Good day all, been battling a Code 43, check engine light. Light comes on once you are above 30 MPH, if you shut down and start again, it is gone till you go over 30 MPH, you have to get the codes to show before you shut down the engine, if you do not and turn the ingition back on Code will not show. Replaced, plug wires, distributer cap, fuel filter, wires, spark plugs ( 3) O2 sensors in 3 months, if you put in a brand new O2 sensor, ya OEM, light will stay away for about a week then return, just replaced fuel pump with an OEM pump(260 bucks). Almost broke from chasing this code, car runs great even with light, occasionaly, once a month or so it will stumble at slow speeds but clears up, there is no code when it stumbles. Even repaced main relay twicwe in 3 months as a precaution. Any help appreciated

 

What is the year & model of your Accord?

Have you done any sort of electrical troubleshooting? I.E. Check to see that there are proper voltages at the O2, ECU and Fuel pump? Just wondering becuase it could be a faulty wire or your ECU. When your not having any driveability issues in conjunction with a code 43 usually indicates the O2 heater circuit. If you notice stumbling and hesitation however, it usually points towards a fuel supply issue. You replaced the fuel pump and filter, have you checked for clogged injectors or tested the injector resistor box?

 

Thanks for the prompt response, the vehicle is a 92 accord ex sedan with 115 thousand miles on it. I pulled the distributer off as it had a small leak also and installed a new gasket, cleaned everything up with electrical cleaner and sealed all connections with dialectric grease. usually the CEL does not come on till you are on the road for at least 4 to 5 minutes and disappears once you shut down and will not show again till you are driving for for 4 to 5 minutes. I did check the voltage at the plug for the o2 sensor that seems good, one thing I am thinking about is a new coil possibly, but the new plugs are running clean with no carbon or any kind of build up, indicating the cylinders are firing correctly it seems. One interestign this is that if I install a new 02 sensor the CEL will stay off for about a week till it returns, but voltage wise across the contacts on the sensor itself shows it is still good. Of note even with the CEL car runs like a champ and gets great milage on the highway. No loss of performance at all
Thanks

 

Sorry forgot to add to the post, I have not checked the fuel injector resister box. Does anybody have some info on how to do that.
Thanks

 

I have attached a PDF of the 5th gen (94-97) Accord fuel supply system trouble shooting guide. It should be the same procedures for the 4th gen (90-93). Testing the resistor box is on page 15 (11-89)

 

Hi Ghost,
Thanks for the diagrams, ran the tests on the resister box, checked good, tested the coil also and it was a bit weak, replaced coil cleared code, test drove, CEL returned and it is a 43 still. Hesitates if accelerated hard when the engine is warm, anybody with ideas as I am stumped??????

 

Do you know anyone with an 92-93 Ex Accord that you could swap out the ECU and test that out?

Other than that I'd suggest testing the fuel pressure regulator. What condition is the FPR vacuum hose in?

 

Thanks again for the tips, I will take a look at e-bay and see waht I can come up with as far as an ECU for the EX.
Much appreciated

 

Bought and swaped out ECU's, changed out fuel pressure regulator, and installed another new o2 sensor, check engine light still comes one with the code 43, basically anything remotly associated with the fuel system has been replaced.

 

Wiring?