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

Which wire is the ground wire? Boost Pressure Sensor

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Old Jun 17, 2007 | 03:08 PM
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From: lancaster pennsylvania
Which wire is the ground wire? Boost Pressure Sensor

This is for an 88 TII. Click on the link below for the picture. Which one of these wires is the ground wire for the boost pressure sensor? I think the ground wire is the top right pin of the terminal, but there are two wires coming out of that pin. Are both of these wires ground wires? If I splice into them should they be kept separate? Thanks

http://img.photobucket.com/albums/v3...interminal.jpg
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Old Jun 18, 2007 | 03:35 AM
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Don't waste your time. Regrounding that wire applies to 86 models only.
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Old Jun 18, 2007 | 04:55 PM
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From: lancaster pennsylvania
"Don't waste your time. Regrounding that wire applies to 86 models only."

Ok, are there any additional grounds that you would suggest adding for an 88 TII. Since I grounded the ecu, the 3800 hesitation has gone away, except when I have my lights on. The only other ground I have dealt with so far is the battery ground, and I just cleaned that. Thanks for all the help
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Old Jun 18, 2007 | 05:10 PM
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http://www.aaroncake.net/RX-7/grounding.htm

Read.
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Old Jun 18, 2007 | 08:16 PM
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That article says to reground the boost sensor, his question was which wire is the ground. So which is it?
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Old Jun 18, 2007 | 08:46 PM
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Are you ******* serious?!

Locate the ground wire (this is the brown/black wire on '86-'88 cars, and the black wire on '89-'92 cars)
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Old Jun 18, 2007 | 09:21 PM
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Yes I am serious, I have an 88' and there are no "brown/black" wires. Thanks for your attitude though!
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Old Jun 18, 2007 | 09:31 PM
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Name:  PressureSensor4pinterminal.jpg
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I see brown wires....... EDIT: "I see brown wires" was sarcasm FYI....

Good call though... Might want to ask Aaron cake. The FSM shows what wires you have. Probably a typo in his write-up. So. my apologies

Last edited by micah; Jun 18, 2007 at 09:49 PM.
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Old Jun 18, 2007 | 10:17 PM
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im planning on regrounding my car this week and imma run an all new ground from my ecu to the block, ecu is located on the passenger side by your right foot right?
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Old Jun 18, 2007 | 10:26 PM
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86-87 had brown/black wires for sensor gnds. Later cars had pure black. Compare a 86-87 wiring diagram with a 88 and you'll see.

On a 86-87 there should be a brown/red output wire to the ECU, a black/white 12vdc pwr wire, a brown/black gnd wire and a brown/white ref voltage wire.

In some later cars you'll see two wires coming out for a gnd.

The gnd was put on that wire not because of a boost sensor problem, but a afm problem. That plug was just handy I suppose, since you all know that all the gnd wires for the sensors in the engine bay are spliced together inside the EM harness and terminate at pin 2A of the ECU. Yes.
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Old Jun 18, 2007 | 10:39 PM
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I just used the solid black wire.
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Old Jun 18, 2007 | 10:56 PM
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Originally Posted by HAILERS
86-87 had brown/black wires for sensor gnds. Later cars had pure black. Compare a 86-87 wiring diagram with a 88 and you'll see.
Ahh hah! Aaron Cake should update his document.
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Old Jun 19, 2007 | 06:20 AM
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Originally Posted by kevino
Ok, are there any additional grounds that you would suggest adding for an 88 TII.
Basically just do as Aaron describes in his grounding article, and bring the factory grounds up to as-new condition. If all the factory ground points are working as they should (i.e. completing electrical circuits with minimal resistance) then adding additional ground wires won't really achieve anything except cluttering up the engine bay.

Originally Posted by teezlr
That article says to reground the boost sensor...
Like I said, that only applies to 86 models, and was covered specifically in a Mazda TSB. It won't do anything for other years.
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Old Jun 19, 2007 | 07:34 AM
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Originally Posted by micaheli
I see brown wires....... EDIT: "I see brown wires" was sarcasm FYI....

Good call though... Might want to ask Aaron cake. The FSM shows what wires you have. Probably a typo in his write-up. So. my apologies
The '86 should have a brown/black wire. My '86 has a single black wire, but I think the harness has been changed.

I'd assume that Mazda fixed the issue by adding the 2nd black wire you see coming out of the connector. My '86 only has 1 wire coming from there.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/pressure-sensor-ground-3500-hesitation-fix-572799/
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Old Jun 19, 2007 | 09:43 AM
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The sensor ground is an '86 only thing. I'll update the article to be more clear.
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Old Jun 19, 2007 | 10:39 AM
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86-87
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