93FoxGT

Im new to this honda stuff so bear with me... i have a 91' hatch with the jdm ZC non-vtec engine, im in the process of installing a Y8 vtec head and mani. Im just getting to the part where im starting to hook everything back up, well my OBD0 fuel injector clips from the harness wont go onto the Y8 injectors.. thats the problem im dealing with now, ive been doing my research and just making sure what you guys would tell me on here. it is already converted to MPFI and i have the OBD0 to OBD1 jumper harness etc... What could i do to get the injectors working properly?

Thanks

b20teggy

take the y8 injectors out and put the ones that came off with the zc head on and it should work

93FoxGT

so if i use the old injectors, will i still need to run the resistor box then? and is there any real diffrence between the ZC injectors and the Y8's ? will my obd1 ecu accept the obd0 injectors? Thanks!

hatchblack

you need obd1 injectors and no you wont need a resistor box unless you use the y8s.

but you will end up needing to change out a bunch if you try to match everything just for the injectors

but i think you have to match the dizzy to the ecu too... i may be wrong but im pretty sure

Fabrik8

You have two options for injectors: Either use the OBD0 injectors and the resistor box, or use the Y8 injectors. The OBD0 injectors are a low impedance type, which is why you need the resistor box (the resistor box makes up the extra impedance). The Y8 injectors are already high impedance so nothing else is needed. It's the same with all Honda ECUs.

Do not use low impedance injectors without a resistor box, and do not use high impedance injectors with a resistor box.

You can use the Y8 injectors if you change the harness connectors or you can get harness adapters from someplace like RyWire. Honestly though, if the injectors are the same flow rate (I can't remember if they are, that's for you to verify) there isn't any reason to not use the OBD0 injectors.

93FoxGT

i dont think theres a huge diffrence, but i'll do some research on them.

240sxkid

theres a hughh different between the injectors

0bd0 injectors& res. box is 5.5volts obd1 and obd2 and 12 volts

Fabrik8

No, no they're not.

They're both 12V injectors. The resistor box limits the injector current because the injector coil is a low impedance (low resistance) type. The OBD1 injector coils are high impedance and effectively current limit themselves (because the coil impedance is high enough).

I could see how you'd get confused and think they were 5.5V or whatever if you measured voltage between the injector and resistor box while the injectors were firing. There would be a voltage drop across the resistor box when the injectors are firing, and the almost-squarewave signal might average out to be 5.5V at a certain RPM if you're using a multimeter. But no, they're not 5.5 V injectors. When the injectors aren't firing, you'd measure 12V at the same spot (no current means no voltage drop across the resistor box), and if the RPM changed you'd see some other value than 5.5V. Your multimeter is playing tricks on you because you can't actually see what that signal looks like with a multimeter.

Just to repeat what I already said, you can either use the low impedance injectors and a resistor box, or the high impedance injectors without a resistor box.

240sxkid

sorry fab,
he is correct, i wasn't thinking when i was writing, i just did the swap on my ef, and i went obd1

93FoxGT

yeah i got obd2 head on a ZC obd0 bottom, i'll just throw in my obd0 injectors.