1jz issues

[jon3171]

Hi there,

I have some questions regarding my 1jz engine and just wondered if any experts out there can help.

I have the hks turbo timer installed and it has various other functions including showing digital rpm reading. I checked the peak rpm earlier after revving the engine and found the peak to be 9120rpm. I'm not sure if this could be right or not as my 1jz is stock and i thought the rpm limit is somewhere around 7000-8000rpm.

The other thing is i feel the car is underpowered. To me it seems like the boost doesn't go up as fast as it should. I have to really push the car hard on high revs just to get it to hit around 0.6 bar. So i was wondering if i could have a vacuum/boost leak of some sort. the boost at idle is -0.7. My hoses are all silicone and i have checked them and found no leaks. In any case, would it show on the boost gauge if there is a leak?

Yet another thing, is when i drive fast on the highway, high revs...the car seems to hit a dead spot like there is a very obvious dip in power. My fuel pump is brand new(Bosch external standard
pump for BMW 528i). and im using an adjustable fuel regulator. The reason i mention this is a mechanic told me that my fuel pump was not enough to support 1jz power. Having said this, i have previously not encountered this problem even while running 0.9 bar boost.

These are the symptoms i can think of, i realize its kinda vague but the car just does not feel right lately. Any feedback is appreciated.

Thank you.

 

[al.montere.7]

i had a similar problem that you have...

About the revving:
my situation is while drag racing my 1jz losses power at 6800rpm... i resolved this problem by getting a 2nd hand factory ecu... and bought a Dastek Q piggyback... and brought it for tuning...

About the underpower during boost...
my problem was... although i was pushing my car.. ""Pedal to the floor"" it didnt react instead it started jerking.. (like there was no fuel being burnt) so i opened up top cover above the spark plugs (dunno wats it called ><) and i realised there was water in the chamber... it came in from the fins/grill on the cover... so i custom made another cover... and it worked really well...

I hope this helps...

 

[jon3171]

Thanks alot for your reply. I hope it helps too. I was also considering whether it could be ECU related...but i want to rule out other small things first before buying another ECU. In any case i will open up the cover and check the plugs and stuff to see if they're nice and dry.


How was the performance after your tuning?(what exactly did u tune? just afr or more than that?)
and how much did it cost for the piggyback and tuning/installation?

 

[al.montere.7]

Thanks alot for your reply. I hope it helps too. I was also considering whether it could be ECU related...but i want to rule out other small things first before buying another ECU. In any case i will open up the cover and check the plugs and stuff to see if they're nice and dry.


How was the performance after your tuning?(what exactly did u tune? just afr or more than that?)
and how much did it cost for the piggyback and tuning/installation?

from bone stock 220whp.. after installing the piggyback and slight boost... to 280whp...
Dastek Q incl. installation + tuning + dyno... rm1800

just yesterday... i had a problem with the sparkplugs again... remember to check the rubber seals/housing covring the ignition coil...

 

[cheeft]

standard turbine don't really produce power at high rpm... in fact the the power tapers off at high rpm... so in my opinion really no point pulling it all the way up to the rev limit... and stock standard ecu is way too rich and can't produce much power unless you lean it out...

---------- Post added at 01:19 PM ---------- 6 hour anti-bump limit - Previous post was at 01:16 PM ----------

from bone stock 220whp.. after installing the piggyback and slight boost... to 280whp...
Dastek Q incl. installation + tuning + dyno... rm1800

just yesterday... i had a problem with the sparkplugs again... remember to check the rubber seals/housing covring the ignition coil...

wow you got a really healthy engine... mine stock standard only around 190++whp... after tuning with unichip Q with 1bar only around 250whp...

do you encounter any problem with unichip??? i took it off just after two days because the engine kept dying off after driving for a while and left me stranded quite a lot of times!!! so now back to standard but the power difference is huge with only a piggyback install!!!

 

[jon3171]

does it automatically lean out if you increase boost?

 

[al.montere.7]

standard turbine don't really produce power at high rpm... in fact the the power tapers off at high rpm... so in my opinion really no point pulling it all the way up to the rev limit... and stock standard ecu is way too rich and can't produce much power unless you lean it out...

---------- Post added at 01:19 PM ---------- 6 hour anti-bump limit - Previous post was at 01:16 PM ----------



wow you got a really healthy engine... mine stock standard only around 190++whp... after tuning with unichip Q with 1bar only around 250whp...

do you encounter any problem with unichip??? i took it off just after two days because the engine kept dying off after driving for a while and left me stranded quite a lot of times!!! so now back to standard but the power difference is huge with only a piggyback install!!!

haha you have no idea how much i spent restoring my old 1jzgte... the halfcut was given free to me.. but in no condition to start... had to change almost everything... from ignition coils to factory pistons...

honestly, yeah... i just installed unichip last week... now i cant rev above 2.5k rpm... has anyone encounter this problem? im thinking my ecu is the culprit..

and i agree with u abt the ecu releasing too much fuel.. when my 1jz was really bone stock... everytime i revv to 7k rpm... and release the throttle... i keep hearing explosion from my exhaust... (btw my muffler is right under the drivers seat) :p

 

[jon3171]

so you completely overhauled your 1j? how much did that cost you? could get all the new parts here?

 

[al.montere.7]

so you completely overhauled your 1j? how much did that cost you? could get all the new parts here?

yeah...
not sure but estimating cost till now with mods... 4k..
toyota parts not cheap... but what to do i love 1j and 2j...

abt the parts... not all new... i got 2nd hand water pump and hydraulic pumps... took too long for a new one to arrive...
i mostly bought them online (in a kit)... but honestly, dont do what i did... i bought everything and asked someone else and overhaul my 1jz...

rite now... i cant rev the car... ive trouble shoot every possibility.. ive changed my fuel pump and all six ignition coils and spark plugs... nearly close to 1k... now ive got to fix my ecu...

 

[jon3171]

yea i'm lucky in that sense that my engine has no big issues....i went thru 2 ecus previously...the 2nd one i just replaced the capacitors and it seems fine....even consumption is ok...but just some weird problems here and there like i mentioned above...but still unsure which is the exact cause....but in your case...you'll probably have a nice engine once your ecu is working properly!

 

[cheeft]

does it automatically lean out if you increase boost?

unfortunately no... the fuel is so rich that it is off the chart!!! they can't really measure it!!! but in my opinion, a simple piggyback will do wonders to our 1JZ engine... still thinking of what piggyback to put in my car now...

---------- Post added at 04:04 PM ---------- 6 hour anti-bump limit - Previous post was at 04:03 PM ----------

haha you have no idea how much i spent restoring my old 1jzgte... the halfcut was given free to me.. but in no condition to start... had to change almost everything... from ignition coils to factory pistons...

honestly, yeah... i just installed unichip last week... now i cant rev above 2.5k rpm... has anyone encounter this problem? im thinking my ecu is the culprit..

and i agree with u abt the ecu releasing too much fuel.. when my 1jz was really bone stock... everytime i revv to 7k rpm... and release the throttle... i keep hearing explosion from my exhaust... (btw my muffler is right under the drivers seat) :p

no wonder your power figure is nice!!! hmm i don't know whether is unichip or the toyota ecu... but mine is definitely unichip... after taking it out, i don't encounter engine stalling and can't start problem...

 

[al.montere.7]

unfortunately no... the fuel is so rich that it is off the chart!!! they can't really measure it!!! but in my opinion, a simple piggyback will do wonders to our 1JZ engine... still thinking of what piggyback to put in my car now...

Try using Greddy ultimate or switch to standalone(don't really know how it works)

 

[cheeft]

standalone is too expensive for me... all my friend is using emanage blue and it seems ok... no problem at all unlike unichip... but i'm not saying unichip is not good maybe mine is a odd case...