PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

start-up/idle issues...imagine that?

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Old Aug 19, 2008 | 07:30 AM
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Default start-up/idle issues...imagine that?

start-up issues since new build install...
this is after ALOT of idle tuning...

LS1, Procharger P1SC, Patriot Stage III heads,
218/230 .605”/.604” 112LSA +3, longtubes

mornings...fires up on first turn over and usually catches itself and idles...
however, after several minutes of warming up @ idle, putting it in gear its fine but usually cuts off when I turn the wheel to exit the driveway...

rest of the day it MAY fire up on first turn over but will not catch itself and idle...
sometimes on the 3rd or 4th attempt it will catch if I don't decide to go ahead and pedal it...

if I pedal it for a little while, it idles fine...still wants to cut off when I start to leave the parking space though...this is after noticeably going into closed loop...

once I'm on the road...its all good...morning, noon or night...

tried adding more air at start-up...worked for a day or so...
tried adding a couple seconds to delay @ start-up...worked for a few starts, then right back to same issues after driving 15-20 minutes, parking and attempting to restart about 30 minutes later...

only SES code active is TPS performance range...I assume this is due to idle screw adjustments made during idle tuning...could this also be my catching @ start-up issue as well?

what specifically to I need to be looking at?
thanks in advance!

Last edited by Superado; Aug 19, 2008 at 07:40 AM.
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Old Aug 19, 2008 | 07:49 AM
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Robin L's Avatar
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Give the guys at Abaco a call. THey have a Digital Mass Air meter that will take care of all those problems. They are just finishing up the tables for the GM stuff right now.

Robin
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Old Aug 19, 2008 | 01:01 PM
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current tune...a work in progress...
Attached Files
File Type: tun
al-no_mil_egr_dyno.tun (473.5 KB, 290 views)
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Old Aug 19, 2008 | 02:28 PM
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also...
As of yesterday...I have a hesitation @ WOT...meaning...
when I mash the pedal to the floor...instead of it going WOT, it hesitates for a couple seconds...then goes WOT...
This has never happened before...where should I look?
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Old Aug 19, 2008 | 03:34 PM
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I'm going to attempt to log that this afternoon and post tonight...
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Old Aug 20, 2008 | 01:33 AM
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Hi, Guessing. When you adjusted the throttle plate settings. The plate settings work with the idle air control motor. The IAC controlled by the ECM, "Engines computer" Can only work within certain values. To control air flow for idle. Plate open or closed too much. The IAC can only open or shut so much to control air flow for idle. Could you remember where it was set at before? Dave
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Old Aug 20, 2008 | 06:32 AM
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you're referring to the idle adjustment screw?
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Old Aug 21, 2008 | 12:21 PM
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The TPS Sensor is Acting up..

Try this... GOTO ENGINE DIAGNOSTICS

Change the P0121 Error MAX MAP to 100
Change the P0121 Error MIN MAP to 10

Larger Cams can cause interesting situations.

If that does not work, un plug the TPS sensor run again, or borrow a friends and see if the swap to another one or a new one fixed the situation.

Clint
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