Hi,

I have a 1992 Toyota 4X4 DX 3.0L 6 cylinder EFI truck. It has 259K miles and I am the original owner (since new). I haven't made any mods to the vehicle, it's completely stock. I've done regular oil changes, tune ups, etc. Everything still works ok, though I'm slowly losing compression and considering an engine swap in the next couple of years (assuming it holds out that long of course). But that's a subject for another thread.

Right now I have a more immediate problem. Here in TEXAS, at least in certain counties and I live/have the vehicle registered in that county, we must do both a safety inspection and emissions test each year. The emissions test is not required once a vehicle reaches its 25th birthday, but mine still has a few years to go. Anyway...I fail the emissions test. Here in Travis county the TSI (Two Speed Idle) test is the one administered, which doesn't measure NOx ironically, but I digress. My 4X4 passes the high speed test (~2500 RPM) with around a 71 (first test) or 140 (second attempt) PPM on the hydros count. However it's the low speed idle (~800 RPM in my case) where I fail, blowing around 1100 (first test) or 1400 (second attempt) PPM for the hydros count. Associated with this is a slightly rough-running idle. If you press the accelerator, the roughness smoothens out.

I have done some research (last night) on the net already, including this forum, regarding this phenomenon with a Toyota product, concentrating on the Pickups, naturally. I have already tried most of the suggestions/recommendations that were offered, such as checking the vacuum system and intake for leaks, changing the spark plugs, cables, distributor cap and rotor. I also checked the timing and replaced the air filter. Today I plan to check the compression and see what is happening there, the idea being that if one cylinder is considerably off from the others, that could be the problem right there. Maybe it's burning oil in that cylinder and that's contributing to the rich hydros reading. I had thought of switching over to a synthetic oil, thinking that it would burn "better" at the lower RPMs, thus giving a better reading. Eh dunno. Currently I am running with Castrol 10W-30 high mileage conventional oil. I had also thought of a leaky/faulty injector, but that seems too unlikely to my ears, though possible.

So...if anyone has any suggestions or if you've seen this type of thing before, I'd appreciate any feedback you'd care to offer.

Thanks,

Jerry

Hi y'all-

Well I was kinda surprised to not see any replies to my thread, but I suppose that there wasn't really much to say about it, given what I had done. Eh, dunno. Anyway, the compression test revealed that a couple of cylinders were low, lower than they should be. Thought maybe I was doing something screw-eee so I took it in and had a pro do the same test. I wasn't screw-eee. #1 and #3 cyls were at 30, that's right 30! So no wonder it was idling rough and I'm getting a high hydro count.

Don't know what to do now though. It's a blow for me personally because I really, REALLY like my 4x4. I am the original owner, kept the maintenance up, did the factory recalls, etc for 17 years now. Hmmm. So I suppose I'll take the weekend to think about it. The shop I took it to wanted to swap in a used engine with 130,000 miles on it for $5000! Hahaha! I said hell no. I called around and found a bunch of factory remans for $2500 and up, less the installation. Now I am considering a rebuild by a local shop that has good references and is in good standing with the BBB, for whatever that's worth. We'll see.

Don't wanna sell it. Don't even know how I could go about doing that with the engine "on the way out the door" so to speak. 'Could take a beating via a trade-in, but wasn't anticipating buying from a dealer ever again, so...

Dunno.

Thanks, I'll let everyone know what I end up doing.

Best,

Jerry

Hi y'all,

Well just an update, though I am still surprised that no one has ever responded to my posts, but hey...

I decided that I couldn't let my 4X4 go to someone else let alone to the crusher. So I opted for an engine rebuild. I considered a factory reman, but decided that I have a used engine already and would prefer to just rebuild it instead, provided of course that there wasn't anything seriously wrong with it, which there wasn't, save the problem stated below.

Ok so when I saw the low compression I figured it had to be either the gasket or the valves. I was placing my money on the valves and that ended up being correct. When I brought my 4X4 into a Toyota dealership for the gasket recall, I paid ~$400+ for a valve job. Turns out that the valve job wasn't done to specification and thus the cam was eating itself and several of the valves had been burned. Thus they weren't seating properly, thus some of the air was escaping during compression, thus not getting good burning, thus the high hydro count and rough running. However a couple of my rockers were about to go anyway, so it was time for a rebuild. I got 260K out of the first engine, let's hope this rebuild gets into that same ballpark. While we were there I went ahead and replaced the clutch, pressure plate, tranny seal, fluids, idler arm, master and slave bushings and of course every hose and belt is new. Now I gotta watch the tranny itself for leaks, as it's still original equipment. It may be time to rebuild it next, dunno, we'll see.

Attached are a couple of photos of the block with the heads already on. Then we rotated it and I took a couple of photos of the underside. One is attached...

So now my baby passes the emissions test with flying colors (of course) and we're back on the road together. I've decided to go ahead and look for some new seats and would like to change the 60/40 split bench crap out for a couple of buckets and a center console. Mine is the DX model, wish now I had paid the extra $$$ and gotten the SR5, but at the time I couldn't afford it, so...

I'm also considering switching out the original bedliner for a spray-in. I've never had a spray-in though nor do I know anyone who's had them, so I don't know how "good" they are...we'll see.

Just glad to be able to pull up to my regular oil-changing place and say "Castrol 10W-30 WITHOUT the high mileage"!! The guy looked up from his little computer thingamabobber when I said that and asked me "What?" ... that's when I got to tell him about the rebuild! Ah, life's little pleasures...it's my Toy though, I'm the only owner and it's gonna stay that way until it falls completely apart. Hopefully that'll be another 17 years from now...

Thanks,

Jerry