Hey everybody, doing some troubleshooting on the XJ. Was already talking to Cruiser and so I'll just paste some of the convo here as it may be useful to people:
_______________
So....I have an 89' renix XJ 4.0 with 140k on her, had about 120k when I bought her before the winter. She drives very well, and doesn't have a spot of rust (had rockers done previously with the metal work and coating already) and I got her for $2k. So far, I've done quite a bit of work - she had quite a good deal of wobble so I have already swapped out literally every wobble related thing possible minus lower control arm and shocks (they're next), did the ground refreshing, new battery cables, cap/rotor/plugs/wires, trans cooler, bunch of other goodies.

So she's been getting a decent amount of blowby (since I had her) so I had removed the valve cover and trimmed down the oil drain tubes (as you had suggested) - by the way there were already small holes drilled in the tops of the tubes, looked factory, but we trimmed them anyway and it did seem to help a bit - new felpro vcg, cleaned it up a bit, new ccv hose, cleaned out the air box area, etc. Cut down on oil into the air box for awhile by a good amount. After a few months, however, it seems to have gotten worse. There's a LOT of smoke (or vapor?) out of the oil fill cap (and dipstick tube) when it's running, but never a single bit of smoke out the tailpipe. The smoke is not bluish, definitely not a coolant issue.

I'm losing (burning or leaking) a lot of oil - I'm talking like a quart every week or two. I'm leaking the tiniest bit of oil, but I 'm definitely losing a lot more. If it's the pan/RMS, I'll be doing them soon anyway, no big deal. Could also be the oil filter adapter o ring(s), but it doesn't seem to be. Either way, I seem to be burning quite a bit of oil. From what I remember when I bought the jeep, there wasn't any smoke out of the oil filler cap, but I could be wrong...now there is a ton.

I will be doing a compression test tonight or tomorrow, should give me a good idea of what could be the issue - but I guess I'm trying to wrap my head around the issue(s)...

From what I've been reading, there's a chance it could be rings/head gasket, or just simply valve seals. If the latter, I want to get ready to them this weekend or next, gonna buy an air compressor and the plug adapter and take the valve cover off and a friend and I will tackle that, no biggy really. But could that really account for all that blowby? Would it be worth even doing this if I would have to take the head off anyway? I suppose a wet/dry compression test will tell me more, so I'll see tonight. Figured I'd set up this post and then later I'll follow up with those results.
___________

Great work on your part.

Make sure the CCV port on the intake manifold is not carboned up on the nipple where the hose attaches.

Valve seals generally let you see a poof of blue smoke at idle or on take-off.

How sludgy is it under the valve cover, on the rockers etc?

___________

The inside of the valve cover wasn't THAT bad, but it was pretty sludgy. We cleaned it out as best we could (without an air compressor at the time) and changed the oil about a month after doing it. I've definitely seen worse, but it was pretty sludgy. Also was thinking about cleaning out the area where the MAF is/general intake cleaning (though I've steered away from seafoaming anything, since it has never sat well with me as a good idea for these older 4.0's)

All in all, the engine is doing everything it should be, and hasn't lost any "*****" (though that is hard to tell if its only a little) - but compared to my last 96 HO, this thing is just as ballsy (and after recently doing the kickdown cable adjustment, is much more ballsy than ever, IDK why I didn't do that years ago with my old ones, holy crap what a difference)

Like I said, I don't want to do anything unnecessary (and risk having to take the head off anyway) if it doesn't need it. I guess my main concern was how normal it is to see so much smoke. The oil loss could still be explained by a leak, which is a pain because I have to tackle that and pray that it's not burning all that much anyway.

___________________

See post 15 for oil leaks.

Add a quart of Marvel Mystery Oil to the crankcase.

I'm not a fan of Seafoam.

Interesting comment on the "ballsiness" of your Renix. LOL.

Read this:

HO myth buster


Renix in 90 made 182 HP. HO in 91 made 190 HP. That's 8 HP difference.

HO only made more HP than Renix at higher RPMs and not a bit more torque. HO had 58 mm throttle body versus a 52 mm throttle body on a Renix and also had a better design header. See where I'm going with this?

The whole 8HP was not mostly from the head, but from the bigger TB and better exhaust manifold.

Put a 60mm TB from www.strokedjeep.com on your present head, eliminate the "crush" in your headpipe with proper re-routing, and go for it.

HO stands for Highly Overrated.

__________________


Small update - there is very good suction on the CCV, and the metal nipple it attaches to on the side of the engine seems fine (though I don't really know the inner workings and where it goes from there) so it seems to be doing its job, which would mean the smoke is at least getting cleared out of the valve cover, but why it is there in such a quantity is the question. I dumped some Marvel into the crank case too just to help clean it a bit.

I am still not seeing hardly any oil on the ground whenever I park, like a very small amount if anything (I've dealt with oil leaks of all sorts for a long time on different vehicles and it doesn't seem to be nearly enough to warrant how much oil I'm losing, it's barely any.)

I made a quick video showing the smoke while engine is running, and that there isn't any dripping underneath the jeep, and that the CCV has good suction (you can hear the jeep get rough when you disconnect it). My friend said he does see a little bit of smoke when I take off out of the parking lot, but very little, and it dies off in like a second.


_____________

A dry, then wet compression test is in order. Valve seals smoke like you're describing, but don't use much oil.

_____________

So that marvel mystery oil (I added just about 16oz bottle) cleared up my smoking by I'd say like 85-90%, though it may be too early to tell. Did my normal commute home with my wife (it's technically her jeep, she's learning to drive with it) and that usually gets it plenty hot enough to be smokin like crazy in the valve cover. Barely any now. When I open throttle with the filler cap off I do get puffs still, but not all that bad.

I think this all points towards valve seals, no? I'm thinking it like cleaned off stuff or unstuck some stuff? (that's as in depth of a guess I want to make at this point, lol.) It even seems to idle a bit better! (though, again, it could have started running better for whatever reason, for whatever amount of time it felt like, I know...)

Will be comp testing it tomorrow after work, that way I can have her broken into on a weekend. Also HF is doing a lot sale starting tomorrow so I wanted to snag some cheap crap.


Thanks Cruiser and anyone that was brave enough to read all that and maybe throw some tips at me (it will be much more useful once I comp test it, I know)

I will be posting some stuff here to give back a bit to the community, though I never really put any tutorials or took pictures really, which is kinda something I always regretted, since I did a LOT of work on my trucks. I will try to at least post some good pictures with a few tips of my own from my experiences.

 

I'm just marking this thread for now. Canning salsa and got jalipino in my eye. I didn't read all, U checked your oil filter adapter for leaking?

 

That lower "bab bab bab" is just what our jeeps do. You could listen to mine here but I promise it's the same. > It's the "you Will die before 500K" signal, I assume.

Yes the wet/dry compression. I'd do it at a mid temp, not hot or cold. There's all sorts of teky stuff about how much it climbs each stroke. May well be worth studying, but I log what I get after 5 or 7 strokes. Cyl's 1 through 6. Then add a couple tablespoons of oil. A nifty way to do that is with a clear vinyl tube. You put it into your (Castrol 30WT, (only good oli), suck in 2 two or three inches, then blast that into the plug hole. You want it all the way around the rings. Crank it a few seconds before you take the wet reading.

Your noise and your oil consumption makes me think at least one of your cylinders are going to come way up with that wet test.

13 pints of home grown salsa done !

 

Congrats on the salsa! I make a lot of stuff, bbq sauce and all that, but haven't delved into salsa quite yet.

I haven't done an in-depth look at leaks quite yet, just been kinda keeping my eye on all of it. Will be getting in there real good under it tomorrow. Now that I got so much other stuff done on it (like....everything outside the engine pretty much that could possibly be done), I'm ready to tackle the leak and/or burning, which has been getting worse on consumption for sure.

Ya I knew these were noisy engines, and I guess I'm not all that concerned about the noise(s), which it sounds like you're saying I shouldn't be?

I guess doing the compression test is the only thing that will tell me what's going on, but from what you're saying, it could be worse than just the valve seals? What would one cylinder coming way up with the wet test indicate? I'm sorry I'm just a bit hazy on engine work, I've done just about everything else on vehicles and/or planes, but not as much actual motor/head diagnostics.


Thanks for the info about doing it, pretty eager to get it done tomorrow....and worried.

 

Because there is not a major oil spot on your driveway, (or anywhere you park), the oil loss is probably not a leak. Valve stem seals...a sure give-away is when is smokes a minute when fired up, say 1/2 hr after it's been parked hot. The oil has leaked down past the seals into the cylinder then ..there you have it. Btw, feeding a length of small nylon cord into the plug hole, then rotating the engine with a wrench on the crank pulley bolt to bring one cylinder up on that cyl. is a another way, besides compressed air to hold the valves up.

The wet/dry indicates where the compression loss is. More accurately, it tells you if it's loosing down past the rings or not. If the numbers come up with it "wet", you can assume compression was getting past the rings. If not, the HG and the valves would be suspect. The valve stem seals do not seal in compression. When the intake valve is open, the intake valve seal is subject to some vacuum.

I'd start with the wet/dry compression test. Only 140K, not high for a 4.0. Let's hope somehow something went wrong with the valve stem seals...instead of a bad cylinder/rings

 

That was actually another question I had...the nylon rope method. Seen it mentioned quite a bit. My friend and I thought it sounded pretty ghetto...but if it indeed is a reliable method I would much rather do that. I just don't want anything to fall into the head, etc.

I'm definitely leaning towards valve stems seals at this point, but not trying to give myself false hope. Hopefully it isn't raining tonight so I can comp test, but I think it's supposed to. Also, I have had bad valve stem seals on my c1500 4.3l for awhile now, but it is MUCH more obvious. Huge puff of smoke for about a second upon startup, doesn't happen every single time, but usually does after being parked. The thing is though, I lose like no oil whatsoever with it, and yet the smoke is much worse. I actually caught a puff of smoke this morning when I reversed out of my spot with the Jeep, so I know it's happening, though with the Jeep it's probably happening consistently as I drive it, whereas the truck probably only does it on startup. Still, the oil loss in the Jeep could be attributed to a small leak as well, which again I will be doing in-depth diagnosis of this weekend, even though as I said I really don't think it's anything major at this point.

Thanks for all the help, will be updating asap as well as submitting a bunch of pictures and such. She's a beauty, just trying to get these last few things done before this winter. Last winter was the worst one I've seen since 95/96, but I was a kid then and didn't drive. This jeep got us through it no problem, and I was glad I bought her right before the winter.

 

Ghetto?

I resemble that remark.

I've done it both ways......air and rope.

 

Oh believe me, I ghetto rig whatever I can, but having never done this before, it sounded kinda iffy. I'm going to do it with the nylon rope, then. Any good writeups/tips on it? From where I've seen it mentioned, it was a quick "ya just shove rope down there and rotate the engine" kinda thing.

I need to do it on my truck (4.3l) as well, so if it's doable with a length of rope, and spares me having to buy a compressor (which I really should buy soon enough anyway) I'd rather do that.

Something I forgot to mention - I've done all the work on this Jeep at my apartment in my parking spot, lol. No one has said anything to me, but I try to keep power tool (and air compressor) usage to a minimum.

I need a garage....very badly. Luckily my good friend was renting one with some buddies for awhile so I got a ton of stuff done on the truck there, but got the Jeep after he moved out of there.

 

Bring #1 cylinder up approaching TDC. Add rope into cylinder. Rotate engine til it stops, all by hand of course. See post 12 in my link.

Follow the firing order 1,5,3,6,2,4. using the rotor as a reference.

Here's the tool for compressing the valve springs:

http://www.harborfreight.com/univers...sor-60335.html

 

You the man. Sounds simple enough, I should be able to tackle this no prob.

I had to put the comp test on hold again til tmr.


And ya, it still doesn't smoke nearly as much since that MMO...

 

So the compression isn't lookin good....I don't think?

.......DRY......WET
#1....90........110
#2....90........110
#3...100.......125
#4....40.........50
#5...100........90
#6...100........90

I did a few of them a few times to make sure, and let it crank like 7 times each time, these results should be correct, unless the HF compression tester I bought is really low for some reason.

So the numbers didn't shoot up on them all that much when wet, so the rings should still be ok, no?

I've seen a few posts about renix compression readings in the ~100 range, so I'm not all that worried about the average, just cylinder 4.

I'm tempted to spray some "deep creep" or pb blaster in the spark plug holes and let it sit overnight. Is that a bad idea? Also, would I have to run it for awhile before re-compression testing it again to see if it helped at all? I couldn't just check it the next morning could I?

 

Did you have the throttle wide open during the test with the CPS unplugged?

#4 isn't particularly exciting...

Why would 5 and 6 go DOWN wet?

Do the deep creep overnight.

Drive it tomorrow like ya stole it, and do another test.

 

I didn't unplug the CPS, no. And actually, I did forget to have the throttle wide open when I did the test, realized it, tried it again with the pedal to the floor on #4, and 2 other ones (2 and 3 I think) and the numbers were pretty much exactly the same, so it didn't seem to make a difference honestly.

I unplugged the fuel pump relay and the ballast resistor from the starter relay, purged the schrader, and unplugged the ignition wire. All plugs and wires unplugged (and labeled). Cranked 7 times, checked gauge.

 

You say to-MAt-o. I say to-mah-to. mes a mes. Lo mismo.

I would do everything the same after the deep-creep or MMO, just have it at WOT for the next test.

 

I should have mentioned having the throttle open and pulling the (second)fuel pump relay. Suppose Cruiser has a good one being the CPS unplugged would kill both spark and fuel.

I can't think or any odd, remote, unlikely reason compression would go down on the wet test. It's got to be some sort of test error. Then you need to ask how reliable are the other numbers if something is wrong with the test....

That said it does seem you have some real issue with #4. In your shoes I might repeat the test again (after running it some). I might pull the valve cover and verily the valves are operating like the others on #4. Also there is another "leak-down" test. I'm not so familiar, but you put say, #4 at TDC on compression and apply compressed air the the spark plug hole. If you hear a hiss from the TB an intake valve is not seating. Then I've seen posted you can actually listen at the tailpipe for an exhaust valve. I guess it's plausible that the sound could make it past the converter....

Like said I'd repeat the test, but it looks like you are pulling the head.

I forgot to mention....what did the plugs look like? Were any really black, wet? With some luck ether the head gasket, or the head it's self will show to be seriously boogered. With the exception of #4 your #'s are not a death sentence.

A breach in the gasket between a cyl. and an oil return "gally" would explain high oil consumption and excessive blow-by. I suppose you might hear the hiss at the oil filler with a leak-down test if that were the case.

Added. Here it's pointed out hissing would be heard at the oil filler from rings leaking http://www.jspecauto.com/files/jspecautotechcenter9b.htm