Thread: EMS thinks lean - why?

Hi did you get anywhere with this fault? I have the lean bank faults too and the LTFT is showing 25%...I guess that is quite high? I cleared the fault to see if it will come back.

Do you have the high LTFT showing for both banks or just one? Check for intake leaks after the MAF... for example, cracks in the hoses from the rocker covers to the throttle body, leaking inlet manifold gaskets... make sure the large hose from the MAF to throttle body is properly seated and that the hose clips holding it in place are likewise seated and firmly tightened...do not over tighten!
Cheers

EDIT: if u use the Aulro-specific google search function in the bottom left hand corner there's an extensive thread/posts following up on the one you quoted in yr first post. Good luck with it!

Will have a look...pretty sure it was both banks reading 25% on OBD Torque.

Everything Hoges said, plus -

25% is not just high, but its as high as the Eng ECU will go before throwing a fault and moving from closed loop operation to open loop, where O2 sensors are ignored from ECU fuelling decisions. Clearing the ECU faults normally resets it back to closed loop operation, until the faults are raised again.

MAFs are often the key here. You wont always get a MAF fault, even when it is unservicable. Worse still, a MAF can be giving you valid looking values in real time but be outside the operating range. Any decent bump on them, especially an LPG inlet backfire is sure to frag it.

Aftermarket MAFs are not advised, nor for O2 sensors. If you eliminate air leaks on inlet and exhaust side, then clean the MAF with a proper MAF cleaner spray can and then consider replacing MAF and then O2 sensors.

I pulled the MAF...like new but sprayed with degreaser. Truck running a little better but will test run tomorrow night and check for faults again/ltft readings... the MAF readings are in g/s...is that right? Any other readings I could post on here?

These are some numbers I found

At Idle...................... 20 kg/hr (5.5 g/s) ± 3 kg\hr (8.3 g/s) (^)
At 2500 rpm............... 61 kg/hr (16/9 g/s) ± 3 kg\hr (8.3 g/s) (^)
At 3000 rpm............... 90-100 kg/hr (25-27.8 g/s) (*)

22-25kg at idle,90-100kg at 3000rpm in neutral,engine hot all loads off.

At Idle 20 ± 3 kg/hr
At 2500 rev/min 60 ± 3 kg/hr ..

Steve

Thanks Steve...will post idle and 3000 figures...great to have g/s values there!

Originally Posted by Tikka7mm08

Will have a look...pretty sure it was both banks reading 25% on OBD Torque.

This is a long shot...but... check the plastic threaded hose fitting on the inlet manifold to which is connected the hose from the RHS (Driver's side) rocker cover. It can crack and draw air in without being immediately obvious.

In my case, LTFTs on both banks had maxed out at 25%, all connections, hoses etc were tight... was only by luck felt some "give" in the hose and discovered the fitting had cracked with age. You can't drive the car without the inlet manifold hole being plugged somehow.

IF it is a failed fitting, a 1/4" BSP (metric) brass fitting is an exact fit for the existing hose from Rocker cover as well the thread in the inlet manifold. Available from REPCO or Supercheap (<$5NZ -I'm guessing). Wrap the thread with a couple of rounds of PTF plumbers tape before you install to prevent galling (brass/aluminium). It's a tapered thread so don't over-tighten...just enough to nip it up + a little bit!