HighIdle Electrical Help

[jamierayo]

I've been thinking of wiring a high idle switch through a thermal switch made for an electric fan. That way, when I flip the switch on, it would remain at normal idle until the temp dropped to the set point (I'm thinking 160* F), then it would automatically throttle up (I'm thinking 1360 RPM), and then drop back to idle when the temperature rises.

Here's the problem: I need to connect the ECM B7 wire to ground to enable the high idle. All the thermal switches I've found are normally open, and when the temp rises, the circuit is closed. I need it to do the opposite & complete the circuit when the temp drops below the set point.

Any electrical gurus know how I could make this work?

If you are wondering why, it's because I sometimes need to leave my truck idling for a while, and at temps below perhaps -25*F, and at normal idle, after 5 minutes of idling (cooling off), the engine is so cold that the needle on the temp gauge is bottomed out, and the heater blows cold air. -Yes I have a cold front over the grill & cardboard in front of the radiator.

 

[ak diesel driver]

Have you checked Frigid North in Anch?

 

[jamierayo]

No, what's that?

I have already installed a high idle switch in my rig, I just want to make it self-regulating now.

 

[ak diesel driver]

It's an electronics store carries diodes relays etc.

 

[DennisG01]

Forgive me, but why wouldn't you just leave it at the 1,000rpm setting? I thought that one of the benefits of the high idle was increased lubrication for the engine as it keeps oil circulating better. I'm not knocking your idea - it's a very interesting one. I'm just wondering if it's necessary.

By the way, try Mouser Electronics for some help on finding the right thing. They have an incredible supply of stuff and are very helpful. If you know right what you're looking for, you can use their website - if not give them a call.

 

[THEFERMANATOR]

Simple solution would be to find an old style advance switch like the 6.2's and the FORD 6.9's and 7.3's used. It would close the circuit around 110-130 degrees to activate the cold advance in the pump to allow for faster warm-up's. Or you could wire up a relay to a normally open switch so that when it is engaged the relay opens the circuit instead of closing it.

 

[jamierayo]

I didn't know a relay could be wired that way. That sounds like the way to go.

Yes, I could just leave it on the 1070 RPM setting, but when it's real cold out, that's not enough to warm the engine either.

 

[DennisG01]

Yes, I could just leave it on the 1070 RPM setting, but when it's real cold out, that's not enough to warm the engine either.

Jeesh, how long does it stay that cold up there? Or, is it more like how long is it not that cold up there? :smile5:

 

[ak diesel driver]

It's colder where Jamie's at then where I'm at. It'll still get -10- -15 in the mornings if it's clear skies but will warm up to 25-30. In the middle of the winter it'll only warm up about 10 degrees. So you can see our longer daylight hrs are starting to make a diff. Next few weeks there will be a huge diff. We kind of get spring all at once.

 

[jmiller]

I've left mine engaged. Cold weather, hot weather, its usually on most of the time.

If its in gear, for press the brake it idles down.

The only thing to remember is to press the brake and wait a seconds to idle down, before putting into gear.


This keeps the heater and A/C at maximum output when setting.

 

[packratt]

If 1070 rpm isn't enough. There are 2 more idle speed settings you can set the high idle up for.

 

[jamierayo]

I know there's two more settings, but I don't want to leave it on, I want it to stay warm & self regulate. I figure 5-10 minutes at the middle setting (1360 RPM), then drop back down to idle for 5-10 minutes. I used to drive an F450 Powerstroke for work & it was already programmed to do this & it stayed warm all the time (in Prudhoe Bay).

Our current temps are pretty close to what AKdieseldriver said -10 to -20 at night & warming to +10 or 20 in the day (It's +36 right now :dance: ) It can be -30 from October through March -not constant, of course. Jan & Feb are the coldest & it can get -40 for weeks at a time, with lows around -65 F.

 

[ak diesel driver]

So I take it your a sloper?

 

[buddy]

Use the switch with a 5 spade contact relay like suggested. The 5 spade contact relays have an 87A contact which is "ON" when the trigger current is not present. That means when the thermal switch is not active (below 180*F or so) the PCM pin can ground through 87A if you hook contact 30 to ground. Then when thermal switch activates it can power the relay trigger (contacts 85 and 86) and switch the relay to the regular 87 output which you will just leave unhooked, or have it complete the circuit as ground on an actual fan for an oil cooler or something.

It would be better to get a switch that work the way you were thinking, but theres always a work around.

 

[jamierayo]

It would be better to get a switch that work the way you were thinking, but theres always a work around.

Yeah, I knew there was a way around, I just didn't know what it was. I didn't know a relay could be used that way. I've only used them to supply power, with a powered switch. Thanks everyone for the help.
I probably won't get to this project for a while, since it's nearly summer now. When I do, and after it's cold enough to test it, I'll post the results.

I don't work on the Slope any more. I did that for a few years when I was single, but I have a wife & kid now, so I like to keep around town. I didn't mind that work at all when I did it, but I don't miss it either.

 

[DennisG01]

I probably won't get to this project for a while, since it's nearly summer now. When I do, and after it's cold enough to test it, I'll post the results.

Someone correct me if I'm wrong, but I think you can disconnect the ECT and trick the truck into thinking it's -40*? Probably'd be much easier to get this working before it gets cold - or in your case, down right freakin' fridgid!