JSpec TPS adjustment , From Japan

sametime as i was helping a friend to get the info for TPS adjustment on a NA from the genuine Japan manual i got this and found it is different from other manuals, like uk and euro spec.

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please have a look

Jspec 2JZGTE TPS adjustment.pdf

This may look 'gobbledegook', but this information will be useful to many.

Setting the Throttle Position Sensor on a J spec TT, at UK (export) TT spec settings, confuses the engine ECU.

If it is an auto, then it confuses the transmission ECU too.

With an N/A, the differences are even more poignant, because the UK (export) spec engine functions using MAF, and the J spec engine functions using MAP.

Exagerated if it is an auto, because it confuses the transmission ECU too.

J spec TPS setings have only ever been published in Japanese.

Untill now

This little snippet of information could be the cure for many 'misbehaviours' of J spec engine, and auto transmissions.

I am surprised that no-one has questioned this before.

Stefan, could you please post the N/A settings also.

Thank you

David

This may look 'gobbledegook', but this information will be useful to many.

 

Setting the Throttle Position Sensor on a J spec TT, at UK (export) TT spec settings, confuses the engine ECU.

 

If it is an auto, then it confuses the transmission ECU too.

 

With an N/A, the differences are even more poignant, because the J spec engine functions using MAP, and the UK (export) spec engine functions using MAF.

 

Exagerated if it is an auto, because it confuses the transmission ECU too.

 

J spec TPS setings have only ever been published in Japanese.

 

Untill now

 

This little snippet of information could be the cure for many 'misbehaviours' of J spec engine, and auto transmissions.

 

I am surprised that no-one has questioned this before.

 

Stefan, could you please post the N/A settings also.

 

Thank you

 

David

Hello, me again

Is that a translation or all your own surmising? Because I don't think any of that is really correct. For a start, the TPS can be set almost anywhere as long as you're on the "throttle closed" switch when it's actually closed, and the ECU merrily learns what's what. Also I'd like to hear more of the "many 'misbehaviours' of J spec engine"

All the TPS does is give a 0-5v reading depending on how far open it is. The range of adjustment on the slots is a small percentage of this. I've personally removed and replaced mine a fair few times and I just put it back roughly in the middle (apart from once, which is how I know about the throttle closed switch issue).

With an N/A, the differences are even more poignant, because the J spec engine functions using MAP, and the UK (export) spec engine functions using MAF.

You may be surprised to hear that the TT versions have this setup as well. So the differences aren't more pertinent ( ) between NA and TT. Which is all irrelevant to the TPS position anyway really...

If this sensor is not set in the correct position, the auto transmission ECU cannot function correctly because it does not receive the correct information.

The engine ECU will compensate, but would function better if set correctly.

That's why Mr T. seals it in the correct position with a blob of paint.

If this sensor is not set in the correct position, the auto transmission ECU cannot function correctly because it does not receive the correct information.

 

The engine ECU will compensate, but would function better if set correctly.

 

That's why Mr T. seals it in the correct position with a blob of paint.

It does indeed take info from the TPS, along with a scary amount of other inputs, but what's the exact issue with the auto ECU? Just thinking this through, I can understand it using the input as a guide to when the driver has lifted off (change up), rapidly accelerated (change down), slowly accelerated (don't change down, don't change up) or hasn't changed the pedal position for a while (change up if possible). All of those are just delta's though, they don't require any exact voltage, and that's probably a good job because the TPS can be adjusted The only thing the autobox needs to know exactly is WOT, and that's dealt with by a switch - probably for this exact reason.

So what issues do you know of that arise from a +/-0.1v max discrepancy in the TPS signal? From an autobox and "many 'misbehaviours' of J spec engine" perspective? The only one I know of from experience is the IDL1 switch issue, where you lose injector cut and the idle gets very ropey as the ECU never thinks it's idling. Otherwise, anywhere around the middle does the trick to no noticeable detriment.

The paint seals are there as a guide to put it back, but if it had to go in one set position, there wouldn't be the adjuster slots (although why you can adjust it to the point the IDL1 switch never engages I do not know!). Come to think of it, you see the same paint splats on the throttle stop screw so maybe they are more there to see if anything has drifted from what it used to be?

-Ian

With an MT5/MT6, tick over is definitely influenced, and light throttle position information to the engine ECU is altered.

Additionally, with AT4's the overdrive function can become 'dithery', and I suspect torque converter lock is influenced too.

N/A UK (export) spec engines operate using MAF, and J spec operates using MAP.

Because of this, I expected to find that the settings would be different, but have also learned that the TT settings are different too.

Until now, we have only had workshop manuals with the export spec settings, and this information has been hiding in, never before translated J spec workshop manuals.

With the amount of J spec Supra's now over here, this 'snippet' must be useful to some, I am just one of them.

Setting the sensor to the correct position is a 1-minute job; so surely, it would be foolish not too.

Stefan and his pals at Mr T HQ have researched and translated this technical detail especially at my request, and we have shared this information with others who may be interested on here.

Personally, I am very grateful for this, 'beyond the call of duty' service from Stefan and Willem in Belgium and A N Others in Japan.

Thank you very much.

Um, ok, well that didn't really answer any of my questions so I'll draw my own conclusions there.

You know there never was a UK spec NA? Not sure what you meant by "N/A UK (export) spec engines"?

I've had another look at the PDF, I find it a bit hard to read the handwriting, but from what I can glean it gives you the resistance specs to test, to ensure the TPS isn't broken (sections 1, 2, and 3), and section 4 just covers positioning the TPS so the IDL switch is engaged at the right time (which, if it isn't, will certainly cock up the idling as mentioned before, but it's a binary thing, it's either cocked up or it isn't)

Anyway - I'm all for people contributing hard information, but you could have just asked on here my dear chap, see attached pic. It's got the specs for an NA as well

As for calibrating it beyond the IDL switch, well, I wouldn't worry too much, as you can see on the attached table, Toyota's acceptable ranges are fairly huge - 3100 to 7200, 2400 to 11200, that sorta thing. So one less thing to worry about, hurrah!

-Ian

Um, ok, well that didn't really answer any of my questions so I'll draw my own conclusions there.

 

You know there never was a UK spec NA? Not sure what you meant by "N/A UK (export) spec engines"?

 

I've had another look at the PDF, I find it a bit hard to read the handwriting, but from what I can glean it gives you the resistance specs to test, to ensure the TPS isn't broken (sections 1, 2, and 3), and section 4 just covers positioning the TPS so the IDL switch is engaged at the right time (which, if it isn't, will certainly cock up the idling as mentioned before, but it's a binary thing, it's either cocked up or it isn't)

 

Anyway - I'm all for people contributing hard information, but you could have just asked on here my dear chap, see attached pic. It's got the specs for an NA as well

 

As for calibrating it beyond the IDL switch, well, I wouldn't worry too much, as you can see on the attached table, Toyota's acceptable ranges are fairly huge - 3100 to 7200, 2400 to 11200, that sorta thing. So one less thing to worry about, hurrah!

 

-Ian

Does this apply for the VVTI 2jzgte engine from an Aristo?