1jz r154 gear box problem and tuning questions

[drdre]

gearbox

can anyone help me in giving a probable diagnose before i dismantle the gear box for repair?

1. it gives out a sound like grinding metal after i've driven it hard and will stop when i press the clutch pedal, let it go, it'll sound again. when driving normally for whole day, there wouldn't be any sound.
2. when shifting, from 1st to 2nd, 2nd to 3rd, sometimes it feels like it'll push back or difficult to shift. down shifting when driving fast for 1st, 2nd & 3rd, it's hard to shift in. i have to force it in. what is the recommended type of gear box oil? range?

timing

1. it's running too rich now, have sooty deposits in exhaust tip & black smoke. exhaust temp meter shows between 200(idle) - 700c(speeding). how do i tune this engine? what gadgets do i need to access the comp box? it's already chipped when i bought the clip from japan
2. with air-cond on. idling around 900-1000, if i adjust the tps, it'll drop to 500 but engine will vibrate. how to get it idle at 650?

if i install a safc (the one with 5 buttons), will it help for the two problems above. it's drinking fuel like mad, pls help.

really a newbie with 1jz, any comments are really appreciated

 

[Zazzn]

sounds like you could have a bad throw out bearing .... Maybe you need to adjust the clutch for the hard shifts. could not be fully disengaging.
you can't just tune a car with out a wb well you can try and guess but thats all you are doing guessing...

I'd pull out some fuel form idle 500-1000 -15-25 % then see how it idles.

I wouldn't touch anything underboost unless you have a WB or a dyno around.

 

[drdre]

doesn't sound serious for my gear box problem, i am just afraid that it's not the clutch but the gear itself. it's very difficult to find a replacement manual trans for 1jz in my country.

what's a "wb?"

"I'd pull out some fuel form idle 500-1000 -15-25 % then see how it idles" - do you mean i need to get the safc to control this? i am trying to try find the closest possible diagnose on the problem as my budget is tight, i will get it on a dyno but need to sort out which should come first. thanks for replying, happy 2007

 

[Zazzn]

yeah s-afc will work..... Also you may want to look for a 02 sensor.. if yours is bad it won't know how ot control it.

 

[p5150]

drdre -

I think I can help you with a couple of your problems....

- A WB is a wide-band oxygen sensor. The stock sensor is a "narrow band" sensor. All the WB sensor does is allows you to see EXACTLY what your air/fuel ratio is. However, in most cases it is only good for a gauge in your car. Sometimes, a stock computer cannot understand the output of a WB oxygen sensor, even though the sensor is designed to emit a signal on the feeder wire that "mimics" the stock O2 sensor.
As a short term fix, you should get a new oxygen sensor, re-adjust your TPS and give your car a basic tuneup. Your problem might be something really simple.

- To fix the grinding or hard shifting in your transmission you should try changing the oil in your transmission to a good synthetic brand. That helped the synchros in my transmission. We use Red Line MTL here in the states but im not sure if you have any there.....

- Do you have an official Toyota repair manual for your 1JZ? Toyota has certain procedures for adjusting the TPS. It is supposed to be in a very specific position relative to the throttle body butterfly - you cant just adjust it like you would an idle screw and change the idle....

www.cygnusx1.net has the entire repair manual for the MKIII supra on it. I know it doesnt apply to your 1jz but the transmission is the same.

 

[annoyingrob]

I would check the shifter bushing, that can cause hard shifts if it's damaged. As for the grinding, when it's grinding, try pushing in the clutch while coasting to see if it goes away. If it does, I bet that there's an issue with the clutch assembly, an not the transmission.

Your motor is supposed to idle higher with the AC on. It puts extra load on the engine, so to compensate, the ECU raises the idle. Don't change it.

 

[drdre]

woah! super, thanks for your detailed explanation. i'm not sure if i will be able to find the replacement 02 sensor, other thread in this forum said they modified the 7m sensor and it worked fine. i'm also not sure if i can find this sensor either but i'll give it a try. wide band 02 cost a bomb here, that will have to wait.

the other day i think when i jumped the codes when it wasted 42litres in 2days of town driving, it came out 21 but when i reseted the ecu by disconnecting the battery terminal. it didn't show again, it's the 02 sensor fault code right? never seen anyone dealing red line products here, maybe i'll get some compatible with grade SAE75W-90. hope it'll help eliminate the difficulty in shifting the gears.

about the tps, how do i adjust it back to the optimum setting?

thanks again for the feedbacks guys

 

[p5150]

On the 7MGTE its easier to adjust with it off of the car. There is a long detailed procedure for it. As for the 1jz, I dont know for sure but it cant be too different from the 2jz which is illustrated on the attached pic

You can download the 2jz manual online - perhaps somebody can tell you where to get the 1j because I dont know. The motors are very similar though.

 

[annoyingrob]

There is no english 1JZ manual. There's a link around here somewhere to a download of a Japanese one though. I think JohnnyRedline posted it.

the 7M adjustment of teh TPS works, just use a shim of 0.6mm

 

[Russian70]

1. it gives out a sound like grinding metal after i've driven it hard and will stop when i press the clutch pedal, let it go, it'll sound again. when driving normally for whole day, there wouldn't be any sound.
2. when shifting, from 1st to 2nd, 2nd to 3rd, sometimes it feels like it'll push back or difficult to shift. down shifting when driving fast for 1st, 2nd & 3rd, it's hard to shift in. i have to force it in. what is the recommended type of gear box oil?

I have the same problems with my r154. I use Castrol TAF-X 75W90 GL-4+ trans oil. Severals days ago I installed new clutch (master cylinder, release cylinder, flywheel and ect) that is why I exclude incomplete clutch inclusion (everything were done by TSRM)

Previous owner didn't install bearing primary shaft (little) in fact primary shaft has backlash) now I install this bearing but it's still hard to shift 1-st gear when the car stand and 5-th when run. I want to change primary shaft bearing (in gearbox, big one) but I'm afraid that it doesn't improve the situation