David Guevara

Recently got this code "System bank 1 running lean"
And I hear a creaking noise under my car when Im at a full stop while the car is on and them rpm is very low at points the car shakes almost like it wants to turn itself off, its not the fuel pump because I just changed that and its not the fuel injectors. Im suspecting it can be a faulty fuel filter? It runs normal it doesnt surge or hesitate.

delsolintegra

What kind of car, year and engine?

When you say "bank" that sounds like a V6 or V8.

If it's a civic it could be the O2 sensor or a cracked exhaust manifold near the O2 sensor causing a lean reading condition to the ECU.

Recluse

Its a 1999 honda civic ex 1.6L

David Guevara

Its a 1999 honda civic ex 1.6L

NotARaCist

iTrader: (1)

Reset your ECU, does the code return? How do you know it isn't the injectors? Have you done a fuel pressure test?

Why are you answering for the OP?

David Guevara

Yes i reset it and because I recently had the fuel pumped replaced and it the pressure was good, i have been having trouble with the cat, i couldnt pass the smog idk if thats the issuee

NotARaCist

iTrader: (1)

You say the pressure was "good". Exactly how did you measure it, and exactly what is your fuel pressure? Did you test with the FPR connected, disconnected, both, or did you follow proper testing procedure? I repeat, how do you know it isn't the injectors? Not being able to pass smog is quite possibly related - take a picture of the test sheet and post that.

Former User

Post the CEL codes.

David Guevara

I took it to the mechanic because my cylinders were misfiring all of them and he fixed that issue by changing the fuel pump and fixing some of the injectors with low pressure and that day i got the code of the system running to lean so i cant tell you how he tested it. And the ok i will post the smog sheet but when i got it tested was before all these issues.

NotARaCist

iTrader: (1)

If it threw the code when you picked the car up from the person who worked on the fuel system, they evidently did something to screw things up. If you're willing to do diagnostic tests, we can help you. If you just want us to tell you things to tell your mechanic, then you need to understand that that's not what we do here. It's insulting to your mechanic, and a waste of the time of everyone involved.

David Guevara

I will do diagnostics test I want to try and fix this on my own i want to be able to fix my own car. I will pull up cel codes and post the smog test. How would I test the fuel system? Sorry im still learning on how to fix cars

NotARaCist

iTrader: (1)

Attachment 517180

David Guevara

Here are the CEL codes and Emissions test

NotARaCist

iTrader: (1)

The numbers all look like passes. The fails are what, the fuel cap and the catalytic converter visuals? Why did you fail those two visuals? The smog tech should have told you.

So, you reset the ECU and the code returned? Do us a favor, reset your ECU again, and see if it returns again. Tell us exactly how you're resetting the ECU, and tell us roughly how long it takes for the code to return after resetting your ECU.

David Guevara

He told me the catalytic converter was more than 5 years old and needed to be replaced and the fuel cap he didnt give me a reason why I needed to replace it but the cap did look old and yellow

Former User

Very suspect^, given that you passed the tailpipe emissions test.

Replace the fuel filter, and then go from there.

What exactly was done to the fuel injectors?

David Guevara

Yeah before i took it to the emissons test the computer had got the P0401 code,

I will, and they were pressure tested by the mechanic i took it too and he replaced two of them. I will check them as soon as I can.

Former User

Are you sure? P0401 is an EGR system code. A D16Y8 engine does not have an EGR system.

Are you saying that the mechanic found 2 clogged injectors? If so, he may not have actually fixed the problem.

David Guevara

Sorry it was p0420 code

He told me he replaced the faulty injectors. After he found out the pressure

Former User

This^ is the reason that the cat was replaced.

Low fuel pressure? Why would he replace fuel injectors if the fuel pressure was low?

David Guevara

I havent replaced the cat, but I did reset the ecu after and that code hasn't came up. And for the System running too lean code I reset that and it comes back in a day.

Yes, im not sure tbh all I know really is that I had my fuel pump replaced and two injectors because he said they were faulty. Sorry if that doesnt give you much

Former User

Don't replace it unless P0420 reproducibly repeats.

You seriously must begin critically questioning your mechanic, as he is being paid to fix your car. I would be concerned that he's replacing parts unnecessarily. Was the fuel filter replaced when he replaced the fuel pump? If not, why not? Did he replace the pump because the fuel pressure was low? If so, how did he rule out a clogged fuel filter?

It's very difficult to help you if you don't gather all crucial information from your mechanic and post it.

David Guevara

Im not really sure my car was misfiring when i took it to him on all four cylinders and he changed the fuel pump because the pressure was too low and he told me he had changed two fuel injectors that were faulty. When i went to pick up the car the car was fixed had no misfires up until later that day my car got a CEL with the system bank running lean code.

And if i cant pass the emissions test because of visual inspection on cat wouldnt that mean I have to replace it?

delsolintegra

I had a similar problem with a 93 del sol si D16Z6 (OBD 1).

Turned out to be a hairline crack in the exhaust manifold in the runner just behind the bung hole for the O2 sensor. Caused a lean condition reading to the ECU.

In a OBD 2 system it probably would cause a longer fuel pulse in that cylinder and possibly clog that injector.

I would remove the heat shield over the exhaust manifold and try to visually inspect the area around the O2 sensor bung hole. You will probably have to remove the exhaust manifold to see behind the runner. The crack is something a fingernail will barely detect. I used a ebay header as a replacement. You may not have that option if emissions inspection don't allow a header.

David Guevara

I will check that out, I hear a creaking noise under my car when Im at a stop and the car is idling and it is intermittent and it sounds almost like a cow mooing ha.

Could that be a sign of an exhaust leak that may be causing my car to run lean?