Alright this car is driving me up the wall with this lean condition. The motor is a stock cubed rebuilt LT4 with a CC503 cam and about 1k miles now. The car gives off a rich smell that burns your eyes a little. After scanning with Datamaster, the right side of the motor has a BLM of 145-150 while the left side is about 132-135 at idle. Also whats weird is that once you step on the gas a little the BLMs shoot right to 128 in all the cells. Its only at idle when the car is lean.

I did notice after spraying some carb cleaner looking for vacuum leaks that there was a small leak near a vacuum nipple fitting on pass side and at the pcv valve grommet. After replacing and fixing those issues my car still shows the same really lean condition?!? I have no more vacuum leaks, I cant hear any exhaust leaks, replaced injectors, checked all header and collector bolts, and I even replaced my intake manifold gaskets thinking those might be leaking. The O2 sensors are Denso and were brand new when put on, I had tried swapping the O2s from side to side to see if the more lean condition would follow and it didnt.

I am tired of throwing new parts at the car and not solving the issue, my wallet is getting thinner by the week haha. Im not sure how read the datamaster file to troubleshoot any more deeper. Any help on solving this issue would be great!

 

What size/type of injector are you running? And are the correct constants being used in the tune? Sounds like your injector constants are off. And the BLM's going back to around 128 at anything over 75% throttle is normal.

 

Right now I have 30lb Redtop SVO injectors. I had Ion at madz28 tune the car, I just pulled up the injector constants and they are:

305
305
7782
7782
7782
7782
5585
3998
2960
2411
2045
1770
1556
1373
1190
1038
977
854
763
671
549
488
427
366
336
305
275
214
183
61
0
0

How would I go about correcting the constant values?

 

It should be just one value like 31.XX and so on.

Actually what program are you using? Are you using a tuning software like tunercats or a scanning software?

 

Opps sorry man, the constant is 31.73

 

Ok here is a link you should check out
http://www.lt1pcmtuning.com/tips/#DataMaster
and to reflash your pcm your going to need a tuning software like tunercats.
http://www.tunercat.com/

Heres another good link you should read!
http://www.injuneer.com/ScanMast.html

 

Hey thanks alot man! Im gunna read up on injuneers website, lots of good info

 

Lean but running rich. Wouldn't that indicate it is a false lean? Meaning the O2s think it's lean and the PCM richens the mix.

Since moving the O2s from side to side and nothing happened, wouldn't that indicate you may have a wiring issue? If one the signal wires was near ground, that would give the PCM the indication it was running lean. No?

Mine was just the opposite. The PCM thought it was running rich and it pulled fuel continually until it ran so rough it would jump out to open loop and then go back into closed loop and start the whole crap all over again.

A very easy way to see if it's related to O2 wiring is disconnect one of the O2s and let it operate in open loop.

You can also monitor the signals from the O2s. When disconnected they will go to bias signal of about 450. If they are disconnected and stay near 0, you know they are near ground.

You can also short the signal line to ground and be sure they go to 0.

 

Good idea Speedy, Im going to try to disconnect the o2s and see how the car responds.