Say, what is the real reason GE’s, (most commonly caught) throw such a flame or fire out of the exhaust?
I’ve researched it a little bit & found a couple of scenarios;
Fuel (unburnt) residing in the exhaust system &/or a purge like a backfire cough.
Bad, or going to be bad, turbo.
My mechanicalness says that the bearings in the turbo may be passing raw lubrication oil into the exhaust stream (& possibly the intake side, creating a fuel imbalance as well) but I would like to know from someone that has real world experience, (not arm-chair, DVD experience, -such as myself)…
I don’t have a definitive answer, both are very plausible. The newer diesel trucks have a diesel particulate filter purge where they super heat the exhaust to burn out the built up carbon/soot in the filter. Some of the first trucks were known to have heat issues out the end of the exhaust tips. I believe there was a warning about vehicle proximity to other vehicles when the filter was being purged. Venturi type exhaust tips on the newer diesels scavenging atmosphere air at the exhaust tip and mixing it with the exhaust solved that issue. Very possible the newer low emission GE’s might have this sort of system without the special exhaust tips, and what you see is the exhaust super heating the filter’s and burning out the particulates.
And of course, a bad turbo with a leaky exhaust or impeller seal could indeed puke lube into the exhaust and catch fire. Leaking from the the intake or compressor side of the turbo won’t normally cause an exhaust fire as the combustion will burn that oil and then the exhaust travels through the impeller or exhaust side again, which would normally just cause really smokey exhaust.
There are other reasons possible, but I don’t know the particulars of the engines exhaust setup to make a more educated guess.
When GE went to the lucas EFI fuel system on the -9’s they were pretty famous for having excess fuel puddle in the exhaust and esp the turbo when they were idling for a long time That was some what improved when they were converted to the bosch style but will still happen especially when the air filters are pretty close to being plugged or there is a nozzle or two leaking fuel. Lots of them will blow the oil feed line to the turbo, then they will look like the flame is out the stack, but its really out the carbody. Lots of them also have the sides burnt due to HP fuel lines leaking and spraying atomized fuel right on the superheated exhaust manifold. Hope that is what your looking for