Idles High

[Rascal]

HELLO, I'm new here and bought a 03 3500 4X4 back in the summer and one of the problems is when you let off the acc pedel the rpm stay for a sec or two before dropping. The truck idles at anywhere between 750 and 1150, while idling high you can let the clutch out alittle and get the truck to idle right until you go again. Also then the weather is warm the truck wants to die and rpms drop to about 300 and them jumps up to 1100. Brought truck to local 5 start dealer they looked at everything and said OK. Bring the truck back when there is a engine light on. The truck is all stock. Thanks Everybody







2003 Dodge Ram

 

[HBarlow]

That is not normal. I think something is wrong. My '01 manual six speed never did that, even now with 350k miles on the odometer.

I should say that I haven't owned a HPCR (2003 and up) with a manual transmission. There may be some emission related component that controls idle speed to prevent black smoke emission that I don't know about.

 

[AH64ID]

Not normal.

Is the enigne sound changing or just the tach?

But probably an issue with injectors.

 

[JJPage]

It sounds like you may have a couple of things going on that may cause your symptoms.



#1, the hanging throttle could very well be a sticking FCA(fuel control actuator). It is the solenoid on the rear of your CP3 injection pump, Cummins part #4932457. Personally I think they are replaced for no reason far to often, sometimes a quart of 2 cycle oil(ashless tc-w3) to a full tank of fuel may loosen it up.



#2, your fuel lift pump, located on the back of your fuel filter canister, could be starting to fail, that also will cause irratic rpm's, especially at idle. You stated the truck was all stock, these pumps are no longer available at the dealer, but Geno's Garage has a direct replacement.



There are a number of sensors, and a couple other mechanical scenarios that could be occurring, but this is where I would start.



I do not have alot of faith in dealers, 5 star or not, there is one that has altered my belief's a bit... . Dave Smith, Kellogg, ID.



Jess

 

[MMeier]

I'd start by replacing the FCA.

 

[cerberusiam]

The idle sticking around 1000-1100 seems to be some type of built in program trying to guess when the clutch is going to be engaged. A lot of the manuals do it with no issues. I think its another one of those things designed to 2nd guess the driver that didn't work out too well. Or it could be a sticky FCA, its hard to tell.



Revs stayiing up after releasing the accelerator pedal is normal on a CR engine. The ECU does not immediately chop the fuel to the injectors but rather ramps it down to keep the rail pressures under control. Or it could be a sticky FCA, its hard to tell.



Dying at an idle and\or clutch engagement is really the only abnormal thing you have posted. Thats is frequnetly a sticky FCA. You can try running extra lube in the form of 2 stroke oil and diesel conditioner like Power Service for a bit and see if it changes the symptoms, or, just buy a new FCA and go from there.

 

[BrettDuke]

The idle sticking around 1000-1100 seems to be some type of built in program trying to guess when the clutch is going to be engaged. A lot of the manuals do it with no issues. I think its another one of those things designed to 2nd guess the driver that didn't work out too well. Or it could be a sticky FCA, its hard to tell.



Revs stayiing up after releasing the accelerator pedal is normal on a CR engine. The ECU does not immediately chop the fuel to the injectors but rather ramps it down to keep the rail pressures under control. Or it could be a sticky FCA, its hard to tell.



Dying at an idle and\or clutch engagement is really the only abnormal thing you have posted. Thats is frequnetly a sticky FCA. You can try running extra lube in the form of 2 stroke oil and diesel conditioner like Power Service for a bit and see if it changes the symptoms, or, just buy a new FCA and go from there.

There seems to be 2 common denominators... ... ... ... ... " Hard to tell " and FCA Failure :-laf

 

[cerberusiam]

There seems to be 2 common denominators... ... ... ... ... " Hard to tell " and FCA Failure :-laf

Yep, gotta love diagnosing electronics with no codes. :-laf

 

[subodh]

put in a modded fca while your at that route

 

[Prairie Dog]

put in a modded fca while your at that route

o



Modded??? Got more info?

I think I probably need one. . Oo.

 

[JJPage]

You can purchase from Floor it, Wicked, Industial Injection, or do it yourself.

Here is a Link with more info and pictures, just scroll down to the pics.

Relentless Diesel • View topic - DIY CP3 Mods

 

[Rascal]

News Up Date.

The truck still takes a sec or two for rpm to drop when ya let of acc pedel or clutch the truck. I replaced the fca, inlet sensor, and map sensor. Any more ideals would be helpful. Gauges now is on my list. Which fuel gauge is needed more the fuel or the rail??

 

[cerberusiam]

The truck still takes a sec or two for rpm to drop when ya let of acc pedel or clutch the truck. I replaced the fca, inlet sensor, and map sensor. Any more ideals would be helpful. Gauges now is on my list. Which fuel gauge is needed more the fuel or the rail??

The idle not dropping right away is normal as I said, its the way they are designed. Since you replaced everything except the injectors, its probably normal.



You really need both gauges to monitor if you are playing, just low side if not.

 

[CSilkowski]

... ... one of the problems is when you let off the acc pedel the rpm stay for a sec or two before dropping. The truck idles at anywhere between 750 and 1150, while idling high you can let the clutch out alittle and get the truck to idle right until you go again.....

2003 Dodge Ram

Mine started to do the same thing within the past week so this thread is helpful.

 

[ECaracino]

Starts on high idle

Anyone run into this: when the temp is 25 degrees or less the truck start on high idle (1000rpm). It used to start at low idle and run for a few minutes before idling up. Any suggestions on what this could be?? (no codes)

 

[AH64ID]

Anyone run into this: when the temp is 25 degrees or less the truck start on high idle (1000rpm). It used to start at low idle and run for a few minutes before idling up. Any suggestions on what this could be?? (no codes)

Thats perfectly normal.



At temps ~32*F it takes 2 minutes to slowly ramp the idle up to 1,000 rpms. At temps ~15*F (thou I have seen it as warm as 23*F) the rpms go to 1,000 instantly.



The ECM does this to aid in cold weather warm-up and starting.

 

[cerberusiam]

Anyone run into this: when the temp is 25 degrees or less the truck start on high idle (1000rpm). It used to start at low idle and run for a few minutes before idling up. Any suggestions on what this could be?? (no codes)

Mine will go directly to high idle if its cold enough, in the mid 20's or lower. Done it since new.

 

[TFrazier]

I too have an 03. it has done what you described (minus the dropping to 300 rpm and almost dying) since i bought it with 90,000 miles on it. i too can let out the clutch a little and get it to drop to normal. I have recently replaced the stock fuel pump, and all injectors (for other reasons) and it still does it. i have never had a problem because of it and get the general consensus is that a lot of 03's do this without any other problems. i left it alone. hasnt gotten any worse over the last 4 years...