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Old 05-31-2021, 06:55 PM   #1
MidnightSun
 
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Question Stuck in open loop

My truck has probably around 3000 miles on a fresh rebuild vg33 swap.

To get to where i was looking for a problem. I noticed my truck seemed to go sluggishly through some of the passes in my area.(could be im just used to sportier cars) Im at about 5400' and the passes im usually going through peak at about 7800'. Initially i thought it could be my timing, because i consistently was having a harder time starting when i was in town around 6500'. Had it set at 15 btc, now set at 20. Didnt seem to change much. Ran codes and got #13, coolant temp sensor. Went through the diagnostics and everything seems to check out. (Ground continuity was jumpy a bit but stayed steady eventually.)

Checked some other diagnostics for relatable problems, #4 cylinder(when pulling spark wires) didnt cause a slow down and seemed to be kinda sparking in the cap. I still plan on pulling the plug and cap to look for any damage and what not.

Afterwards i made sure all the codes are cleared and went on a test drive. Using mode 2 (for afr) i determined after driving about 16 miles that it never went into closed loop.

Lot to go through, but heres my general questions and concerns.

1) Am i expecting too much from my truck, with limited truck driving experience, when going through passes?

2) I know theres a drain on my electrical since my battery drops when parked. How can i pinpoint what circuit could be causing that?

3) I'm assuming that having a possible misfire or some other problem with that would cause not going into closed loop. If that doesnt fix the problem, where would be the best place to go from there?
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Old 06-01-2021, 12:38 AM   #2
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How do you determine the AFR from Mode 2? I've never done that before. Do I need any special tools?

For the battery drain, use a voltmeter to check voltage drops. You can also pull fuses from the fuse panel and look for voltage drops between the terminals.
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Old 06-01-2021, 12:57 AM   #3
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Mode 2 is mixture ratio feedback control monitor:


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Old 06-01-2021, 01:22 AM   #4
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Quote:
Originally Posted by ahardb0dy View Post
Mode 2 is mixture ratio feedback control monitor:


Yeah, but how do I use that information while driving the truck down the road to determine the AFR is 16 like MidnightSun said that he did for 16 miles???
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Old 06-01-2021, 03:07 AM   #5
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Quote:
Originally Posted by jp2code View Post
How do you determine the AFR from Mode 2? I've never done that before. Do I need any special tools?

For the battery drain, use a voltmeter to check voltage drops. You can also pull fuses from the fuse panel and look for voltage drops between the terminals.

Thanks, ill tackle the fuses probably to see if i can track it down.


As far as Afr, i guess i could be using the wrong term. I used that mode and what i did was drive it down the road to get it to temp. My thinking is that when it would get up to temp it should be in closed loop and i could use the blinking to see if im running rich or lean. Since it never went to blinking and both lights either stayed on or off, i assumed it would still be in open loop. Let me know if im doing that wrong. I didny double check going to mode 1, which also has different things going on between open and closed loop.
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