Rich Idle - Please Help!

[white01ss]

Connected the LC-1 to the scanner this week and did a short logging session. Yesss, it worked! My wideband scan shows about .1-.2 lower than the XD-16 gauge. I assume the gauge is correct since it has a digital connection to the LC-1. I'll need to fix that, but the results are still pretty darn close.

So back to topic... Looks like I'm averaging around 13.5-7 AFR at idle. It seems to bounce all over the place. This was in CLSD so the front O2s/LT headers are probably causing some of my richness. Next step is to turn off the O2s and do my first OLSD AutoVE tune.

On a side note here's a summary of my WOT readings:

RPM	Commanded	AFR	Error
3600	10.006452	11.3	13%
4000	10.006452	11.3	13%
4400	10.006452	11.6	16%
4800	9.907182	12.0	21%
5200	9.822727	12.8	30%
5600	9.571667	12.9	35%
6000	9.571667	13.3	39%

Holy smokes! It leans out like a big dog past 4800 rpm. Shouldn't go any lower than 12.2 or so on the upper RPMS, but I'm seeing 13.3.

[SSpdDmon]

I didn't read through the whole thread - but if you're still having problems with a rich idle due to IPWs not falling below 1.8xx, you can change that by zeroing out B4005 and adjusting B3701 until you get the IPWs where you want them. The reason why these tables work is because the base IPW is determined using a calc'd cyl. airmass and what's 'known' about the injectors (i.e. IFR). B4005 and B3701 are then added on top of that. Keep in mind if you go too low, you'll hear it on decel when the injectors don't fire appropriately - it'll " pop" a bit.

[white01ss]

... you can change that by zeroing out B4005 and adjusting B3701 until you get the IPWs where you want them.

I attempted that already but thought MANVAC and MAP were the same thing so I was tweaking the rows around WOT instead of idle! Now that I know what it means (thanks Joecar!), I will tweak MANVAC rows 70, 75, and 80 and see what happens.

The reason why these tables work is because the base IPW is determined using a calc'd cyl. airmass and what's 'known' about the injectors (i.e. IFR). B4005 and B3701 are then added on top of that.

I was wondering what the relationship of CALC'd IPW and IPWVA, thanks SSpdDmon! I assume that the Min PW is checked as the very last step, so if I set it to 2.5 ms then it would never go lower than that.

[SSpdDmon]

I attempted that already but thought MANVAC and MAP were the same thing so I was tweaking the rows around WOT instead of idle! Now that I know what it means (thanks Joecar!), I will tweak MANVAC rows 70, 75, and 80 and see what happens.



I was wondering what the relationship of CALC'd IPW and IPWVA, thanks SSpdDmon! I assume that the Min PW is checked as the very last step, so if I set it to 2.5 ms then it would never go lower than that.

I believe you are correct.

[white01ss]

Lowered my O2 Switch Point table by 8% and it fixed the problem. My idle/cruise AFR now averages 14.7. Also updated the IPWVA table by making each column the same value like hquick did which lowered the idle MANVAC range as well. These changes made other parts of the VE table lean and messed with the idle a bit, but I'll deal with them later.

Also fixed the commanded AFR problem by multiplying the 105 kPa column in the VE table by the BEN factor. Now my WOT AFR doesn't go over 12.0 and is very close to commanded. Again, I'm glad I didn't blow my motor. Thanks for everyone's help, let's go have a

[SSpdDmon]

Lowered my O2 Switch Point table by 8% and it fixed the problem. My idle/cruise AFR now averages 14.7. Also updated the IPWVA table by making each column the same value like hquick did which lowered the idle MANVAC range as well. These changes made other parts of the VE table lean and messed with the idle a bit, but I'll deal with them later.

Also fixed the commanded AFR problem by multiplying the 105 kPa column in the VE table by the BEN factor. Now my WOT AFR doesn't go over 12.0 and is very close to commanded. Again, I'm glad I didn't blow my motor. Thanks for everyone's help, let's go have a

Please post up a copy of your tune (or email me at SAJ79 at aol dot com). I'm curious to see where your injector values ended up for voltage adjustment, min pulse width, etc.

[white01ss]

Please post up a copy of your tune (or email me at SAJ79 at aol dot com). I'm curious to see where your injector values ended up for voltage adjustment, min pulse width, etc.

Sure... I didn't touch the min pulse width table, only the voltage adjustment. I think most of the improvement is due to the o2 switch point table.

	   {B4105} O2 Switch Point 
	   Stock		  LT Headers
CL Mode	Bank-1	Bank-2		Bank-1	Bank-2
0	365	365		340	340
8	435	435		400	400
16	435	435		400	400
24	435	435		400	400
32	450	450		414	414
40	500	500		459	459
48	500	500		459	459
56	550	550		505	505
64	550	550		505	505