How can you be sure that you have this feature? I was told that I do, and it makes sense that on cold days (like my previous thread "Lights Dimming") the engine idles @ 1100 rpm. Also, sometimes when I'm at a stop light the engine idle will go up to @ 1100 and eventually it will settle to the cool 750. Sounds like a silly question but is this the high idle feature? Never heard of it before this truck and it's my first diesel.

 

The automatic high idle is what you have no control over; it's in the programming. I'ts used to warm up the engine.

The manual high idle is a dealer enabled feature.

Not sure if you have it on the '03, but here is how it's activated on mine. (After it's been enabled at the dealer)

1 - Truck must be in Park or Neutral w/ the parking brake on.

2 - Turn the cruise control on

3 - Hit the set button. RPM's will jump to 1100.

4 - Use the accel button to raise the RPM's, decel to lower them.

5 - Turn the high idle off by a - stepping on the brake, b - turning the cruise control off, or c - put the vehicle in R or D.

 

So basically what I'm referring to is the high idle, but it's the automatic one. Like I said its my first diesel so this is all new to me. I bought it in the dead of winter and one day at a stoplight wondered why my truck slowly started idling higher on it's own.

 

isn't the clutch and the brake also suppose to kill the high idle, even the automatic high idle?

 

Yup! Sorry, I have an auto (I'm lazy), so I didn't think of the clutch.

Was it going to high idle while the truck was in gear or met any of the other conditions that would turn off the high idle? If it did it while in gear, brake pushed, clutch in, etc., then something may be wrong.

 

I don't know if the clutch has a switch hooked up to the fast idle to allow it to turn off the high idle. IIR the engine high idle should not idle up when the trans is in any gear even with the clutch pushed, it should only do it when the trans is in Neutral with your foot off the brake pedal. I’ve had my high idle come on when in N and not moving while waiting for it to warm up in my garage and with the e-brake off.

 

It does it whether it's in gear or not and if I'm on the brake pedal or not. If it doesn't idle down by itself, sometimes if I rev the engine it will or if I put it in gear and let the clutch out until it grabs it will idle down. But like I said it only does it when it's cold out and when I just turn it on. I haven't had the truck in the warm months yet.

 

Sounds like you need to get it in to the dealer to have them look it over as that is not safe if you live where they have snow or ice.

 

When I say it does it when it's in gear, I don't mean if I'm moving just in gear at a stop. While I'm in motion the rpm's don't change unless I hit the throttle

 

the high idle on the 6spd's works a bit different. . .you first have to ground pin 22 PCM plug B. then have the high idle option enabled through the dealer. once you have it enabled just follow the above steps.

now on cold days there is an automatic high idle the engine will go through. and the lights dimming is just the grid heater and also the fact the altenator is turned off so the current draw from the heaters doesnt kill the diodes.