Join Date: Jun 2014
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
2000 7.3 white smoke and sputtering *stuck in Birmingham on road trip
-White Smoke (smells like unburnt fuel...I think)
-Hard Sputter on Accel with TONS of smoke
-Smoke from valve cover (blow by)
-Exhaust Back Pressure Sensor Circuit Malfunction code all the time
-Cyl 7 Misfire code most of the time
-Cyl 8 Misfire code sometimes
-ICP Pressure Out of Range code sometimes
-Replaced Injector 7 slight change
-Replaced Injector 8 no change
-Moved around other injectors no change
-Checked Exhaust Back Pressure reading on scanner found 22-35psi range
-I have shim in my fuel pressure regulator (maybe I should take that out, didn't cross my mind til now)
-I have an edge tuner but I put it back to stock after having problems
So I'm pretty good with diag and such but I am still new to Diesel engines. This truck has a long history and I've touched just about every nut and bolt on it but I'll keep this short. I'll do my best to describe every symptom and repair that I have made to figure this out.
I live in Salt Lake and I'm on a racing circuit hauling 2 cars in a 45 foot trailer so we are pushing the limits of what we should be towing. We are now in Alabama and are having some issues that seem to be getting worse. I have one day left to work on this before I need to tow up to New Jersey so any help is appreciated.
Truck is a 2000 F-250 with ZF manual transmission. The engine has about 250k miles and I run CNG on this truck. This engine has been in this truck for about 2500 miles. Injectors and HPOP are all from this same engine of unknown prior condition.
The truck ran pretty good from SLC to Atlanta. After that it developed a misfire. I got a code for cyl 7. I continued driving and began to notice difficulty starting and white smoke on start and slowly decreasing until warmed up. The misfire would also diminish as it warmed up but I still feel as though there was a weak cylinder. I have what I would consider an excess amount of crankcase smoke (blowby) when I remove the oil cap and when I ran without the valve covers (diagnosing injectors... I'll get to that part). This entire time I have been getting white smoke from the tailpipe. It smokes a lot when cold and diminishes as it warms up. The smoking is clearly from one cylinder cuz I can see it puff out once per rotation. By the time it is fully warmed up you can barely notice the smoke but faintly can still hear the misfire.
Seems simple enough like a bad injector and the code even pointed me to cyl 7. I happened to have a spare newer reman Alliant injector so I threw that one in cyl 7 and it made no difference.
I continued to get new symptoms as I kept driving. I now have a Exhaust Back Pressure Sensor Circuit Malfunction code, I got Cyl 8 Misfire a few times but not as many times as the Cyl 7 which seems to come up every time I cold start. I occasionally get ICP Lower than Expected but not consistently. I replaced Injector 8 today and got no change. I moved around all injectors on both banks to mix up the order and try to get the misfire to move from cyl 7. That didn't work. I ran the truck with the valve covers off and unplugged injectors one at a time to find the weak cylinder. It seemed that 7 was the culprit... however as the truck warmed up the misfire went away AND the truck continued smoking from the tailpipe... EVEN with the injector unplugged cuz I considered the idea of a wiring problem causing the injector to fire at the wrong time or stick or whatever.
At this point I know you are yelling thru your screen telling me that I have low compression or a broken piston. Well let me tell you why I think that is not the case... On acceleration the misfire is very intermittent and at around 2200 rpm the truck begins to sputter and cut out to the point that the rpm stops climbing and the truck DUMPS white smoke like crazy. If I change throttle position to less throttle it seems to clear out and accelerate but still with a misfire. If I stay hard on accel then it just continues to sputter and RPM will not climb. If I had a mechanically dead cylinder then it wouldn't have intermittent accel problems and the misfire would be consistent.
One more thing, it seems to me that I have a leaky injector. On start up the smoke seems to be excessive for a second after it finally starts as if it is clearing out extra fuel and then it knocks at idle as if there is fuel in the chamber at the wrong time and at higher rpm it clears out and stops knocking. Also when I turn on my cng it seems that the misfire smooths out a bit.
Please shoot me any ideas to check and anything that you may have in mind.