Getting 8.5 mpg need help

[swathdiver]

Swap downstream O2 sensors then make a deal with GotExhaust for a new Y-pipe and cats.

 

[BlueCollarTahoe]

gonna swap out the downstream sensor on b2 since b1 was already swapped. save up for that ypipe and cat. i got to fix this emissions code before september. i got a bad feeling its coming from the fuel pump assembly.

 

[BlueCollarTahoe]

So just so I'm clear the b2 downstream is what looks off on the graph right? Ordered the new one this morning

 

[BlueCollarTahoe]

hopefully will be changing out tomrrow. wish me luck. i just put 21 dollars of 87 oct gas/7 gallons at exxon and the EST miles was 35 miles till empty.

 

[swathdiver]

I didn't figure the sensor was bad, I figure the cat is bad. You are wanting to be very thorough so that is why I suggest swapping sensors, if you get the same reading on that side, you know its the cat. If the reading moves to the other side, its the sensor.

GMT900s have different PNs for upper and lower sensors. GMT800 have all four of the same PN# correct?

 

[JollyRoger01]

If the cat is working properly the rear O2s should be half of the max min of what the upstream sensors are doing. Typically in the 400mV range. Uppers will constantly switch. If the rears mimic the uppers on a graph, the cats have failed. Hotter the cat temp the tighter the graph will be.

 

[JollyRoger01]

I had a death in the family so I've been away. Sorry for the late reply.

 

[BlueCollarTahoe]

If the cat is working properly the rear O2s should be half of the max min of what the upstream sensors are doing. Typically in the 400mV range. Uppers will constantly switch. If the rears mimic the uppers on a graph, the cats have failed. Hotter the cat temp the tighter the graph will be.

I had a death in the family so I've been away. Sorry for the late reply.

Sorry for your lost.

I posted the graphs of the 02 sensors at 2k rpm. I was driving yesterday highway speeds and the upstream were jumping downstreams were steady. I hacent changed the downstream sensor on b2. Now today...ran a smoke test for thr evapcode 0455 large leak...folloeing the smoke we foubd a cloud coming from the fuel pump.

 

[HiHoeSilver]

Sorry for your lost.

I posted the graphs of the 02 sensors at 2k rpm. I was driving yesterday highway speeds and the upstream were jumping downstreams were steady. I hacent changed the downstream sensor on b2. Now today...ran a smoke test for thr evapcode 0455 large leak...folloeing the smoke we foubd a cloud coming from the fuel pump.

Could you see where on the pump with a mirror up there?

 

[BlueCollarTahoe]

Could you see where on the pump with a mirror up there?

 

[BlueCollarTahoe]

Was able to touch with hands after we pulled off the wheel well...saturated with grime that smelled like gasoline.

 

[Scottydoggs]

fyi, a large evap leak can mess with your trims.

that looks like the pumps seal is failed, its a O ring.

or it was replaced and not installed right. looks like its time to drop the tank.

 

[BlueCollarTahoe]

fyi, a large evap leak can mess with your trims.

that looks like the pumps seal is failed, its a O ring.

or it was replaced and not installed right. looks like its time to drop the tank.

Yea too bad y'all can't hesr tj4 vid3o lol we were like damnnnnnn. I went to th3 mechanic showed him th3 video quoted me 225 to drop abd replace if I bring the pieces. My inspection is coming up I gottw this done next. Tine to research the pump assemblies. I have the maintence records from the original owner...this is the original pump and seals from the factory was never changed.

 

[HiHoeSilver]

Yea too bad y'all can't hesr tj4 vid3o lol we were like damnnnnnn. I went to th3 mechanic showed him th3 video quoted me 225 to drop abd replace if I bring the pieces. My inspection is coming up I gottw this done next. Tine to research the pump assemblies. I have the maintence records from the original owner...this is the original pump and seals from the factory was never changed.

No research. AC Delco. Rock auto. 5% discount code.

 

[BlueCollarTahoe]

Which one? I seen a few that will fit it seems. I would prefer to get the best one I can afford. This is not something I want to deal with anytime soon again.

 

[Scottydoggs]

job really dont seem all that bad.

 

[BlueCollarTahoe]

I dont have a garage to work at. I basically have a parking spot at work that in can only do so much in lol

 

[Scottydoggs]

i know you all do repairs in the pep boys lots over there, hell ive done brakes in my own pep boys lot here.

i also dont have a garage, but i manage to do engine and tranny swaps, brake jobs, what ever else pops up. i do as much myself as i can. all but alignments really. you could do this job in a parking spot on the street too.

 

[JollyRoger01]

That can definitely create a vacuum leak via the evap system. Take a can of carb cleaner and spray around the base of the passenger side intake manifold. There's definitely something leaking on that side. Looking at the data it's showing almost double the reading throughout all conditions. Except 50 mph.

It's easiest to for a gasket leak first thing in the morning while the engine is at its coolest point. The longer it runs the gaskets will begin to expand bc of convection.

 

[BlueCollarTahoe]

i know you all do repairs in the pep boys lots over there, hell ive done brakes in my own pep boys lot here.

i also dont have a garage, but i manage to do engine and tranny swaps, brake jobs, what ever else pops up. i do as much myself as i can. all but alignments really. you could do this job in a parking spot on the street too.

That can definitely create a vacuum leak via the evap system. Take a can of carb cleaner and spray around the base of the passenger side intake manifold. There's definitely something leaking on that side. Looking at the data it's showing almost double the reading throughout all conditions. Except 50 mph.

It's easiest to for a gasket leak first thing in the morning while the engine is at its coolest point. The longer it runs the gaskets will begin to expand bc of convection.

Yea ive done allot of stuff on the truck but when i run into frozen bolts and stripped stuff thats when it gets tricky sometimes once your past a point there's no going back and if u cant do it gotta get the car towed to a shop.

Will grab some carb cleaner tomorrow and try this Monday. Should I turn on the engine then spray around right on start up? Should I wait until after the fuel pump is changed out sinxe it can be affecting this or it doesn't matter?