Fast Idle with no switch needed

[Modified]

I wanted the Fast Idle on my "02" Duramax/Allison installed with no switch, no holes to drill, and fool proof so no one could drive off with the fast idle on. I also wanted to prevent being able shift the tranny out of Park when above normal idle.
I wired my 12 volt supply for Fast Idle to the A/T Shift Lock Control Solenoid, (wire 1135, Dk Grn/Wht, pin F on the Stop Lamp Switch), to the TCM, with no switch. Reference Helms pages 7-170, 8-369 and 5-64, . This 12 volt signal is only present when ignition is on, transmission is in Park, and the brake peddle is not depressed.
While warming up with Fast Idle, when I'm ready to drive off, I first must depress the brake to shift out of Park. The 12 volt signal goes to 0 volts, (deenergizing the solenoid), and in less than a half second, the idle drops down to the normal 600 RPMs, and I'm ready to shift out of Park. The idle remains at 600 RPM's until I re-initiate the Fast Idle with the Cruise Control. Seems foolproof with no switches, and the Fast Idle can not be on with Tranny out of Park.
The first time I want to initiate Fast Idle after startup, I must press "Set" button twice. After that, I only need to press the "Set" button once to return to 1250 RPM's, or Resume for 1700.

[mackin]

Did you take it for a test ride??

How does it run above 2000+ RPM??
Mine will function just like that when I leave the switch on ....But run like crap above 2000 RPM.....


MAC :D :D :D

[ 02-02-2003: Message edited by: mackin ]</p>

[Modified]

No crap here. Truck runs like normal at any RPM. As stated in original post, when transmission is NOT in Park, this signal is at 0 VDC, so there is no signal enabling Fast Idle.

[GM Smitty]

I installed fast idle on my truck as per JK's instructions. If I step on the brake to put in into Reverse or Drive, it automatically shuts off the high idle. I still have to turn the switch off though, or the truck will run funny.

[CntrlCalDmax]

Modified,

Can you turn the high idle off other than with the brake or shifter?

Leo

[sdaver]

dummie proof.......that would work well for me :D dave

[wakely]

Sounds fantastic!!!
Let us know if any problems show up after having it hooked up for a while.
I plan to do the same thing to my 2002 Dmax.
If I back my truck out of garage for warm up, to set the fast idle, all I do is push SET on cruise control (with selector in park)? Sounds too good to believe!
Thanks, wakely

[ 02-04-2003: Message edited by: wakely ]</p>

[hoot]

What happens when you want to use the cruise control for it's intended purpose?

[BROKERS]

Get a broom handle and cut it to 27"3/4 and jam it between the front of the seat and the go-pedal! For rpm adjustment hit the power seat forward or reverse! :D

[Kennedy]

Pretty slick setup!

The key is that he has this hooked up to automatically engage when in park just like if you were to turn on a dash mounted switch. It then automatically turns off just as if you flipped the switch.

All will work normally in this type of setup EXCEPT that the standby version of the fast idle (which '02 and '03 don't seem to have) will be active whenever idling in park UNLESS an override switch is added...

[SoCalDMAX]

This is very similar to the setup someone else had posted on here quite a while ago. The other poster used a relay energized off of the parking brake switch. This one's a little better.

Hoot, you don't normally use cruise control with the tranny in park... ;)

Regards, Steve

[ 02-04-2003: Message edited by: SoCalDMAX ]</p>

[hoot]

Wow, I like it. Now i can use my existing hole in the pillar for OD lockout...... unless somebody comes up with something slick for that one.

Thanks for the research Modified!

[et]

BROKERS,

With your technique, we can use the driver's seat memory control to set two seperate rpms.

Does the broom handle have to be API Certified? I do not want to jeopardize my warranty.

Modified,

What pin/wire color did you connect the other end of the wire to at the TCM? And did you splice into the wires or use some type of connector at each terminal?

[sdaver]

ok one of you electronics wizards(socaldmax are you listening) make us a dummie proof set of instructions like hoots transmission flush......please include a shopping list of connectors and wire color codes with locations of wires and access points.......I would assume us 02's would have to have the latest update to enable the fast idle function.........just remember that it takes a little more explanation for some of us......especially me I slept thru most of my circuits classes.......V=IR.......by the way color pictures would be nice......(might even have a northstar application?) :D dave

PS you know if I would just read instead of running my mouth I would have realized that my friend john kennedy had already done this for us and its at this link http://www.kennedydiesel.com/ under tech tips for the duramax........dummie dave

[ 02-05-2003: Message edited by: sdaver ]</p>

[Modified]

CntrlCalDmax :

Here are the ways I thought of and verified, to turn off the Fast Idle on my "2002", in the order of my preference :

1). Depress the brake. The idle returns to normal idle RPM. The idle will not change from normal, unless the brake pedel is released, and the Cruise Control "Set" or "Resume" buttons are depressed again.

2). If Fast Idling at the "Set" speed, depress the "Set" button again to return to normal idle RPM.

3). If Fast Idling at the "Resume" speed, depress the "Resume" button again to return to normal idle RPM.

4). Turn the iginition key switch to "Off".


Note: When Fast Idling at either "Set" or "Resume" speeds, turning the Cruise Control to "Off" had NO effect.

************************************
Wakely :

I wire my Fast Idle at Christmas, and I've had no problems.


************************************
Hoot :

As soon as you position the tranny out of Park, the 12 VDC signal falls to 0 VDC, which removes the PTO Enable signal at C-1, Pin 71. Now the Cruise Control operates normally.

You mentioned the ODLO. I installed the GM factory switch 15174508, which mounts in my 02 dash, left of the Air Bag Keyswitch. Snaps right in with the Factory look. Momentary pushbutton with a green light. I added some info to post, "factory ODLO switch" under "2500/3500 Drivetrain". If anyone is wiring Fast Idle, and doesn't have ODLO, you might as well wire both through the firewall at the same time.


************************************

Kennedy :

I think you're right again. I didn't think about the "standby" speed, seeing I own a 02.

*************************************

et :

I used the Light Green wire, as shown in Helms and mentioned by JK. The 12 VDC supply side of wire was terminated to connector mentioned in original post above. The other end of wire goes to the ECM, C1, Pin 71, using GM Pin 12084913, as mentioned by many, and in great detail on JK's site. The connector I used at the Stop Lamp Switch, is a less than desired Scotch Lock type connector, where you run two parallel wires through connector, and squeeze the metal blade in to make connection. It is under dash, not in harsh environment, so it probably will work for a long time.

**********************************

[Kennedy]

Since I reprogrammed my idle speeds (900 set and 1100 resume) I have a goofy idle in standby. The balancing on the injectors gets switched off and the idle gets all goofy. Aside from this problem, the auto on feature would be neat.

In reality, I seldom use my fast idle as I have found the exhaust brake to be much more effective!

[wakely]

Modified:
Your great !!
They should have wired it your way from the factory!!!
Is the stop lamp switch on the brake pedal?
Is pin F easy to find?

Thanks again, wakely

[Modified]

wakely :

Yes. The Stop Lamp Switch is mounted about 12" above the brake peddle. The six conductor plug has the following pins and wire colors:

A - WHT
B - ORN
C - PPL
D - BRN
E - LT GRN / BLK
F - DK GRN / WHT

You want the Dark Green with White wire.

[ 02-06-2003: Message edited by: Modified ]

[ 02-11-2003: Message edited by: Modified ]</p>

[Modified]

Kennedy, and others :

I'm not sure if Kennedy's following quote about needing a Override Switch with Fast Idle on 2001's, from a previous post, is correct :

"All will work normally in this type of setup EXCEPT that the standby version of the fast idle (which '02 and '03 don't seem to have) will be active whenever idling in park UNLESS an override switch is added..."

The way I understand, to enable Fast Idle, you need a 12 VDC signal to the PTO Enable, (C1, Pin 71), AND the Cruise Control must be turned On, (Standby, Set, or Resume for 2001) or (Set or Resume for 2002/2003).
If the 01 truck is started with the Cruise Control "Off", the idle should remain at normal RPM.
I mentioned in earlier post, on my 2002, once Fast Idle is initiated, if I turn my Cruise Control to "Off", the idle RPM does not change. If this is true with the 2001 trucks, I would think if the 01 truck is running and you want the idle to reduce to normal RPM, you would need to depress the brake AND turn the Cruise Control to Off, at the same time. This should remove both the PTO Enable and the Standby Speed signal at the same time.
I don't have a 2001 to verify this on, but I think this should work the way I explained.

[mdrag]

Modified,

Good idea!!!

...BUT I like switches smile.gif :D

If I understand the GM Upfitter's document correctly, the HI function will work in Park and Neutral - but not in your set-up, probably not very important though. Also, torque converter clutch lockup using the PTO circuit only occurs in Park and does not occur in Neutral.

I don't know much about setting up PTO's, but this may be important for the chassis cab owners.

[ 02-07-2003: Message edited by: mdrag ]</p>

[Stoner]

Modified

Thanks a million for the "HOT TIP"!!!

I've been thinking about doing this mod for at least a year now....never could decide what type of switch...where to put it.....maybe do it when I install guages.......etc.,etc.

Finally did the install on my 2001 on Saturday....the "MODIFIED" way...and it works just as mod described it, with one slight differance on the 2001. At -any- idle speed...turning the cruise control off returns the engine to normal idle. I don't know that we need to install an over-ride switch on the 2001....the cruise control is the over-ride.

Works as advertised, no known side-affects.....yet!!
;)