Engine Lost

[thejeepdude]

Originally posted by midlife crisis

Well now, dont I feel like a jacksss. I was sure the injectors were fired by the computer, connected via an electrical connection. And you further correct me by telling me there is no way an injector driver, for whatever reason, couldnt be keeping an injector open, or timed wrong. I stand corrected.

Man I love sarcasm... The injectors ARE fired by the computer. They ARE connected via an electrical connection. I never said they weren't. I also never "corrected you" by saying an injector couldn't be messed up and therefore screw up your timing. All I'm saying is no matter how long the injector is held open, there's still no way fuel is going to end up in the crankcase oil unless there's a MECHANICAL problem... something has to be leaking somewhere. There's no path between the top of the cylinder (where the injector dumps, in a case of stuck injector as you mention) and the crankcase, unless there's a problem with the cylinder, piston, or rings. I would be glad to admit I'm wrong if someone wants to enlighten me with some knowledge that I might not be aware of instead of a bucket full of cynicism.

 

[Dog Licked Racing]

Low Oil Pressure

My new truck (purchased 7/26 with 450 dealer miles) is having much the same problem.



The first 50 miles the oil pressure seemed to stay steady near mid range (40psi). But when I started it up the second morning (yesterday) it would drop to the very bottom of the operating range at idle.



Its back at the dealer as of late yesterday (now 575 miles), for a check out.



As a newbie, I was wondering how the oil pressure is supposed to behave in these trucks?



I sure don't feel great about seeing a gage sit just off the red zone.





Frank

 

[rashwor]

Oil Pressure.

For my '99, the manual says that anything above 10 psi at idle and anything above 30 psi WOT are acceptable pressures.



For reality, my '99 gauge (never had the oil pressure reflash) reads about 25 psi at idle and about 50 psi at cruising rpm (2000 rpm or so). If mine were to vary much from this, I would be concerned and have it checked out. The truck has done this for its entire life and currently has 173,000+ miles on it.

 

[travisch]

thejeepdude - In this case the chipped valve (intake or exaust) will cause a missfire on the affected cylinder. with the injector stuck open the fuel will get past the rings and into the crankcase.

 

[mberry]

Originally posted by travisch

thejeepdude - In this case the chipped valve (intake or exaust) will cause a missfire on the affected cylinder. with the injector stuck open the fuel will get past the rings and into the crankcase.

How can it do that? Wouldn't the pressure being bled off by the chipped valve prevent pressures high enough to push the fuel past the rings even if they were high enough to initiate combustion? Wouldn't it take the path of least resistance?



Since we know he burned a hole in the piston, I would think that is where the fuel in oil situation came into play. It would take much more convincing for me to believe that it could get past the rings and into the crankcase the way you describe.



If that were the case, then how come new engines don't have problems with fuel in the oil until the engine is broken in?



If I am wrong I freely admit it. I am not a diesel engine expert but I have to back jeepdude on this one.

 

[Pawpaw]

Re: Low Oil Pressure

Originally posted by FClark

My new truck (purchased 7/26 with 450 dealer miles) is having much the same problem.



The first 50 miles the oil pressure seemed to stay steady near mid range (40psi). But when I started it up the second morning (yesterday) it would drop to the very bottom of the operating range at idle.



Its back at the dealer as of late yesterday (now 575 miles), for a check out.



As a newbie, I was wondering how the oil pressure is supposed to behave in these trucks?



I sure don't feel great about seeing a gage sit just off the red zone.





Frank

The oil pressure "gauge" on the 3rd Gen trucks is a sham. There is no oil pressure "sending unit". Instead, it's just a switch that closes at 6 lbs or so (as I recall). That is fed to the computer, which makes the "gauge" on the dash behave "according to customer expectations.



In other words, we just have a fancy idiot light.

 

[rbattelle]

Bob Hall is right on... get yourself an aftermarket gauge and pay NO attention to the factory junker.

 

[midlife crisis]

I know there is some cast iron under all those wires, no sarcasm intended. I was merely trying to point out that the failure was known, but the CAUSE was in doubt. Mavbe a hung injector washed down a cylinder, or carboned up a ring land, or put a hole in the piston. Jdude- it is possible an injector can cause the damage to the cylinder/piston/ thats were I was going.