Head Gasket/Head vs Rebuilt Motor
- Thread starter slothy49
- Start date
brillo_76
Elite Member
It's possible but like [MENTION=8262]badluck[/MENTION] said rare. I personally only seen 1 3rd gen have an injector fail. Granted the engine sat with 0 fuel for a few years and I think that was it's cause of failure. As it only had 169k on it...
And that injector was seeping too.
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And that injector was seeping too.
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The weird thing is this is the 3rd one that has gone bad. I had one die in late 2020 if I remember right. Had that one replaced; I think it was an odd numbered one. Then another died in Spring 2021 so that’s when I had a friend help me replace the whole set with Motorwest, figuring I wouldn’t have to hear about fuel injectors again for a while!
brillo_76
Elite Member
If chucks of lacquer are plugging them, maybe. I Blame my one failing for long time non use. It's the first one I had to replace in working on my personal toyotas for over 30 years.
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I swapped the #6 and #2 spark plugs and I replaced the wires with a brand new set of NGK’s. Unhooked the battery for a while to reset the codes. When I started the engine it was still idling rough. Driving it around, it seems to be a little better than before but when I got the codes checked, AutoZone still says P0306 but it’s only a secondary Diagnostic Trouble Code. I repeated this a second time to be sure: disconnected the battery, cycled the ignition key 12 times, left the battery disconnected a little longer, and then drove it a good 15 miles on the highway before checking the codes again. Same thing - Secondary DTC Cylinder 6. I’m not entirely clear on the definition of a secondary code. Is it not clearing when I disconnect the battery? Both tests since changing the wires haven’t given a primary code.
19963.4lsr5
New member
When you replaced the wires did you also replace the bootie on the coil? All my missfires have been the spark burning through the coil boot.
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gamefreakgc
Elite Member
Many codes are two-trip codes. First time it shows up, the error is stored on the ECU's memory but does not display the light. Second time it shows up the CEL lamp illuminates on the dash. It prevents unnecessary codes showing up from one-time situations that are not really problems, just flukes. This is one of those codes. Some readers will call it a "Pending" code.
Also, if pulling the battery is messing up anything else you have connected you can reset the codes and fuel trims by pulling the EFI fuse (fuse, not relay) in the engine bay fuse box. I find myself having to do the same about every 6 months or so because of this or that and it means less things have to be reset or re-learned.
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brillo_76
Elite Member
gamefreakgc
Elite Member
That was the best case scenario! So glad you got it fixed and back on the road driving confidently again!
brillo_76
Elite Member
You have more power because all your injectors are working properly.
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Daryl Elmore
Junior Member
Slothy, I had the exact same symptoms as you, rough cold start, clears after a few seconds. Also had smoke out of the exhaust during startup but its cold here in Idaho so that may have been the cause. after a compression test and testing the coolant for exhaust gasses #4 was down to 165 and the others were all 185-200 so I pulled the left head. End result was 2 cracks between the valves which seems to be not uncommon. New head and gaskets and she's back running great. When I pulled the head, #4 piston was clean compared to 2 and 6 which was the dead giveaway coolant was getting in.
I have the same experience as Daryl, except my problem was a head crack between the valves over the #3 cylinder. It really wasn't a tough job. If you've done a timing belt job and valve cover gaskets, you've covered 80%+ of the job. Other than that, it's removing exhaust manifolds and heads. Plan your parts list, set aside two full weekends, watch Tim's videos and Chigger's videos, and you can knock it out.
You have more power because all your injectors are working properly.
Yep definitely better than when it was misfiring! I wonder though if it was subtly failing for a while before the misfire started and I was losing a little power from it. It definitely feels like more power now than before the misfire, so it’s either that or the Engine Restore additive really had a positive effect.
Today I finally got the crusty old fuel filter changed. That seems to have made a positive impact too but how much I can’t say.
I feel like I have the same issue as I'm starting to have the same symptoms. Going to confirm it here soon with a leakdown test and coolant system pressure test. If my compression test comes back good i'll probably just replace the head(s) if it's cracked. Does anyone have a good place to recommend getting new heads at?
gamefreakgc
Elite Member
There are not any brand new cylinder heads outside of Toyota that I'm aware of due to the complicated process of casting and manufacturing cylinder heads. There are some high quality remanufactured/refurbished cylinder heads such as Yota1's product here at a rather decent price:
5VZ OEM 3.4 Reconditioned Cylinder Head 95.5-04 - Yota1 Performance, Inc.
Outside of them, honestly your best bet is pulling one off an old junkyard unit, buying new valves, springs and seals and sending it to a machine shop for assembly and testing.
