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Old 05-13-2016, 06:20 PM   #1
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Default Low Vacuum at Idle

At idle, I'm only seeing 14-15 inMg on the boost gauge, and 55kpa in TS. I've set the timing to 20*, AFRs are about 13.8 now. What would be some things to check for the cause of this? There are no vacuum leaks, timing belt is good, stock cams. I'm really lost as to what could be causing thing.
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Old 05-13-2016, 06:25 PM   #2
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55kpa at idle in TS is extremely high. I average between 30-35kpa depending on the load of engine at idle.
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Old 05-13-2016, 06:38 PM   #3
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20* is a lot of timing for idle.
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Old 05-13-2016, 06:50 PM   #4
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It is a lot of timing. And 55 is insanely high. But I would like to know the cause of it. It's really bugging me.
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Old 05-13-2016, 07:10 PM   #5
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Set your timing at idle to around 17. Then lean it out to mid 14s for afr.
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Old 05-13-2016, 07:13 PM   #6
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When I do that, it doesn't like to idle as smoothly. Anything over 14.0 and it's unhappy. It will just just around a lot. I was "told" it had low compression wiseco pistons, and a cometic head gasket. I've done a compression test and it seems pretty normal.
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Old 05-14-2016, 10:40 AM   #7
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Either you have a leak somewhere or cam timing is off.
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Old 05-14-2016, 05:25 PM   #8
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There's no way there's a leak, I've done a boost leak test half a dozen times. I suppose the cam timing could be off.. It runs, drives, and boosts just fine. I'll look into that.
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Old 05-14-2016, 07:11 PM   #9
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My tired 1.8 idled in the 45-48 range. Ran fine. Never found a cause. New engine build is like 28-33
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Old 05-14-2016, 07:17 PM   #10
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Compression test came out at 175 across the board. Oil brought them up to ~195 across the board.
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