Truck goes to high idle 1,000 rpm and running warm

[Davyjones007]

Okay, so about a week ago I noticed that when I got back from driving my 06 2500 5.9L 4X4 automatic, when I came to a stop in my driveway and put it into park, it went straight to idling at 1,000 rpm's. when I switch it to reverse, it went back down to regular idle. Then I put it in neutral and it automatically went back to idling at 1,000 rpm. I got a video of it doing this if anyone can Pm me their number so I can send it to them. The truck usually runs at normal temps but now when it gets warm while driving it is running higher than normal. I even caught a glimpse of it surging almost all the way to the black line before the red line at 245 temp. Please help.

 

[Bob4x4]

I would diagnose the running hot condition first

 

[AH64ID]

They are programmed to increase idle rpms when hot. I would guess you have a sensor issue or are low on coolant and have a hot air pocket.

 

[Davyjones007]

I am taking it to a diesel shop this weekend, it sounds to me like I would be a little out of my league when it comes to sensors, whenever I bought the truck it was low on coolant, I filled it up and it hasn't dropped at all. So it sounds like to me that I am having a heating issue and the truck is doing what it is suppose to by reving up to 1,000 rpm to get rid of the heat. Thanks a lot for the input guys

 

[BILTIT]

How low was it? Possibly have an air pocket as said above.

Whenever i fill the coolant with any large amount i pull the heater hose off the nipple on the left side of the top of the head (about midway) and let the air escape there until coolant flows out. This prevents most air pockets.

 

[Davyjones007]

I put almost a gallon of coolant into my truck biltit. I also just put a k&n cold air on it last weekend and we noticed that the hose going into the left top radiator(looking at the motor)(by the air filter) was hanging down. It wasn't hooked up. Now I don't know if it was us that mocked that off when we removed the stock air box. The truck had this symptom before we "might" have knocked this hose off. And I hooked it back up and am still having the same symptoms as before the new k&n intake. Could it be possible that I have a clogged thermostat? I added a photo I think, that hose was plugged in right below the radiator cap right by the k&n filter

 

[AH64ID]

On a side note... take that K&N off ASAP! K&N is about the worst filter you can run on a turbo motor.

Unless you're running a different turbo that cannot use the OEM filter or more than 450-500 rwhp you cannot beat the OEM air box and filter, period. The best thing to do is run an OEM filter and do a home deopt CAI mod (search on here for it). The OEM box will pull cooler air as well as filter better.

 

[Bob4x4]

The hose you knocked off is just the overflow,unless it runs hot it wont be a big deal over a short period but may drop the coolant level enough to be an issue over time

 

[DavidC]

On a side note... take that K&N off ASAP! K&N is about the worst filter you can run on a turbo motor.

Unless you're running a different turbo that cannot use the OEM filter or more than 450-500 rwhp you cannot beat the OEM air box and filter, period. The best thing to do is run an OEM filter and do a home deopt CAI mod (search on here for it). The OEM box will pull cooler air as well as filter better.

Agree unless you like spending thousands repairing/replacing a dusted engine.

Dave

 

[sag2]

And besides the potential to pull dirt into the engine with that filter, we need to clear up that it was a CAI with the stock box, but now you have a HOT air intake system.

 

[Motorhead]

All the above guys are right on about the K&N filter. Every turbo Cummins I have ever serviced with one of those or even a gauze type drop in filter in the original filter housing, let grit in. All I had to do was remove the big intake hose from the filter to the compressor blades of the turbo, wipe the compressor inlet with my finger and you could feel all the grit!
Check close the pipe plugs inserted into the cylinder head. They can seep.

 

[Prairie Dog]

They are programmed to increase idle rpms when hot. I would guess you have a sensor issue or are low on coolant and have a hot air pocket.

.

Or very cold. Either one will make it jump to 1000 RPM.

 

[Bob4x4]

On the 06 a common slow coolant leak source is the short hose under the exhaust manifold

 

[AH64ID]

.

Or very cold. Either one will make it jump to 1000 RPM.

Indeed. Here is the stock rpm vs ect table.

 

[gofastman1]

I agree with sag2, all you have done is installed a hot box for a motor that likes cool air, take it off, put stock back on, your motor will love you for it.
K&N filters are for junk, they don't filter nothing but to keep the bugs and leaves out , everything else passes right through it

 

[cerberusiam]

Total nonsense, the myth that an open filter under the hood ingests hot air has been proven wrong ages ago. Even on 2nd gen with the filter in a much worse piston it is not an issue in 99% of driving scenarios. On a 3rd gen the point is moot, the factory cold air vent is right there along side the filter plus the air flow around the headlights and grill keeps temps in that area so close to ambient it doesn't matter. On a stock tuned engine it is looking for high IAT's anyway for efficiency, unless you retune and max boost and HP it makes no difference. There trucks have a CAC for a reasons, it is a air COOLER any bump air intake temp is not even noticeable down stream form the filter.

A K&N is not that bad if one is a low dust environment, boost is generally low, and it is maintained correctly. Just not the best solution for an FI engine that is being worked hard, lots better and cheaper ones available.

 

[gofastman1]

Total nonsense, the myth that an open filter under the hood ingests hot has been proven wrong ages ago. Even on 2nd gen with the filter in a much worse piston it is not an issue in 99% of driving scenarios. On a 3rd gen the point is moot, the factory cold air vent is right there along side the filter plus the air flow around the headlights and grill keeps temps in that area so close to ambient it doesn't matter. On a stock tuned engine it is looking for high IAT's anyway for efficiency, unless you retune and max boost and HP it makes no difference. There trucks have a CAC for a reasons, it is a air COOLER any bump air intake temp is not even noticeable down stream form the filter.


A K&N is not that bad if one is a low dust environment, boost is generally low, and it is maintained correctly. Just not the best solution for an FI engine that is being worked hard, lots better and cheaper ones available.

Everyone has there opinion, I go off of facts, I seen tests run with K&N and they are not good at all, but each is his own.

 

[cerberusiam]

Everyone has there opinion, I go off of facts, I seen tests run with K&N and they are not good at all, but each is his own.

Would be easier to judge opinion vs fact if some were presented, not the same tired clichés. FYI, YouTube videos are far from fact in the real world.

If you were actually present at a K&N test you would find it is not as clear cut as you are trying to make it. Up to a point the K&N, or any oiled filter for that matter, works as advertised. It is always the extremes that are shown and touted as IT, not the norms. Fact is there are many trucks that have run 100's of thousands of miles and years with no issues using an oiled filter, K&N and others. Like anything else, the failures are big news with the successes much less so.

If you were referring to hot air and open filters, simple test to prove it. Watch your IAT's, that is where it matters.

 

[ColemanR]

Yep I go off facts too....K&N been on my truck for 896K....zero blow -by or oil consumption.

 

[Davyjones007]

So let's get that out of the way first, this was happening with my stock air intake on my truck so let's forget that I have a K&N cold air on the truck and stop talking about the intake cuz that right there rules that out. Can anyone tell me what else I can check since my truck is running warm? Now I did the tachometer fix on my cluster a couple weeks ago, could it be possible that the temperature gauge is not reading correctly? If so how do I check that? And how do I check the temp of the engine without using the temp Guage and using a temp gun on the engine??? To rule out that the temp guage in the cluster is working properly?