White smoke on cold start up. About to service the TJ, suggestions on what I should include?

JoshNZ

TJ Enthusiast
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It's the middle of winter here in NZ, so I decided to convince my girlfriend to join me for the day out in one of the local forests.
About 7am, 5 degrees out (5 degrees Celsius, 40F for you lot, doesn't get that cold here!) and the first start for about a week.
There was a lot of white smoke, more than I would expect, and it smelt a lot like gas.

I'm going to change engine oil and trans/tc fluid soon and was thinking I might throw some new O2 sensors in there while I'm at it.
No OBDII codes and it still runs like a champ, but I have a new set of O2 sensors so may as well.

Hopefully one of the sensor elements is failing and it fixes it right up,
Otherwise, any suggestions on good maintenance that may relate to cold start over fueling?

As I mentioned, it sat all week, was quite cold, I'd expect a fair bit of condensation, but not all of the gas smell.
Doesn't use oil, oil is old, but doesn't smell bad, and the coolants as clean as it was when I flushed and changed it a year ago.

Pic of the startup. And yes, despite all of the complaints from my girlfriend, we still went without the roof or real doors.
She loved the hour trip down the freeway to the forest...
And bonus pics because why not!

D0E04553-A3B5-4297-A06B-230F6799FDE7.jpeg

AC2E2432-F9F5-4204-BC0F-9FCEAA374B4E.jpeg DFD2D3E1-4C2A-4313-9F37-9F5F7CC4AA92.jpeg 3B0A357D-58A0-4F2C-8E67-AAD89E8CBCA1.jpeg 576AD087-B8E9-4598-B2DA-CF1C35D42E1D.jpeg

C3ED25D4-157C-4DA6-B630-BBD6F2FBF3AC.jpeg AC497427-F473-4FB7-9FFE-7BF42BD0092F.jpeg
 
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Jeeps at 150k kms, so getting closer to the 100k miles mark.


Also, anyone able to tell me when the 4.0 fuel pressure changed?
TJ is a '97. My last Jeep was a '95 XJ and when I bought it I was given a set of reconditioned 4 hole injectors (from K Suspension)
I never installed them in the XJ. I've seen the experts weigh in saying they're bit of a gimmick, but why not? New injectors are new regardless of how many holes are in them?? Assuming they function correctly of course...

However, I'm pretty sure the rail pressure changed at some point? In the meantime, I'll check to make sure they even have the same physical dimensions and plug connector type.

Again, I know there is no real need to, and I don't expect miracles, but before I swap the plugs out I was curious to see how it ran (i.e the same, or terrible)
 
The white smoke at startup is usually an indicator of bad valve seals.

As for when the fuel pressure changed, that one I can't answer. Maybe @Jerry Bransford knows?

In regards to the 4-hole fuel injectors, that is a complete gimmick and nothing more. Will they hurt performance? No, they don't. However, you won't gain anything from them whatsoever, and anyone who tells you otherwise is tooting their own horn. This is one of those stupid internet myths that some asshole started who knows when, and the rest of the idiots took it and ran with it.

I would definitely replace the O2 sensors while you're in there.
 
It’s so pretty where you live, I’d push my TJ around if I had to to see it.
 
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The white smoke at startup is usually an indicator of bad valve seals.

As for when the fuel pressure changed, that one I can't answer. Maybe @Jerry Bransford knows?

In regards to the 4-hole fuel injectors, that is a complete gimmick and nothing more. Will they hurt performance? No, they don't. However, you won't gain anything from them whatsoever, and anyone who tells you otherwise is tooting their own horn. This is one of those stupid internet myths that some asshole started who knows when, and the rest of the idiots took it and ran with it.

I would definitely replace the O2 sensors while you're in there.

I refuse to believe its the stem seals... so will be taking other suggestions ;)
I refuse to believe because it smoked like that for a good few minutes (surely longer than it takes to burn off residual oil) and because it wasn't oily, it smelt very very rich..
But I'm not an expert
I'll start with the O2 sensors and see if anything changes.

And noted re the injectors. I was more curious about the rail pressure (may as well add it to the knowledge bank) than if they'd be any good, I've read all the comments here too!
 
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It’s so pretty where you live, I’d push my TJ around if I had to to see it.
Yours must weigh a lot less than mine! This is just the North Island, everyone (except me) will say the South Island's even prettier
 
Yours must weigh a lot less than mine! This is just the North Island, everyone (except me) will say the South Island's even prettier
Place looks like paradise.
 
The white smoke at startup is usually an indicator of bad valve seals.

Dammit, now you've got me over thinking it and worrying. You could well be right, the seals are 22 years old now, and it had pretty infrequent use over the last few years, the perfect recipe to cause them to have dried up and started leaking.

Are leaky valve stems on the 4.0 common?

Place looks like paradise.

Not as much open space for wheeling and exploring as you'd hope though. Unless you're part of a club which can gain access, such as this trip.
I'm jealous of all the space and types of terrain available to you up there!
 
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Dammit, now you've got me over thinking it and worrying. You could well be right, the seals are 22 years old now, and it had pretty infrequent use over the last few years, the perfect recipe to cause them to have dried up and started leaking.

Are leaky valve stems on the 4.0 common?

I don't want to say they are "common" since you don't hear about it too often, but on a vehicle that is 22 years old, it's very, very possible (especially if it's been sitting for a long time).

All I am saying is that don't rule it out completely. That's what I am putting my money on.

I suppose it could potentially be a head gasket as well, though that usually has other symptoms to go along with it.
 
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