The UNICHIP Experience

[Lakhum]

Interested in the long term update. Is the vehicle running fine, any problems?

[rustam54]

Interested in the long term update. Is the vehicle running fine, any problems?

My apologies for replying late to your query.

As the purpose of the thread was to describe experience, (not promote), i think this demands honesty.

First off, the vehicle is running fine Alhamdulillah. No problems due to the installation of piggy back.

However, the plugs were cleaned recently and I could see the plug condition explaining a slightly rich burn (not usual for a controlled emissions vehicle)

Regarding experience, Over time, I have realized that the vehicle re-learns that there is a tweaking and it learns through the secondory O2 sensor.

Although there were slight improvements (so slight that only a daily driver can experience), but it vanishes over time as the vehicle learns to lean out itself.

But I would also say here that I never got the chance to hook up another meet with the tuner. May be, in another session, he might be able to bring forth some more prominent gains. I have heard its going good with Toyota diesels mostly. Honda's are a bit intelligent.

[MAXTORQUE]

Thanks for your feed back, we always look forward to customer feed back. I been waiting for you to come for the next tuning but I came to know you are away from country from a while. When ever you feel free do come over and we will have next tune up.

Regards

[MAXTORQUE]

As far as if you believe that ecu has learned the changes, to test that we have a 5 mins test. You can put the unichip bridge plug and then test the vehicle. If the performance of the vehicle goes down then it means everything we put in the unichip was working and no changes then in that case you are right and the ecu has learned.
What happens in most cases a human being get used to the performance gain by the time and it started to feel that no gain in performance is present now. In this case we perform the above mentioned test and till date we have not found a single case in which vehicle has learned back.

[SER_GTR]

AFR's Also Tell Exact Story....If You Change TheM And They Return To OEM....!!

The Reverting Thing Is Quiet Common Issue Known...!!

[atta1111]

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[Xulfiqar]

The fuel trims tell the exact scenario - in a given condition as the engine runs and wears out - (including sensors like MAF and O2) - the ECU manages to keep the fuel trim in spec to keep emmissions happy.

Remember that the ECU programming does not care about your driving pleasure, its first motto is to keep emmissions happy (car build specs have to follow it)

that is why you see fuel trims changing as MAF and o2 sensor wears out. It will give a rich or lean error when the threshold parameter gets out of hand - (usually set to 20%).

[SER_GTR]

The fuel trims tell the exact scenario - in a given condition as the engine runs and wears out - (including sensors like MAF and O2) - the ECU manages to keep the fuel trim in spec to keep emmissions happy.

Remember that the ECU programming does not care about your driving pleasure, its first motto is to keep emmissions happy (car build specs have to follow it)

that is why you see fuel trims changing as MAF and o2 sensor wears out. It will give a rich or lean error when the threshold parameter gets out of hand - (usually set to 20%).

Yes Exactly...That's Where You Also See AFR's (Wideband) Working out NOT As You Planned....So You Will Know The Changes Made Remains Or Reverts........!!

If You Set 13's For Particular Revv Range And It Never Remain 13's And Go Close To 14.7...Means Its Worked Out By ECU..That's My Point

[rustam54]

The fuel trims tell the exact scenario - in a given condition as the engine runs and wears out - (including sensors like MAF and O2) - the ECU manages to keep the fuel trim in spec to keep emmissions happy.

Remember that the ECU programming does not care about your driving pleasure, its first motto is to keep emmissions happy (car build specs have to follow it)

that is why you see fuel trims changing as MAF and o2 sensor wears out. It will give a rich or lean error when the threshold parameter gets out of hand - (usually set to 20%).

True.

However, the Primary O2 (wideband) and MAF are both fed to piggybag and manipulated. How can the ECU learn out??

My guess, through the secondary O2 (which in this case is a narrowband) after the CAT. If the external wideband can pick change in AFR after CAT, its likely the Secondry O2 tipped the ECU off.

Anyways, I am trying to find time to plot Trims over a course of journey. InshaAllah will share the details as I have them

[rustam54]

Yes Exactly...That's Where You Also See AFR's (Wideband) Working out NOT As You Planned....So You Will Know The Changes Made Remains Or Reverts........!!

If You Set 13's For Particular Revv Range And It Never Remain 13's And Go Close To 14.7...Means Its Worked Out By ECU..That's My Point

Sir, you are correct as well.

However, if someone doesnt have a dyno and a wideband, looking at the Trims on (Before, After) changes would be easy with a cheap ELM.

[SER_GTR]

Yes.....That Tells You The Deeper Story....!!

[Xulfiqar]

The post cat o2 is there just to monitor cat converter performance, as soon as the voltage swing goes high (large pulse) an error of cat ineffieciency is recorded.

Your precat is not wideband, its either an AFR sensor that gives a fixed voltage to the ECU - the ECU itself has commanded, achieved and actual AFR reading. If the achieved AFR is not in sync with the ECU logic drive, it will record an error (silent one) and proceed to correct the faulty area.

Its a bit of a loop back error check type of scenario going on.

[wasay_ahmed]

the precat one is AFR sensor n reading is fixed. once Hocked up an afr gauge n no movements.also same on parts manual.What abt Greddy Emanage Ultimate in these motors?1nz 2nz 2zr etc..

[rustam54]

The post cat o2 is there just to monitor cat converter performance, as soon as the voltage swing goes high (large pulse) an error of cat ineffieciency is recorded.

Your precat is not wideband, its either an AFR sensor that gives a fixed voltage to the ECU - the ECU itself has commanded, achieved and actual AFR reading. If the achieved AFR is not in sync with the ECU logic drive, it will record an error (silent one) and proceed to correct the faulty area.

Its a bit of a loop back error check type of scenario going on.

SIr,

If i understand what difference you mean by using terms "AFR" and "Wideband", I can say with confidence that the primary sesnor is a wideband. It measures lambda and not just Rich/Lean indication with fixed voltage.

One wire is set by ECU at 2.2V fixed. The other wire voltage is varied by sensor so that the current in the loop is either positive or negative. The ECU learns the actual lambda by current value and direction. Much like the BOSCH sensor shown below

Wideband Oxygen Sensors

Infact the installed one is reported to be BOSCH sensor. Not sure which part number.

To hook it up with unichip is not a break loop and inject voltage situation. You actually tap into the fixed 2.2V line and allow the reference voltage to drain (controlled) outside the ECU to ground. Since the reference is changed, the current flowing into the ECU can be varied without actually breaking the loop.

[rustam54]

To those who cannot understand how a 2 wire device can actually measure and generate output on the same 2 wires it is getting power from, take example of either a 2 wire temperature or pressure transmitter used in industry.

The device is fed with 24VDC power and a return line which is fed to measuring module . The transmitter powers itself up from the same line and yet controls the current in loop based on the pressure or temperature it senses.

The measuring module (in this case ECU), drains the current to 0VDC and in the process measures the current.

This configuration also helps to check when the loop is open.

This is different from 3 wire devices like TPS or APP sensor. Having one 5V, one 0V, and one signal output wire.

Hope it helps

[Xulfiqar]

Thats the same principle on how the modern hot wire MAFs work too - the amp draw is measured across the pins - the differential of amp draw is then taken into calculation.

btw - whats the part no. for the wideband sensor you have? Wideband O2 sensor are a pretty piece of engineering.

[rustam54]

Thats the same principle on how the modern hot wire MAFs work too - the amp draw is measured across the pins - the differential of amp draw is then taken into calculation.

btw - whats the part no. for the wideband sensor you have? Wideband O2 sensor are a pretty piece of engineering.

I think the part number is 36531-RB0-003 (or similar). Cannot Identify the Make. Shown as OEM

The description as per manuals for Primary and secondary are as follows.

[Xulfiqar]

yep as I thought, its an AFR sensor - Toyota started using it in the late 90s.

[rustam54]

yep as I thought, its an AFR sensor - Toyota started using it in the late 90s.

Pardon my ignorance,

Whats the difference then??

Its working on the same principle as the one in example by Bosch. One can see the same current direction and lambda value in OBD??

[Xulfiqar]

Pardon my ignorance,

Whats the difference then??

Its working on the same principle as the one in example by Bosch. One can see the same current direction and lambda value in OBD??

toyotas mostly maintain the threshold at the .3 or .45V level - the commanded and seen AFRs go through the explanation you gave above, the Bosch one varies a lot.