1jz rich at idle and lean while revving

JAMDUN17

New Member
Aug 1, 2011
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Germantown MD
Ran into another problem and headache. I recently installed a wideband sensor and found out that at idle the car is running very rich, around 9:1 when i rev the car the mixture goes very lean and cutting out. When i hold the rpm where it cuts out it goes back to rich and stays there (around 10-11:1). I pulled the plugs and they are extremly black and shows no sign of detenation. Plugs are gapped to .44 via ngk specs.

The narrowband 02 sensor is a 4 pin from a 2jz and the system ground pin is wired to the head, voltage output showed .8 v at idle when hot, the heater pin never seems to ground itself and just keeps showing 12v on both ends. Wideband is an lc1

Any ideas?
 

Radial

New Member
Aug 20, 2011
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Norway
yep, the vacuum hose for your MAP-sensor has probably snapped off somewhere :) had the exact same error on my drift-car last year... black smoke at idle (9afr), and 15 (ish) afr lean on boost and fuelcuts and so on.... found the vacuumhose hangin down the firewall without connection, haha problem solved within 5 seconds ;)
 

JAMDUN17

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Aug 1, 2011
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Germantown MD
Ill try bringing down the gap a bit, The hose to the MAP sensor is good but maybe the MAP sensor itself is bad? I took the hose of the map sensor and it made no difference (it picked up the idle a bit but it was from the new vaccum leak, I blocked it off and it went to as it was with the map sensor) however when i unplugged the sensor the car stumbled then shut off. Dont know what to make of it....
 

Radial

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Aug 20, 2011
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sounds like your MAP is fucked somewhere.... check your wiring first, especially the pins on the connector.... if everything is ok, then you should get a hold on a *JZ-GTE map sensor (Same connector, same values, just different design) and try it.
 

JAMDUN17

New Member
Aug 1, 2011
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Germantown MD
^ yeah it would shut off, but it idles so low to begin with that i think any disturbance would do that.

I took down the gap on the spark plugs and it helped a bit but it still cuts out and has a crappy idle. I think all of you who said the map was right but mine is something different, i unplugged the Map and tested the voltage, the middle pin showed 5v but when i connected the map sensor the voltage fell to .5 v also the other pins dont change when revving so something is definetly up.

I got my wiring done by chase bays and found a couple of mistakes in thier work and had to swicth over a couple of pin already so it wouldn't surprise me if they messed this up too.

when i searched i found this about the map sensor pins, can anyone confirm this
from left to right.
On the 1jz map sensor:
1 - ground
2 - signal
3 - 5v

Chase bays colors are all different so i cant gauge by colors.
 

T701jz

3M ENGINEER - R.&.D
Jul 23, 2005
657
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Santa Clarita Ca.
Send that harness back to chase and demand a tested and working harness from them. You could second guess what's wrong with your car all you want but why. You your self know that there is a possibility the harness is crap so start there.
 

IBoughtASupra

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Mar 10, 2009
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Queens, NY
T701jz;1842240 said:
Send that harness back to chase and demand a tested and working harness from them. You could second guess what's wrong with your car all you want but why. You your self know that there is a possibility the harness is crap so start there.

+1

There are too many issues with them with guys over at SupraForums.

They were a vendor here and Mike removed them because of inactivity. I sent them E-Mails about building a JZ harness and got no response.
 

Radial

New Member
Aug 20, 2011
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Norway
The Brown wire is supposed to have Ground and is supposed to be the right pin, looking into the mapsensor (aka Pin 1)

One of the others should have +5v constant to ground

The last one remaining is the signal wire... it should move between 0,5 to 4,5 or something,depending on the pressure in your manifold. If this is Stuck, then your map is fucked.

if the Supply-voltage dropps to 0,5 when you connect the map, then something is shorted to ground in the circiut...
 

seoul4korea

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Nov 6, 2008
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San Diego, CA
www.supraforums.com
JAMDUN17;1842195 said:
^ yeah it would shut off, but it idles so low to begin with that i think any disturbance would do that.

I took down the gap on the spark plugs and it helped a bit but it still cuts out and has a crappy idle. I think all of you who said the map was right but mine is something different, i unplugged the Map and tested the voltage, the middle pin showed 5v but when i connected the map sensor the voltage fell to .5 v also the other pins dont change when revving so something is definetly up.

I got my wiring done by chase bays and found a couple of mistakes in thier work and had to swicth over a couple of pin already so it wouldn't surprise me if they messed this up too.

when i searched i found this about the map sensor pins, can anyone confirm this
from left to right.
On the 1jz map sensor:
1 - ground
2 - signal
3 - 5v

Chase bays colors are all different so i cant gauge by colors.

Have you tried tracing the wires back by chance?
 

JAMDUN17

New Member
Aug 1, 2011
60
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0
Germantown MD
Yep so Chase bays did it once again, another wire in the wrong place, not even close to the right area. The power wire for the Map/TPS was in IDL2 on the flying lead and no wire came from the VC on the ECU. Depinned it and placed it in VC and bang the car idles and revs to redline with no missfire. Also this turned off my check engine light as well, but the problem is i think my wideband has gone haywire because its reading insainly lean while reving, so lean that i couldnt imagine the engine even running much less revving somtimes pegging 22:1, not getting any check engine light, cant hear pinging and the car doest sound like its pulled timing so is there any explaination for this?

PS. i would love to shove the harness back into thier face but the community is starting to come down on me so this project needs to be finished. Just FYI I wouldnt recommend chase bays anymore, they have a good concept but there work is terrible, im finding absolutly amature mistakes. between the fake tracking numbers and bogos 'we sent it threw usps and we dont they dont provide tracking numbers' line then get a fed ex tracking number two days later and this stuff, everyone should just plain stay away till they get thier acts together, im done.
 

Radial

New Member
Aug 20, 2011
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Norway
the wideband o2's easily gets clogged with rich mixtures, such as in your case. Take the sensor out, and flush it in hot water, and blow it clean and dry with compressed air and Heating gun.
Run a re-calibration, and its probably good to go again.

Just dont use chemicals and hardware on the sensor-core... thats why I mention water and Air. The cores on the 02 sensors are very fragile and delicate.
 

JAMDUN17

New Member
Aug 1, 2011
60
0
0
Germantown MD
Radial;1842626 said:
the wideband o2's easily gets clogged with rich mixtures, such as in your case. Take the sensor out, and flush it in hot water, and blow it clean and dry with compressed air and Heating gun.
Run a re-calibration, and its probably good to go again.

Just dont use chemicals and hardware on the sensor-core... thats why I mention water and Air. The cores on the 02 sensors are very fragile and delicate.

Thanks ill see if it helps