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I have noticed recently a strange sound, or sensation while my truck is idleing. The best way I can describe it is it feels like a random intermitten stumble.. Like an AC clutch engaging against head pressure. I have not had a chance to investigate with the hood up yet to see if it is in fact something belt driven or not.

 

I read another post where a member had experienced what he called an intermitten studder while idleing, and it was his FCA..?

 

 

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Well I left for work this morning at 45 degrees Truck starts idles normal, I get to work sit in the parking lot idleing for about 15 mins everything sounds perfect. I leave work, its 65 degrees stop at the farm, pop the hood and let it idle for about 10 mins.. She purrs like a kitten?? 

 

So maybe I`m just a hypercondriac?? But I have noticed something that seems peculiar a few times lately.

 

Would an injector failing begin as just being random from one day to another?

 

If it happens to be just an injector getting coked up what is the best way to burn it out?

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You should only idle your pickup for a couple of minutes. Idleing only uses the injectors more, burns fuel and also allows the cylinder temps to drop so your fuel isnt completly burning. Which cause carbon and can cause injector to stick open (seen it many times). Mine does the same thing, one time it idles rough and the next time it idles fine. Im gonna throw in a fca but I am getting injectors because I have 224,000 on the origional injectors. You also need to build/buy a 3 micron filter setup for it and run a baldwin pf7977 filter in the stock housing

Edited by mopartechnician
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You should only idle your pickup for a couple of minutes. Idleing only uses the injectors more, burns fuel and also allows the cylinder temps to drop so your fuel isnt completly burning. Which cause carbon and can cause injector to stick open (seen it many times). Mine does the same thing, one time it idles rough and the next time it idles fine. Im gonna throw in a fca but I am getting injectors because I have 224,000 on the origional injectors. You also need to build/buy a 3 micron filter setup for it and run a baldwin pf7977 filter in the stock housing

The new BD lift pump I just installed has a Donaldson 3 micron particulate filter. and I have been running the Baldwin pf7977 for the last couple of years.

I noticed this evening that it acted like something is cycling on and off. it is 65 degrees and the AC/ defrost are turned off. It was already dark so I didn`t have a chance to investigate, but I have never really noticed it doing this before.

 

Does the fan clutch cycle on this truck?

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Could be clutch cycling. You shouldnt feel the fan cycling. But when a fca acts up, it will be rythmic.

You know an FCA is about the cheapest replacement part you can find for a CR. I`m going to get a new one just for PM

 

Thanks for the input.

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The only things that should "cycle" normally on a regular basis would be the "fan clutch", the AC compressor, and the grid heater.....................all of which are temperature sensitive via some sensor.

 

 

Or could it be the alternator?????  You know how when you're "jumping" another vehicle and they hit the starter how your vehicle grunts a bit.......................just thinking out loud here!!

 

 

No aftermarket add ons to your truck??

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The only things that should "cycle" normally on a regular basis would be the "fan clutch", the AC compressor, and the grid heater.....................all of which are temperature sensitive via some sensor.

 

 

Or could it be the alternator?????  You know how when you're "jumping" another vehicle and they hit the starter how your vehicle grunts a bit.......................just thinking out loud here!!

 

 

No aftermarket add ons to your truck??

 

It usually takes a about a minute for the alternator to kick in when I start my truck. When its cold and the headlights are on I always notice the lights dimming with the grid heater. Once the alternator bumps up to 14.5 volts you never notice it anymore.

 

The other night it was 65 degrees AC off, and the truck was fairly warm already. It idles @ 750rpm and doesn`t fluctuate, but there was a random change in the exhaust tone. So I guess it could be alternator? but I did`nt notice any change in the volt gauge.

 

I may be just chasing a phantom here?? ( but prior to changing the lift pump). The truck stalled once under accelleration, and there were at least a few episodes where there was a noticeable "stumble" after a cold start which felt like an AC clutch engaging hard.

 

I`m going to wait and see if some more symptoms emerge.. Or this may be perfectly normal??

Edited by angus
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