Lean at Cold start on Speed Density w/ 9417 rom
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Lean at Cold start on Speed Density w/ 9417 rom
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
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
Last edited by HornstarBU; Jul 20, 2011 at 12:11 PM.
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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.
Last edited by HornstarBU; Jul 21, 2011 at 05:31 PM.
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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,
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Code:
-25.6 -0.4 17.6 44.6 68 93.2 122 170.6 179.6
Code:
1.99219 1.99219 1.99219 1.99219 1.99219 1.99219 1.75781 1.5625 1.5625
#11
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.
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.
#13
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.
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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?
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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.