5.3 IDLE issues!!

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03-28-2009, 10:38 AM
RacerChris

5.3 IDLE issues!!

I have a 5.3 Vortech in a 95 Sierra that I have just installed but I am having a tuning issue. I run EFI Live and I have had to put my VE table numbers up to around 130 at idle to get it to idle right, even then my Wide Band says im running 18-19:1 at start-up and then it slowly comes down to 14-15:1
Does anyone have any ideas???
Also... For whatever reason at start-up, I get a really clean start-up and then as the idle comes down it starts to hesitate and becomes harder to hold an idle, then I can hear the IAC motor begine to open up (probably 100%) as its sucking huge amounts of air through the TB. Sometimes it will just die and others it makes it past this point and the idle cleans back up and the IAC begines to close back up. But every couple of combustion cycles the idle will drop to 300 as it feels like it had a miss and then resumes to 650.
Any help would be great!!
03-28-2009, 01:24 PM
JHART

there is a gasket directly under the TB that closes some vacum gaps on your intake. Or it may be the gasket under the intake. Its been 15 years or more since i had to deal with it but that fixed it for me.
03-28-2009, 01:43 PM
RacerChris

Quote:

Originally Posted by JHART

there is a gasket directly under the TB that closes some vacum gaps on your intake. Or it may be the gasket under the intake. Its been 15 years or more since i had to deal with it but that fixed it for me.

15 Years???? I hope thats a TYPO! I dont believe it to be the intake to head gaskets as they are brand new, I just checked the TB gasket and it looks fine and is not blicking anything.
03-29-2009, 09:08 PM
RacerChris

Well I figured out the problem!!!!
Under DTC Processing Enablers if you disable any of the MAF tables P0101, P0102, P0103, the engine will not run correctly. You can disable them under MIL enablers but not Processing Enablers.
Hope this eventually helps someone out.
03-29-2009, 09:30 PM
RedHeartbeat

well, found the DTC controls under the Engine Diag tab. Where are the other controls you speak of?
03-30-2009, 05:35 PM
JHART

Quote:

Originally Posted by RacerChris

15 Years???? I hope thats a TYPO! I dont believe it to be the intake to head gaskets as they are brand new, I just checked the TB gasket and it looks fine and is not blicking anything.

mine was a 95. So yes actually more like 14 years. 2009 subtracted by 1995 makes it 14 ...lol but i always round up.

Glad you found your issue good work.