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MAP problem?

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Old May 17, 2012 | 09:56 AM
  #1  
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Default MAP problem?

After fixing a bunch of random mechanical issues with the car, I got back to tuning this week.

The car has been running ok, not great. AFR is pretty rich, but it ran smoothly.

Yesterday the car had some issues with hesitation, cutting off when in neutral at stop lights, and it sounded rough. Lots of rumbling noises from the exhaust.

Today I connected the laptop. At first I noticed very rich AFR, 7-8, during warmup. I did a short drive around the block and AFR came up to 11-12 under normal driving.

However, MAP never went below 50 or so. Not during idle or low speed/low rpm cruise.


I think the car was using VE numbers for higher MAP than it was supposed to. IE, using 50 MAP instead of 25. Which I think might result in the richer AFR.

Thoughts? How would I verify MAP if that is THE issue?
Old May 17, 2012 | 10:14 AM
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What does your MAP sensor read with the key on and engine off?
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Old May 17, 2012 | 11:32 AM
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Good question. It was showing 98.
PS, thanks for your book. I started reading it again this week.

Last edited by travisb; May 17, 2012 at 12:08 PM.
Old May 17, 2012 | 03:36 PM
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Added a copy of my log.
Attached Files
File Type: msl
2012-05-17_06.41.03.msl (1.92 MB, 163 views)
Old May 17, 2012 | 03:43 PM
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Attached VE Tables.
1. Before run
2. After run - megalogviewer analyzed
3. Difference between the two
Attached Thumbnails MAP problem?-capture.png  
Old May 17, 2012 | 09:19 PM
  #6  
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Ok. I found the problem. The hose to the boost gauge was split on the end and fell off.
Old May 18, 2012 | 09:04 AM
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I was starting to think it was a leak, but you beat me to it.
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