jm93rx7

iTrader: (7)

How can you tell if injectors are high or low imp if they are not in the car. I came across a set of 720cc injectors from a friend and i dont know if they are high or low imp. They are for an rx7 but he doesnt remember what year rx7 they came from. Can i test them some how ? Or is there anything that says high or low imp? any info will be greatly appreciated.

iceblue

Im sure this is in the archive. Use a multi meter to test the OHM resistance of them.

jm93rx7

iTrader: (7)

i can test them with a multi meter with out them bieng on the car?

WAYNE88N/A

On the car, you can, but you have to know what you're doing. You'll have to totally isolate each injector in the circuit by disconnecting the ECU plug and either the main relay or the fuse (if you jumper the main relay).

Probably be easiest to read from the ECU plug, and jumper to ground the other end of the circuit that you opened. All power off. You'll read about 12 feet of wiring too, so the resistance will be slightly higher than if you were reading just the injector...

Off the car, simple- just read the two terminals on the injector with the meter...

jm93rx7

iTrader: (7)

thank you very much

stacher

For most part 720cc and bigger will be low imp

iceblue

How did you ever come up with this conclushion?

ilike2eatricers

Because they are almost always low impedence. Try to find 720s and up in high impedence you'll have a hard time. Also search for differences in how high and low impedence injectors react and perform and youll see why most big injectors are low impedence.

stacher

Thank you "ilike2eatricers"!

As injectors get larger, their impedance drops and the power increases.

Whizbang

okay....

take multimeter

measure ohms across injector

high impedance will read 12 -13 ohms
low impedance will read 2 -3 ohms.

WAYNE88N/A

Ehhhh...

The larger injectors probably have the lower impedance coils so that they can react faster electrically. A larger injector bore will have to have a larger coil surrounding it. The higher the coil impedance, the slower the field charges and collapses, which sets limits as to how fast they can cycle. My conjecture, anyway

Gotta remember, the low imp setups have the resisters in series with the circuit, so the ECU will see the same load on either the hi or low setups. Therefore the power used will be the same between the two...