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Unread 01-19-2009, 05:13 PM   #1
comptiger5000
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WJ High Idle Switch

I may be getting a 99 WJ Laredo (4.0 I6) at some point over the next year. Out of curiosity (and because I can't find any answer to this), is it possible to add a high idle (or "extended idle") switch to one of these, like on the 4.0 XJs? If so, how complicated would it be? If there is no simple way of doing it, is there a way to trick the TPS to raise the idle to about 1200rpm on command?

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Unread 01-19-2009, 06:23 PM   #2
theksmith
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interested in this as well, i did it on my old cherokee and it was as easy as grounding a single wire with the switch. to my knowledge though, the WJ wasn't a popular government/police vehicle, so i don't know if it ever had that option.

i know there was a writeup somewhere about making the cruise-control switches work even in PARK to raise the idle as much as desired... not sure where that was though
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Unread 01-19-2009, 07:32 PM   #3
madrabbitt
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on the 92+ cherokees its in the computer.

On the WJ's it may be as easy as a programmer that plugs into the obd port, but i havent heard of anything.

It would a nice option though
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Installing HID's in stock housings is bad. Here is why.

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Unread 01-19-2009, 07:57 PM   #4
windsors03cobra
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Couple options, one for $4 and the other for $40
http://www.7slotgrille.com/tech/handthrottle/index.html
http://www.jamestowndistributors.com...id=51976&BASE#
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Unread 01-19-2009, 08:00 PM   #5
comptiger5000
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I see one problem with a hand throttle... Aren't those meant for carb-ed engines? Unless I'm missing something, I don't see a way to mate one of those to an EFI engine with a TPS.
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Unread 01-19-2009, 08:14 PM   #6
windsors03cobra
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The first link has pictures of the whole install the guy did on a EFI 4.0.
A EFI throttle body is similar to a carb but without the gasoline mixing aspect, linkage-venturi(s) and throttle plate(s) are still right on the "carb like" throttle body.
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Unread 01-19-2009, 08:19 PM   #7
theksmith
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Quote:
Originally Posted by comptiger5000 View Post
I see one problem with a hand throttle... Aren't those meant for carb-ed engines? Unless I'm missing something, I don't see a way to mate one of those to an EFI engine with a TPS.
yeah, you're missing something
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Unread 01-20-2009, 04:23 AM   #8
comptiger5000
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Ok. That sounds like the easiest way to do it then.
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Unread 01-20-2009, 08:36 AM   #9
alexsious
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forgive me for asking, but what does High Idle do?
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Unread 01-20-2009, 10:00 AM   #10
comptiger5000
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High idle raises the engine RPM at idle (in Park or Neutral) to 1200-1400 rpm (sometimes 1000). This improves alternator output when you are going to be idling for a few minutes, as well as allowing faster warm up on cold winter mornings. Also, it is bad for an engine (less oil to top end, fuel dilution of oil, etc) to run at a normal idle for more than a few minutes. At high idle, these problems are reduced or eliminated.
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Unread 01-20-2009, 12:02 PM   #11
madrabbitt
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on the topic of improving alternator output, most alternators put out their peak amperage at typical driving RPMs, not idle. So, running high draw electronic accessories at idle can actually drain the battery.

This is why police and service vehicles typically have an extended idle option.
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Installing HID's in stock housings is bad. Here is why.

"When you see someone who needs help, help them. When you see someone who needs a hug, hug them... Help those who can't help themselves." -Sgt Andrew Tingwall, NMSP. End of watch 6-10-2009
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