Feedback in a simplistic explanation is how long it takes each piston to travel a cycle. The + and - numbers means the injector is either adding or reduce fuel from a predetermined map to say idle at 700rpm. If a piston is slow it will add fuel, if a piston is fast it will reduce fuel. The feedback numbers should in theory for each revolution add up to 0 . It only occurs at at idle upto100rpm above idle. It’s a NVH thing some injectors have a max + - 5 value. But don’t be fooled by only looking at theses numbers. Alway check you desired and actual fuel pressures and the scv duty cycle.and current. Seen so many people and companies just replace the injector and the problem is still there. I always replace injectors and scv regardless. Things like blow by, valve regress, valve adjustment , lifter issues could also be a contributing factor . Air in fuel system, etc etc . Wrong sensor reading that are plausible to pcm but when it’s 25 degrees outside and you sensor is reading -17 degrees that’s going to send huge amounts of fuel in as the system things the air is dense that it is. PS never assume ,just because it new it works. Items can be faulty out of the box .
My 2012 hilux with 220000ks had the same problem when cold. Number 3 reached -3.9, was very noisy when cold and had like a tiny misfire like shake every now and again whilst warming up. I replaced the injectors and have never lookedd back. They were full DLC to.
Just a thought. Nr. 2 have a positive value, and nr. 3 is negative. Can it be that nr. 2 is bad, and the compression is lower, valves not sealing, etc., therefore nr. 3 -in a better cylinder- have to compensate more in negative to keep the idle in place?
Thanks a lots. I have hilux 2gd ftv engin 2016,it blows black smoke and when i diagnostic 1 to 4 injuctor, injunction feedback all of them are less than 1. I changed all the injuctor then the black smoke disappeared. I asked many mechanics and thy told me that new Toyota engine are different and your method does not work. Why...
Do you ignore all other readings until warm? After getting injectors replaced with new ones, my knock under load is gone but still loud idle, engine load comes down to around 12 when warm, fuel rail pressure stays between about 32k kpa and 35k kpa give/take 500, feedbacks are all tight and close to 0. Can't find why else my idle is still so loud though, car had a reman in injector 1 from old owner shown to me by my diesel mechanic comparing with the new ones . Lost as can be currently
What is a couse of Inj. FB Vol for idle is so low? I've changed injectors, feedback volume for each injector is within +/- 1mm3 but Inj FB Vol for idle I have -4,5 mm3 to -5mm3. Other people have +2-+3mm3.
![เจ็บที่ยังฮัก - ม่อน วรวิทย์ [ Official Mv ] จอนนี่มิวสิค](http://i.ytimg.com/vi/KALIGSRSjFs/mqdefault.jpg)
Feedback in a simplistic explanation is how long it takes each piston to travel a cycle. The + and - numbers means the injector is either adding or reduce fuel from a predetermined map to say idle at 700rpm. If a piston is slow it will add fuel, if a piston is fast it will reduce fuel. The feedback numbers should in theory for each revolution add up to 0 . It only occurs at at idle upto100rpm above idle. It’s a NVH thing some injectors have a max + - 5 value. But don’t be fooled by only looking at theses numbers. Alway check you desired and actual fuel pressures and the scv duty cycle.and current. Seen so many people and companies just replace the injector and the problem is still there. I always replace injectors and scv regardless. Things like blow by, valve regress, valve adjustment , lifter issues could also be a contributing factor . Air in fuel system, etc etc . Wrong sensor reading that are plausible to pcm but when it’s 25 degrees outside and you sensor is reading -17 degrees that’s going to send huge amounts of fuel in as the system things the air is dense that it is. PS never assume ,just because it new it works. Items can be faulty out of the box .
Will be checking my injectors after watching this. I get a similar knocky idle sound when cold, almost 160k
My 2012 hilux with 220000ks had the same problem when cold. Number 3 reached -3.9, was very noisy when cold and had like a tiny misfire like shake every now and again whilst warming up. I replaced the injectors and have never lookedd back. They were full DLC to.
Does replacing injectors solved the " tiny misfire like shake every now and again whilst warming up" ?
Just a thought. Nr. 2 have a positive value, and nr. 3 is negative. Can it be that nr. 2 is bad, and the compression is lower, valves not sealing, etc., therefore nr. 3 -in a better cylinder- have to compensate more in negative to keep the idle in place?
My Prado had a crack between exhaust and inlet valve in number 3 cylinder.
Great information, thanks Anthony
Good information. I have one question. What is it -inj FB volume for idle?
Thanks a lots. I have hilux 2gd ftv engin 2016,it blows black smoke and when i diagnostic 1 to 4 injuctor, injunction feedback all of them are less than 1. I changed all the injuctor then the black smoke disappeared. I asked many mechanics and thy told me that new Toyota engine are different and your method does not work. Why...
Do you ignore all other readings until warm? After getting injectors replaced with new ones, my knock under load is gone but still loud idle, engine load comes down to around 12 when warm, fuel rail pressure stays between about 32k kpa and 35k kpa give/take 500, feedbacks are all tight and close to 0. Can't find why else my idle is still so loud though, car had a reman in injector 1 from old owner shown to me by my diesel mechanic comparing with the new ones . Lost as can be currently
What is a couse of Inj. FB Vol for idle is so low? I've changed injectors, feedback volume for each injector is within +/- 1mm3 but Inj FB Vol for idle I have -4,5 mm3 to -5mm3. Other people have +2-+3mm3.
was there a follow up video to this one?
Great info mate👍