Another Can't rev over XXXX Rpms

[agrabau]

Here's what I've checked

Boost leak test
Gapped plugs to .028 then to .023 (no difference)
Using Walbro 255lph pump
TPS hasn't been touched although it could be a problem
Car idles fine/drives fine
Replaced caps on ECU
Car is a Manual with manual ECU
Plugs not fouled
Swapped map sensors/no difference
Unplugged TPS- same behavior

Revs limited to approximately 4000rpm.

Questions as I spend hours searching..

What is the pigtail 4 pin connector for that comes off the ECU (JZA70)

The TPS is getting 12v on the yellow and blue wire

The black and Blue wire is getting 5. Not sure if that's okay.

Thanks for any help.


Alex

 

[tlo86]

limit or does it feel like it cant really go past 4k (like if it were a timing issue?)

 

[Doward]

Why are you trying to spin XL rpm? Seems like you'd spin at least C rpm just cranking it up.

I'm confused by the title of this thread

 

[tlo86]

Why are you trying to spin XL rpm? Seems like you'd spin at least C rpm just cranking it up.

I'm confused by the title of this thread

:biglaugh::biglaugh::biglaugh:

 

[agrabau]

It's not a hard rev limit. Timing, as far as I can tell is fine. The car does a whub whub whub and sorta falls on it's face. I did the mechanical (belt) timing while the engine was out and the car runs great, good spool up good power without a hitch up to about 4000 rpm.

I was thinking maybe the car has a neutral or clutch switch that prohibits high rpm while not moving like an Evo 8?

I didn't get the joke. I'm sure it was outrageously funny.


Alex

 

[Gritz]

check your coil packs?

 

[agrabau]

No but I will if it's a potential issue. What's the procedure for checking them?

Thanks for the suggestion.

Alex

 

[tlo86]

It's not a hard rev limit. Timing, as far as I can tell is fine. The car does a whub whub whub and sorta falls on it's face. I did the mechanical (belt) timing while the engine was out and the car runs great, good spool up good power without a hitch up to about 4000 rpm.

I was thinking maybe the car has a neutral or clutch switch that prohibits high rpm while not moving like an Evo 8?

I didn't get the joke. I'm sure it was outrageously funny.


Alex

as far as i know only the automatic 2jz ECU's have a limit like that (you can bypass it easy enough though)

i doubt its the coil packs that are solely responsible but to check them pull them out and take off the blue boot and look for obvious signs of cracking and chipping. fix it with jbweld, epoxy, or heat shrink. cars seem to either have damage or not which i find interesting (out of the last 5 jz engines ive had only one of the 2jz's had cracked/chipped coils)

also i would follow the 2jz TSRM procedure for checking the sensor resistances

 

[sctwinturbo]

check your fuel pressure with the vac line off.
3 1jz's were fix by this mistake including my own
the difference is all the 1jz's were at 3000rpm break up

 

[Dr Tweak]

Did you uh, run the ECU trouble codes?

And I'm pretty sure that Doward was using Roman numerals... in which case, the title of your thread says "Another Can't rev over 40 Rpms", if my memory serves me correctly.

 

[foreverpsycotic]

as far as i know only the automatic 2jz ECU's have a limit like that (you can bypass it easy enough though)

Awesome, glad to hear that, I now have a factory launch control .

 

[tlo86]

Awesome, glad to hear that, I now have a factory launch control .

:biglaugh: i never thought about that. i dont remember the RPM limit though =/ 4500 maybe?

 

[agrabau]

It finally threw a code tonight. Four Blinks followed by a gap, then one. All blinks were the same short duration. Is that a 41?

41 is a TPS code. I tried to find the TPS pinout on the connector everywhere but couldn't find anything definitive.

Can someone reference me?


I installed a Sard FPR off my race car to play with the fuel pressure a few weeks back. I ran it down to 25 and then up to 43. It didn't seem to change the behavior. It's at 38 with the line off now.

Alex

 

[agrabau]

can someone tell me what happens when the TPS fails? looking for clues.

 

[jzxseven]

check to see if the brown wire on the tps is getting a 12v signal or is a ground with KEY ON. it should NOT get a 12v signal with key on of course. and as for your question about the pigtail that comes out of the jza70 ecu, thats for the MAP and TPS sensor.

so if your tps connector shows 12v on the brown wire with key on, cut it with reasonable length. now the wire you just cut, from the connector side ground that brown wire to the chassis and try your car again. also make sure you plugged your harness up to the pigtail of the jza70 ecu.

it can also be a faulty ecu, the jza70 ecu's are prone to failure.

 

[88supraTT]

look at a toyota service book, google it and you should be able to find one i will try to get a pic of mine tonight and post, i am also having issues with a 4K rpm limit i orderd a new tps for the car i hope that fixes my problem. i did diagnoise it but. the only problem that i saw was when i swept the sensor it would show OL in sertin spots so i hope it just a dead spot in the tps. the only codes i have is 02 sensor code and a knock sensor code(werent pluged in at the time) and some times i get the intermitin miss code.

 

[agrabau]

jzxseven, that's an interesting lead you just gave me with the brown wire. I do think it's getting 12v and I will check again tomorrow. What does grounding it do? I'm on my second ECU. The board is very clean and I did the caps already. Thanks for the help man!

Alex

 

[jzxseven]

well that wire is supposed to be grounded, so grounding will make sure the tps has a ground. if that works, problem solved!

 

[agrabau]

Unfortunately it is grounded. The only pin on the 4 wire tps that shows power is the blue black, key on, no throttle it shows 5v. Is that spec?


Alex

 

[agrabau]

I tried to run the car today with the pigtail plugged in, then unplugged. It makes no difference. The car displays the same issues running in both configurations. Does this suggest anything in particular?