I just swapped an '05 5.3 into my '68 Chevy. Starts, runs, and drives, but is running rich on the driver's side bank. So rich that it will blow black soot all over the concrete, but just on that bank. I just pulled codes and I get PO131, PO135, and PO155. I left all of the O2s and had W4M tune it. I modded the harness, but didn't touch any of the engine wires. Any suggestions? It runs great until it warms up, which would tell me it should be an O2, right? I'm wondering if I didn't wire something I needed to. Love the swap though, but am ready to get it running right! Thanks for any help.

 

Sounds like you have issues in closed loop, IE the 02's are feeding info to the PCM for lean/rich conditions. I would suggest that you break out the trusty multimeter and check for continuity between the O2 sensor pins and the PCM. If it is good, go back to your tuner.

Jack

 

Thanks for the reply. I'm wondering if I maybe pinched the wires when I installed the engine. It seems weird that 3 out of 4 O2 sensors would magically go out at the same time.

As a side question, bank 1 is still the driver's side on a LSX right?

 

I believe that is correct...don't quote me on that one

On a side note, why did you keep all 4 sensors, are you running cats?

Jack

 

Yes, I'm running the cats, but if I have to send my PCM back I will have Jesse remove them. I figure if I run it like this too long I'll have to anyway since they'll be plugged...haha.

 

The easiest way to remember bank one. It's on the same side as cylinder one.

 

Check the continuity through those O2 Wires, if they are good, then give Jessie a call and see what he has to say.

Jack

 

Well I'm still having problems. I traced all my wires, all have continuity. I did find a burnt fuse though, so I replaced it and those codes disappeared...of course, I'd forget the obvious things like the fuse box...haha.

Well, that didn't help matters, so I borrowed my uncle's scan tool that displays live data, and found things waaay out of wack. First off, After the o2 codes disappeared, a PO171 showed up.

Now the truck is running poorly all the time, not just before it warms up. I took live scanner data down earlier. I had not ran it before this, so it was cold. I wrote down the data before I started it and while it was running.

This is what I recorded--

Throttle--18%
fuel sys 1--OL Fuel sys 2--OL
Airflow (g/s)--0 Off, 15.9 running Map (KPA)--100 Off, 48 running
LT Trim B1--25%
LT Trim B2-- -2.3%
ST Trim B1--0 off, when started it climbed to 50 over the course of about a minute
ST Trim B2--0 off, went to -1.6 when running
02 B1-S1 (v)--1.105 off to 0 when running
Trim B1-S1--0 off to 50.8 running
02 B1-S2--.415 off to .035 running
Trim B1-S2--said N/A
02 B2-S1--.445 off to .15/.7 running
Trim B2-S1--0 off to -1.6 running
02 B2-S2--.415 off to .730 running
Trim B2 S2--said N/A

When running, the exhaust wreaks very heavily of raw fuel.

I guess my next steps are going to be vacuum leak hunting and I'm going to clean the injectors. I'm probably going to send my PCM back to Jesse and have him remove the rear 02s, since I'm wondering if a cat may be plugged; and also my fan isn't kicking on. It also seems like my front 02s aren't working correctly? As you can tell, I'm kind of lost. Hoping you guys can help me out!

 

not sure if this will help. we had a jeep that done the same thing. We did not have the emisions canister on the jeep. the tune was supposed to have deleted the canister but we did not vent the tank and it was making it run rich. As soon as the ck engine light came on it would try and clear up.

 

Hmm, that's also a possibility. I had W4M keep the evap, but I cut the wires that run to the canister. I guess I need to have him delete that also, but it wasn't throwing any codes for that, so I wonder if it could still have anything to do with it? Thanks for the thought, I'll check into it!

 

Any more insight? I'm ready to drive this thing. It's gonna be very very fun...alot more powerful than my 350 I had just built!

 

you are right your o2 senors are way off. they are actually telling the computer that you have a lean exhaust and it is just dumping fuel to try and richen it up. try just unhooking them and see what happens. this should send the system back into open loop. if it clears up, i would look at bad o2 sensors. also. check for exhaust leaks expecially before the fron o2 sensors since they are the ones that control fuel. check for some leaky injectors and correct fuel pressure. make sure that you have good grounds as well.

just out of curiosity, did you happen to look at the coolant temp. with the scan tool?? you could be running into a problem there with it dumping loads of fuel from thinking the engine is cold. would also explain why your fans are not coming on.

 

is that long term a positive 25%?

 

Yes, it is running 25% LT on bank 1. The temp was climbing on the scanner.

 

i would check for any unmetered air like exhaust leaks or intake leaking on that bank. Use some brake cleaner and spray around the intake to see if it afects the way it is running.

 

Ok, Will check this weekend. Will also try unplugging the o2s.