EFI Injector Tester

[ransil]

I built an injector tester this past week, I needed a way to test my injectors.
It will also test Fuel pumps and regulators.

Its computer controlled some features:
Adjustable injector on/off time from 1 msec to on all the time.
It primes the fuel rail upon start up and a bleeds off pressure on shut down.
Measures injector and fuel pump current.

I still need to program a fuel flow rate timer and volume calculator.
If anyone know how to to this let me now.

 

[wpaeb]

Nice test stand.
Are looking for a formula for injector flow in lbs or fuel pump in lph?
Like a formula to plug volume and time into and get an appropriate answer?
I like math! Or have I been working to long missing the point

 

[ransil]

Nice test stand.
Are looking for a formula for injector flow in lbs or fuel pump in lph?
Like a formula to plug volume and time into and get an appropriate answer?
I like math! Or have I been working to long missing the point

yea both of them.

Also how do I factor in flow rate to get the "hour"
on time will most likely be 20-50 Milli seconds to get a measurable volume I would need to run it for 5-10 minutes.

I will program it to do a timed run say 10 minutes at an injector on time of 20 msec off time of 1 second, then after the cylinder fills I will input the fluid measurement in Milli liters.

Fuel pump I will run with out firing the injectors and measure the volume from the return line.

 

[Dave]

Nice tool!

I think this is what you were asking: 3785 ml/gallon

The density of gasoline varies from about .7 to .8 Kg/Litter or about 6 lbs/gallon.

I would check the approximate flow rate and make sure it is close to the rated flow (i.e. 19 lbs/hour) for the injector but that will vary slightly with rail pressure, wear, etc. As long as they are close and have a good spray pattern, I would use volume to match a set of injectors.

The normal fuel injector duty cycle at idle (800 rpms) is about 400 5ms pulses per minute and put out about 200 ml per minute (total injector on time) of fuel. I'd do the mesurements near normal opperating parameters. That will also vary with your regulator pressure which is within specifications at 30 to 45 psi. When you test the regulators make sure they respond to vacuum on the pressure ballance line. Volume of the fuel pump is not as important as output pressure and smooth quiet opperation. I wouldn't worry too much about measuring the pump volume.




Here is a handy conversion calculator: http://www.psinvention.com/zoetic/convert.htm

 

[grant_71]

wow, i can't even program the clock on my VCR... (j/k)

nice, if you get a parts list written up how about a tech article??

 

[Recko555]

Equation to see what your injector is outputting (mass flow rate which is lb/hr).

min=minutes
gal=gallons
hr=hour
lbs=pounds
mL=milliliters

(mL/min)*(60min/1hr)*(1gal/3785.412mL)*(6.073lbs/gal)= lb/hr

All one has to do is measure the amount of fluid (milliliters)in a certain amount of time (minutes) and plug it into the equation above.

I have refined the equation even more for ease of use.
(mL/minutes)*.0963=lb/hr

example 1:
measure 200 mL in 1 minute

(200/1)*.0963=19.26 lb/hr


example 2:
measured 150 mL in 1 minute and 30 seconds

(150/1.5)*.0963=9.63 lb/hr


In example 2, something is definitely not right with your 19 lb/hr injectors.

Gabe

 

[cesco]

you guys are making my head hurt just reading the post

 

[cesco]

ransil, I take it that you did not get your motor running any better...

 

[ransil]

ransil, I take it that you did not get your motor running any better...

First step was to change the fuel rail to one that had a schrader valve to check the fuel pressure, I figured since I had it down that far I needed to check the regulator and fuel injectors and fuel pump.

And that is why I built this.

I hate trouble guessing.

 

[cesco]

i thought we did all the guessing at harlan;D ;D

 

[ransil]

i thought we did all the guessing at harlan;D ;D

And that is why is still runs like crap.