Are the injectors in an OEM Honda systems driven directly by the ECU or does the ECU trigger a driver which powers the injectors?

The reason I ask is if the ECU itself does the driving why do people need to run resistor boxes if they are using the right ECU?

If I have an obd1 car with saturated injectors and I put in an obd1 motor with peak/hold inectors and the corresponding obd1 ECU for THAT motor, it doesn't make any sense to me why you would need to use a resistor box....unless there is another electronic device that drives the injectors.

 

it is because there is different resistance between saturated and peak&hold injectors. its more of a matter of electrical knowledge... say you have high impedance injectors on the high impedance system, and are changing to low impedance injectors on the high impedance system... you need higher resistance to even it out so the ecu can know what to expect without damaging internal components. if peak& hold injectors are around 2 ohms, and a typical resistor box resists about 7 ohms per injector, it would make the overal impedance higher (9 ohms) which the ecu would expect. does that help?

 

Not really.

I already understand the difference between satruated and peak and hold injectors very well.

My question is about the driver.

 

Most obd1 honda ecu's have a saturated injector driver, and most large (over 750cc) injectors are low impedance (peak and hold). The band aid is to use a resistor box, although it is not the right way to do it and does not drive the injector properly. You have a few options at this point, find larger saturated injectors, change ecu's, or get a true injector driver unit from a place like FJO. I find it easiest to use the injector driver. (not an injector resistor box).

Oh, and to answer your question, the drivers are built into the ecu.

 

Let see if I can make what I am saying more clear.

I have a 92 Civic. It uses an obd1 ECU with a saturated injector driver and saturated injectors in the engine.

If I were to swap in an obd1 h22 engine and p13 ecu, that engine comes with 345cc peak and hold injectors and the p13 is the OEM ecu for that engine.

But everywhere that I look says that I need to use a resistor box to swap this engine into my car because the h22a comes with Peak and Hold injectors.

My question is WHY do you need a resistor box if I am using the p13 ecu?

 

you shouldn't have to, unless the prelude your h22 came out of needed one.

 

Wrong answer.. All factory Honda cars that came with Peak and Hold injectors also came with an injector resistor box.

Yes, you need one.

 

Thanks. Thats what I needed to know.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aaronhume &raquo;</TD></TR><TR><TD CLASS="quote">it is because there is different resistance between saturated and peak&hold injectors. its more of a matter of electrical knowledge... say you have high impedance injectors on the high impedance system, and are changing to low impedance injectors on the high impedance system... you need higher resistance to even it out so the ecu can know what to expect without damaging internal components. if peak& hold injectors are around 2 ohms, and a typical resistor box resists about 7 ohms per injector, it would make the overal impedance higher (9 ohms) which the ecu would expect. does that help?</TD></TR></TABLE>

No, it does not help because the majority of it is wrong.