need help deciphering scan tool info

[bufordanthony]

Got a P0420 code popping up on my 99 4L, so I hooked up my scanner to see what's going on. I kinda somewhat know what it all is, but I don't know if it's all happy (suppose not, or I wouldn't have a check engine light). Here's what it says
Fuel system 1 Closed loop
Calc Load 39.2
Ect 195*F
STFT B1 -3.9 to -1.5%
LTFT B1 25 (bad I know)
STFT B2 -3.9 to -1.5
LTFT B2 24.6
Spark adv @ idle 9 and at 2K rpm is about 19
IAT 78*F
MAF 0.537lbs/min @ idle
TPS @ idle 18.8
O2S B1S1 0.080-0.795V (fluxed pretty fast)
STFT B1S1 -2.3 to 10.5
O2S B1S2 0.060-0.710V (fluxed like sensor 1)
STFT B1S2 NA (this is the one that's throwing me)
O2S B2S1 0.070-0.755V (fluxed as fast as bank 1)
STFT B2S1 -4.6 to 0.7

Don't know what all this means together. I know LTFT over 10 ain't good, but what could be causing that along with the code. Cat maybe?

 

[kaytbugsdad]

P0420 is "catalyst efficiency below threshold-Bank 1"....... and since your STFT (short trim) reading on Bank 1 sensor 2(the o2 sensor AFTER the cat) is NA, more than likely your bank 1 catalytic converter is plugged up......

 

[bufordanthony]

Yeah, pretty much knew the cat was shot, but wanted to address the long term fuel trim. Turns out I got 60psi on the fuel rail vacuum hose on, off, no matter what. Reckon all that extra fuel did the cat in. Got a new regulator, and cat on the way. All will be normal again soon. Thanks for the reply

 

[lorenambrose]

I think the fuel pressure is good. There should not be a change in pressure with the vac hose off. What you are looking at under the hood if i'm not mistaken, is a fuel pressure damper. The reg is in the tank. 97 and earlier have the reg on the fuel rail. Pressure should not change vac hose on or off, and 60 psi is darn good as the range is 56 - 72 psi.

 

[bufordanthony]

Ummm, pretty sure it's the regulator. The 3.0L's are in the tank. All the pubs I have on this motor says it's supposed to be at 35psi idling, and with the vacuum hose off it goes up to about 45 psi. Either way 60 is way more, and would explain the super high LTFT, and the "thick" exhaust. Unless of course about 3 of my books are wrong. I don't think this truck fits the "norm" any way. It came from the factory with no EGR.

 

[bufordanthony]

Well lorenambrose, I think you were right, and me and my books are wrong. Hate admitting that, but I have found contradicting info on PSI on my truck. So the right PSI on the 98 and laters are in the 60's and not 30's? If so, sure would have been nice if Haynes clued me in.