Am I running to lean on the 1jz?
10-09-11, 08:19 AM
#1
Am I running to lean on the 1jz?
I have a digital air fuel ratio on my 1jz and it read like average 14s most of the time, When I hit boost it goes to high 13s and comes back to 14s. I was talking to a supra guy and hes surprised my engine hasn't blown up. The car has been driving like this for a year now.
Heres whats done to the car so far
*FMIC
*manual boost controller
*Single t3t04 ebay turbo conversion
*Stock ECU
*Stock Injectors
*Stock Pump
*Everything else stock in the motor
more info on the car
*Car is auto
*Turbo doesn't even start really spooling till after 3k rpms, so about 90% of the time I stay out of full boost
*The car is daily driven more than 400 miles a week
*I am the third owner of the car since the swap and I beleive the car has always been running like this
*I feel no signs of engine failure even in full boost
*Car does smoke ALOT blue and white smoke, which I think and hopping its coming from the ebay turbo which has lots of shaft play
I've searched and heres what i've found, which ade me feel alot better
Should I be worried about detonation with the bigger single setup?
14/13 too lean?
I have a billet 6262 t4 that i'm going to put in after my t3 to t4 adaptor comes in. hopedully that fixes the smoke
Heres whats done to the car so far
*FMIC
*manual boost controller
*Single t3t04 ebay turbo conversion
*Stock ECU
*Stock Injectors
*Stock Pump
*Everything else stock in the motor
more info on the car
*Car is auto
*Turbo doesn't even start really spooling till after 3k rpms, so about 90% of the time I stay out of full boost
*The car is daily driven more than 400 miles a week
*I am the third owner of the car since the swap and I beleive the car has always been running like this
*I feel no signs of engine failure even in full boost
*Car does smoke ALOT blue and white smoke, which I think and hopping its coming from the ebay turbo which has lots of shaft play
I've searched and heres what i've found, which ade me feel alot better
The AEM wideband needs to be on everyones swap list. It's an EXCELLENT diagnostic tool.
Part throttle cruising, idling or light acceleration, the 1JZ Ecu keeps the Air/Fuel ratio between 14.2-15.8m, which is perfectly stoich, not rich or lean...(I've verified this with 3 different Ecus on the same car- The auto trans Ecus lean out after everyshift and the manual trans Ecu is full rich after each shift.)
So, anytime my wideband reads any differently then 14.2-15.8, off boost I get curious.
I wouldn't change the fuel pump or fuel filter to fix this problem. I would replace the cheap Ecu coolant temp sensor before either of those.
I also get 22MPG combined driving on premium gas.
I would say something isn't right, but if your burning that much fuel when your not on boost you should see gas/smoke out the tailpipe. Your Ecu coolant temp sensor could be bad, or you could have a leaky injector. You might pull the plugs after it warm and smell each cylinder and shine a flashlight into each cylinder.
What does your oil look and smell like. If its really rich you can washdown a cylinder with gas and gas into oil also is a BIG problem as gas dilutes the oils protective qualities.
You might check for codes since it takes 1 min.
Without an AEM wideband hooked up, it's impossible to say if your fuel mixture is rich or lean.
Part throttle cruising, idling or light acceleration, the 1JZ Ecu keeps the Air/Fuel ratio between 14.2-15.8m, which is perfectly stoich, not rich or lean...(I've verified this with 3 different Ecus on the same car- The auto trans Ecus lean out after everyshift and the manual trans Ecu is full rich after each shift.)
So, anytime my wideband reads any differently then 14.2-15.8, off boost I get curious.
I wouldn't change the fuel pump or fuel filter to fix this problem. I would replace the cheap Ecu coolant temp sensor before either of those.
I also get 22MPG combined driving on premium gas.
I would say something isn't right, but if your burning that much fuel when your not on boost you should see gas/smoke out the tailpipe. Your Ecu coolant temp sensor could be bad, or you could have a leaky injector. You might pull the plugs after it warm and smell each cylinder and shine a flashlight into each cylinder.
What does your oil look and smell like. If its really rich you can washdown a cylinder with gas and gas into oil also is a BIG problem as gas dilutes the oils protective qualities.
You might check for codes since it takes 1 min.
Without an AEM wideband hooked up, it's impossible to say if your fuel mixture is rich or lean.
14/13 too lean?
I have a billet 6262 t4 that i'm going to put in after my t3 to t4 adaptor comes in. hopedully that fixes the smoke
10-09-11, 10:45 AM
#2
During FULL boost you should be 12:1 or lower, and 12:1 is usually considered pushing it.
The stock ecu with no tuning at full throttle should be running really rich at close to 10.5:1
Half throttle into boost 12-13:1 is acceptable
The ecu may be seeing knock and pulling a lot of timing which has saved you
The stock ecu with no tuning at full throttle should be running really rich at close to 10.5:1
Half throttle into boost 12-13:1 is acceptable
The ecu may be seeing knock and pulling a lot of timing which has saved you
10-09-11, 12:17 PM
#3
on stock twins , running in the 12's is perfectly fine as long you are on the lower end of spectrum and upon initial full boost hit you dip in the 11's to dump some fuel... toyota ecu's are tuned rich like said above .. you should by virture of toyota be seeing high 10's to low 11's... if i read correctly you are on stock sc 300 pump which should be changed as its aged and most of the time cant keep up with boost
10-09-11, 01:15 PM
#4
That is way way lean and most likely has done some sort of damage so do a compression and leak down test to determine the health of the engine and you are still on a stock fuel pump? That is a major issue right there so get a walbro asap.
Afr's should be between 12.0-12.3 on full boost.
The smoke may be a cracked ring land from all that detonation.
Afr's should be between 12.0-12.3 on full boost.
The smoke may be a cracked ring land from all that detonation.
Last edited by xspsi6; 10-09-11 at 01:19 PM.
10-09-11, 01:17 PM
#5
Because of the crap 91 octane we now have to deal with, I have found that 10.8:1 AFR is the safest street tune at WOT with stock-ish timing maps. Cars I have tuned have run this for years at over 400hp with no failure.
There was once a time we could run 22 degrees timing @ 10.8:1 with no knock at all. But now there is no 93 where I live, so timing must come down to a safer 15-18 degrees at WOT.
It's all about the Fuel, a lot of people disregard this.
Obviously the Jz engines are incredibly tough, but yeah 13's at WOT is bad, do something about it.
There was once a time we could run 22 degrees timing @ 10.8:1 with no knock at all. But now there is no 93 where I live, so timing must come down to a safer 15-18 degrees at WOT.
It's all about the Fuel, a lot of people disregard this.
Obviously the Jz engines are incredibly tough, but yeah 13's at WOT is bad, do something about it.
10-09-11, 02:35 PM
#7
ok i drove around to check my afr, full boost im around low 11s to high 10s, cruising im at 14s but i keep seeing the car go up to 15s after the auto shifts gears,
in still on the stock sc300 fuel pump
ill update with a compression test probably tomorrow
in still on the stock sc300 fuel pump
ill update with a compression test probably tomorrow
Trending Topics
10-09-11, 11:06 PM
#10
Rookie
iTrader: (4)
Join Date: Sep 2011
Location: alabama
Posts: 74
Likes: 0
Received 0 Likes
on
0 Posts
Out of boost the numbers are fine and yes 1jzs do run rich.Whan was the last time that wide band sensor was changed I do a lot of racing so I change mine once a year 75 bucks for a pice of mind is a good deal any day of the week.
Thread
Thread Starter
Forum
Replies
Last Post
kwbeach
Performance & Maintenance
25
07-25-12 01:46 AM
sikes
Performance & Maintenance
25
03-23-11 01:11 PM
