injector resistance question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Javi802 · 01-25-2015, 04:46 PM

I only have the s15 sr20 service manual and it states that the resistance of the injectors should be "approximately 11 ohms"

It doesn't give an out of spec number though.

Ive read that the s13 resistance should be 11.5 ohms. Is this correct? How far off would call for me to need to replace them?

I tested mine today and here is what i have (starting from injector closest to firewall)

24----17.9----17.8----17.9

All them are obviously out of spec, especially the last injector. How would one expect an engine (sr20det) to run with the injectors reading higher than the supposed 11.5 ohms?

Matt300ZXT · 01-25-2015, 05:34 PM

Holy shit that's some crazy resistance. I know for my 300ZX with high impedance injectors, the ohm ratings should be anywhere from 11-14 to be within spec. I just tested all mine the other day (1 had died so I replaced them) and all read about 11.7-12.2 except the dead one.

Are you testing them through the EFI harness, or at the injectors themselves?

Javi802 · 01-25-2015, 05:44 PM

The injectors themselves.

Unplugged all of them and one by one connected the two leads from the multimeter to the pins on the injectors.

Matt300ZXT · 01-25-2015, 05:46 PM

Are they stock injectors or aftermarket?

***S14DB*** · 01-25-2015, 05:57 PM

Anything over 16 is out of spec. Do you have a multimeter you can trust and the contacts where clean?

Javi802 · 01-25-2015, 06:02 PM

Just stock purple top 370's

Trust? lol . Its a cen-tech cheap multimeter. So no, not really haha.

But then again, according to nissan data scan, my battery voltage is about 14.2

Same reading i get on the multimeter.
Not sure if that guarantees accuracy...?

Matt300ZXT · 01-25-2015, 06:39 PM

Shoulda posted this a week ago, I sold some perfectly functioning 550s for cheap

I'd say get new injectors.

01-25-2015, 04:46 PM	#1
Javi802 Zilvia Junkie Join Date: Jul 2012 Location: Oklahoma Age: 32 Posts: 472 Trader Rating: (10) Feedback Score: 10 reviews	injector resistance question I only have the s15 sr20 service manual and it states that the resistance of the injectors should be "approximately 11 ohms" It doesn't give an out of spec number though. Ive read that the s13 resistance should be 11.5 ohms. Is this correct? How far off would call for me to need to replace them? I tested mine today and here is what i have (starting from injector closest to firewall) 24----17.9----17.8----17.9 All them are obviously out of spec, especially the last injector. How would one expect an engine (sr20det) to run with the injectors reading higher than the supposed 11.5 ohms?

01-25-2015, 05:57 PM	#5
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	Anything over 16 is out of spec. Do you have a multimeter you can trust and the contacts where clean? __________________ Comments should be taken as Opinions not as Statements of Fact

01-25-2015, 05:34 PM	#2
Matt300ZXT Leaky Injector Join Date: Apr 2007 Location: Chattanooga, TN Age: 43 Posts: 122 Trader Rating: (0) Feedback Score: 0 reviews	Holy shit that's some crazy resistance. I know for my 300ZX with high impedance injectors, the ohm ratings should be anywhere from 11-14 to be within spec. I just tested all mine the other day (1 had died so I replaced them) and all read about 11.7-12.2 except the dead one. Are you testing them through the EFI harness, or at the injectors themselves?

01-25-2015, 05:44 PM	#3
Javi802 Zilvia Junkie Join Date: Jul 2012 Location: Oklahoma Age: 32 Posts: 472 Trader Rating: (10) Feedback Score: 10 reviews	The injectors themselves. Unplugged all of them and one by one connected the two leads from the multimeter to the pins on the injectors.

01-25-2015, 05:46 PM	#4
Matt300ZXT Leaky Injector Join Date: Apr 2007 Location: Chattanooga, TN Age: 43 Posts: 122 Trader Rating: (0) Feedback Score: 0 reviews	Are they stock injectors or aftermarket?

01-25-2015, 06:02 PM	#6
Javi802 Zilvia Junkie Join Date: Jul 2012 Location: Oklahoma Age: 32 Posts: 472 Trader Rating: (10) Feedback Score: 10 reviews	Just stock purple top 370's Trust? lol . Its a cen-tech cheap multimeter. So no, not really haha. But then again, according to nissan data scan, my battery voltage is about 14.2 Same reading i get on the multimeter. Not sure if that guarantees accuracy...?

01-25-2015, 06:39 PM	#7
Matt300ZXT Leaky Injector Join Date: Apr 2007 Location: Chattanooga, TN Age: 43 Posts: 122 Trader Rating: (0) Feedback Score: 0 reviews	Shoulda posted this a week ago, I sold some perfectly functioning 550s for cheap I'd say get new injectors.