Hello there,

First Post here.

I have a Japanese import '03 RX8 (High power model). It has recently developed steering problems
with the Electric Power Steering (EPS) namely light 'juddering' at low speed when turning the wheel left and right.

My local garage man hooked it up to his diagnostic computer which revealed that the Torque Sensor is faulty.

I have learned that this can sometimes be caused by water from the coolant overflow pipe damaging the 'intermediate'
connectors which run from the torque sensor itself back up to the EPS unit- I have performed a continuity test between these
two devices as advised and it revealed no break in current flow.

So I am quite confident that the Torque Sensor itself is indeed the culprit.

The problem is that I can't find anyone who will sell me the sensor separately. Everyone wants to sell me the entire steering rack and the cheapest of those I can find costs €250 for a second hand one. So naturally I am keen, if possible, to buy just the sensor.

Would anyone be able to help me to obtain one of these? I have attached a link, below, to a photo which I took of the sensor in question.

It's for a right hand drive car (Ireland). I'm not sure if the sensors are different or not between the left/right hand drive versions.

http://www.wix.com/johnrx8/rx-8-torque-sensor

Thanks in advance,

John.

 

Hmm, I'd say you are right, most (if not all) places are going to want to sell you the entire rack. The issue is going to be "how removable is it?" In theory, if you can find a wrecked 8 and pull it off the existing rack, you should be fine. I don't know how many wrecked 8s are in Ireland, and if RHD vs LHD are different to potentially have someone grab you one from elsewhere.

Checking with Mazmart (US vendor, can get anything OEM) might yield some results as well.



Before you go through that hassle though, I'd suggest you make sure that those connectors are completely clean. Or, if you are comfortable with proper wiring, cut the data connector out completely and wire it straight. Just a continuity test may not be properly verifying that it is a completely clean signal. It's a much more likely culprit than the sensor itself.

 

Hi RIWWP,

Many thanks for your reply. You make a very good point there.

I'm wary of spending a great deal of time and money replacing the entire rack and sensor only to finish up with the same problem due to an improper contact on those connectors being to blame.

It looks like a quite a task to take out the air filter in order to reach down to those connectors but if it needs doing I'll get it done, thanks.

I also did a Torque Sensor inspection as per the service Manual I downloaded from rxblog. com -


TORQUE SENSOR INSPECTION

1. Measure the resistance between torque sensor connector terminals A and B, and B and C.

*

If there is any malfunction, replace the steering gear and linkage.

* Standard

A—B: 12—15 ohms
*

B—C: 12—15 ohms


The measured resistance I got was almost double that value.

However the test is performed on the terminals at the EPS end so the current runs through those intermediate connectors first.

In which case might they be the cause of the incorrect resistance value and NOT necessarily be indicative of a faulty Torque Senor?

Anything you could add would be much appreciated.

Thanks again,

John.

 

The thing to keep in mind with Mazda inspection procedures is that they are only directionally accurate (in general). There are plenty when are exactly accurate, but over time we find more and more situations where they "pass inspection" per Mazda's guidelines, but are clearly still failing to perform as they are intended. So take them with a grain of salt and not a hard-line definitive answer, especially if there is any potential scaling associated.

With double the resistance, I'd say that the connector is likely your problem. So far, the general feel of your posts suggest that you know what you are doing with electrical work? If that is an accurate statement, I would HIGHLY recommend cutting out the connector and properly wiring it solid (solder, proper heat shrink, proper shielding, etc... that is exposed to the elements and radiator heat down there). It simply and completely removes that connector from being a possible source of difficulty. It doesn't permanently cause any problems, as the connector is just a mid-harness connector, from the wiring harness down to the rack itself. Removing the rack or wiring harness is still accomplished by simply disconnecting the rack side connector.

If you aren't comfortable doing this, then thoroughly cleaning the connector and/or replacing that short length of harness between the wiring harness and the rack (it's less than $50 USD if I remember correctly, quite a bit less I believe) is your best bet.

Reaching the connector is actually not difficult at all, and less than 5 minutes of work. Just loosen the intake accordion ring clamps, lift the front of the air box up to clear the frame, pull it forward to disconnect from the accordion, fold it out of the way (or disconnect all the wiring and vacuum lines to set it aside completely, but it isn't needed), free up the one vacuum hard line that snaps into the bottom of the air box tray, 2 air box tray bolts on the bottom and 2 nuts on the top against the frame and the connector is right below that against the fan motor.

 

Hi RIWWP,

Thanks again. Gaining access to those connectors doesn't sound like as much of an ordeal as I had feared.

I'm overseas in Asia with work until next month so I won't get to it until then. When I do though I'll put a post up here to let you know how it went.

Regards,

John.

 

Hi again RIWWP.

I accessed the connectors and they appear pristine, not a speck of contamination on them anywhere so I doubt they are to blame really.

So It looks like I'm reduced to buying a steering rack complete with torque sensor and just replacing the sensor.

Cheers,

John.