Plum Nuts' Datamaster Log

[98blackbeauty]

Thats a bummer on the wrong connector.

Im glad it worked for you, but with all the problems I had, and from what ive read, im betting thats your problem. I didnt half ass mine either, soldered and heatshrunk then wrapped in a factory like mesh. I kept getting o2 codes and it would spit and sputter, and the exhaust smelt like gas bad.

Just my experience.

the problem with lenthening the leads on the o2 is there is german silver wire used and very hard to solder. That is why I decided to lengthen the wire harness plug side. The stock o2 will always work..

[meissen]

But isn't in a silver wire on the other side of the plug or is it normal wires on the engine harness side?

[steve40]

extending the wires on the harness is no biggie....i'd recheck what was done to make sure that nothing is arcing and you have good joints. getting readings that high points to something not right/bad sensor/big air leak.

[meissen]

He switched the o2s and I datalogged last night while it went from cold start to closed loop and then threw the Left Bank o2 Lean code again. Seems like it's the wiring on the left side that's doing it, independant of the O2 sensor.

[steve40]

how where the short term fuel trims on the right side when it hit closed loop?

[meissen]

On the second data log the Strim Left and Rights were identical to the 1st data log - that's why I think it's the wiring on the left bank that's causing the issue since it didn't flip when he changed the o2s.

[sman]

Didnt realize you lengthened the harness, I figured you extended the sensors themselves. If the condition the doesnt move with the sensor then its either something with the wiring on that side. Could also be a clogged injector on that side, starving a cylnder of fuel? All of the injectors seated properly? Got good fuel pressure?

[meissen]

He didn't take the intake manifold apart that I know of so theoretically - which means jack shit when it comes to cars, I know - there shouldn't be any changes with the fuel injectors but maybe one got clogged while the engine was pulled. Dad's going to work on it some tomorrow and see if it's a wiring issue with the harness.

[sman]

It was just a guess, with the fuel system being apart, did you check to see if you have good pressure?

[meissen]

Well, we know that the pump he is using is ... less than adequate.

Today was pretty productive but also a let down at the same time. We begun by dad redoing the driver's side wiring splice for the O2 sensor. One or two of the solder joints didn't look "great" but they weren't bad either. After he finished that, I asked him where the banging noise was coming from under the car and he said it was the y-pipe hitting the floorboard. He also said it looked like the y-pipe slipped off of the header a little bit, and I was like "Well SHIT, that explains the o2 issues on the left bank... if there's a leak right by the o2 sensor."

So, the next order of duty was to get the car up in the air and fix the y-pipe. We re-clamped and sealed using muffler tape so there's no leaks between the headers and the y-pipe and the y-pipe to the intermediate pipe. So then we did the data log. Unfortunately, that didn't change the left bank o2 lean code.

Dad went out again and kept working on it and he checked the block offs for the AIR system and the driver's side AIR plug was loose. SHIT, that'd let air in.. So he tightened it down and then we datalogged again. While this last data log shows the o2s being a lot more uniform while it's in open loop, the second it goes into closed loop it goes flat and then throws the Lean O2 code.

Oh, and incase anyone wonders, we did pull the PCM BAT fuse so the engine would have to re-learn idle. Figured that was better than using whatever it learned while there were all these exhaust leaks.

Our plans are to wait until the Walbro 340 fuel pump comes and then get my v6 fuel pump out and put the Walbro 340 in. We could be chasing our tails this whole time and it could simply be that my v6 fuel pump just isn't supplying enough fuel to the engine. If that doesn't fix it, we're going to see about checking if any of those injectors are clogged - we still have the stock injectors that came with my LT1 so he can use those if he needs.

Here's the last data log:
http://www.meissenation.com/datamaster/PlumNuts4.uni


The thing that kinda bothers me about the data log is that if you look at this PlumNuts4 log, if I rev the engine while it's in open loop, both O2s go up and seem like they're reading and working normally. It's only in closed loop that the Left O2 goes flat and doesn't want to move anymore. Seems kinda weird to me.

[steve40]

could be a bad sensor, if you had some issues with the wiring, could of caused damange to the sensors.

i did find a set of o2's that are fairly new, the joys of gen 3 changing the connector, so if you want, you're welcome to them.

on the bright side, like you said, looks like you did find some issues and got them sorted out. good thing you got the balance back between the banks, def getting closer to sorting it all out.

do you have a fuel pressure gage around that you could put on the schrader valve to watch the fuel pressure as you rev it and also when it goes to closed loop?

[meissen]

Don't have one right now - we know the v6 fuel pump that it's using would idle at about 30psi when it was in my car and the moment you rev it it would drop psi to about 20 so that's probably part of the problems - hopefully all of the problems - but once the new Walbro 340 pump comes in we'll slap that in and see how it's acting. If that doesn't fix it, then we'll start replacing O2s.

[steve40]

if those numbers are with the vac line removed, you're way off the 43.5 psi factory setting, def sounds like not enough fuel to me

[meissen]

That's with the vac line plugged in.

[sman]

Should be around 50-60 IIRC.