Strangeness with open loop idle lean limit (B3607)

[turboberserker]

If I set this to 13.5, the truck idles at 13.5.

If I set this to 14.63, the truck idles at 14.63-14.7

If I set this to 14.999 the truck idles at the AFR I have set up in B3647 (15.5 with a command AFR of 15.06)

If I set this to 15.25 the truck idles leaner than my target AFR (15.6-7 with a commanded AFR of 15.19)

If I set this to 15.5, the truck dies from being too rich (runs about 60-90 seconds and goes from 12-10 AFR and then dies).

What gives? For now I'm using 14.999 and pretending I understand it :)

[MN C5]

If your VE table is off by a large amount your commanded AFR vs your WB will be off.

You might have a few VE cells that are wacking it up. Depending on how its idling the map readings might be hopping around hitting those cells. Are your timing readings pretty steady?

Those are my thoughts...

[turboberserker]

I think something is screwy -- today I was doing some tranny tuning and burning a bunch of tunes... Well, long story short, it was as if I've never done any VE tuning at idle... It was all over the place. It was also about 20* hotter today than previously (was 83*) but it was making the truck run pretty rich at idle, then 2 minutes later it was back to normal.

I'm starting to wonder if I have a faulty injector or something.

[MN C5]

Hope you get it figured out, and its some thing easy. You could do the cylinder balance test shift ctrl F7 ....


83 degrees, its up to 3 above zero at my house.... To darn cold to even fire up the SS.

[turboberserker]

Ouch! That's a bit nippy


I'll get it figured out -- it may just be that I need more autotuning like you suggested above. The problem is that I see strange splits (794mv bank1 - 59mv bank2) and given who I bought the injectors (APE) from and how they arrived (in a greasy ziplock bag), I don't really trust them. They are all the same injector, but no telling how many miles they have on 'em. I purchased the stuff and put it all together a few months before it came out that APE was looting other people's cars in their shop for parts due to internet customers...

The injectors are probably fine, but given that whole mess, its always the first thing I think of when something screwy happens to my fueling. I need to do a resistence test on them to see if I have a sticky loop somewhere, but I keep thinking it would be cheap to just buy a brand new set.. lol