No CL Idle or Idle Advance using MAF (Solved)

[PDX5]

Closed Loop Idle and Idle Advance work fine on speed density.

Switch to MAF and Closed Loop Idle and Idle Advance do not activate. All conditions for both features are met and neither engage. Code bug?

SOLVED: The fuelload threshold for CL Idle and Idle Advance in MAF mode is based on MAFload, not MAPload. EGO Control and Over-run Fuel Cut are still based on MAP.

[ol boy]

Looks like your CL idle target was zero during the log. How did you get such a large cranking PW? My car never see higher than 3 to 4 ms when its really cold out. Doesn't start well like that.

[PDX5]

Looks like your CL idle target was zero during the log.

Yup that's what I'm trying to figure out. Do you have CL Idle and/or Idle Advance working on a MAF?

How did you get such a large cranking PW? My car never see higher than 3 to 4 ms when its really cold out. Doesn't start well like that.

We've had sub-zero (-10F) temps here in the NE and the car starts brilliantly year-round.

[ol boy]

I turned cl idle off a while back and have been doing warm up open loop. I noticed your MAF adc6 values are nice and steady. Did you do some sort of large cap before the processor or is the internal wiring as the manual suggests? My MAF ADC line is very noisy. Could be the nature of my set up.

[PDX5]

No cap on the MAF, just wired using the manual.

James, if you happened to check in here can you take a look at the code. I find it odd that Idle Advance and CL Idle work perfectly on Speed Density, but stop working on MAF (with no other changes to the tune).

[muythaibxr]

Idle engages based on fuelload being above a certain value, throttle being closed, and rpmdot being below a certain value. In all liklihood the fuelload is below the threshold you set.

[PDX5]

Idle engages based on fuelload being above a certain value, throttle being closed, and rpmdot being below a certain value. In all liklihood the fuelload is below the threshold you set.

I (incorrectly) assumed fuelload was still based on MAP. What is fuelload for MAF based on (g/sec, volts, ...)?

If I idle at 6g/sec and 1.6 volts: what should my fuelload threshold be?

[ol boy]

You need to look at the value of MAFload. Should be pretty low 15ish.

[PDX5]

Great! That makes sense.

However, my cold idle MAFload is 35-40 and warm idle MAFload is 15-20. In the summer I think idle MAFload may be 10-15.

What should my threshold be for year-round operation? My other conditions (TPS, RPMdot) are pretty strict, but I can see the MAFload stalling the engine with the wrong setting. I'm still learning about the MAF tune, so feel free to correct me.

Also, what about Over-run Fuel Cutoff and EGO control: are they still based on MAP in MAF mode?

[ol boy]

I did not touch the over run fuel cut when I switched over (it still works!). All the parameters seems to be standard MAP, TPS, CLT. EGO is still MAP i believe. What is your car/engine combo?

[PDX5]

I made some datalogs and confirmed that EGO and Over-run fuel cut are still MAP based.

After adjusting the fuelload threshold based on MAFload both CL Idle and Idle Advance are engaging correctly.

Thanks for pointing that out Ken and ol boy.

I have more MAF tuning questions but I'll make a new post in the Support section.