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87.5+ harness in a pre 87.5 car(injector resistor box question)

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87.5+ harness in a pre 87.5 car(injector resistor box question)

Old 04-20-11, 04:56 PM
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87.5+ harness in a pre 87.5 car(injector resistor box question)

I am using a 87.5 and up engine harness in a Turbo II that was built 7/86. The original harness in the car was tore up. The car obviously uses the injector resistor box and the original harness has a plug for it. I will be using a N332 ecu.

But the new harness I bought(s4 TII harness) does not have that plug for the injector resistor box. My questions are:

-Is there a difference between the two harnesses besides for the lack of that plug for the resistor box?
-Can I simply splice in resistors on the HOT side of the injector wires? If so, what size resistors(I've heard either 6 or 10 ohms)
-Is there a simple way to just wire this harness through the stock resistor box?



I have the series 4 service manual printed out, and I cannot find in the wire diagram where it mentions that resistor box. It just shows the power for the injectors going from the main relay, to the injectors, then to the ecu.

Thanks in advance!

Heres a pic of the injector resistor box for good reference:
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Old 04-20-11, 05:03 PM
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10ohm/10watt resistors from radioshack. http://www.radioshack.com/product/in...ductId=2062290

I actually just added these to the harness I picked up from you.
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Old 04-20-11, 05:28 PM
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Two options:

1) Use high impedance injectors

2) Splice resistors into the LG, LG/W, LG/B, LG/R injector wires at the ECU. Confirm with the FSM before chopping things up. OEM resistors are only 6 ohm, so there's no need to use 10 ohm. I use four 6 ohm, 10 watt resistors, which came from Mouser Electronics.
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Old 04-20-11, 06:38 PM
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Cool. Thanks a lot guys
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Old 04-20-11, 07:19 PM
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Take the cover off the resistor package and you'll see ..........stamped on the side of the resistors................6 ohms written there. See for yourself.
Attached Thumbnails 87.5+ harness in a pre 87.5 car(injector resistor box question)-sixohms.jpg  
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Old 04-21-11, 08:51 AM
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just use high impedance injectors from an 88 model. The less you cut up an OEM harness, the better.
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Old 04-21-11, 09:05 AM
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Thanks.

I already have 720cc low impedance injectors for it. Hate to hack up the harness, but I don't want to buy another set of injectors.
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Old 04-21-11, 09:16 AM
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You can wire in the OEM resistor pack. Guys do that on Hondas all the time because Hondas had a similar transition from low to high impedence injectors as the model years went on. I don't think the diagrams for the pre 87.5 harness are widely available, so you'd have to get in there with a multimeter and figure out which wires do which.

Here is a thread on wiring up a resistor box into a Honda. http://www.honda-tech.com/showthread.php?t=517274

and another article from Hondata http://www.hondata.com/techinjectorwiring.html
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Old 04-21-11, 09:25 AM
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Old 04-21-11, 01:46 PM
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as satch posted...



"solenoid resistor" on the left.
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Old 03-20-15, 12:19 PM
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Bringing this thread back from the dead (that's why the zombie meme).

I have an 88 S4 TII that I'm putting in my first gen. It has the high impedance injectors and the right side wiring harness didn't have the plug for the Solenoid Resistor since it's on high impedance injectors.

I hacked up an 87.5, or prior, S4 TII dash harness and it has the injector solenoid plug in the harness for the solenoid resistor. So the wires come from the ECU to the injectors, and the brown wires go to the plug for the solenoid resistor.

So my question is, this: Since I'm running high impedance injectors, what do I do with the wiring for the solenoid resistor? You guys hint at being able to delete it but I'm not entirely sure I want to hack up the harness to find out I needed it in the first place.

I believe that I don't need the solenoid resistor it since I'm running these injectors: 88 13b T high square offset 550cc purple 195500-1370.

Any help would be appreciated!
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Old 03-20-15, 02:20 PM
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You don't use the solenoid resistor. You bypass it by fusing the Black/Yellow wire to all of the Brown wires.
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Old 03-20-15, 03:26 PM
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Originally Posted by satch View Post
You don't use the solenoid resistor. You bypass it by fusing the Black/Yellow wire to all of the Brown wires.
Thanks man! I also found it in this post here after some more thorough searching:
https://www.rx7club.com/2nd-generati...6/#post6731084
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