Has anyone else noticed their rail pressure fluctuating 500-1000psi. at steady throttle? I was really eyeballin' my r/p guage today and noticed it would bounce a little about every second or so. I recently replaced my FCA so I would'nt think that would be the problem, but who knows? Does any of this sound normal?

 

never had that problem, Your in the same boat as me. I would say you need a modded CP3. I am going with a stage 1.

 

I want one, but it's not at the top of the mod list right now. That's why I went with smaller stix...for now!

 

Just a shot in the dark here.... But could this possibly be caused by the voltage draw from your grid heater kicking on and off?

..

 

My rail pressure fluctuates at steady throttle. At least 500 to 1000psi.

 

Yeah, it definately does that, but only while idleing/warming up. And there's a lot more movement when that's going on.


Well, at least I'm not alone. It was really acting up today as well. Anyone else seeing this or have any thoughts?

 

Kept a closer eye on pressure this morning and I'd have to say it's around 500psi variation, not 1000.

I don't feel there is anything wrong with this. I just believe the differences in cylinder to cylinder, and injectors, etc. are what makes for the differing pressures. Nothing is perfectly balanced... well... maybe an Indy car engine may come close.

 

I've only had my injectors back from F-1 for a couple of weeks, so they should be pretty well even from one to the other. As for differences from cylinder to cylinder, who knows!

 

My rail pressure bounces around quite a bit as well. Never stays at any one level long. Why did you replace FCA, and where did you get it? I may need one.

 

I replaced mine because after doing my injector swap when I started my truck my FCA kind of worked backwards. It idled at 27,500 and came down as you applied throttle. It drove just fine, although it sounded like a 12 valve.

I believe the best place to get a new FCA is from Cummins. $90-$95 from what I've read here.

I got mine used from Tim at TRE Diesel. I bought my injectors through him and explained my problem to him after I noticed it. After a few phone calls and trying a couple of things, we figured it was probably the FCA. He then offered to take one that he knew was good off one of his own pumps and send it to me to try. Sure enough, that was the problem.

Many thanks go out to Tim for top notch customer service and going way, way out of his way to help a first time customer. I'd reccommend TRE to anyone.

 

Mine does really wierd stuff, even the stg 2 from john. It will fluctuate but after driving for a while it will idle below 3000psi but is still just as reponsive. Ill have to try beta software that idles at or around 7-8000psi and find out. I wonder what the deal is.

 

Yeah, mine will idle pretty low from time to time as well. Well at least I'm not the only one seeing these strange readings. Maybe it's normal!?!