Rough idle, poor driveability! Please help.
06-30-11, 03:48 AM
#17
Driver School Candidate
Thread Starter
Yes I think I have. Just removed the whole fuel rail earlier today and will be getting the stock injectors cleaned. I just want to make completely sure that this is indeed the problem. I'd hate to install the larger injectors and have a terrible time trying to tune them with the SAFC only to find out that I left out some item that needed fixing after all. Will be checking cylinder compression tom since the mechanic left the compression test gauge.
By the way Ali, by any chance are you still using an SAFC unit? and if so, are you still using stock MAF (Karman type)? Just had to know what setting to do on the sensor (in & out) for SC300 OBD1 Karman type. Thanks for all the help.
By the way Ali, by any chance are you still using an SAFC unit? and if so, are you still using stock MAF (Karman type)? Just had to know what setting to do on the sensor (in & out) for SC300 OBD1 Karman type. Thanks for all the help.
06-30-11, 10:26 AM
#19
yeah not running the safc anymore, but i used to for a good amount of time.
if you are using the safc you may want to check out the safc section at club na-t.
you will find alot of your issues in threads over there.
theres a thread called how to install an safc-2
http://www.clubna-t.com/forums/showthread.php?t=17
I want to say if you are using Karmen, you just select Karmen. I dont remember if you have to set in/out for Karmen. If you have to try the 1 in 1 out.
For a stock GE the compression should be in the 180-190 range if i remember correctly. a GE with a TT headgasket is around 170-180.
I wouldn't worry about the max as much, but the variation across cylinders, especially the one with the faulty injector.
if you are using the safc you may want to check out the safc section at club na-t.
you will find alot of your issues in threads over there.
theres a thread called how to install an safc-2
http://www.clubna-t.com/forums/showthread.php?t=17
I want to say if you are using Karmen, you just select Karmen. I dont remember if you have to set in/out for Karmen. If you have to try the 1 in 1 out.
For a stock GE the compression should be in the 180-190 range if i remember correctly. a GE with a TT headgasket is around 170-180.
I wouldn't worry about the max as much, but the variation across cylinders, especially the one with the faulty injector.
The OBD1 1993.5-1995 supra will use the KARMEN sensor
The OBD2 1996-1998 supra will use the HOTWIRE sensor
*******FOR OBD1 (1993.5-1995) N/A's-************
-Use PINK wire, instead of YELLOW wire
-Use ORANGE wire, instead of WHITE wire.
-YELLOW and WHITE wire are NOT used
--------------------------------------------------------------------------
IF YOU ARE OBD2, FOLLOW THESE STEPS EXACTLY AS THEY ARE WRITTEN. OBD1 READ DIRECTLY ABOVE FOR CHANGES YOU MAKE.
--------------------------------------------------------------------------
1. Splice the GREEN wire (RPM) into 58
2. Splice the GRAY wire (Throttle) into 43
3.Cut wire 66 in half, leave yourself enough room to connect a wire to ECU harness.
4.Connect the YELLOW wire to the 66 wire connected TO the ECU harness.
5. Connect the WHITE wire to the 66 wire heading AWAY from the ECU harness.
6. Splice the BROWN wire (ground 1) into 69, close to the ecu.
7. Splice the BLACK wire (ground 2) into 69 at least 1cm away from the Brown wire.
8. Splice the RED wire (12V+) in to ECU wire 31.
9. PINK and ORANGE wires are not used.
--------------------------------------------------------------------------
OK, Now you have all of the wiring done, double check all of your connections, reconnect the wiring harness to your ECU. Make sure all of those wires are still tight. Plug the harness into the S-AFC. Reconnect your battery cable. Turn the ignition to the ON position. The AFC should boot up and display A'PEXi, if screen did not light up, stop disconnect the battery and find out what went wrong. Most likely it is power or ground problem (or a loose ecu harness.)
If the unit Powers On, follow these steps:
First start off by Resetting the AFC. Many have often complained that their AFC does not show full throttle(%100), regardless if it is brand new. Go under [etc.] and press NEXT~>. Confirm "YES" when prompted "Init. All?" and press NEXT again, Now turn the ignition OFF and then back ON, and the unit should now be reset and ready.
Next enter the following basic settings:
1.-Go to [main] ~>[setting] ~> [3. TH-Point] ~> [Lo-94, Hi-95]
*2.-Go to [main] ~>[etc.] ~> [1. Sensor Type] ~> [1. Hot-Wire] ~> [in-12, Out-12] ~> [in-1, Out-1]* (SELECT KARMEN IF YOU ARE 93.5-95)
3.-Go to [main] ~>[etc.] ~> [2. Car Select] ~> [Cyl:6, Thr: UP]
4.-Go to [main] ~>[etc.] ~> [3. Graph scale] ~> [Ne = 7000rpm]
5.[Ne-POINT = 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000]
[Dec. -Air = NOT USED, unless you want to use it to compensate for venting your BOV to atmosphere]
Do not modify the low throttle settings. While at low throttle (in closed loop mode) the ecu will counteract any changes made and over time your long term fuel map will be modified. I recommend modifying your high throttle fuel curve on the dyno with an air/fuel ratio meter & egt gauge installed. For maximum power, one probably wants to run an air to fuel ratio of between 11:1 (rich) and 12.5:1 (lean) Do yourself a favor and pay a professional to tune it. If you lean your engine out, things can melt.
------------------------------------------------------------------------
BLUE WIRE MOD INFO
This allows you to read Oxygen Sensor Voltage on the AFC display. On the wiring harness for the AFC the blue wire is not normally used. The blue wire is meant for the second Mass Air Flow Meter on a Nissan 300ZX. You will connect this wire to the O2 sensor wire right at the ECU. To read the O2 sensor voltage, scroll down to and select the "etc." menu. Select the "Sensor Check". Of the three readings, O2 voltage will be the middle one (#2).
--------------------------------------------------------------------------
VPC+AFC
If you are installing the VPC with the AFC, then install the AFC on the output wire of VPC
--------------------------------------------------------------------------
The OBD2 1996-1998 supra will use the HOTWIRE sensor
*******FOR OBD1 (1993.5-1995) N/A's-************
-Use PINK wire, instead of YELLOW wire
-Use ORANGE wire, instead of WHITE wire.
-YELLOW and WHITE wire are NOT used
--------------------------------------------------------------------------
IF YOU ARE OBD2, FOLLOW THESE STEPS EXACTLY AS THEY ARE WRITTEN. OBD1 READ DIRECTLY ABOVE FOR CHANGES YOU MAKE.
--------------------------------------------------------------------------
1. Splice the GREEN wire (RPM) into 58
2. Splice the GRAY wire (Throttle) into 43
3.Cut wire 66 in half, leave yourself enough room to connect a wire to ECU harness.
4.Connect the YELLOW wire to the 66 wire connected TO the ECU harness.
5. Connect the WHITE wire to the 66 wire heading AWAY from the ECU harness.
6. Splice the BROWN wire (ground 1) into 69, close to the ecu.
7. Splice the BLACK wire (ground 2) into 69 at least 1cm away from the Brown wire.
8. Splice the RED wire (12V+) in to ECU wire 31.
9. PINK and ORANGE wires are not used.
--------------------------------------------------------------------------
OK, Now you have all of the wiring done, double check all of your connections, reconnect the wiring harness to your ECU. Make sure all of those wires are still tight. Plug the harness into the S-AFC. Reconnect your battery cable. Turn the ignition to the ON position. The AFC should boot up and display A'PEXi, if screen did not light up, stop disconnect the battery and find out what went wrong. Most likely it is power or ground problem (or a loose ecu harness.)
If the unit Powers On, follow these steps:
First start off by Resetting the AFC. Many have often complained that their AFC does not show full throttle(%100), regardless if it is brand new. Go under [etc.] and press NEXT~>. Confirm "YES" when prompted "Init. All?" and press NEXT again, Now turn the ignition OFF and then back ON, and the unit should now be reset and ready.
Next enter the following basic settings:
1.-Go to [main] ~>[setting] ~> [3. TH-Point] ~> [Lo-94, Hi-95]
*2.-Go to [main] ~>[etc.] ~> [1. Sensor Type] ~> [1. Hot-Wire] ~> [in-12, Out-12] ~> [in-1, Out-1]* (SELECT KARMEN IF YOU ARE 93.5-95)
3.-Go to [main] ~>[etc.] ~> [2. Car Select] ~> [Cyl:6, Thr: UP]
4.-Go to [main] ~>[etc.] ~> [3. Graph scale] ~> [Ne = 7000rpm]
5.[Ne-POINT = 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000]
[Dec. -Air = NOT USED, unless you want to use it to compensate for venting your BOV to atmosphere]
Do not modify the low throttle settings. While at low throttle (in closed loop mode) the ecu will counteract any changes made and over time your long term fuel map will be modified. I recommend modifying your high throttle fuel curve on the dyno with an air/fuel ratio meter & egt gauge installed. For maximum power, one probably wants to run an air to fuel ratio of between 11:1 (rich) and 12.5:1 (lean) Do yourself a favor and pay a professional to tune it. If you lean your engine out, things can melt.
------------------------------------------------------------------------
BLUE WIRE MOD INFO
This allows you to read Oxygen Sensor Voltage on the AFC display. On the wiring harness for the AFC the blue wire is not normally used. The blue wire is meant for the second Mass Air Flow Meter on a Nissan 300ZX. You will connect this wire to the O2 sensor wire right at the ECU. To read the O2 sensor voltage, scroll down to and select the "etc." menu. Select the "Sensor Check". Of the three readings, O2 voltage will be the middle one (#2).
--------------------------------------------------------------------------
VPC+AFC
If you are installing the VPC with the AFC, then install the AFC on the output wire of VPC
--------------------------------------------------------------------------
Last edited by Ali SC3; 06-30-11 at 10:40 AM.
06-30-11, 02:42 PM
#20
Driver School Candidate
Thread Starter
This was really helpful info. Thank you. I hope to get all the little gremlins out soon so I can start enjoying this car again. The help provided by this forum and its members has been instrumental to getting me back into this hobby. I'm just glad to be back. 
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