MTX-L erratic readings

track_addict · Postby **track_addict** » Sat Oct 08, 2016 11:16 pm

Hi guys,

I've run into some issues with my MTX-L. I'm getting almost the same symptoms as in this thread viewtopic.php?f=55&t=66396

There's a few differences. First one being that I don't get any error codes show up. Secondly, once the gauge starts doing stupid things, it will generally come back and act normal. Thirdly, this happened to me this evening and wouldn't "reset" itself. So I pulled into a side street and turned the car off for a few minutes before restarting it. The gauge just read "HTR," for the heating of the probe, but would not disappear. Turned the car off and on 3 or 4 times and it wouldn't fix it. Ended up continuing on my way home and about 5 mins later it started working as per usual. Then it went all haywire again. The car drives normally when this happens. Not one hesitation or splutter or anything.

With some googling, some people have mentioned something in the heater control goes and the sensor cools down, gives bad readings then throws the error message. Some have mentioned to re-calibrate it but I'm not sure if that will help my situation. Others have tried new sensors to no avail. Am I up for a whole new wide band?

The gauge is powered from the cigarette lighter and is grounded at the throttle body. I'll have an eyeball of the wiring tomorrow.

Thanks,

Ash.

Dweezle · Postby **Dweezle** » Sat Oct 08, 2016 11:44 pm

Ive had it happen twice.

Both times it turned out to be the Heater Controller inside the Gauge.

track_addict · Postby **track_addict** » Sun Oct 09, 2016 12:24 pm

So its a case of suck eggs and replace the whole unit? What causes the heater controller to go? Is it from short trips or starting the car to move it around the yard etc? Going to be pretty annoying if a $350 item becomes a consumable.

manga_blue · Postby **manga_blue** » Sun Oct 09, 2016 1:25 pm

Fixed link. http://mx5cartalk.com/forum/viewtopic.php?f=55&t=66396

Mine is going mad too. Reads mostly OK up to about 4000rpm then jumps straight to AFR22 and sticks there.

Postby **NitroDann** » Sun Oct 09, 2016 1:29 pm

Might be an exhaust leak

manga_blue · Postby **manga_blue** » Sun Oct 09, 2016 2:57 pm

That was my first thought too, Dann. Smoke test on the hoist found nothing.

Postby **NitroDann** » Sun Oct 09, 2016 3:00 pm

Hmmm...

Sensor I guess.

manga_blue · Postby **manga_blue** » Sun Oct 09, 2016 3:05 pm

Hope so, if you hunt around you can find Bosch ones for under $60 these days.

In case anyone is wondering: https://www.amazon.com/gp/product/B000BZI4ZW/ref=od_aui_detailpages00?ie=UTF8&psc=1

sailaholic · Postby **sailaholic** » Mon Oct 10, 2016 7:12 am

You can now use the newer Bosch sensors with the mxtl but you need a new cable between the gauge and the sensor as the plugs are different.

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track_addict · Postby **track_addict** » Mon Oct 24, 2016 8:17 pm

Just as an update, I decided to replace the whole unit. Have done so and have the new sensor as well. So far so good. Seems to be abit more accurate and responsive but not by a massive margin.

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