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I see lots of posts in this forum about white smoke from the exhaust, but I didn't find any that explicitly list out the checks below. I'm just not convinced (yet) that it is the LIM or gaskets. Apologies if I missed.
Checks completed:
1. No oil in the water. No water in the oil.
2. Plugs look normal. No signs of fouling, carbon build-up or "steam-cleaning."
3. Compression test showed similar readings on all cylinders.
4. Leak down test show no signs of issues.
5. Fuel pressure regulator was leaking fuel into the LIM. Replaced, no further issue.
6. Cooling system pressure test: Holds 15lbs all day long.
7. The 4WD actuator is full of tranny fluid due to a bad vacuum switch. Both parts are ordered.
Notes:
How I found out the fuel pressure regulator (FPR) was leaking was the usual case where fuel pressure was not holding.
Prior to replacing the FPR, I noticed a yellowish fluid that was leaking out of the flange between the exhaust manifold and the downpipe. It smelled a little like a mix between hydraulic fluid and gasoline and water. After replacement no further issue.
Questions:
1. Anyone experience this before (with the same checks above). Has it been solved?
2. Is is possible the leaking FPR could have flooded the Cat and the white smoke is just a side effect until it all burns out?
3. Is there a path through the 4WD actuator/switch system to the intake vacuum that could allow tranny fluid back through the intake?
4. Other ideas?
I surmise the transfer case input shaft seal may be the root cause. However, i am now leaning toward the switch as this appears to be the only path for the transmission fluid to get back to the engine. Seems odd there is no evidence of oil in the lines at the manifold.
After i replace the switch and actuator, I will try the blow out test to see if stuff just needs to burn out of the cat. More to follow.
Seems I am on the right track to resolve my white smoke issue... I found what appears to be proof tranny fluid is getting to the combustion chamber. The engine vac source at the back of the manifold is sucking fluid through the (bad) T-case vac switch. The proof came while while surveying what's needed to drop the T-case. I see a mount arm on the cat that appears to be leaking what looks like tranny fluid. it fairly clean now after my fingers wiped it off...I guess this mount arm is hollow and goes inside the cat? Seems weird to me as this would be a lot of heat for a rubber mount, but there is no other place tranny fluid can get to that arm. Also, the cat is mounted upside down, so this arm isn't used as a mount anyway.
So far, the T-case vac switch, vac actuator, and vac lines have been replaced. The vac actuator was so bad the post just flops around. Vac ball also full, so I flushed out really good with hot soapy water. Next step is to resolve the well documented T-case seal issue, which is obviously the source of the fluid throughout the vac system.
I'll update again after the t-case is back in. Not sure if the tranny fluid has ruined the cat, so I hope it will just burn out. Side note, between this issue and the previous leaky regulator, maybe this is why the cat is mounted upside down and the paper work shows previous owner replaced the cat twice in 3 years...
You didn't mention whether you have any codes. Sounds like you might be on the right track, or you could have a lean condition causing the white smoke.
Well I am quite happy to report the t-case is back in with the new front seal. I can tell you already there is no more white smoke and the exhaust smells pretty much normal. I drove it about 5 miles and so far so good. I have not activated the 4WD yet, so until then the jury is still out for me. After I finish working on some other issues on this rig, I'll check out the 4WD and see if the original issue comes back. Hopefully I have the same answer (fixed). Stay tuned for the next update!
White smoke
