Leviata-N

Hey people I recive the code 43 on my Check Engine ligth. So any ideas why this happend.

platinum00

i believe that code is this:


Fuel Supply System
defective or malfunctioning fuel supply system

have any fuel mods ? , need a new pump ?

platinum.

Ricey McRicerton

I want to say its something about your "Fuel Trim".

I used to have it too. It comes from basically running either too rich or too lean. Have you done anything to your car recently that would change fuel delivery?

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ricey McRicerton &raquo;</TD></TR><TR><TD CLASS="quote">I want to say its something about your "Fuel Trim".</TD></TR></TABLE>

Correct - and the Fuel Trim parameter is adjusted by the O2 sensor.

So the question becomes:

Is the O2 sensor just hosed -or- Is your a/f ratio that screwy that the ECU can't use the fuel trim parameter to bring things back to where IT (the ECU) wants things to be?

The ECU has a job to do - clean emmisions, good gas mileage, good driveability, etc etc...when you try and change things from that equation, the ECU is gonna complain.

B18C5-EH2

I'd say that 9 times out of 10 the code 43 is a direct result of a bad oxygen sensor. Lots of times the code 43 is accompanied by a code for an o2 sensor as well.

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">I'd say that 9 times out of 10 the code 43 is a direct result of a bad oxygen sensor. Lots of times the code 43 is accompanied by a code for an o2 sensor as well.</TD></TR></TABLE>

Chicken or the egg....

Which came first: Did the O2 die from normal use or did a rich afr kill it?

If a rich afr exists and the O2 is replaced, the problem really isn't corrected and is bound to show up again in due time, which means the new O2 will suffer the same fate.

B18C5-EH2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

Chicken or the egg....

Which came first: Did the O2 die from normal use or did a rich afr kill it?

If a rich afr exists and the O2 is replaced, the problem really isn't corrected and is bound to show up again in due time, which means the new O2 will suffer the same fate.</TD></TR></TABLE>

Well what do you suppose the diagnostic flow chart for a code 43 looks like then?

I'd check, but our All-Data isn't working because those ******* sent us last quarter's discs again!

EDIT:

I'm about to look in our 1992 Civic book to see what it says about a code 43.

EE_Chris

I'd have to check my Helms for the diagnostic flowchart but I don't see too many people complaining of code 43 (or 45) from a stock setup.

I'm coming from this angle: A person uses a GS-R ECU w/ VAFC on a B20 and gets a code 43. He replaces the O2 with new unit only to arrive back at the code in a matter of days.

So what was wrong here - we know the O2 ain't bad?

Or how about someone has a crack in their exhaust manifold leading the O2 to output a lean signal making the ECU richen things up when in fact the target a/f ratio was initially spot on?

I'm just hesitant to ever say its the O2 sensor when the setup is not stock - is that the case with the original poster - I dunno - his post lacked that info.

B18C5-EH2

I checked the honda book for 1993 Civics.

A code 43 with no other codes, and no drivability or idling problems has a flow chart on it. It envloves testing voltage between pins, etc. etc. and guess what it all boils down to?

Primary o2 or the ECU itself.

If the code 43 is accompanied by drivability or starting then it's a different ballgame. Then it can be all sorts of different things such as injectors, fuel pump, main relay, fuel pressure regulator, etc. etc.

So again if the car exhibits no sort of drivability problems and has only a code 43 then it's probably the o2 sensor.

I hate thropwing parts at a problem just as much as the next guy, but unfortunately sometimes we're not left with much choice in the matter.

EE_Chris

Agreed - if things were stock, I'd suspect the O2 as well.

So I'm curious then: Where do you see the majority of Code 43's coming from (here on HT) - stock or modified setups?

I hate throwing parts at a problem as well, and sometime you are left with no choice but that - but I would hate to see people throw in a fresh O2 EXPECTING it to fix their problems when in fact their a/f ratio is just that screwed up or their setup is just so far off from what the ECU can handle.