bugguy68

92 3vze 4x4 5 spd. on 33s. 221K, everything is stock set up. Had bad compression in #6 cylinder. Ran good except when cold and idling when hot. I installed new head gaskets and had the heads completely re-worked. Ended up replacing #6 intake valve. During troublshooting with leak down test found intake vlv on #6 was always leaking, never any clearance between vlv and cam at any point in cam rotation. Cylinder walls looked awsome and compression in all other cylinders was awsome except #6, obviously. 1,2,3,4,5-195, #6 145. Long story short. Put it back together, new cap rotor, wires, plugs. Timing was dead on @ 10* BTDC. Idles great. Problem now is that I have a serious power loss as I accelerate. Just feels like a dog as I come up in RPMs. Notice pinging too, which was not an issue before, always and still running 87 octane. Is it possibly an O2 censor that got jacked by the bad valve, or maybe a cat clogged. Just doesn't make much sense though, cause I didn't have this kind of issue before while running with a crap vlv. Any advice would be appreciated?

thook

It's possible the valves weren't adjusted/shimmed properly. One would hate to think so, but it does happen. I wound up burning one on a newly rebuilt 3.0 for that very reason.

Another possibility is the knock sensor/wire. Was it replaced? Did it get fubar'd somehow in the removal/installation? I suppose the CEL should come on if there was a problem there, but it may not.

bugguy68

Replaced the knock sensor pigtail brand new from toyota. Same with the timing belt. As far as the valve adjustment, I took them to a machine shop that specializes specifically in head work, and they claim to have done millions of these 3.0 heads. Part of the work also included a leak test which I would have figured based on that I could have ruled valve adjustment out as the issue. It definitely seemed to be a gradual loss of power, though. Ran really great out of the box but the more I drive it, it's more noticable. I have only been driving it about a week on this new head work though. Doesn't smoke or seem to be burning any oil. Is it possible that the timing may have to come off stock numbers due to the head work? Another question is the plugs. I notice that most foreign parts suppliers tend to stick with NGK. Thats what I removed from previous owner. I installed Autolights, @.032 gap, since thats what I have always used in my domestics and never had an issue? Just currious?

TNRabbit

Did you adjust the timing with the bypass wire shorted??

ALso, if it has no power AND is pinging, the issue is probably not timing. What spark plugs are you using? Gap? What all was changed replaced?

bugguy68

Yes, had it jumpered out to check the timing. I mentioned in last reply, TN Rabbit must have responding while I was typing thats cool, went from NGK to AUTOLIHTs .032 gap. Sure is odd that you mention the plugs, since I was questioning the same thing? The Autozone that I bought them from says thier computer showed .032 gap, which thats what I went with on install. Couldn't find the info on the emissions placard under the hood like Haynes recomended. Since then I looked in owners manual....wish I went there first, says .031. Wouldn't have thought that .001 would make that much of a difference unless it's all do to the brand being the issue? So TN Rabbit, you'ld rule out the vlv adjustment?

bugguy68

Well I went and re-verified my timing. Yes I know this may or may not be my problem, but I wanted to check it out just the same. 10* BTDC right on. I couldn't help but get a little curious so I tried adjusting it 5*+/- either way. Didn't really make any difference. Had a little more power @ 5* BTDC but not enough to say, yeah that was the problem. Still had same issue any position. As far as the pinging, it is very slight, if thats what it is at all. When the truck is idling and I'm under the hood all I hear is a strange, what can only be described as a mechanical gurgling coming from the air intake box. Is this normal, never noticed it before? Very similar sound to when I'm accelerating just not as loud and as intense. Can't really duplicate it reving it up under the hood, suspect cause not under load. Leaning more and more toward that plug issue though. I do have one question on the timing though. They did resurface my heads. No idea how much they took off, but would that not make some slight changes to the compression hense the timing may need to be different as well? Just currious? Still would love some more info on this to get it running right. Thanks.