Smoking at start up

Joined
Jun 9, 2021
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10
Location
lenoir nc
Bought 94 80 has 256k. Smokes heavy at start up. Still has everything but cats. Does this engine need new rings or just need total rebuilding. Runs great just doesn't have a lot of gitty up and go. Using mobile 1 high mileage syn 1030. New to this platform. I don't know if it is AWD or 4wd. Has separate shifter that has h n L. Any thing you can take off this sled to make it accelerate any better. Seems like a lot of stuff could be deleted. Any help appreciated.
 

Irish Reiver

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Oct 24, 2015
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Orlando, Florida
A compression test and leakdown test would be a great place to start. I would also check you PCV valve and change it as a matter of course. If the grommet that it fits into is hard and brittle then you can be 100% sure the valve stem oil seals are in the same shape.
 
Joined
Oct 7, 2013
Messages
331
usually if it smokes only at startup then it clears up it's the valve stem seals that are toast, if it's always smoking then it's rings or other cylinder wall damage.
 
Joined
Sep 15, 2016
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Chattanooga, TN
FYI, the valve stem seals are known to harden and start leaking over time. It varies but at your mileage if they haven't been replaced then you can be sure that yours are leaking. Startup smoke would be a symptom as would be oil consumption without matching oil leaks.

Compression test and a general assessment of engine condition is the next step I'd take. If all is up to snuff then I'd lean towards doing the head gasket, stem seals and updating other rubber while in there. With a solid engine otherwise, addressing your oil leaks/consumption and doing the head gasket as PM likely buys you another 100k plus miles, easy. Unless you are still racking up the miles this could translate into many years of trouble free operation.

Along with your compression check, listening for knocks, perhaps a blackstone oil analysis, etc. to assess engine condition you should also try to drive another '94 fzj80. Yours may be 100% but still feel slow as many describe these as very slow. If your 80 is slow in comparison to modern suvs then there's likely no problem. If it's slow compared to another '94 then you may at least need a tuneup and some easy repairs. Tire size (depending on regearing) can also change the performance so if it's on larger than stock tires and not regeared and/or loaded with accessories/weight then those are other reasons it may be slow.

I don't recall if they had gone to AWD in '94 or not but someone will likely chime in on that point. In any case, as I understand it the only difference is that to make these AWD they added a viscous coupler that doesn't have much strength. Per some at least performance is equivalent in most, if not all, relevant ways with and without the VC. My 80 doesn't have the VC and I've never tested one with it so I just have to pass along 2nd hand info on that.
 

flintknapper

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May 22, 2004
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Deep East Texas
At your mileage (actually way before this) your Valve Stem Seals have gotten rock hard and not sealing efficiently. Oil runs down the valve stems overnight (or anytime the engine is off a significant amount of time) and what you are seeing is the oil burning off in the cylinders.

There are two different seals (intake and exhaust) they have the same I.D. but the exhaust seal is flanged.

VS Seals1.jpg

VS Seals2.jpg
 

ppc

M Go Blue
Joined
Aug 18, 2003
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3,738
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Nashville, TN
What color of smoke are you seeing. This time of year a cold start will generate a lot of water vapor which will be white and quickly dissipate which is perfectly normal.
 

lumbee1

Native American
Joined
Sep 21, 2011
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3,896
Location
Holly Springs, NC
Valve stem seals.

My guess is the longer you let it sit, the more it smokes on startup. And if you let it sit for more than a month, it will hiccup and choke on startup from all the oil in the cylinders.
 

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