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Thundewrmax O2 Sensor Problem

Started by bc1, May 19, 2019, 06:30:02 PM

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bc1

OK, time to ask, I don't have much more hair left to pull out.

I have an older ThunderMax Gen 2 (309-340 ECM and 309-350 AT module) on my 03 Ultra Classic. Basically stock everything, don't use additives,

The problem started last year when I got a check engine light with the message, fault front O2 sensor not found. Replaced it, everything was fine for a month or so. Then another check engine light, Tmax software reports rear O2 sensor not found. Replaced it.

All ok for a brief time, then started getting check engine light, diag. code now reports both front and rear O2 sensors bad.
Checked connectors, wiring, all ok.

Collected the data, it went to TMax, they reported nothing wrong. Couple months later, I sent the entire module in for a check up. Again, they reported all is fine.

The interesting thing is that when they returned my unit, I had to enter a different speedo cal code than I have been using for years to get my turn signals to cancel.

Now what happens is that I will be riding (length of time doesn't matter). At some point, my check engine light comes on, bike starts running ruff, cutting out, almost stalling for a bit. If I can keep it running, it settles down and the check engine light goes out. The idle is also rougher than normal with or without the check engine light on. Again the diag codes report front and rear O2 sensors not found, historic fault.

Should I just load a good known map in the module and run in open mode, forgetting the autotune?

Any ideas welcome.


Ajayrk

Are the spark plugs fouled?  An exhaust leak can cause an over rich condition.  Also make sure there is a good ground at the battery.  Be sure the head temp sensor is working properly.
AJ

doubletrouble

x 2 on the grounds , locate ALL the grounds on that bike and clean all the powdercoat out from under them and apply some dielectric grease , any connections that come apart during that process , clean them up and a light coat of d/grease on them as well , after that go into t/max while running and verify the codes , Are the 0-2 sns. working or are you dealing with an intermittant issue ? induse a rich and lean condition while monitoring the return voltage to see how the sensors respond , do they show rich with a lite mist of carb. cleaner in the t/body ? Snap the throttle and see if they respond while monitoring . Keep in mind that not all replacement 0-2 sns. are created equal , sometimes i will go thru 2-3 before i get one that works properly . Also ... while monitoring make sure you give them enough time to warm up , 0-2 that arent warmed up will act slow and lazy

q1svt

May 20, 2019, 09:14:16 AM #3 Last Edit: May 20, 2019, 11:29:24 AM by q1svt
What does this mean?  "Checked connectors, wiring, all ok."

You visually check? used an ohmmeter? ???

Had the same issue on a front o2, turned out it was a connector [wire to pin]

Not found message is a wiring issue


EDITED: Here is why I asked... if you sent the units [309-340 is for the TMax; PLUS 309-350 is the auto tune unit, separate back then on GEN I units] TMax checked the wiring.

BUT back then the install for auto tune 309-350 attaches to the 309-340, but to talk TM ECU unit the auto tune connects to the standard HD ECU data port.  That uses the HD wiring through the main ECU connector plugged into your TMax.   

I would review your original manual to understand what pins are what.
Greatest obstacle to discovery is not ignorance, it's the illusion of knowledge.

bc1

Ajayrk,  brand new plugs, I keep an eye on them, change them at least once a year needed or not.

q1svt, Checked wiring with a DVM, also checked for 12V on the data plug. My unit came as one assembled module, 340 aqnd 350 already joined, that was how I sent them back to Tmax.

doubletrouble, I have cleaned and used D-grease on grounds and plugs. I can monitor the afr's as the bike warms up. There was one time when I got the message O2 sensors not found then the error went away. Hope you're wrong on getting bad new O2 sensors, those sensors aren't cheap!

Now exhaust leaks have me thinking about the time line when this happened. I had to remove my exhaust to replace the oil pump last year, and I am fairly certain I have them installed properly. Hummm... I'll have to check that.

Thanks for the ideas.

q1svt

Quote from: bc1 on May 20, 2019, 03:09:31 PM

q1svt, Checked wiring with a DVM, also checked for 12V on the data plug. My unit came as one assembled module, 340 and 350 already joined, that was how I sent them back to Tmax.

Thanks for the ideas.

Joined yes but they are not wired together... the autotune talks via the HD data connector, to the 32-36 ECU pin connector, then into the TMax ECU...

It's a four wire connector positive, negative, front o2 data, rear o2 data.

ThunderMax checked the units result good
You have switched out the o2's result should be good

But you get an error messages:
If not found = bad positive or ground w/HD wiring [data connector to the 32-36 pin connector]
If you get the fault o2 code it's either/both the front/ rear HD wiring [data connector to the 32-36 pin connector]

You have indicated that the problem is intermittent ... so look for corrosion/fraying @ both connectors you'll need to open them and check wire to pin attachment
OR just purchase a new data pig tail and install it into the 32-36 ECU pin connector.
Greatest obstacle to discovery is not ignorance, it's the illusion of knowledge.

Hossamania

The timeline and exhaust removal leads me to a damaged wire.
If the government gives you everything you want,
it can take away everything you have.