DIY PGMFI Diagnostics - Code 43 FSS

[ECU-MAN]

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!


No part of this DIY is to be reproduced with out acknowledgment of the site and author it came from, ie me and ozhonda.com. Do not rip parts off and claim them as your own.




FSS ( Fuel Supply System ). The Fuel Supply System consists of the fuel pump, fuel pump strainer, fuel lines and rails, Fuel Filter Fuel Pressure regulator, Injectors and return line. However the oxygen sensors play a big role in diagnosing this code.



Aim:

Diagnose code 43.






Symptoms

Engine light comes on and code 43 registered in ECU memory. Car will still drive as normal. Common causes for code 43 are a faulty oxygen sensor. However its been known for a blocked fuel filter or failing fuel pump to trigger this code. The ECU will adjust the pulse width ( duty ) of the injectors to achieve a target fuel mixture and expect to see a change in the fuel mixture by monitoring the Oxygen sensor. If it does not see the change it know's it has made it will trigger code 43.


This code can be difficult to diagnose. So reset the ECU and see if it comes back. If it does then read bellow.


Items to inspect are


- quality of your fuel used
- Oxygen Sensor(s)
- fuel filter
- Injectors
- fuel pump
- main PGMFI relay
- fuel pressure regulator. ( ensure the vacuum line is connected )
- fuel return line. ( ensure its not clamped off. Its been known to have left a clamp on the return line after a fuel injector flush ).


as mentioned above, you could have this code and have nothing wrong with your car, so reset the ECU and see how it goes.


* Notes

KOEO = Key On Engine Off

KOER = Key On Engine Running

Back probe the sensor, use a paperclip and push it into the connector then touch/clip your multi meter lead to the paper clip





Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

[dsp26]

Hi John,

your right this one is tricky and i'm in need of your skills for this one...

- getting this code now 1 week after rebuild with cams
- had O2 sensor issues prior to rebuild and was replaced during
- CEL comes on 5 or so minutes of idling after driving regardless of how i drive the car
- reset ecu and will check again tomorrow
- genuine honda fuel filter is less than 5000km old
- adjustable fuel pressure regulator set to 38psi vacuum on as per honda specs (45psi vac off i think)
- running the p30-j02 rom but never caused an issue in the months i've been using it
- run on both bp 98oct and mobil synergy 8000 (98oct)

now my question is, is this code solely related to hardware failure or can be due to starvation issues also?

i doubt its a starvation issue though as i'm only on about 136whp..

Thanks in advance

[ECU-MAN]

did you put in a new O2 sensor ?, and has the code come back after you replaced the sensor ?

comonly is due to a lazy O2 signal back to the ECU from the sensor. You may need to monitor the O2 signal to see how snappy it is in regards to throttle responce.

[dsp26]

did you put in a new O2 sensor ?, and has the code come back after you replaced the sensor ?

commonly is due to a lazy O2 signal back to the ECU from the sensor. You may need to monitor the O2 signal to see how snappy it is in regards to throttle responce.

yep replaced O2 because i was getting an 01 code.. that cleared, and cel + stumble stopped (misdiagnosed and thought it was ICM)

i reset the ecu and it's only come back since.. my pgmfi relay's been soldered a while back too.

where would i monitor the o2 signal? at the connector? do you know the voltage expectancy of the o2 for idle signal and which 2 wires/pins? i thought i may as well check for fluctuations on idle since the CEL 43 only comes on after a while of idle anyway...

[CRXer]

click on the o2 sensor link in the first post ron.

u could measure at the ECU,between D14(white/red) & ground(black wire on A plug),just flip the little flap open on the back of the plugs,it will give u better access to the pins to measure,becareful not to short anything out with your probes.

it should fluctuate on idle between about 0.1 & 1V,if it just stays low then it is lazy or possibly your "magic" rom is just idling lean.If i was u i would promptly bury that rom & appoint the new engine manager & then work from there.

btw do u still have your old dead sensor,i might be interested in it?

[dsp26]

click on the o2 sensor link in the first post ron.

u could measure at the ECU,between D14(white/red) & ground(black wire on A plug),just flip the little flap open on the back of the plugs,it will give u better access to the pins to measure,becareful not to short anything out with your probes.

it should fluctuate on idle between about 0.1 & 1V,if it just stays low then it is lazy or possibly your "magic" rom is just idling lean.If i was u i would promptly bury that rom & appoint the new engine manager & then work from there.

btw do u still have your old dead sensor,i might be interested in it?

haha thanks.. will dotomorrow morning, good thing i still have those trust expensive old school analogue multi-meters to do this stuff.. much easier to see fluctuations.

btw ecu-man was the one that provided me the 'magic' rom upon my request.. it clearly works far smoother than the shitty skunk2/spoon whatever i had that came free with the chipping kit + because x-over is slightly higher, it doesn't have the minor dip other stock b16s have... good investment from John methinks though

as for the dead o2 sensor.. shoulda asked me a week ago, just chucked it out.. why would you want the dead one anyways.. my car seriously randomly shut off with it..., i do however have 2 new icm's now :/

[CRXer]

my apologies,i thought u were still on "the" rom.It could still be idling lean though with the new setup,idle mixtures are fairly fine tuning.

i just wanted the plug off the old sensor,cos my engine loom plug is just hanging there still live now on the heater side & i wanted to plug it off to stop it getting full of crap & potential problems.

[ECU-MAN]

that rom you have is a stock 203 JDM rom,

anyway was the O2 sensor a New Honda one or new aftermarket one or 2nd hand ?

[dsp26]

that rom you have is a stock 203 JDM rom,

anyway was the O2 sensor a New Honda one or new aftermarket one or 2nd hand ?

lol, didn't wanna admit it.. don't think it's Honda... it was purchased from the USA.. advertised as an OEM... i knew OEm was Denso, but I was hoping they had different OEMs over there....

but I put one in the Mrs DC4 as well and no issues whatsoever.. been on hers 1 week longer than mine and I dare say she drives her car a tad harder...

as for the rom, thanks for it i love it.. so smooth as per dyno graphs... the one Jason and I label as "the rom" was the spoon/skunk2 one i was telling you about... absolute rubbish... no gains anywhere versus stock p30-a00 but a massive loss in midrange (about 5kw) due to x-over being set to 5200rpm, dip isn't even flat, it actually curves down before climbing again sharply though.. hence the "feel vtec harder"

can post it over to you in case your curious about what the maps look like.

[beeza]

and I dare say she drives her car a tad harder....

[stevo716]

My cars pretty extensively modified
but I get a fluctuatin idle and once the ecu lights come on (throwin this code)
it stops
alot of things to diagnose so thought id ask first, to see if this goes in a certain direction.

I've got a 68mm tb and skunk2 IM , bigger valves and stage 2 cam that wud affect air flow
Im yet to get tuned, but dont wanna go to the tune, if i got somethin faulty
so wondering if its a tune prob or not

[ECU-MAN]

if your AFR at idle is out of whack then you can get code 43


best start by checking the operation of your O2 then your AFR throught the RPM Range