did you look in the 8v air horn at the injector spray cone , not looking RATTY. (bad pattern)? link is video.
Lets talk Pulse widths
the MP4 quad injectors to this in photo 1.
HOT engine 800rpm
this is MPI but my 1991 TBI shows same PW. pulse wide same. 1.4ms same. (running) 8v)
this is and online (web) engine simulator, and very accurate, (plenty)\
the MPI failed like this....
1.8ms (.0018 seconds) calc'd and 1.4mS actual. his ECU was doing WRONG 4.5MS rich as a pig and bad China MAF caused, (pure trash MAF) and cured next .
the same kind of failure can be on 8v bad MAP sensor, or bad hoses or connected to wrong vacuum, ports.
or injector clogged.
https://www.rbracing-rsr.com/calcinjpulse.html
1.4mS hot.800.rpm 8valve
![[Image: 522_8v-inj.jpeg]](https://fixkick.com/forum/gallery/522_8v-inj.jpeg)
now what do I get on 91,8v , yours will be the same. hot and cold. if not SENSORS are wrong.
as you can see hot is lean and normal mix, called stoich.
cold is 3.5 and hot is 1.4
if yours is normal, then the injector is clogged up,
but if wrong , ID say map is failing, or ECT fibbing like a lawyer., at OJ';s trail)
the uses of a scope will tell you if the ECU is right or the Injector is dead (weak)
even with clogged injector the ECU will will still try to go to 5MA PW, pulse width, due to MAP going to near 0v.
this photo is off my scope, and 8v and hand drawn by me to make it easy to see all details, on one page.
see the chopper effect here, called injector cooling? The total time is delta T. fuel flows at 0.7m delay.
![[Image: TBI-pwm-wave1%20.jpg]](https://fixkick.com/INJECTORS/TBI-pwm-wave1%20.jpg)
the below is bench tested ECU with fake map sensor inputs. I can force any MAP reading I want. here. so is not on running real engine.
and last and best, the transverse test, this is scope probe directly across the 2 injector wires and scope ground busted from AC line, to not hurt my ECU.
the point here is seen correct wave forums.
the first 12v pulse wakes up the slow injector , about 1mS long , total is 1.3mS total, (0.7 mS is fuel flow time)
![[Image: INJ-red-to-yel-w1.jpg]](https://fixkick.com/INJECTORS/INJ-red-to-yel-w1.jpg)
https://fixkick.com/INJECTORS/TBI-pwm-wave1%20.jpg
Lets talk Pulse widths
the MP4 quad injectors to this in photo 1.
HOT engine 800rpm
this is MPI but my 1991 TBI shows same PW. pulse wide same. 1.4ms same. (running) 8v)
this is and online (web) engine simulator, and very accurate, (plenty)\
the MPI failed like this....
1.8ms (.0018 seconds) calc'd and 1.4mS actual. his ECU was doing WRONG 4.5MS rich as a pig and bad China MAF caused, (pure trash MAF) and cured next .
the same kind of failure can be on 8v bad MAP sensor, or bad hoses or connected to wrong vacuum, ports.
or injector clogged.
https://www.rbracing-rsr.com/calcinjpulse.html
1.4mS hot.800.rpm 8valve
now what do I get on 91,8v , yours will be the same. hot and cold. if not SENSORS are wrong.
as you can see hot is lean and normal mix, called stoich.
cold is 3.5 and hot is 1.4
if yours is normal, then the injector is clogged up,
but if wrong , ID say map is failing, or ECT fibbing like a lawyer., at OJ';s trail)
the uses of a scope will tell you if the ECU is right or the Injector is dead (weak)
even with clogged injector the ECU will will still try to go to 5MA PW, pulse width, due to MAP going to near 0v.
this photo is off my scope, and 8v and hand drawn by me to make it easy to see all details, on one page.
see the chopper effect here, called injector cooling? The total time is delta T. fuel flows at 0.7m delay.
the below is bench tested ECU with fake map sensor inputs. I can force any MAP reading I want. here. so is not on running real engine.
and last and best, the transverse test, this is scope probe directly across the 2 injector wires and scope ground busted from AC line, to not hurt my ECU.
the point here is seen correct wave forums.
the first 12v pulse wakes up the slow injector , about 1mS long , total is 1.3mS total, (0.7 mS is fuel flow time)
https://fixkick.com/INJECTORS/TBI-pwm-wave1%20.jpg
http://www.fixkick.com