Figured it out thanks to homewrecker!! It was the FCA (Fuel Control Actuator) causing my issues!! Thanks for all the help people this is why I love this forum


OK for a little over a month now I have had some idling problems with my truck more recently it has been getting worse.

OK first when I start it up I do have some white smoke HOWEVER I have had this for over a year now and havent had any problems but now I still have the white smoke but a really bad idle when first starting it the next day sometimes it even has stalled on me and one morning stalled 2-3 times till I just held my foot down on the pedal for a bit.

Seems like I have more of the bad idle when the grid heaters are on and cycling but have had it when they werent on as well like this...

Other problem I am having is kind of along the same thing with a bad idle however this is at stop lights and such if I have to hit the brakes a bit harder to stop (like car in ftont of me slams on brakes at a yellow) when I go to take off the truck will spudder and a few times has died on me, now I just ride the clutch a bit more and still notice the studder but doesnt die on me at least this has also happened to me when I havent just broke hard as well but seems more likely to happen when I do brake harder.

I had it hooked up to a scan tool last night and was watching things and then also shutting down injectors as well, well first thing I noticed is that the fuel pressure seemed to jump around anywhere from around like 4500-8000psi just sitting at idle and the volts for the lift pump seemed to drop the more I pushed the pedal down pressure went up to around 18kpsi give or take a little but voltage came down? And also when I would shut down the truck then restart it (going by what the scan tool was saying to do) I would get my rough idle (with the grid heaters cycling) and at times the rpms would drop way down low then jump to over 1k rpms and the fuel pressure would go from like around 4-5k psi all the way up to 18k psi without touching the pedal just during the rough idle patch.

Now I was thinking lift pump (I have 370k on my truck and still on the stock lift pump and do have a GDP walbro kit that I have to install but havent yet) and was thinking this due to the fluctuating fuel pressure?

I was also thinking injector due to the white smoke and from reading other people having idling problems but I dont have any "extra" oil, my oil level stays steady only uses about a quart every 3k miles and never had more than I was suppose too. However when I was shutting down the injectors for the most part they all sounded the same one sounded slightly different but then again they all had kind of their "own" reactions each time the scan tool would disengage then re-engage it I may try the pulling the valve cover and unplugging each injector individually and see if I notice a difference there or not.

So this is where im at now not sure what to do exactly have the fuel pump that I WILL replace however dont have injectors lying around Any help or suggestions would be appreciated!

 

replace the pump first since u already have it. the white smoke is an injector issue. i have had 4 sets go bad and none of them added anything to the oil on either truck. you could run some cleaner thru them and see if it helps

 

Thanks for the reply I am hoping to do the pump this weekend and see if that helps anything.

As for the white smoke I had seen before that someone had posted up a TSB for my truck with the white smoke on start up however after the update the truck didnt seem to run the same (this is just word from others) thats why I had never worried about it being an injector problem considering I have had slight white smoke on start-up for over 100k miles more recently is when it got worse, and as for cleaner I usually do run PS a lot of the times although I have to admit I have been slacking on that for awhile now I might try the seafoam in the fuel filter canister and see if that helps any as well and then do regular addatives from now on out.

Oh and I am running the Baldwin PF7977 (5 micron) in canister Fuel filters but have been thinking about adding the GDP 2 micron kit along with the pump.

 

I believe that considering the sensitivity of the fuel systems on these trucks and the potentially high expense involved with problems resulting from fuel issues, the 2um secondary filter is a very wise investment.

 

I agree just checking out some prices.

 

Any other suggestions or just straight pointing towards injectors?

 

Those rail pressure fluctuations seem kind of odd. But in any case I would suspect the problem lies somewhere north of the fuel filter (CP3, injectors and related). I doubt the lift pump is the problem at all, but wouldn't hurt to know the low side line pressure anyway.

I don't know about the idea of using Power Service or other additives for the purpose of cleaning injectors. If one or more injectors is hoofed now, it's too late anyway. I suspect most of the fuel add products purported to clean injectors do more harm than good. Anything in terms of fuel adds should be going towards lubing the system, IMHO.

 

The erratic rail pressure doesn't seem normal.You mentioned the voltage dropping as RP went up.This is normal(assuming you where watching the control voltage to the fca)The lower the voltage,the higher the RP.The white smoke is normal if it clears up quickly.If its continuous then you might have an injector issue.Another thing to look at is the fca.They can cause problems related to the poor idleing and stumbling on excelleration.

 

OK the voltage is normal thats good, As for the white smoke yeah it only happens RIGHT on start up then its gone in fact at times when I had to keep the pedal down a bit to keep it from stalling there were times it dropped really far down then revved up and then its black smoke during that time. White smoke is only for a second when first starting it.

As for the FCA would that be the Fuel Control Actuator? If so I dont know much about it nor its location I will do some searching for it now.

Thanks again for the replies.

 

Well thanks homewrecker (didnt think I would ever say that ) it was indeed the FCA!

$114 and some change from Cummins, funny though I found the part number for the FCA on here and when I called them I gave them that number and yes they had it but when I gave them my engine serial code (just to verify) he said it was coming up as the whole pump and that it wasnt available seperately he then referenced the part number 4932457 and it wasnt coming up with my pump at all??

So I pulled it off my truck and brought it up there it was identical but different part numbers called another Diesel supplier I know in town and he gave the same number 4932457 so I bought it brought it home threw it on and she fired right up little white smoke for about 20-30 seconds but ran great no sputters no misses and no stalling and I didnt have to touch the go pedal ONCE!

So well yeah Thanks again for everyones help next step is the 2 micron and the GDP pump hopefully this weekend!

 

Glad to hear you got it resolved!I chased my tail a year ago with some problems fca related and got lots of help from the members on here.Happy to be able to return the favor.

 

Well considering I was pricing out injectors that saved me close to $2k dollars!! Now that can be put towards the 2 micron filter set up (even still a fraction of the price) and also a couple of new hubs since one of mine is bad