Gauge Questions
#21
RE: Gauge Questions
ORIGINAL: Silver_Dodge
Mine pegs to rich as soon as I start the truck because it is in open loop mode (warm up mode) until it warms up. Once warmed up (which can take several minutes), the truck goes into closed loop mode (idle mode), and it starts operating normally, dithering with the closed loop fuel trims, or locking into an a/f setting when I get on the gas (back into an open loop mode like full throttle mode). Maybe you didn't let it run long enough to get into closed loop mode.
I'll post a picture of the wires I used, but you'll will have to wait till this weekend.
Mine pegs to rich as soon as I start the truck because it is in open loop mode (warm up mode) until it warms up. Once warmed up (which can take several minutes), the truck goes into closed loop mode (idle mode), and it starts operating normally, dithering with the closed loop fuel trims, or locking into an a/f setting when I get on the gas (back into an open loop mode like full throttle mode). Maybe you didn't let it run long enough to get into closed loop mode.
I'll post a picture of the wires I used, but you'll will have to wait till this weekend.
#22
RE: Gauge Questions
If you're using a narrow band o2 sensor on your a/f meter, then when the engine is in closed loop mode (idle or cruise for example), the lights should jump up and down at a fairly consistant rate. This is called dither. When your engine is in any closed loop mode, it is (or should be ideally) operating very near the stochiometric point, the point were the air/fuel ratio is 14.7:1 and your mixture is ideal for the the most efficient combustion. A ratio higher then that means you are too lean, a ratio below that means your are too fuel rich. During closed loop modes, the PCM is constantly adjusting the air/fuel ratio in an attempt to maintain the stochiometric point, hence why it dithers. So if it dithers above and below 14.7:1 equally, and at constant rate (about 1 cycle per second), then your PCM is dialing in the air fuel ratios very well. That is what you want to see.
Then, when you get on the gas or otherwise go into any other open loop mode, the a/f will stop dithering and lock into a more exact a/f mixture. Usually you want this to be rich because as you add more throttle, the PCM is giving more fuel to make more power. If you get on the gas, and it shows only lean, you have a lean issue. You also shouldn't see rich conditions that are more then about 12:1 air to fuel. If you do (even under full throttle hard accelerations), you are probably too rich for a naturally aspirated engine using pump gas. With that said, keep in mind that a narrow band o2 sensor is not going to give you a real accurate reading. The best it is going to do is tell you if 1) during closed loop operation if your fuel trims are good, and 2) during open loop mods if you are in a rich condition or lean condition. If you want to know your exact a/f ratio at all times, or want to operate outside a range of about 12:1 - 17:1 (like if your using race fuel on a blown engine), you need to upgrade to a wide band o2 sensor and a a/f meter that can interpret its signals.
For me, all I wanted to know is if my fuel trims were good, and if I was rich or lean. I drive at some very high altitudes sometimes, which can reak havoc on a speed density design engine because it isn't able to accuratly tell that the air pressure and air volume is much less and that your getting less air/oxygen. So that is why I wanted the a/f meter. To go with it, I also have a air/fuel calibrator that allows me to manually force a rich or lean condition by modifying the MAP sensor signal to fool the PCM. This is nice when you are running rich at high altitude, you can simply lean out the fuel with a turn of a ****, which restores power and keeps you from fowling plugs and sensors with excess fuel/carbon buildup.
If someone has a place to host some video that can then be posted on this site, i'll take some video of my a/f meter in some closed loop and open loop operations, email it to you, and you can post them up for me. Then you can see how mine operated under various conditions.
Hope this helps.
Then, when you get on the gas or otherwise go into any other open loop mode, the a/f will stop dithering and lock into a more exact a/f mixture. Usually you want this to be rich because as you add more throttle, the PCM is giving more fuel to make more power. If you get on the gas, and it shows only lean, you have a lean issue. You also shouldn't see rich conditions that are more then about 12:1 air to fuel. If you do (even under full throttle hard accelerations), you are probably too rich for a naturally aspirated engine using pump gas. With that said, keep in mind that a narrow band o2 sensor is not going to give you a real accurate reading. The best it is going to do is tell you if 1) during closed loop operation if your fuel trims are good, and 2) during open loop mods if you are in a rich condition or lean condition. If you want to know your exact a/f ratio at all times, or want to operate outside a range of about 12:1 - 17:1 (like if your using race fuel on a blown engine), you need to upgrade to a wide band o2 sensor and a a/f meter that can interpret its signals.
For me, all I wanted to know is if my fuel trims were good, and if I was rich or lean. I drive at some very high altitudes sometimes, which can reak havoc on a speed density design engine because it isn't able to accuratly tell that the air pressure and air volume is much less and that your getting less air/oxygen. So that is why I wanted the a/f meter. To go with it, I also have a air/fuel calibrator that allows me to manually force a rich or lean condition by modifying the MAP sensor signal to fool the PCM. This is nice when you are running rich at high altitude, you can simply lean out the fuel with a turn of a ****, which restores power and keeps you from fowling plugs and sensors with excess fuel/carbon buildup.
If someone has a place to host some video that can then be posted on this site, i'll take some video of my a/f meter in some closed loop and open loop operations, email it to you, and you can post them up for me. Then you can see how mine operated under various conditions.
Hope this helps.
#23
RE: Gauge Questions
For more info for you, here is my original post back from long ago when I installed my a/f meter. Good info there.
https://dodgeforum.com/m_610407/tm.htm
https://dodgeforum.com/m_610407/tm.htm
#24
RE: Gauge Questions
Don't know if this helps But: from '96 factory manual
"up-stream O2 sensor"
16 gage-dark green with orange tracer---auto shut down relay
18 gage- blackwith white tracer---chassis ground
18 gage- tan with white tracer---PCM signal -I think this is the wire you want to tap in too
18gage- black with light blue tracer---PCM sensor ground
"down-stream O2 sensor"
16 gage- dark green with orange tracer---auto shut down relay
18 gage- blackwith white tracer---chassis ground
18 gage- black with light blue tracer---PCM sensor ground
18gage- orange with blacktracer---PCM sensor
I believe these are the wire colours on the harness after the connector, not the colours on the sensor.
[edit wrong wire indicatednow fixed]
#29
#30
RE: Gauge Questions
ORIGINAL: padodgeram
Hey silver , must of been busy and all , but still waiting on these pics...
Hey silver , must of been busy and all , but still waiting on these pics...
[IMG]local://upfiles/9095/1A4CB77082AC4DC282227B82D13CAE08.jpg[/IMG]