Gmecm [Gmecm] Idle problem

[Programmer]

That'll definitely do it ! Wrong scanning mode.

Lyndon

----- Original Message ----- 
From: "Robert W Hughes" <rwhughe at oplink.net>
To: <gmecm at diy-efi.org>
Sent: Monday, August 22, 2005 11:24 AM
Subject: Re: Gmecm [Gmecm] Idle problem


> Another possibility if you are using a scan tool at all is that the ECU
> when it sees 10K or a short on the sense line of the ALDL connector
> (A&B) moves the idle to 1000rpm.
>
> > Are you guys using a tach to see the RPM, or the ALDL data? Maybe the
> > ALDL data actually says 750? I'm far from an expert, but there are
> > things that could mess up the perceived RPM by the computer, like #
> > cylinders.
> >
> >>> On Monday 22 August 2005 12:03, Programmer wrote:
> >>
> >>>>> Those IAC numbers are not indicating a vacuum leak. Check the
> >>>>> "P/N" signal to the computer. If it's getting an 'ingear'
> >>>>> signal when you're actually in park, you'll have a high idle.
> >>>>> Another problem is a false VSS signal (from RFI or EMI) down
> >>>>> the signal line to the computer (if it thinks you're on the
> >>>>> move, the IAC counts will rise). Drop your commanded RPM
> >>>>> values...750 doesn't really equal 750...
> >>
> >>>
> >>> How is it that 750!=750? ... I have this problem too: I just did
> >>> a swap from a carb to a 7747 ECM + TBI on a Ford 302, and the set
> >>> the idles to about 850RPM (a bit bigger than stock cam), and I
> >>> get about 1200 RPM no matter what I do too. The IAC speeds the
> >>> thing up whenever I do something to lower it.
> >>>
> >>> I'm sure the P/N switch signal is in "N", and the ALDL data
> >>> doesen't show any VSS pulses.
> >>>
> >>> The closed loop also kicks in at a temp much-much higher (about
> >>> 85°C) than what the calibration says (35°C). Why these
> >>> discrepancies?
> >>>
> >>> -- Tomas J. Sokorai Sch.
> >>> _______________________________________________ Gmecm mailing
> >>> list Gmecm at diy-efi.org
> >>> http://lists.diy-efi.org/mailman/listinfo/gmecm
>
>
> -- 
> Robert W. Hughes (Bob)
> BackYard Engineering
> 29:40.237N, 95:28.726W or perhaps 30:55.265N, 95:20.590W
> Houston, Texas "The city with too much Oxygen"
> rwhughe at oplink.net
>
> _______________________________________________
> Gmecm mailing list
> Gmecm at diy-efi.org
> http://lists.diy-efi.org/mailman/listinfo/gmecm

_______________________________________________
Gmecm mailing list
Gmecm at diy-efi.org
http://lists.diy-efi.org/mailman/listinfo/gmecm