Need a 'really high' idle setting...A/C switch?...

2000 Camaro LS1 ECM. The harness is cut down to run stand alone in a buggy. Running SDOL.

I'll be brief: I race a single seat offroad race truck. When I have to get out and winch I'm all by myself. I'd like to have a 'High Idle' button so that I can keep the alternator rpm up when I'm out of the car winching as I'm not able to press the gas.

I'm thinking I could accomplish this with the A/C switch. No?

First thought is 12 volt to the A/C Status (Red plug, Pin 18, DkGrn) and set the A/C on idle to 2k rpm or so. That sound right? Does the IAC have enough adjustment to make that happen?


Or do you see a better way to accomplish this? (No throttle adjuster cables, I've got enough crap in the car as it is.)

Thanks.

Actually sounds like a cool idea. Thanks for sharing it with the community, don't know if this is a first timer for this topic or not. Only problem I see is that not every OS can set idle to the same max. I've seen 1200, 1588, and so on but I think I remember an earlier V8 based OS with like a possible 12,800 RPM max idle speed so you may be O.K.

IAC is a stepper motor driven by a 4-phase chop waveform.

Edelbrock and Holley sell A/C bump-up solenoids for carbs
that you might adapt up to push the throttle.

A cheap 12V solenoid valve could be let to pass air into
the PCV suction port with a T fitting. That or a little air
valve in the cabin, etc. I have somewhere in the junk
pile a small one that looks like a toggle switch for
panel mount. You'd set up a roughly-right orifice somewhere
in the line to get the right answer RPM.

A/C on will put you onto a different idle air and idle RPM
table row, so you might get that to work. But minus A/C
you might have some underpressure or missing-hardware
lockouts / codes to bypass before you get to use that.

I understand your need for off road winching power. I own and have tuned a few LSx powered buggies or daily driven weekend warriors with 9000 -12000lb winches. The drain is definitely there, but you've gotta start with the basics first before manipulating the tune.

If you have an AGM battery capable of 750-1000+ CCA, the first thing I'd do is look for an alternator upgrade. You didn't say what you have currently, but in all honesty most 5.3/LS1/6.0 factory alternators can support a decent size winch when combined with a good gel-cell battery (Optima comes to mind). If you don't have a good battery, replace yours with a new 34/78 group Optima Yellow Top, Exide Orbital or something with a spill proof AGM design (which you should have anyway if you're racing an off road buggy :doh: ). Most stock alternators run in the 105-145amp range. They make 200A and bigger units, as I have a 280A alternator that when combined with two 750CCA AGM batteries in parallel, my system doesn't even know I'm winching most of the time :D .

Secondly, depending on how high you're revving, you could bolt on a smaller alternator pulley and get a shorter serpentine belt. The smaller pulley is what made the most difference for a buddy of mine running a factory 5.3 alternator. My only caution is if you're racing constantly at 7000 engine rpm, because your alternator would be spinning much faster than that, especially with a smaller pulley. Any 6000k engine rpm redline and typical racing strategies would allow for a smaller alternator pulley to increase the low RPM amperage for when you're winching.

Third, how big is your charging cable size from the alternator stud to the battery? Your winch uses 4ga or bigger, and your charging cable should be at least 4ga but preferably twice that size. My winch uses 1ga cable, and all my battery related charging cables are 0/2 gauge audio wire (high copper strand count). Your battery negative(s) should be as big of cable as the largest wire in your entire buggy. Hopefully this is the case.

After that, I really like your idea for using the A/C switch to bump up idle during winching situations. I've used a similar trick before using the "high" fan speed trigger wire on the PCM to command extra airflow for a friend's 5.3/manual buggy who used a single 16" fan to cool his radiator and he only had the PCM trigger low speed within the PCM when temps climbed. This gave him the option to flip a panel switch in the cab to engage the "high" fan speed which did nothing related to fans, but it gave me the ability to add extra airflow to the base running airflow as if it saw the increased alternator load of the fan running on high. This bumped his 600rpm idle speed to 700-750, which in combination with the smaller alternator pulley and good battery (one Yellow Top), made for effortless winching of a 4500lb unimog buggy on 49" Iroks.

Keep us updated on the A/C switch idea, as it would be an interesting choice for someone who uses both low and high speed fans and needed some other form of IAC bump.

Resurrecting an old thread. I'm in the planning stages of an LS1 swap into a 01 Jeep XJ Cherokee and I'd like to have a high idle option when winching. The vehicle will have AC, so I can't simply use the AC option to set a high idle. Is there any other way to trigger a high idle setting on the 0411 PCM?

Quote:

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Originally Posted by wcialrlter

2000 Camaro LS1 ECM. The harness is cut down to run stand alone in a buggy. Running SDOL.

I'll be brief: I race a single seat offroad race truck. When I have to get out and winch I'm all by myself. I'd like to have a 'High Idle' button so that I can keep the alternator rpm up when I'm out of the car winching as I'm not able to press the gas.

I'm thinking I could accomplish this with the A/C switch. No?

First thought is 12 volt to the A/C Status (Red plug, Pin 18, DkGrn) and set the A/C on idle to 2k rpm or so. That sound right? Does the IAC have enough adjustment to make that happen?


Or do you see a better way to accomplish this? (No throttle adjuster cables, I've got enough crap in the car as it is.)

Thanks.

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Bringing it back from the dead.

Did you ever figure how to do this? A buddy has swapped a 5.3 into a genie, and we would like to have regular idle then 2800 rpm on demand. I'm looking at the Idle-Airflow tab, and I dont think thats where I should be playing.

Quote:

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Originally Posted by jake1086

Bringing it back from the dead.

Did you ever figure how to do this? A buddy has swapped a 5.3 into a genie, and we would like to have regular idle then 2800 rpm on demand. I'm looking at the Idle-Airflow tab, and I dont think thats where I should be playing.

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Nope, never did.

Quote:

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Originally Posted by 2001CamaroGuy

Nope, never did.

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I would imagine if you were really trying to get tricky you could put a relay in line with the coolant temperature sensor. Have one side of the relay be stock current temperature, and then when you hit the switch it runs to a resistor that puts the temperature in the 240? range. And in the idle speed, RAF tables have the new set speed adjusted accordingly. You would obviously need to go through your timing modifiers and make sure that nothing kicks in at 240 to mess with it. But it could work as a rudimentary idle up switch.

Quote:

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Originally Posted by 240sxpooter

I would imagine if you were really trying to get tricky you could put a relay in line with the coolant temperature sensor. Have one side of the relay be stock current temperature, and then when you hit the switch it runs to a resistor that puts the temperature in the 240? range. And in the idle speed, RAF tables have the new set speed adjusted accordingly. You would obviously need to go through your timing modifiers and make sure that nothing kicks in at 240 to mess with it. But it could work as a rudimentary idle up switch.

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I guess that would work.