[Gmecm] 454 TBI 1988 suburban

[David Cooley]

The 5 volts as a max is pretty misleading.
The PCM scales the TPS.  It has limits for max idle volts and Min idle volts
and sets a code if either is exceeded, and also has a max volts that will
trip a code if it exceeds 4.5-4.75 volts WOT as well.
The PCM learns the idle voltage (if within spec) and scales so WOT is
considered when it reaches 3.25-3.5V


________________________________

	From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org]
On Behalf Of Bobby Morgan
	Sent: Sunday, March 27, 2005 12:56 AM
	To: gmecm at diy-efi.org
	Subject: RE: [Gmecm] 454 TBI 1988 suburban
	
	

	Sorry about the following book report but it should explain a lot.

	 

	 

	It looks like you already have it figured out but this info should
be very helpful in the future.  If the IAC did not fix it I would have
suggested a temp. sensor.  Have seen more than one out of range causing an
out of spec. high idle.

	 

	Even though all reference material always will say a TPS is not
adjustable, many are, or can be made to adjust.  Actually to get the maximum
performance from a computer controlled engine you want to adjust the TPS to
a maximum as close to 5 volts wide open throttle as possible.