I was having fueling issues with my car and i believe it to be clogged up injectors so i pulled them off took them to kinsler fuel injection http://www.kinsler.com and had them cleand screens replaced and and flow tested.

well i picked them up today and the flow sheet reads average if 46 LB/HR on 1000cc injectors... WTF

i say somethings not right my s300 was calibrated to 1000cc injectors. the part number 17113744 is for a 1000CC injector so are the injectors just fucked? any help im baffled lol

 

you were having fueling issues because those are not 1000cc injectors.

 

so it seems. but wtf @ the part numbers. http://www.fiveomotorsport.com...S.asp

 

it says at 10.00ms... not 90% duty like others


10ms at 6000 rpms is about 49.5% duty cycle

 

sweet, so they are 1000s thats the kind of answer i was hoping for.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">it says at 10.00ms... not 90% duty like others


10ms at 6000 rpms is about 49.5% duty cycle</TD></TR></TABLE>
wouldn't the pulse time not make a difference on flowrate? Sure there will be more fuel injected with a larger pulse width, but the flow rate isn't going to change. If the injectors are rated at 1000cc/min flowrate at 42psi then they should have flowed near 1000

 

but they didnt act like 500cc injectors in my car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SwappedTURBOegg &raquo;</TD></TR><TR><TD CLASS="quote">but they didnt act like 500cc injectors in my car.</TD></TR></TABLE>
What caused you to send them off in the first place? You said that you were having fueling issues so were duty cycles higher than expected?

 

for a while everything was fine. i could add fuel and run in the 11 AFR range. i changed map sensors and widebands.it started to happen slowly. im reading afr though s300 and now i couldn't get it to rev past 7200 or get the afr past 12.5 no mater how much fuel i added. i could add the slightest bit and it would spit and pop everywhere and not make the afr any better. it led me to think that maybe the injectors were clogged up. so i got them cleaned. i hope this fixes it. if not im changing the walbro out for something els maybe even another. my duty cycles were in the 70s at one bar.

 

hmm i guess put these back in and see if duty cycles are any better. Maybe they wrote in the wrong flowrates or something, but i doubt it.

 

yeah i ruled that one out for sake of my sanity lol. i guess well just see what happens.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">
wouldn't the pulse time not make a difference on flowrate? Sure there will be more fuel injected with a larger pulse width, but the flow rate isn't going to change. If the injectors are rated at 1000cc/min flowrate at 42psi then they should have flowed near 1000</TD></TR></TABLE>

because the flow rate means how much fuel the injector flows at 100% duty cycle

they only flowed these injectors at ~49% duty cycle so they flow about 1/2 what they should

 

when a wideband sensor goes out, it starts to read closer to lambda. does the sensor ever show it going to 11af's or is it always in the 12s? as sometimes having too much fuel will cause it to cutout too.

otherwise, sounds like what i'm getting into with my random misfire and I've replaced injectors and I'm now replacing all the fuel filters.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">

because the flow rate means how much fuel the injector flows at 100% duty cycle

they only flowed these injectors at ~49% duty cycle so they flow about 1/2 what they should</TD></TR></TABLE>
but duty cycle is a measure of how long the pulsewidth is in relation to the time to complete one engine cycle at whatever rpm the engine is at. Its just a time thing. If you turn on a hose with a particular water pressure the flowrate isn't going to change overtime except at the moment the valve is being switched open.

 

if you turn on a hose a leave it on that is 100% duty cycle. If you were to turn the hose on for 60 secs measure how much came out compared to turning the hoses on for 30 secs and measured how much came out it would be different right. the 30 secs is like 50% duty cycle.

 

i have a question, would those differences in the injector flow make a difference in tuing? one cylinder would receive more or slightly less fuel than the other becasue of the small differences? Or are they small enough where it doesnt matter?

 

well because i do have the injectors marked and i know how much they flow. im going to use the individual cyl trim in s300 to make them all the same. might as well right?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aj99si &raquo;</TD></TR><TR><TD CLASS="quote">if you turn on a hose a leave it on that is 100% duty cycle. If you were to turn the hose on for 60 secs measure how much came out compared to turning the hoses on for 30 secs and measured how much came out it would be different right. the 30 secs is like 50% duty cycle.</TD></TR></TABLE>
Amount of fuel injected is different from flowrate. Flowrate doesn't care how long something is left on. In this case it is a measure of how many cubic centimeters of fuel is injected per minute and not a measure of how much was injected total.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">
but duty cycle is a measure of how long the pulsewidth is in relation to the time to complete one engine cycle at whatever rpm the engine is at. Its just a time thing. If you turn on a hose with a particular water pressure the flowrate isn't going to change overtime except at the moment the valve is being switched open. </TD></TR></TABLE>

right... at 6000 rpms there is a total of about 20ms time avalible to inject fuel, they only used 10ms, therefore they flowed the injectors at about 50% duty.

so with the injector going 1/2 the avalible time its going to flow 1/2 its rated flow

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">

right... at 6000 rpms there is a total of about 20ms time avalible to inject fuel, they only used 10ms, therefore they flowed the injectors at about 50% duty.

so with the injector going 1/2 the avalible time its going to flow 1/2 its rated flow</TD></TR></TABLE>
So at a 10ms(.000167minutes) pulsewidth with a 1000cc/min injector you are flowing a total of 1000cc/min * .000167min = .166667cc volume of fuel injected. If they were at 100% duty cycle then you would have .33333cc volume of fuel injected. Volume is measured in cubic centimeters in this case. Flowrate is cubic centimeters per minute. The flowrate does not change. Thus if these injectors are rated at 1000cc/min and they were flowtested only producing around 485cc/min something isn't right. I'm guessing the injectors were just marked wrong.

 

can you enplane how your theory makes sense with this? i don't follow..

 

this lol

http://www.ecanfix.com/~mdhamilton/dutycycle1.html

 

jdogg is correct,

i don't know how many of you have seen an injector being flow tested but they pulse them, not leave them wide open.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SwappedTURBOegg &raquo;</TD></TR><TR><TD CLASS="quote">this lol

http://www.ecanfix.com/~mdhamilton/dutycycle1.html</TD></TR></TABLE>
That just shows you how many ms you can open the injectors per cycle. The higher the rpms the less time you have to open the injectors. Like Jdogg said 100% duty cycle at 6000rpms is 20ms. 6000revolutions/minute*(1minute/60sec) = 100revolutions per second. 1/100 = 10ms per revolution. Multiply this by two and you get 20ms per cycle. Duty cycle is simply how long the injector is open compared to the max allowable time at that rpm. If you change the duty cycle the flowrate does not change. You should still get 1000cc/min of fuel. However if you raise the duty cycle there will be a larger amount of time that the injector is open thus raising the volume of fuel injected on that cycle, but the flowrate(i.e cc/min) or mass flowrate (lb/hour) will stay the same. You can raise the flowrate by raising your base fuel pressure or by going with larger injectors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sewell94 &raquo;</TD></TR><TR><TD CLASS="quote">jdogg is correct,

i don't know how many of you have seen an injector being flow tested but they pulse them, not leave them wide open.</TD></TR></TABLE>
Why is pulsing the injector going to change the flowrate while the injector was open vs. if it was wide open? It sounds like people are confusing flowrate with volume flowed in a given amount of time. I may be wrong, but i dont see how. If i am then give me a technical explanation of why a different pulsewidth is going to change the flowrate which is what injectors are rated by.