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Old 08-03-2009, 10:19 AM   #10
Element Tuning
Former Vendor
Member#: 54918
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Gaithersburg, MD
673 WHP Element
Tuning Pro Comp Engine


Originally Posted by n2oiroc View Post
how about cold starting. when its 80 out it starts great, when its 60ish and colder it chugs along at 1,200 rpm or so (target is 1,500) and vacuum is 12" or so compared to 20" normally. i tried adding and subtracting fuel and it makes no difference. after a couple minutes it just snaps right out of it and runs normal.
Ok the couple minutes and it's fine is a key sign. Typically when the car is excessively rich at start (low idle and vacuum is a sign of this) but cleans out after 1-2 minutes it's due to the "Post Start Enrichment" and "Post Start Enrichment Decay." Basically you need to reduce your post start at the colder coolant temps and possibly the decay time also. First start by reducing the "Post Start Enrichment" only at the coolant areas where you are having issues.

Post Start Enrichment: This is used to increase fueling right after the engine starts to help stabalize the idle. This settings varies quite a bit if you have an engine with cams, TGV deletes, porting, etc vs. a standard engine.

Post Start Enrichment Decay: This how long you want the Post Start Enrichment to remain active the engine starts. Typically this is set to 60-120 seconds but decays the fuel enrichment over time.

Phil Grabow
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Last edited by Element Tuning; 08-03-2009 at 10:25 AM.
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