2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Weird Red chip connected with ecu*(PIC)*

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Old Nov 25, 2004 | 03:02 PM
  #1  
AsianFlip06's Avatar
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Weird Red chip connected with ecu*(PIC)*

Whats up everyone i bought a rx7 and need some help with it.

This red chip is one that got me stumped anyone know wtf is it?
http://home.comcast.net/~asianflip06/Picture.jpg
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Old Nov 25, 2004 | 03:09 PM
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From: Ames, IA
That might be the "resistor mod" - I can't tell what pins it's connected to, but you can increase fuel delivery (and supposedly power) by fooling the ECU into thinking it's colder than it is (and therefore the air is more dense). Makes no sense to me, because NA rotaries run rich anyway...

That's all I can come up with.

-=Russ=-
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Old Nov 25, 2004 | 04:04 PM
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From: Washington
another pic

Ohh btw its an 87 t2...here i took a better pic of the actual splice.

http://home.comcast.net/~asianflip06/Picture_001.jpg
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Old Nov 25, 2004 | 04:12 PM
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So which pins is it connected to? I still can't make sense of it... looks like it's connected to the starter switch, but that doesn't make sense. The water temperature connections aren't on that plug.

-=Russ=-
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Old Nov 25, 2004 | 04:39 PM
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Is that thing Turbo?
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hmm i'm not familiar with the turbo ecu pins but i thought that the resistor went on the air temp sensor not the water temp, usually that mod is done at the airflow sensor tho. maybe syonyk is talking about a different but similar mod tho, also the air flow meter mod i think changes ignition timing slightly could be wrong tho, personally i'd remove it considering it isn't stock, but hopefully someone will actually know what it is or what ity does. Try looking at the wiring diagram (FAQ for FC has a link to an online one if you don't have it) and see what wire it is connected to
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Old Nov 25, 2004 | 04:49 PM
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If its going to the small plug.......far right.......bottom hole, that is connectred to the starter switch. It reads less than 1.5vdc with the ignition switch on and approx 10vdc when cranking. Free FSM's are online.

That pin 3B gets approx 10vdc whenever you are starting the car. It comes from the ignition switch via the clutch interlock switch and the starter cut relay IF you have theft protection. If you have no theft protection it bypasses the starter cut relay and goes directly from the interlock switch to pin 3B. I've not a clue why those wires are spliced to 3B except maybe to a relay that turns some radio equipment off during starting. Or a aftermarket theft protection device.

Last edited by HAILERS; Nov 25, 2004 at 05:00 PM.
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Old Nov 25, 2004 | 05:13 PM
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Like the two jpgs below. Follow the trail from 3B. The ECU needs to know when the engine is being started so it can make adjustments.....such as making the bac go to a full duty cycle to let more air in at startup. Nothing to do with your spliced in wires though. They probably go to a theft unit or stereo etc.
Attached Thumbnails Weird Red chip connected with ecu*(PIC)*-3b1.jpg   Weird Red chip connected with ecu*(PIC)*-3b2.jpg  
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Old Feb 14, 2006 | 08:28 PM
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I was taking my ecu from my 88T2 today and I noticed the same mod made on my harness.

The black/blue wire from pin 3B was cut and has a chip spliced in. The chip has three wires: gray, white and black. The black is a ground wire. The gray and white interupt the factory black/blue wire. The chip itself is covered with a black material like heat shrink wrapping.

Any ideas as to what this is?
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Old Feb 14, 2006 | 10:05 PM
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From: Kansas City/Springfield, MO
its one of the 20HP for $10 ebay *****!
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