Sensor Calibration.
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From: Cleveland, OH
Sensor Calibration.
Hey People,
First off let me introduce myself! My name is Avery. Im pursuing a B.S. degree in Mechanical Engineering at Florida A&M University. Been a part of HT for a while now but now I'm trying to do less reading on forums and more doing underneath the hood of my car. Anyways let me tell you my situation.
I got a 93 Civic Hatch Dx with a B18A1, that I pulled from the junkyard rebuilt and installed myself. The engine is completly stock from TB to Oil Pan. Before making any changes to the engine I want to get my engine running as good as possible with all stock components. I go to alot of car meets and see people with cams clutch kits and full exhaust but they still have idle problems and too much valve lash.
Ive been doing alot of reading and I have a pretty good idea on how pgmfi sysytems work to calculate mass air flow. Which is funny because after all this reading and tampering with my car I can't troubleshoot and diagnose why my car is running slightly lean. Sometimes the car feels great and other times the car backfires when I let off the gas. Sometimes the car throws code 1(O2 sensor) after driving for a while. After looking at the plugs what I think is happening is something is causing this lean condition and 02 sensor is picking it up.
Spark plugs indicate the lean condition. (Ill put pictures up later of the plugs)
Things that I've checked
engine timing
ignition timing
grounds. (thermostat and all other big ones.)
fuel pressure.
Questions:
1.) At what point does my car go into closed loop opperation?
2.) Aside from checking the resistance across the IAT sensor is there anything else that would effect its performance? would cleaning it do any good?
3.) My fuel pump has alot of miles on it. 279*** to be exact. do these things get tire after a while or should I change it with a newer stock one. (fuel pressure is ok)
Let me know what you guys would check if you had a completly stock car that was running would back fire occasionaly when letting off the gas. Ill post some pictures of the setup as well.
My ultimate goal for this car is to have nice reliable boosted car that I built and tuned myself.
First off let me introduce myself! My name is Avery. Im pursuing a B.S. degree in Mechanical Engineering at Florida A&M University. Been a part of HT for a while now but now I'm trying to do less reading on forums and more doing underneath the hood of my car. Anyways let me tell you my situation.
I got a 93 Civic Hatch Dx with a B18A1, that I pulled from the junkyard rebuilt and installed myself. The engine is completly stock from TB to Oil Pan. Before making any changes to the engine I want to get my engine running as good as possible with all stock components. I go to alot of car meets and see people with cams clutch kits and full exhaust but they still have idle problems and too much valve lash.
Ive been doing alot of reading and I have a pretty good idea on how pgmfi sysytems work to calculate mass air flow. Which is funny because after all this reading and tampering with my car I can't troubleshoot and diagnose why my car is running slightly lean. Sometimes the car feels great and other times the car backfires when I let off the gas. Sometimes the car throws code 1(O2 sensor) after driving for a while. After looking at the plugs what I think is happening is something is causing this lean condition and 02 sensor is picking it up.
Spark plugs indicate the lean condition. (Ill put pictures up later of the plugs)
Things that I've checked
engine timing
ignition timing
grounds. (thermostat and all other big ones.)
fuel pressure.
Questions:
1.) At what point does my car go into closed loop opperation?
2.) Aside from checking the resistance across the IAT sensor is there anything else that would effect its performance? would cleaning it do any good?
3.) My fuel pump has alot of miles on it. 279*** to be exact. do these things get tire after a while or should I change it with a newer stock one. (fuel pressure is ok)
Let me know what you guys would check if you had a completly stock car that was running would back fire occasionaly when letting off the gas. Ill post some pictures of the setup as well.
My ultimate goal for this car is to have nice reliable boosted car that I built and tuned myself.
Honda-Tech Member
Joined: Dec 2006
Posts: 996
Likes: 1
From: Portland, OR, USA
Re: Sensor Calibration.
I believe the car goes into closed loop operation once ECT reaches a specific temp "on an oem ecu" this might be wrong. The other option for an ecu to go into closed loop is when the map is a specific value around idle and cruise... or it could be a combination of the two.
On my specific ecu I have it set up so that it only runs closed loop below a specific map value, due to my AF gauge I can see it doing the standard fluctuation of slightly rich/slightly lean 14.1-15.7 ish to 1 during cruise.. If you understand how a fuel/ignition maps work on any tuneable ecu's you will understand the concept.. But I'm sure you do!
Although to actually answer your question I don't know if its possible to tell if an obd1 ecu is in closed loop or not, I believe OBD2 ecu's spit this data out the obd2 diag port.
The IAT sensor on your specific car, I have the same one changes resistance based off of temp. I think its one of these 2 options High resistance is hot, low is cold, or low is high resistance and hot is low resistance.. cleaning it wont help, although a popular mod is to mount the IAT sensor on the actual aftermarket intake tube and block the one on the intake manifold, this will not get inaccurate readings of the intake air temp.
you could clean out the IAC, which is located on the throttle body should have 2 wires going to it.
seafoam the engine if its a high mileage one "or just for fun!", change the oil, change plugs to the right heat range, change ignition wires, change the distributor cap.
It's possible you might be running the wrong ecu... tossing that out there.
Do a compression test, change all the things like water pump and timing belt before you get into tuning it... wash the thing simple green is your friend.
Anyone else should be able to chime in now, good luck on your build should be fun.
remember get neptune RTP for the ecu.! its baller.
On my specific ecu I have it set up so that it only runs closed loop below a specific map value, due to my AF gauge I can see it doing the standard fluctuation of slightly rich/slightly lean 14.1-15.7 ish to 1 during cruise.. If you understand how a fuel/ignition maps work on any tuneable ecu's you will understand the concept.. But I'm sure you do!
Although to actually answer your question I don't know if its possible to tell if an obd1 ecu is in closed loop or not, I believe OBD2 ecu's spit this data out the obd2 diag port.
The IAT sensor on your specific car, I have the same one changes resistance based off of temp. I think its one of these 2 options High resistance is hot, low is cold, or low is high resistance and hot is low resistance.. cleaning it wont help, although a popular mod is to mount the IAT sensor on the actual aftermarket intake tube and block the one on the intake manifold, this will not get inaccurate readings of the intake air temp.
you could clean out the IAC, which is located on the throttle body should have 2 wires going to it.
seafoam the engine if its a high mileage one "or just for fun!", change the oil, change plugs to the right heat range, change ignition wires, change the distributor cap.
It's possible you might be running the wrong ecu... tossing that out there.
Do a compression test, change all the things like water pump and timing belt before you get into tuning it... wash the thing simple green is your friend.
Anyone else should be able to chime in now, good luck on your build should be fun.
remember get neptune RTP for the ecu.! its baller.
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