Need Help With Engine Codes

[AGypsylady]

We have a 2000 Itasca Class A Motorhome with a 7.4Vortex, 454 Chevy Engine, and have been getting numerous codes indicating that there is a problem with the 02Sensor, Bank 2-Sensor 1. The 02 Sensor has been changed several times, as well as the spark plugs, spark plug wires, intake gasket, valve cover gasket, exhaust gasket, MAS airflow sensor, distributor, coil, cap and rotor, MAF sensor, throttle positioning sensor and crank shaft sensor, a new computer, along with several other parts, as well.

Codes are indicating that it is running lean, CO2 sensor showing no activity. Sometimes it runs really good, and other times it barely runs at all. Compression has been checked and appears to be fine.

Have contacted several experienced mechanics, and no one has been able to find a solution.

Really need to find help, as we are in Oregon, and need to get back to our home in Florida, as soon as possible.

Reaching out to this community, and hoping to find answers to get this Gypsy back on the road. TIA

[Our ride]

Check wiring going to o2sensor,breaks,loose grounding out ect.Also if never sieze.was used it will cause issues.

[Morich]

A real stretch and not my field for current info but has there been any test of the fuel pump? They CAN be intermitant. If/when the pump is not giving full pressure, the whole engine may get less fuel than needed but that can change and then seem to work fine for a time.
My case was a pickup going East/West to Ca. and back. It ran fine and could do "normal" hills but when getting into those a mile or two long, it would die. If we set and tried to figure how many miles to a phone, we found it would start and run again!

Yes, it was before cell phones! We coasted four miles backwards down the shoulder of I- 40 one night (to avoid walking) and when we got to the bottom it started and ran home to Missouri without a hiccup!

Best thought was it was pumping but not enough to keep up under longer heavy load???

[bigb]

Classic indication of a vacuum leak commonly from leaking intake manifold or vacuum lines. Symptoms include worse when cold since as the engine warms up and things expand the leak gets smaller or closes altogether. A couple ways to locate, propane (RPM will increase when propane enters leak) or even a squirt bottle with water (you can hear the sucking noise and sometimes see it when you squirt the leak). Also a smoke machine. You said they changed intake gasket but check for leaks.
Also watching fuel trims in live data feed, you will see fuel increase on the lean bank as the ECM tries to compensate for the lean condition.
Also as mentioned check grounding, and if the 02 sensor is heated which most are, check heater circuit and fuse. Saw a jeep where the heater wire shorted on the frame and fuse blew, it's just a normal fuse in your fuse block. By CO2 sensor I assume you mean O2?
Sounds like they threw a lot of parts at this.
Get the codes and check out Scanner Danner's website.

[bigb]

After re-reading your post where you mention C02 sensor it seems you mean O2 sensor and it is not reporting at all? If so I agree to check the wiring, grounding and test for voltage on the heater wire. If it is not reporting at all ECM will use a default, problem is in wiring. If it is reporting lean ECM will richen mixture visible in live data stream, go back to looking for why, (vacuum leak etc)

[bigb]

Since you are not a mechanic and it is not generally a good thing to bring information from random folks to a mechanic I suggest you post on the Scanner Danner member forum with all of your codes and information you gave us here.
These guys live and breathe this stuff. https://www.scannerdanner.com/forum/...ions-here.html

[Eagle5]

Originally Posted by Morich

A real stretch and not my field for current info but has there been any test of the fuel pump? They CAN be intermitant. If/when the pump is not giving full pressure, the whole engine may get less fuel than needed but that can change and then seem to work fine for a time.

I also wonder if a plugged fuel filter could be causing this? Has this ever been replaced?
Eagle5

[bigb]

https://www.youtube.com/watch?v=adkFTSoxM6Q

[bigb]

No reason to keep changing the O2 sensor, it's easy enough to see if they are alive or not

https://www.youtube.com/watch?v=3RFTS22w6tM

[bigb]

The big question here is: Is the O2 sensor in question reporting lean or not reporting anything? The OP says there is a lean condition and also the sensor is "inactive", need more specifics. What is B2S2 (downstream of the one in question) reporting? What are all 4 O2 sensors reporting? Reporting lean is a whole different matter than not reporting at all.

[AGypsylady]

Thanks for your reply. I do understand that the reports are indicating different things. However, we keep getting different codes each time we have it scanned.

The basic problem is this:

When we start out in the morning, the engine seems to run fine.
After a short while, it loses power and even though gas pedal is to the floor, it will not get above 50-60 mph, (even downhill)
Loud and intense backfiring thru exhaust on de-acceleration
If we keep driving, sometimes it reverts back to running ok
All 4 plugs on Bank 2 are constantly fowling out, within less than 100 miles

Any idea what could be causing this?

[Our ride]

Definitely have a wiring issue,as stated before .Loose or grounding out for coil packs on that bank.