Need a little help diagnosing

[1fj]

So I'm wondering if anyone has had this before.

I recently bought a 92 runner with the 3.0 (3.slow I know)

When I bought it, it sat for 3 years prior. With a little fresh fuel and a battery it started right up. I even drive it home right after. On the way home it was smoking from the exhaust like crazy. I was driving at night so it was tough to tell what color it was. Sorry for being vague. Also felt really under powered.

After I got it home, I went ahead and started a quick tue up. changed the spark plugs, checked and replaced fluids.

I had a mechanic buddy tell me to try and put some "marvels mystery oil" in on the pistons to help with the rings. Did that and of course tons of smoke filled the neighborhood. Once it burned off, no more smoke. The power loss feels like it's getting better, but not much.

I understand it also depends on tires, gears, motor etc.. It has 35" and stock gears. So I already know it will be a pain to get rolling, just more than I expected.

The old plugs that came out were charred black, not from oil. Along with what I was told by a buddy, a "fuel ping", not sure about it though. There is no sweet smell from the exhaust, coolant levels are remaining the same. The Motor was rebuilt top half(new heads, seals, gaskets, valves) 6-7 years ago but with it sitting it only had 11k miles put on the motor and tranny. (Have the receipts to prove)

Started a compression test and cylinder 4 and 6 are at 90-95psi. Not sure about the others yet.


Any ideas on the power loss? Or could it just be that crappy with the tires and gears?
Any ideas on what to check/test?
I'm stuck between timing? Piston rings? Valve seals?


Thanks all in advanced

 

[SV_Dude]

Power loss is all relative to the driver on what you think is power loss vs what someone else things is power loss. But with a old tired engine and 35" tires, it will be paintfully slow and lack power. [MENTION=75090]Footofgod[/MENTION] has a stock 3.0 with stock gearing and 35" tires and his is slow but still does half way decent. Yours has low compression on at least 2 cylinders so that may give you a bit more power loss.

As for your smoking issue, it may be from burning oil in your low compression cylinders and the messed up spark plugs almost confirms that.

My bet: low compression and burning oil means that your engine is old and tired.

Warm up your engine and add a small cap full of oil to your cylinders through your spark plug holes. Do another compression test on ALL cylinders. If your numbers vary greatly and are low then you need to rebuild your engine.

I doubt you have timing issues because you will have back firing problems and will definitely have NO power with stock gearing and big tires.

 

[1fj]

I did add oil though the spark plug holes and it did help. I plan on doing the rest of the compression test once I get a chance.

I I'll post up numbers once done.

I don't have any back firing, was reading about that just now. So kind of ruled out the timing now.

I'm back to assuming its piston rings or bad valve seals.

Sv_dude, thanks! I will be looking into all of this.

If it's a rebuild it needs, then I guess I'm shopping for a 3.4

 

[SV_Dude]

I'm back to assuming its piston rings or bad valve seals.

I think you could almost rule out the valve seals since the exhaust smoke went away shortly after you put oil in the cylinders. Once the oil and small oil wall burned off the smoke came back. IF it were the valve seals I would think that you would have constantly been burning oil regardless.

I'm not 100% sure what your issue is yet but I would lean towards the piston rings. You'll know for sure once you pull the heads off

 

[1fj]

Good point about the "continuous smoke" if it were the valve seals. Didn't think about that.