I have started to get code 43 for some odd reason,i read that it may be the o2 sensor so i bought a brand new one from honda,and i still get the cel,and it has fried 3 damn ecu's. Is there a typical cause for this problem,im starting to think it is my fuel pump because it is a walbro 255 lph. I have no driveability issues except a low idle,but it runs good and doesn't hesitate....

So far i have changed..

O2 sensor,all injectors,fuel pressure regulator and filter,distributor,but im still getting this issue and its costing me ecu's!!!!!!!!

Any ideas,or anyone think that it is my fuel pump????


Modified by jaredvabeach at 3:53 AM 5/8/2008

 

what part of the ecu is frying out?

 

q31

 

perhaps you have a wiring problem..did this start right after the fuel pump install? if you suspect the fuel pump to be the problem, why not swap it back to stock and see what happens? it takes alot to fry an ecu man, it might be something bigger than the pump

 

No thats the thing,the pump has been in for a while. I was told that it fried q31 because the evap and iat plugs were crossed,but i check the ecu,the shock tower,and the plugs them selfs and they arent crossed......


I just read this,
The Evap. Purge Sol. is controlled by Q31. It's common when converting from OBD2 to OBD1. If you plug the IAT sensor into the Evap. Purge plug then you will fry both the sensor and Q31 on the P28 board. How do I know? I did it less than 2 weeks ago.


thing is,my evap plug has been cut off and the emissions stuff had been removed,i dont understand.

https://honda-tech.com/zero...10571

 

are you positive that you cut off the EVAP connector? There's basically only one way to blow Q31, the EVAP output has to be seriously loaded or shorted to ground. (ie too much power)
The IAT does this nicely, plugs right in and the harness is the right length.

Even if you only have one of the plugs, in the wrong location it will blow Q31.

What are you wire colors at the IAT? (also which harness are you using?) I can tell you if it's wrong.

It is also possible that your cut cause the wires to be shorted... you did tape them up separated correct?

 

Im not 100 percent positive but i believe the iat is green/white and red/black...

anyways i know its the iat because its a white plug(guess its hondas way of trying to save the ecu)

as for the evap,i cut the plug off because the coolant temp.plug got dry rotted from a heater hose blowing out,so i used the evap one as a replacement,since the intake manifold i was using didnt have the little evap vacum nipple.

but today,i put a new plug on the evap wires,and plugged all the emission crap back up,after pulling my harness basically apart to make sure somehow the wires didnt get crossed.

So far so good,i drove around for about 6 miles,just to get gas and the code didnt come back. sad thing is here is my tally list.......

3 iat sensors
1 virgin p28 ecu
1 p05 ecu converted to vtec with a "skunk 2"chip lol
and today my chipped p72

if it frys my chipped p30 tomorrow im going to go nutsssss.

enough blabbing,the car is a 93 honda civic lx,b16 longblock with brand new 00 type r complete intake manifold,although it also did this same crap when i had a sohc turbo in the car....i just need a new harness to cancel all possibilities of this one being bad


Modified by jaredvabeach at 4:31 PM 5/8/2008

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jaredvabeach &raquo;</TD></TR><TR><TD CLASS="quote">q31</TD></TR></TABLE>

Your IACV and the IAT could be mixed up- the connectors are similar, check it and get back to us...

 

Well the way i check it is i will let the car run,then unplug the iacv,if it throws the iacv code then i know that i have the iacv plugged up correctly. Same with the IAT,but seeing how the evap doesnt throw a code i just plugged it up anyways. I have never had the evap plugged in on my car,and now this started happening.......

 

OK got a new iat,evap solenoid,and ecu,the q31 transistor is good and intact but everytime i drive and get on it i throw code 43,what can cause this,i have no driveability issues till the code comes on.Sometimes it wont even come on.

 

[QUOTE=im starting to think it is my fuel pump because it is a walbro 255 lph. [/QUOTE]
u probably wired tha pump wrong or probably a wire is touching ground. code 43 is fuel supply system

 

Now that its not frying the ECU. The code may actually be coming on because the O2 is working corecrtly and senses a rich or lean condition. Double check the basics like both ignition and cam timein, and make sure your getting a good spark. Im not sure if this is the reason, just putting in my .02

 

Fuel pump has been in for about 6 months and no issues. As for the motor,it has slightly weaker compression on cylinder one because of burnt rings. I plan to rebuild the motor in about 2 weeks,but im trying to get all the kinks worked out before i start tearing stuff apart.

I only have the downstream o2(the front one)the secondary heated o2 has been disabled on crome.

Im kinda confused on the fuel pump issue,i mean it runs good,starts everytime on the first bump of the key,and it has yet to have a no start condition.

 

Ok replaced my fuel pump,o2 sensor,and engine wiring harness and i still get the code if the engine is under load.

 

OK i have changed out the motor,oxygen sensor,fuel pump,.and wiring harness since i started getting this problem.


But the cel still comes on when the engine is under load,what am i missing?????????

 

Still need a little help,i know for sure its not the oxygen sensor,since it still does it while its unplugged.