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Discussion Starter · #1 ·
Hey guys! long time since ive posted a problem, because my car has been running GREAT up until last monday.

im getting a Code 1 on my ECU (oxygen content) and with my fancy new air/fuel ratio guage i got, ive discovered that my idle is running sometimes really rich, sometimes really REALLY lean. i know it SHOULD cycle back and forth from lean to rich, but it doesnt really do that anymore, just sticks in one place, usually at rich for a minute or so, then dives down to really lean.

when im driving, while at cruising rpms (1800-2200 RPM for me) in every gear, if i stomp on the gas, im getting NO power, and the mixture goes REALLY lean, then after about 3-5 seconds, it resumes normal acceleration. if i just coast without giving it much gas, its just like idle... sometimes rich, sometimes lean, but never cycling. at other RPMs and under acceleration, it differs, sometimes lean with power (weird) sometimes rich with power.

I have a 3 month old O2 sensor in there (Bosch) and my injectors have been cleaned out-of-car and spray-pattern tested. i havent replaced my fuel filter in about a year, and i have new plugs and decent over-sized wires as well.

From talking to many mechanic friends, ive heard that Bosch O2 sensors are NOT the kind to buy for a honda. NGK all the way for japanese cars. I have one on order, and i plan on replacing the fuel filter as well, but i am curious if it could be any other part of the fuel system. Do fuel pressure regulators go bad? could it be the fuel sending unit (and is a fuel sending unit the same thing as the fuel pump?)

Since i had this problem before replacing my ancient O2 sensor with the Bosch one, i just assume its the o2 sensor.... but its strange for a sensor to burn out after 3 months, so maybe im running rich from some other problem. Though the air/fuel ratio seemed normal for those 3 months....

im quite frustrated, since this is a recurring problem, and im looking for ANY sort of advice. i want to fix this problem for good, so i dont have to keep dumping cash into an O2 sensor every three months. ive been avoiding it, but as soon as i get a full day off, ill have the time to sit down with my service manual and go through the troubleshooting for code 1, and see what i can come up with.
 

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I have used bosch universals for years with no problems.
If your car does have a problem it can destroy your o2 sensor.
I thought the fuel sending unit was your gas gauge, not the pump.
When you accelerate hard it definitely should go full rich.
I would definitely replace the fuel filter for starters.
 

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Stavros said:
Hey guys! long time since ive posted a problem, because my car has been running GREAT up until last monday.

im getting a Code 1 on my ECU (oxygen content) and with my fancy new air/fuel ratio guage i got, ive discovered that my idle is running sometimes really rich, sometimes really REALLY lean. i know it SHOULD cycle back and forth from lean to rich, but it doesnt really do that anymore, just sticks in one place, usually at rich for a minute or so, then dives down to really lean.

when im driving, while at cruising rpms (1800-2200 RPM for me) in every gear, if i stomp on the gas, im getting NO power, and the mixture goes REALLY lean, then after about 3-5 seconds, it resumes normal acceleration. if i just coast without giving it much gas, its just like idle... sometimes rich, sometimes lean, but never cycling. at other RPMs and under acceleration, it differs, sometimes lean with power (weird) sometimes rich with power.

I have a 3 month old O2 sensor in there (Bosch) and my injectors have been cleaned out-of-car and spray-pattern tested. i havent replaced my fuel filter in about a year, and i have new plugs and decent over-sized wires as well.

From talking to many mechanic friends, ive heard that Bosch O2 sensors are NOT the kind to buy for a honda. NGK all the way for japanese cars. I have one on order, and i plan on replacing the fuel filter as well, but i am curious if it could be any other part of the fuel system. Do fuel pressure regulators go bad? could it be the fuel sending unit (and is a fuel sending unit the same thing as the fuel pump?)

Since i had this problem before replacing my ancient O2 sensor with the Bosch one, i just assume its the o2 sensor.... but its strange for a sensor to burn out after 3 months, so maybe im running rich from some other problem. Though the air/fuel ratio seemed normal for those 3 months....

im quite frustrated, since this is a recurring problem, and im looking for ANY sort of advice. i want to fix this problem for good, so i dont have to keep dumping cash into an O2 sensor every three months. ive been avoiding it, but as soon as i get a full day off, ill have the time to sit down with my service manual and go through the troubleshooting for code 1, and see what i can come up with.
I found those air fuel mixture gauges useless. I disconnected mine.
What is your fuel pressure? You sure you are not getting predetonation and the knock sensor is cutting you off?
 

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Code 1 is not oxygen content it is the signal for a bad primary O2 sensor or a open circuit. Try removing the O2 wire connectors, cleaning them up and reconnecting them. If that does not work, replace the O2 sensor.
 

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Discussion Starter · #5 ·
i did a little expermineting on my way home from work last night. its a LONG drive (about 45 minutes) and i found that if i keep the revs below around 3000, that code doesnt come up, and the o2 sensor cycles normally... which leads me to beleive that my fuel filter is plugged, or my pump is on its way out. if im revving high, my engine needs more fuel, and if the filter or pump are holding things back, then i run real lean... the thing i dont understand is why it would keep happening after ive revved hard above 3000, while driving less sporty.

ill pick up the fuel filter and get honda to check my fuel pressure after replacing it.

since my o2 sensor is only 3 months old, i dont think bad wiring is the issue, since its an intermittent problem

thanks for the input everyone
 

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Actually a code 1 can be triggered by oxygen content data. If the ecu comes to the calculation that it needs more fuel than the trim tables will allow for then it will cause a code 1.
 

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Discussion Starter · #8 ·
i just noticed today after fixing a sudden pin-hole leak in a rad hose, that i have a leak in my two-piece header. its not a substantial leak, but maybe not enough exhaust is getting to the sensor.

Canada gets hit by hot weather and a bunch of little problems spring up.
 

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I was reading my FSM, and there was actually a couple tests you could do on the O2 sensor...one was to hold the rpms at 2000 for something like 15 minutes in second when the car is in the air. If the check engine light flashes on and goes out, loose or damaged wires could be the culprit. I've actually done this (unintentionally, and in 5th) while cruising up the hill to my house several times. I haven't touched the sensor however, so I assume its still working properly. Just my two cens.
 
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