Strange Code

[Sparkplug51]

Hello , I have a 04 L's v8. Running like it has a misfire but when I hook up code reader and show my live events while engine running it shows a fail of OL in the main fuel system. I looked through the shop manual and I didn't see anything about a OL fault. Does anyone here ever heard of it ?

 

[joegr]

How about the actual five character OBDII code?

 

[1LoudLS]

well seeing how often the misfire has to get real bad before the LS will throw a code, it probably is misfiring...

 

[Sparkplug51]

There is no Code. It happens when I hook up my diagnostic tool and watch a live event of engine running. I do know that by running this test I was able to watch all the sensors work. That's when the fault of OL will appear while testing. It will flash O or OL/Drive or OL Fault. O at idle. OL/Drive when gas pedal is touched then the OL Fault will flash and then acts up. Now I have increased Intake air tube size from stock 3" to a custom built 5" intake runner with a cone type filter. MAF , IAT , and all other sensors were reused and incorporated into the new Air filter system.

 

[Sparkplug51]

Once this happens it runs like having a misfire, and the gas pedal does not work

 

[joegr]

The MAF is probably not correctly measuring airflow any more. Put the stock intake back in and see if the open loop problem goes away.

You have a 19.64 square inch area of airflow, when the PCM thinks the MAF is measuring airflow through a 7.07 square inch area. You may be getting about 2.8 times as much air as the PCM thinks you are. This results in a lean mixture and forces open loop mode for fuel metering. That's one theory, anyway.

 

[Sparkplug51]

The MAF is probably not correctly measuring airflow any more. Put the stock intake back in and see if the open loop problem goes away.

You have a 19.64 square inch area of airflow, when the PCM thinks the MAF is measuring airflow through a 7.07 square inch area. You may be getting about 2.8 times as much air as the PCM thinks you are. This results in a lean mixture and forces open loop mode for fuel metering. That's one theory, anyway.

Your probably right. When driven on hwy and you open it up the power level increase is amazing but during city driving and when you just barely use pedal that's when it goes through its loop. I'll give the other a try , but man the power