closed loop oxygen sensor?

[h22a accord]

Hey all, could somebody tell me if my engine has a closed loop oxygen sensor?


engine is h22a with p13 ecu.

thanks.

[Weq]

an oxgygen sensor cant be 'closed' loop. An ECU on the other hand can be.
Closed loop means the ecu is using its hardcoded maps for fuel/ign. Open loop means its also using the various engine sensors to adjust fuel/ign trims.

[h22a accord]

thanks weq, i guess now i need to know if my ecu is closed loop.

[weezer]

i thought it was the other way round?

[saxman]

it is... closed loop is when it uses the o2 sensor info, open is when it doesn't.

Which would be why the option to disable the o2 sensor in all the programs is called "closed loop disable"



also, if your car has a stock ecu, it uses closed loop.

[Weq]

i always get them confused. yes its other way round :)

[h22a accord]

okay thanks guys, the reason i asked is becuase i read an article in a magazine about engine conversions and that thereis always little bugs that have ti be ironed out after the engine swap.

It mentioned that if your car is running very rich with poor fuel economy you should check to see if the closed loop is working.

the reason they gave for this particular vehicle they were working on for the closed loop not to be working was that the ECU that came with the new engine wasnt bolted to the chassis like it should be ( due to the ECU being a different size etc) and for the closed loop circuit to work properly the ECYU must be grounded properly.


The ecu that came with the h22a i swapped into my accord did not bolt into the ECU cradel so i have always had it sitting on the floor under the carpet. So I am going to modify the cradel so i can bolt my ECU into the car to give a it a proper earth and find out if that will fix my fuel consumption :)

[ProECU]

sory to say...that wont fix your fuel consumption, assuming its bad to begin with.

[h22a accord]

oh. is it even worth a try?

[ProECU]

nup :)

[h22a accord]

bummer then. Either way im going to modify the cradle so the ecu fits as im getting over the fact that if u sit in the passenger seat you can rock the ecu forward and back with your feet.


Will it not work because the ecu is already grounded? or with honda's the ecu doesnt have to be grounded for closed loop to work?

[ProECU]

You would very soon know if you were running an ECU that was not grounded!

Open/Closed loop is an algorithm, typically something like a Poportional, Integral Difference(PID) system, which uses feedback from a control variable to determine what action to then take.

It's not a GND issue.

[jimmeh]

In closed loop operation the ECU uses one or more oxygen sensors as a feedback loop in order to adjust the fuel mixture. This gives the name ‘closed loop’ from the closed feedback loop. The ECU won’t run in a closed feedback loop all the time, so ‘open loop’ is used to describe the operation of the ECU when the mixture is not being adjusted in this way (usually when the engine is cold or when running under high load).

In closed loop operation the ECU uses the oxygen sensor to tell if the fuel mixture is rich or lean. However, due to the characteristics of the oxygen sensor it can’t tell exactly how rich or lean, it only knows that the mixture is richer or leaner than optimum. The ECU will enrich the mixture if the oxygen sensor shows that the mixture is lean, and lean the mixture if it looks rich. The result of this is that the mixture will swing back and forward around the stoichiometric point.
reference:http://hondata.com/techclosed.html

[ProECU]

I assume not many people here know what a PID control system is so...

Control Variable: O2 sensor voltage - target Voltage

Proportional - difference of successive control variables
Integral - Integration Algorithm usually trapezoidal applies to control variable
Differenciation - differenciation of Control Variable with respect to Time.

P+I+D algorithm when applied to the control variable (with differing gains & frequencies) is a very effective method for a feedback system to target a specific value.
In this case, the feedback system is the ECU, attempting to target lambda(voltage).

Another example is a boost control system
Control variable = difference between Target psi & Actual psi

I digress i know, however this is a very common algorithm in the industry and if nothing else, if you can understand how this works, you can understand open/closed loop!

[h22a accord]

nice info pro ecu, pq point :) The vehicle i was referring to in the article i read was a nissan fitted with rb engine. Why would there be a grounding issue with that particular ecu in relation to the closed loop control and not with a honda when the symptoms are the same and the fact the ecu not bolted to the floor for a ground?

I was just looking at the bolts that are welded to the floor for the ecu cradel nuts to screw onto and discovered they are made of copper.

Last time i checked my earth straps for the engine were made of copper. is this just coincidence or are they that way for a reason?

[h22a accord]

In closed loop operation the ECU uses one or more oxygen sensors as a feedback loop in order to adjust the fuel mixture. This gives the name ‘closed loop’ from the closed feedback loop. The ECU won’t run in a closed feedback loop all the time, so ‘open loop’ is used to describe the operation of the ECU when the mixture is not being adjusted in this way (usually when the engine is cold or when running under high load).

In closed loop operation the ECU uses the oxygen sensor to tell if the fuel mixture is rich or lean. However, due to the characteristics of the oxygen sensor it can’t tell exactly how rich or lean, it only knows that the mixture is richer or leaner than optimum. The ECU will enrich the mixture if the oxygen sensor shows that the mixture is lean, and lean the mixture if it looks rich. The result of this is that the mixture will swing back and forward around the stoichiometric point.
reference:http://hondata.com/techclosed.html


google is your friend...it sent me to the same site last nite!

[h22a accord]

update- I bolted the ecu to the floor and funnily enough, the CEL that would come on within 5 mins of driving due to ELD and EGR fault code doesnt come on anymore. Weird! I'll have to plug in a scanner to check for fault codes now. Also, the car doesnt burble when backing off the throttle and it is running a lil bit smoother and more responsive.

Coincidence? maybe, cant be sure until i compare fuel consumption figures.....

[ProECU]

I run my ecu in the floor all day every day... no issues

[weezer]

I run my ecu in the floor all day every day... no issues

lol so does mine. It just sits on the carpet

[h22a accord]

somethings up then! I want to get to the bottom of this.