them at 4.9v.. so Why is mine n the 300's?

C

Screenshot 2023-05-24 094916-map transfer.png


MAP_Tranfer.GIF

i change my icp maps and transfer functions so its adding more icp without the truck thinking it has more icp. just like i do with the map transfer function. if the truck says it has 600 psi reading off the factory icp sensor and i connect another sensor to the truck, it will read different. i can make more icp pressure out of the pump but i can only get so much. when you run 190-205 and up injectors you need to run a pump that will produce more icp. your trying to push more fuel out of a nozzle which means you need more pressure to do so.

[Powerstrokecustoms]

Screenshot 2023-05-24 094254.png