Pressure Sensor ?'s
 

So the car I just received is running pretty rough and Im trying to track down some of the causes.
I noticed the "pressure sensor" on the passenger firewall is not connected (vacuum line) and one of the wires is grounded out to the body (someone did this by stripping the wire and soldering it).

Can anyone tell me where the vacuum should be connected, exactly what it is used for, and why one wire would be grounded out to the body?

Thanks

The additional ground wire is a quick fix to improve a possible faulty grounding system present in many cars.


<a target='_blank' href='http://img291.imageshack.us/i/pic049.jpg/'><img src='http://img291.imageshack.us/img291/1702/pic049.th.jpg' border='0'/></a>

Uploaded with <a target='_blank' href='http://imageshack.us'>ImageShack.us</a>

cant miss that nipple. it reeally sticks out ther

Is the MAP necesary? I ask because it has a MAF also and its disconnected. It runs but it runs like crap.

Both sensors should be connected and functioning properly if you have a factory or chipped computer.

Off to get some vacuum hose today then....

The boost sensor hose is supposed to have a "restrictor pill" located inside it to adjust for the necessary proper vacuum.

BULLSHIT!

You ground the engine block, not the Pressure sensor.
The pressure sensor sends out specific ground signals to the ECU. If you groudn it, the ECU does not get the signals and your car runs like shit.


This is the "Orifice" you need to push into that Vacuum hose going to the presuure sensor. You can order one and push in, or just order the complete hose for a buck or two more.
http://www.mazdatrix.com/getprice.as...m=13-9860-8931

I recccomend calling Ray Crowe at Malloy Mazda. He'll be happy to help you and KNOWS his RX-7's. 703-490-8263


Cut that ground, and get the proper Vacuum line. For more info on the Orifice, search.

Did a board member originally come up with the idea of the additional ground or was it Mazda?

[QUOTE=Molotovman;10014757]BULLSHIT!

You ground the engine block, not the Pressure sensor.
The pressure sensor sends out specific ground signals to the ECU. If you groudn it, the ECU does not get the signals and your car runs like shit.


This is the "Orifice" you need to push into that Vacuum hose going to the presuure sensor. You can order one and push in, or just order the complete hose for a buck or two more.
http://www.mazdatrix.com/getprice.as...m=13-9860-8931

I recccomend calling Ray Crowe at Malloy Mazda. He'll be happy to help you and KNOWS his RX-7's. 703-490-8263


Cut that ground, and get the proper Vacuum line. For more info on the Orifice, search.[/QUOT********************************************** ************************************************** ************************************************** ************************************************** **************************

I'm please to be here to help you and the Crow at Mallowry know how the cow chews the cabbage. On series four cars there is a FACTORY SERVICE BULLETIN that indeed added a *extra* ground wire to the existing ground wire on the series four pressure sensor.

Sorry to say, but this added gnd was not related to problems with the pressure sensor. It was added to help the AFM grounding signal. If one ever looks at the wiring diagrams he will see that all the sensor gnds in the engine bay are spliced together into a common brown/black wire (early series four car, pure black on later series four cars).

As you can see looking at the wiring diagrams, those wires are also spliced to the ECU gnd on top of the rear ROTOR housing, gnd 24 or 25..I forget. Plus they all are spliced to pin 2C of the ECU.

Go buy a subscription to ALL DATA.COM and down load all the service bulletins for early RX-7 to see what I mean.

Oh, and they terminated that new gnd wire on the water thermostat housing (from memory).

[quote=HAILERS;10015173]I'll stand corrected HAILERS. I'm thinking of threads a few years sgo where people must have been grounding the wrong wire.
As far as Ray Crowe goes, I'm just talking about him as a parts dealer. I'vew never had a discussion with him about that ground.