Hello all
I took my truck to the dealer last week for a service. I asked the tech if he could reduce my high idle from 1300+ rpm to 1000-1100 rpm. He knows it can be done, but he isn't sure how to do it. Can the techs answer this question for me and I can print it out and give it to him? Thanks for your knowledge and help:ro)

MickD

OK. First go to this site and print out pages 23 thru 28.


http://www.gmupfitter.com/publicat/bull/bull53.pdf


Select the Diagnostics option from the main menu
Select the Model Year
Select the LD Truck, MPV, Incomplete option from the vehicle ID menu
Select the Powertrain option from the System Selection menu
Select the Engine Type from the Vehicle ID menu => (1) V8 LB7 Diesel
Select the Transmission Type from the Vehicle ID menu => 5spd Automatic Trans (M74)
Select the Special Functions option from the Powertrain menu
Select the PTO Options from the Special Functions menu
Press the Change Options key and then select the desired PTO Operating Mode => F1: Preset PTO Speed Control


Change the necesary parameters:


PTO Fast Idle Option =>Preset
PTO Max. Engine Speed =>2200 RPM
PTO Standby Speed =>800 RPM
PTO Set Speed => set to whatever you choose. this is the
lower high idle speed. I set this to 900 RPM. Factory is
1250.
PTO Resume Speed => set to whatever you choose. This is
the higher high idle speed. I set this to 1250 RPM. Factory
is ~1700.
PTO Max Engage Speed =>1000 RPM
PTO Engine Shutdown=> NO
PTO Engage Relay=>NO
PTO Feedback=>NO





The MAX ENGINE SPEED when initially read by the Tech II may show
6000+RPM or more. If I remember, they may all have been like this
when they read mine. Be sure to set all of them (except parameter
#4 and #5) to the suggested settings I listed above.

Most of the time I run the 900 RPM setting when warming up. If
it's super cold out I'll bump it up to the 1250 RPM point after a
while. You can set these to whatever you desire. 900 is
just a little more than idle but not revving too much for just an
easy warm up. Also will help keep the A/C working better in
the summer.


I don't know your relationship with your dealer, but if they will do
this for you I'd print out the pages in that link above to show them
that it's from a legit source if they pull the warranty issue on
you. They hee-hawed around on me since they thought it may not be
OK for them to do this, but settled down when I showed them the
documentation.

quick question....what exactly is PTO and what does it do....thanks

Pto Stands For "power Take Off" It Is A Hydraulic Pump That Is Added,orcan Be Added To Your Truck To Run Additional Equipment That Needs A Certain Rpm To Opperate.

Hydraulic pump, other stuff too. Pretty much just a secondary output from the transmission to power something else via motor power instead of requiring bolting to the motor and running off the serpentine belt. Higher torque stuff, typically.

So what specifically would someone slap on their truck that'd require PTO? I guess I'm still not getting it - all I can think of is a snowplow. But being in Cali, I've never had one so I don't know if they're hydraulically operatered or if you just bolt it on and it sits there in a fixed position. Is there some other accessory that'd require PTO?

And something else that doesn't make sense is that if I were to buy a snowplow or something else that required PTO, wouldn't they come with their own power sources? Why would GM need to provide the hydraulic pump that was used as the means to power these devices? Wouldn't the after-market mfgr normally provide something like that?

Obviously I won't need a plow any time soon being in Cali so this is more for my curiosity than anything else. But who knows - maybe I'll get a wild hair and move to Montana.

But who knows - maybe I'll get a wild hair and move to Montana.
Come on up! Plenty of Californians already here. Maybe some of your neighbors!?!?! ):h :D ):h :D

Ben

I'm thinking that's where I'd like to retire if all the yuppies haven't beat me there by then! ;)

I live near Yosemite and was planning on retiring up near there (Bass Lake) but it's become infested by yuppies and $3M "condos". The money isn't the problem so much as it is the change in lifestyle. Used to be everyone up there wore flannels and drove a truck. Now it's Japanese SUV's and wine and cheese. YECK! -:t