Won-Ton

Hi folks, I have bought some stuff in the classifieds but this is my first technical post.

Motor:
2004 LQ4
Torquer V2 Cam
317 Heads
Stock Bottom End
42 lbs injectors
Yukon Coil Packs
Lingenfelter Ported TB
Lingenfelter MAF #1257932 iirc
Through the mail tune from reputable tuner

Past Issues:
Ran PCV incorrect - Pulled oil into motor, fixed and ran on jackstands fine since.
0200 code - (2) Faulty Injector Plug Adapters
Fouled plugs because of PCV issue

Current Issue:
Especially once warmed up it wants to stall when idling, especially when in gear. Breaks down and backfires under acceleration, the more load on the motor the more it breaks down....and lack of power. Higher RPMs are not as bad, issue more so from off idle to ~3000rpm. I unplug the MAF and it changes the idle slightly but still runs just as poor. Unplug the MAP and it dies instantly. For the first time I got o2 sensor codes, p0154 (x2) and p0155(x2) as well as a p0101.

What I have tried so far:
Compression Test: 180 across the board
Corroded Connector on the MAF
Replaced the MAF Sensor P0102 Code...Currently wired A-MAF Signal, B-GND, C-IGN, D- IAT, E- IAT I believe it is correctly wired now, before I had gnd and ign swapped. I have found 3 different versions of wiring it so far.
Swapped the MAP Sensor 2-3 Times (Had a P0106 code at one point)
Swapped Plugs and Wires 2-3 Times
Tried a longer intake setup, with no change. Might try it again after I swapped to the newest MAF Sensor & Wiring as listed above.
Did all the typical voltage checks, nothing out of the ordinary.


So my question is, should I call the tuner my friend knows and be looking at fuel trims, MAF or should I iron out the codes I have now? I can't image O2 sensors causing it run/stall like this, but maybe in combination with the MAF? This is my first LS build so I am learning as I go. Also, I installed the newest MAF sensor last night and did not check the voltages or frequency response yet

2xLS1

iTrader: (25)

You cannot troubleshoot a problem like that on an engine with those mods without seeing the tune and a data log.

Won-Ton

Thank you for the response... Dang...so I am wasting my time chasing down the ODB-II codes?

Edit: Should I bother adding the Bank 2 O2 Sensor?

subeone

iTrader: (5)

Throw that LPE maf away.

Won-Ton

No wonder it was cheap on here hahaha

dw456post

Edit: Should I bother adding the Bank 2 O2 Sensor?[/QUOTE]

What?? Is the plug just hanging somewhere?

Won-Ton

I would have to check my notes...I ran the bank 1 oxygen sensor to be readily available (which is installed). I cannot remember what I did with the bank 2 #1 oxygen sensor.

That was part of my reason for posting...I never had an O2 sensor code until I swapped the last MAF and wired it the way I listed in the first post. Did it just default to open loop and not post the oxygen sensor codes 0154 or 0155?

So should I concentrate on these codes before calling a tuner in? I also have a brand new 25168491 MAF to swap in to see if my LFE is just being a pita.

2xLS1

iTrader: (25)

The MAF table in the tune needs to match the hardware being used.

Won-Ton

I was wondering if he used maybe the wrong table? Guess I am going to be fishing out O2 numero dos out of my harness.

LSX Power Tuning

iTrader: (4)

You need both front O2 sensors hooked up (Bank 1 sensor 1 & Bank 2 sensor 1) and the tune has to be set properly for the new MAF. The MAF table for that MAF is no where close to what a stock MAF uses. Those 3 things have to be right before going going to the next step.

Won-Ton

Ok assuming the MAF is setup right. Installing the 2nd O2 could potentially fix my running issues and stop it from running in what is probably open loop/sd.

Really appreciate the help guys....its been three years working on this build and I am so close to being able to use it.

LSX Power Tuning

iTrader: (4)

I agree 100%

See quote above.

jimmyblue

iTrader: (11)

I would force it open loop so you don't have to worry
about what the sensors may or may not be up to.

You need to read MAF frequency to see if it's even
working. Either a DMM that reads Hz, or a scan tool.
And since Lingenfelter was pleased to sell you (or
somebody) that piece, you'd be within your rights to
ask them WTF is the calibration curve. Not that this
has ever worked on Granatelli....

joecar

After you sort out the above you should also get VE table corrected to better handle transient throttle/air and in case the MAF fails.

Won-Ton

It was running open loop since the O2 sensors and MAF weren't reading properly. My first issue with this was the schematic I found online screwed me up. They listed a bunch of MAF wiring pinouts....all of them A-B-C-D-E...mine was listed as A-C-B-D-E. So my ignition and ground were backwards, which ruined my first MAF Sensor.

Swapped in a new MAF, and new Denso Oxygen Sensors and she is running mint, minus the stalling issue. Which is a common issue for my type of rigs. So the tuner is going to double check the fuel trim and tables and bump the idle up...680 is too low for what I do. I also got the tables from LPE and sent them to my initial tuner. Reading back through the messages, he mentioned I will probably need it dyno tuned to get it perfect.

Won-Ton

The tuner I was talking to mentioned that. He had to fix the same thing on my buddys rig.

Thank you guys, really a great feeling to be able to drive it around

kingtal0n

iTrader: (1)

something else to consider. I diagnose ALOT of maf cars with maf issues. A maf sensor is very sensitive to the air that passes through it- a slight turbulence caused by a nearby bend or a compressor wheel, or even the shape of the air filter in front, can cause problems- especially if the maf sensor is larger than OEM for the engine. Many people upgrade to larger maf sensors to gain more headroom for airflow but do not realize the impact this has on resolution and fueling. There is a reason the OEM sizes the maf large enough for the job but not much larger and it is to maintain some resolution, which leads to better response, better economy, better drivability. Indeed as the maf sensor gets larger these things fade away.

Secondly, every molecule of air must be accounted for. In other words, leaks in your plumbing after a maf completely ruin fueling, even tiny leaks will cause an engine to run too rich, and large leaks will make the car undrivable. It is therefore imperative that you boost-leak test all plumbing when you have a MAF sensor (even N/A engines should be boost-leak tested for leaks under pressure, it is a cheap easy way to find and fix leaks)

The order I would tackle this (if I had no way to monitor and observe the maf voltage output or tune the engine)
1. boost leak test (a couple psi to make sure the plumbing is tight)
2. ensure the plumbing has no strong bends near the maf sensor, and that an air filter is being used to smooth the airflow
3. put a multi-meter on the maf to get some voltage output numbers (check for obvious problems like a fluctuation in the values without a cause for example, also pass air from your mouth through to the sensor and register the voltage increase. This ensures the maf is at least "working" to increase voltage with airflow)

4. if you have established 1-3 then you have a working maf in an air tight plumbing with smooth airflow, and the next step is to begin tuning the engine by correlating airflow values (maf voltage) with injector on-times at given battery voltages.

joecar

Corrected.

Won-Ton

I will check for vacuum leaks since I have no vacuum operated accessories.

A concern of mine is/has been how short the intake setup is. Is an idling issue a typical symptom of this?

I will try that boost leak test to be sure. Thanks!

And monitoring the sensor wire out of the MAF, am I looking for Hz or Vdc?


I was driving the thing around this weekend and it ran fine minus the not wanting to idle issue. However, I did see a code indicating bank 1 too lean, but the stumble I could hear was on bank 2?

Heres a quick video of the thing in 4HI which it could not do at all before.

joecar

MAF: Hz