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Old 01-04-2013, 11:58 AM   #1
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Default Cold start and idling + bonus problems

Ok I'm having slight issues. I had to put the car back to stock for inspection, I drove it like that for like a 6 weeks. I then put the car all back to the way it was pre-inspection. This is when my issues started...sorta. It's also cold out now (colder then when I took everything off) so I know that's also contributing to my problems. Also I haven't been able to datalog any of these occurrences.

This post may be confusing. Here's the abridged version: What settings do I fiddle with to get a good cold start and cold idle?

Ok cold start problem.
It starts fairly well, I have to use the throttle though or it takes several cranks (It didn't do that before but it's cold). I'm about to go out and fiddle with the idle and start up settings but I really don't know what I should be adjusting. Before I had just fiddled with the priming pulse width to get it to start in the cold.

Idle issues.
Until its warm it will not idle. It'll start then die or will die when I stop driving. It also idles really rich like 11:1. When it starts to idle it idles low like <800rpm and fluctuates (I'm used to ~1500rpm). When it's fully warm it still only idles around 1000rpm and fluctuates. Also when warm it's still very rich (11:1). When before it was between 14 and 15:1. If I hold the throttle at 1500rpm it sounds like it used to before and the afr's are good. Again I'm going to go fiddle with the settings and see what I can achieve.

Relevant things that have been occurring.

It has randomly idled high, like 3.5k rpm and higher. I had idle issues before that was just a shorted wire but I fixed that and checked everything else and cant find anything. Eventually I got mad with the idle went out redlined in first and second and bam, its fine. This has only happened twice. Once was after I re-installed all my stuff after the inspection.

Sometimes it hiccups. Like driving then it just stutters for a moment. Now this only happened when accelerating so I finally concluded that it was hitting boost cut but only for an extremely small amount of time, hence the sensation only lasting momentarily. However I have hit boost cut much harder and I know its that because it was like hitting the rev limiter, but at the peak of my power. Could it be hitting boost cut for a moment and that be the source of my issues? I assume the extra boost is because of the cold. I deduced that because I only hit about 14ish psi before(when it was warm) and then immediately tapered off. My boost cut is 16.5psi.
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Old 01-04-2013, 02:15 PM   #2
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I messed with idle pwm and warmup enrichment. That didn't seem to do anything. So I just went ahead and changed the fuel ve in the cells where it was idling. This helped tremendously. The idle seemed to be stable at ~1000rpm. As I was doing this the car did warm up and fully warmed it idled about the same. Until I went for a drive. At stop signs and with the fan on and even the A/C it seemed fine. When I got home it seemed to be idling higher ~1200rpm then moved back into the ~1000rpm area and afr's were stable. When the idle picked up in speed it did start to richen up again ~13:1. Is it possible that I just need a re-tune? I didn't change any cells but the 4 where it was idling. Obviously as the idle increased it moved out of those cells. Right now I'm letting it cool to see if my changes helped the cold start issue. I took two idling datalogs and I'll upload them when I get my tuning laptop out of my car.
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Old 01-04-2013, 03:35 PM   #3
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is your idle frequency set correctly? Been messing with my bro's and was trying to find a frequency that wouldn't make a really loud noise. Found a few higher frequencies that you couldn't hear when the car was idling, except then it screwed up the idle. No matter what amount of PID would control the idle correctly. Switching it back to a lower frequency, such as 153hz, fixed the idle, but his idle valve humms like mad
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Old 01-04-2013, 05:34 PM   #4
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Here's a datalog of the cold start with my unmodified tune. I will check that stuff.
Attached Files
File Type: msl start up and idle.msl (109.3 KB, 88 views)
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