Zeitronix ZT-3 possible problems

[BlueBlur]

Have said wideband controller and think it went tits up. AFR,s go up and down constantly, needle moves like a windshield wiper. Only have EGO command at 10% so it has a surge when driving. It does it at idle, cruise and at any steady condition. Swapped sensors and no change. Desperate, Zeitronix doesn't answer phone or return calls. It just all of a sudden started doing it today, I even loaded an older tune just see if something changed and no difference. MAP,TPS, IGN load, Fuel load etc. are all steady while its doing this. HELP, im not smart enough to just diagnose this type of issue. Has been working good for 2000 miles and a year.

[BlueBlur]

Zeitronix is being helpful but still not to the bottom of it. Tested both sensors and they're good. Something may be tripping the internal 4a auto-resetting fuse inside I think. This is some weird stuff. Wish they would just send me a new controller to at least try.

[BlueBlur]

Seems the Analog signal from the ZT3 is having sporadic values for some reason. Zeitronix says they have NEVER had a ZT3 fail. Is there any way the MS3 could be having issues with this signal all of a sudden? Im at a loss.

[Roofy]

Shot in the dark.... but how far from the exhaust outlet is your wideband? And is it a turbocharged vehicle? I have seen some issues with my AEM UEGO wideband if the distance from the exhaust outlet to the wideband is too close or too far. I would see a relatively consistent reading and then all of a sudden it would shoot full lean at times, and I believe it's because of the position of my sensor, that an occasional "dead spot" where the exhaust wouldn't be able to be accurately read due to swirling from the gasses from my turbo. At least that's my theory, since I moved the sensor and the issues seemed to have gone away. I would suggest moving the wideband to a different spot if possible and see if that affects the readings at all.

[NigeT]

I'm still trying to get to the bottom of a similar issue but with a PLX SM-AFR 3. Mine only starts agent I've been running for some time, maybe 20+ minutes and usually starts at cruise on the motorway (say 70mph).
I see similar behaviour on the PLX DM-6 gauge as in TunerStudio or ShadowDash and the logs, so I'm sure it's not the connection to the MS3 (there is a tiny fixed offset in that, but not really a concern).

From what I have read a sensor failure normally manifests as a fixed rich or lean output, not an insanely cycling one. I have some concerns about the PLX sensor/controller so I am replacing it with an AEM digital unit with CAN connecting to my MS3, but I'm not convinced it is the cause of this problem so I am checking for both ignition and fuelling issues too.

I have removed the Fab9tuning COPs kit, the "igniter" (?) module of which having been replaced by them at the beginning of the year after failing catastrophically on a track day last October destroying my catalytic converter and putting the car off the road for months. I've been waiting nearly a month for connector parts to be delivered (thank you USPS, UK Customs and Royal Mail) to allow me to wire up some Honda COPs instead.

However I can't be sure this is a problem, so I think I need to check fuel flow, pressure and injectors too.

I'd be interested to hear any suggestions. I should say that this problem came on suddenly after months of use (I don't use it much for commuting so I only did maybe 2000 miles). It was also tuned on a rolling road without tnhe problem exhibiting. The only change reasonably close prior to the problem starting was the catalytic converter finally being replaced (the contents of the old one rattling around before that).


Nigel

[BlueBlur]

What you guys describe is what I'm getting. The sensor readings during warm up are semi steady but progressively get more erratic as the car gets fully to operating temperature. One day it was fine then the next it is whacked. Zeitronix says they have never had a failure of their zt3 controller but it is getting HOT. They say that's normal,but if it's getting real hot there is a short somewhere. Duh! Since they didn't even offer to send a new controller I called Alan at 14point7 and he is sending me a Spartan 2 with Guage to install. My sensor is mounted in the header collector. If the new wideband does the same thing I will change header gaskets, which show no signs of leakage whatsoever. I'll report back.

[NigeT]

How close is the sensor to the exhaust manifold? I don't think the standard Bosch sensors like getting so hot and need to be a good way down the down pipe. Mine is at the catalytic converter end of a Flying Miata 2.5" down pipe, long after the manifold, turbo and elbow. I think you might need a controller that uses NTK sensors if it is closer.


Nigel

[BlueBlur]

Well I changed collector gaskets hoping for a difference and no bueno. New wideband will be here tomorrow but I wont get it in until maybe sunday or monday. My sensor is in the header collector right next to the flange and then I have probably 6 ft. of exhaust behind that. This thing has been trouble free for 2000 miles and then something went bad.

[NigeT]

I think that is way too close for a Bosch sensor to be reliable. The PLX manual says:
Mount the wideband oxygen sensor before the catalytic converter and at least 24 inches downstream from your engine block or turbo. Tip: Mount the O2 Sensor before the catalytic converter or at least 24” downstream from your engine block for naturally aspired and 36” for turbo engines for optimal performance.

[BlueBlur]

It is about 30" from engine block. It's not a sensor problem, I have verified they both work fine. I'm about 99% sure it's the controller putting out a bad analog signal at this point.

[NigeT]

Sorry, my misunderstanding. Do you have a gauge connected to the ZT-3 (sorry if you already said)? Does it show the same behavior as TunerStudio / ShadowDash / logs?

[BlueBlur]

Well replaced Zeitronix with a 14point7 and it is doing the same d*** thing. Here is a video.
https://www.youtube.com/watch?v=zMf2yxjat1Y

[NigeT]

The 14point7 controller has a display doesn't it? Does it show the same fluctuations?

[BlueBlur]

Yep. I wonder if my IAC is causing it. Going to try and monitor it.

[BlueBlur]

SD card command error, can't get a data log. But IAC seems to function fine.

[hiltonlo05]

Not that exact problem your having... but I was fighting similar issues and it turned out to be the 40 pin connection in the ECM at the ms3 card. I think I've got it fixed now but it was causing some funny behavior from my Spartan 2s... During power up, are you getting the AFR 13.3/16.7 calibration readings in tunerstudio?

By the way, Alan is great for tech support and warranty. He's replacing one of my controllers and sensors now in an effort to diagnose a problem there.

[BlueBlur]

Yeah Alan is great and knowledgeable. Im pretty convinced it is not Wideband related at this point and am searching for the cause of these AFR's readings. Could be a vacuum or exhaust leak but the way it pulses so slowly at 2500 rpm is confusing my logic. It acts like vacuum is pulling the the IAC valve open then it goes lean and RPM drops, valve shuts then starts sequence over again repeatedly.

[BlueBlur]

Well when this originally started acting up I thought I reloaded an older tune. Well I did a compare tune and noticed 2 glaring differences, one was the old tune had "do not include afr target" in ego settings. The other was at light load cruise timing had more advanced. I loaded the entire old tune back in and it's all good. Need to do more investigation to see what else I changed. Yeah I'm kicking myself since I swore I loaded the old tune when it first started acting stupid but I guess it didn't load.