replaced fuel filter and now idles rough

[union76]

Hello everyone...well I replaced my fuel filter the other day since it had been about a year since it was last changed out...after doing so I let it idle for awhile...10-15 mins or so and it ran just fine like it always has. A short while later I drove it home which is about a 10 min trip and it ran great until I pulled in to park and noticed it running rough and smoking (white smoke) more than usual. I let it sit overnight and got it back up to my workplace still running in the rough not so good condition...thinking maybe something was up with the fuel filter I removed it and checked to see if anything looked amiss but it all looked OK. I reinstalled it and after bleeding the air out it ran fine again for a minute or two before it started running rough and smoking again.

I figured it might be a faulty fuel filter so I exchanged it for a new one (WIX) and it did the same thing again after I got the new one on...ran fine for a few mins but then started running rough and smoking...it runs fairly smooth if you give it some throttle but will still smoke. In this condition it also runs a lot quieter than a 6.2 usually sounds...sounds kind of sick...in a bad way. Could it be a coincidence that the fuel pump or injection pump may have been on the way out and it just so happened when I changed the fuel filter? Both of them are still original to the vehicle...if anyone has had this happen to them or knows what the problem could be I would greatly appreciate your assistance...thanks in advance...

 

[Iceman3005]

Could be a couple of things, first maybe the O-rings in your filter base are starting to allow a vacuum leak causing it to be starved of fuel, or the lift pump is starting to go. I would check those first, then move on too a possible injector failing, usually white smoke is a sign of a weak or failed injector. If those are ok then your injection is the last part in the fuel system. To check for vacuum leak remove black fuel hose and put clear hose on filter to pump and filter to injection pump, after truck is off if fuel starts to disappear than probably a vacuum leak, to check lift pump put a in line gauge on line feeding pump it should read between 6-10psi. To check an injector I do believe that several parts stores sell a tool to do that but it is expensive, easiest and cheapest is take them to a diesel shop and have them "POP" tested.

 

[union76]

Could be a couple of things, first maybe the O-rings in your filter base are starting to allow a vacuum leak causing it to be starved of fuel, or the lift pump is starting to go. I would check those first, then move on too a possible injector failing, usually white smoke is a sign of a weak or failed injector. If those are ok then your injection is the last part in the fuel system. To check for vacuum leak remove black fuel hose and put clear hose on filter to pump and filter to injection pump, after truck is off if fuel starts to disappear than probably a vacuum leak, to check lift pump put a in line gauge on line feeding pump it should read between 6-10psi. To check an injector I do believe that several parts stores sell a tool to do that but it is expensive, easiest and cheapest is take them to a diesel shop and have them "POP" tested.

Most excellent thank you for the info...I was unaware that the fuel filter bases had O-rings in them I was wanting to change out the fuel pump anyway so I might just go ahead and do that. I don't think it's an injector because equal amounts of smoke come out of both tailpipes in unison. I'll see if I can aquire some clear hose so I can do those checks you talked about...on a sidenote I took it on a quick test drive around the block and it drove fine...no problems with power while you were driving and it ran smoothly as the rpms increase. It did smoke the whole time though and only ran rough when coming to a stop. Thanks again for your help

 

[Iceman3005]

Here are the part numbers for the O-rings.

Fuel heater O-ring:15596600
Fuel purge: (no o-ring but plastic can crack causing a vacuum leak):15535678
Vacuum pressure switch O-ring and sensor: 26159
Fuel heater assembly: (the plastic housing can crack causing a vacuum leak comes with new o-ring):29090

 

[union76]

Thank you for the part numbers I definitely appreciate your help I'll try to acquire them as soon as I can...I was also considering the spin on fuel filter conversion as an option...perhaps it would eliminate any problems such as this in the future