Cold Start Tuning Help

[vn5000]

Yeah you definiteley need to get it sorted before you tune any further.
One thing ive noticed is that your o2 sensor does not rise as hi in voltage as it should for the indicated a/f , it rarely goes over .7 v even when the wideband says 11:1. it should be up around .9 - 1.0 v at this richness.Are you sure you have your exhaust earthed well,and you are not tapping into o2 sig with otther guages.If it were me i would check all your earths .batt to body and batt to engine and exhaust and ecu.Not just visually but with a multi meter.

[muttley383]

Exhaust earthing may not be that critical as I am running a 4 wire V6 O2 sensor.
One thing I have not mentioned is that it is no longer in the original V8 position. I moved it back about 350mm to make sure I was getting gas from all 4 cylinders instead of 2 when using a pacemaker headers.
I have the wideband and narrowband mounted within 100mm from each other.

[vn5000]

Do you have the heater earth and sig earth connected together,or run seperate earth for each.

[muttley383]

I am not sure, it was done years ago.
I do know I have both the signal and 0v wires into the ecm. From memory I tapped into the original O2 sensor signal and 0v wires for signal and run the heater from a relay with the )v being grounded on a chassis bolt.

[monaro308]

A mate of mine had a VY LS1 with pacemaker headers and it kept throwing up O2 sensor codes after having them fitted.
I have heard of a couple more pacemaker fitted vehicles doing the same as the O2 is apparently fitted further down stream.
I read off my Motec PLM and stick to that as i would end up going nuts with EFI-live showing a different AFR to the plm

[vn5000]

Theres a few ways they were wired from factory.vn just had o2 ref earth connected to engine earth ,then later models had two wire and earth connected to d6.As long as you have the sig earth connected to d6 you should be right .And from memory you said its new.
Maybe using that bin i gave you that had ok cold start ,set all main a/f to 14.7 and go for a long drive and see what your blms are telling you.Maybe the o2 sensor mounted further away is not heating properly till you drive it.

[muttley383]

The long drive will have to wait to the weekend due to work commitments during the week.
I fitted the heated sensor because I thought that it could be an issue since I was moving it further away from the engine and may not be getting hot enough.

I assume that if I set all of the main A/F table to 14.7:1 I will have to wait till it has warmed/heated up. Will try this on the weekend and see what happens.

The .bin that you supplied will start from cold and idle but is rich, but does not hunt. When I try and lower the VE's to lean it out it will hunt whilst cold but then smooth out when it warms up. I adjusted all of the suurounding ve cells the same ratio as the .bin you supplied but at a lower level and it would hunt at idle and sometimes stall after approximatley 5 seconds of running.

[delcowizzid]

do you have a knock filter on the memcal cause its all turned on

[VL400]

For cold start you might need to adjust the temp correction tables to get the AFR = target.

Charge Temp - Inverse Temperature term vs Charge Temperature term
Charge Temp - % Coolant contribution for calculating charge temp Vs RPM & MAP


Post start adjustment if its hunting only briefly. You will see the target AFR ramp up to target just after starting it, can adjust that with..
Initial Run A/F Ratio Offset vs Coolant Temperature
Run A/F Param - A/F Time out decay multiplier
Run A/F Time-Out Interval Vs Coolant Temp



This is how the fuel requirement is calculated (there are then a whole heap of modifiers like the post start decay stuff above)...

Code: Select all

		BPW Calculation
 	
	BPW = BPC*T*A/F*VE*BAT*BLM*DFCO*DE*CLT*LSE*F77

  everything labeled "term" is from a lookup table

 BPW = Inj pulse width in milliseconds

 BPC =	KINJFLOW term, Displacement/inj flow rate (Litres/Grams per sec) (0-100% BPW Reduction)
 T   =	Inverse Temp Term (Lookup Based On Charge Temp) (0-100% BPW Reduction)
 A/F =	Inverse air/fuel ratio term
 VE  =	volumetric efficiency term (0-100% BPW Reduction)
 BAT =	Battery voltage compensation term (+-50% BPW Correction)
 BLM =	Block Learn Term (+-50% BPW Correction)
 DFCO=	Decel Fuel Cutoff Term (0-100% BPW Reduction)
 DE  =	Decel enleanment term (0-100% BPW Reduction)
 CLT =	Closed loop correction (result of O2 sensor Proportional/integral closed loop)(+-50% BPW Correction)
 LSE = Low Speed Enrichment Multiplier term (+-50% BPW Correction)



 With Boost...
 F77 = BPW BOOST MULT VS MAP INDEX (Table With 100-200kPa) (0-100% BPW Correction)

[muttley383]

Hi all,
the cold start is not that bad at the moment, just a bit rich. I still have not sorted out my O2 sensor discrepency as I did not have time on the weekend to check it out.

I have a couple of other issues. Engine idle hunting after a hot restart, ie: restarting hot engine after being shut down for only a few minutes.
It is jumping in and out of closed loop idle mode until it settles down. Is this because of the "IAC - Idle MAP Threshold Vs Idle RPM" table set wrong as the engine idles at approximateley 40kpa, or is it scaler "IAC Params - Maximum MAP load limit" that is set to only 35kpa. What should these two parameters be set to or should I leave them as standard.

Other issue is if the engine stalls at idle the IAC increases to approx 110 but fails to stop the stall. On restart the idle stays very high and the IAC steps will only drop to 80 or so and no further even though the TPS is at 0%. Is this related to above parameters?

See attached cold start log and hot idle hunt on restart.