Cold start hi idle issue w a 99
 

Ive noticed this winter that when I start the truck first thing in the morning, that after about a minute, the idle will increase to about 1100 rpm. That's cool, but after maybe a minute or two, at hi idle, I hear a chatter that I think is coming from the drivers side. If I tap the brake, the idle drops and the chatter goes away until the hi idle starts again.

Any ideas on what causing the chatter? I feel like maybe it's the IP, but don't know for sure. The chatter almost sounds like a big rig w the jake brake on.


Thanks,
Sean

Is it below 10F? When it is that cold, out may be cutting out 3 cylinders to aid in warm up. It doors make an awful amount of noise, but works well.

Thanks RA. I looked at my Smarty software and it does have a 3 cylinder warm up. THe noise freaked me out, but as long as it doesn't hurt anything, I'll let it happen.

So I was doing some more reading and it looks like the hi idle is supposed to come on at *32 and the 3 cylinder is supposed to come on at *10. Mine comes on pretty much when the truck is cold. I'm in SoCal, so this morning it was around *50 and it went into 3 cylinder hi idle. Is this part of the smarty software?


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My truck would do the same thing actually and it could be 60 degrees and mine would go to 3 cylinder high idle, have you recently put a new injection pump on cause mine had to do with my ip

definatly something wrong with your IP if its 50 and its going into high idle. i would get that checked out

Does it make a difference that the intake heater and sensor are disconnected?

It's a new II hot rod 44. I checked DTC codes and this is what came back.

P0382
P0380
P0113
P1693


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clear the codes and see if they come back

I know the heater is gone, so the relay codes make sense. I also have a feeling that the sensor is not in the intake. Where would I look to find the sensor? Is that normally in the intake horn, or is it between the air filter and turbo?


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I was working on the truck today and while I had the hood open, I checked the intake to see if any plugs were disconnected. Sure enough, the sensor in the rear was disconnected. I plugged it back in, and now the truck idles normally at startup. I have a feeling that the guy who worked on the truck disconnected it to make the computer think that it was cold, to raise the fuel map. I'll see how it runs now that it's plugged back in.