HornstarBU

iTrader: (7)

I'd like some guidance on my final remaining tuning "issue". The car runs great when warm, and at all speeds, just not when cold. I've attached what basically happens on a cold start in an image file. AFR does okay for the first few seconds, idle is pretty high, and then as idle comes down after the initial start over 3-5 seconds, the car either dies, or sputters and requires a tap on the accel to get it to idle okay. Then, over the next minute, it idles lean, until it warms up a bit, and then runs fine.

I've disabled warmup ignition retard (but tried with it on), the EGR (but tried both ways), and tried adjusting MAF comp vs coolant temp to resolve the issue. The other thing I'm not so sure about are the ISCV steps, I don't know how to tune them exactly, I've just used trial and error of "if it's idling too high, reduce that temps step, if it's not able to stay idling, increase until it can".

Any advice on ISCV and/or the lean idle would be very much appreciated. I tried with the Speed density 2.0 9653 rom, which has that entire timing map for warmup, and I didn't have an issue with idle warmup (there was bad jitter though, so I had to switch back to 9417 2.0SD).

Thanks

HornstarBU

iTrader: (7)

Other thing I noticed is that when warming up, my AFR is lean below 2500 and decent, like 14.7 to 15 above that....does that point to anything? I run in open loop all the time.

Evoryder

iTrader: (55)

I had a similar issue and resolved with the MAf scaling vs coolant temp. Increased the numbers in the problem cold idle area.

Iscv numbers lowered in areas where there is a high idle spike

92LaserRs

iTrader: (3)

Have this same issue. Hasnt been so annoying since its been pretty much 100* here lately. Should both MAF COMP tables be adjusted?

Evoryder

iTrader: (55)

Let me post up my settings to see if it helps you guys

Evoryder

iTrader: (55)

HornstarBU

iTrader: (7)

Im going to try your settings tomorrow morning, thanks a bunch for posting that.

JohnBradley

iTrader: (30)

The issue is related to the Post primer enrich decay not being cranked enough. Do not touch the MAF scaling or Asynch stuff.

aaron

HornstarBU

iTrader: (7)

HHow does the post primer enrich decay work, higher means more fuel? I can see how the above tables would make a difference, I guess I am going to need to make one change at a time and ensure they have the desired effect. Many of there tables seem to be less well publicized as far as what they do, when, and how long they do it.....I guess the point is even if I try some stuff in the morning, it is gonna take a few days to get right,

Evoryder

iTrader: (55)

my post primer enrich decay settings in the problem temperatures are maxed out at 1.99% ...I don't believe I ever touched mine.
^ from left to right Fahrenheit above and % below

92LaserRs

iTrader: (3)

Is this table not defined in 9653 or called something different? Im not seeing it. Maybe i need to add it to my xml.

Are these possibly the Post Cranking Trans Enrichment Tables?

Would be awesome to have a Wiki or an update version of Merlins guide that explains allot of the newer defined tables not currently covered.

Evoryder

iTrader: (55)

My last post was "post primer enrich decay" in the 9417 rom

92LaserRs

iTrader: (3)

Yeah either those havent been defined in the 9653 rom, or i dont have the xml additions to try and play with it. After going back through the cold start threads, i remember i changed my latency to get fuel trims in check. Going to adjust the Startup IPW Latency to match and see if that cures things.

HornstarBU

iTrader: (7)

But 9653 has that big 3d table for timing, and post cranking transient enrichment...and a warmup enrichment vs load, which should allow you to fix with those, aye?

HornstarBU

iTrader: (7)

So....the 2 of you recommended diff things....MAF comp vs coolant and post primer enrich decay. Well, turns out if I adjust one, the other changes too! ! ! Lol, so I guess you are both right. I wasn't able to test this morning, way too late waking up, so I will test when leaving work.