Haaklord

Hi all, so my 1990 4runner is giving me a code 52 knock sensor and runs like crap because of it. The engine is a re-manufactured 3vze from about three years (~40-50k miles) ago. I've read that I'll need to take the plenum off in order to replace it so it'll be quite a project. I've never delved that deep into an engine before but I figure if I take it slow and label/photograph everything it shouldn't be too difficult. Anyway, my question is, while I have the head all apart what else should I replace? Head gaskets? Water pump? Seals? Belts?

Thanks for any help

scope103

1. Don't fall into the trap of "I have code 52 It has something to do with the knock sensor, so replacing the knock sensor will fix it." The Knock sensor is unlikely to be your problem, but the "pigtail" almost certainly is bad. 82219-35010 (about $12). (Having said that, even though I doubt your knock sensor is bad, I suppose replacing it when you replace the pig-tail is just expensive insurance. Your choice.)

2. Don't touch the head gaskets (unless you have reason to believe you need to go that far).

3. You'll need to remove the plenum AND the lower intake manifold. So you'll have to disconnect the fuel rails. You cannot re-use the crush washers, so plan to get them ahead of time. I suggest getting two more of each of the three sizes; they have a tendency to jump out of your hand into the grass. From the dealer, but cheaper than dirt.

4. Replace the PCV hose and especially grommet. Heck, replace the valve too, they're cheap.

5. Adjust (or at least measure, so you'll know how far out you are) the valves.

Co_94_PU

iTrader: (-1)

Study the diagram some more. You aren't taking the heads off to get to the sensor.

You'll want to check all the rubber bits you remove (hoses) for bulging and cracks.

Make a list of the non reusable parts, crush washers and gaskets.

And have the new wiring on hand, since its typically the wire and not the sensor which has failed.

Andrew Parker

The FSM torque for these 17 mm socket sized bolts is 25 ft-lbs. When you put all of the fuel rails and connector pipes back together keep everything loose and get everything assembled in cluding the studs and plastic washers that hold the rails in place. Get all of the banjo's finger tight in cluding the fuel pressure pulse dampener that threads into PS rail. Then torque the banjo's first and the dampener which have to do by feel with a large open end wrench. then tighten the rails to the intake manifold to 15 ft-lbs. I have refused my crush washers three times to date without any problem. They are a soft copper and with the correct pressure from the correct tension in the banjo they work very well in sealing and holding the fuel in from leaking out.

scope103

Yeah. Maybe. And what's the worst that could happen? You and your passengers could all die a horrible, flaming, death. But at least you saved the $1 or so each crush washer costs.

Andrew Parker

Yes, indeed the fuel does spray everywhere when you loosen any of the banjo bolts with a full head of pressure in the fuel rail. And I do agree with you in replacing this critical part of the fuel rail system should any of the washers be a by product of getting lost or over tightening. Between my sons and I we each have a 3VZE engine. Everytime the plenums are removed the cold start injector has to be freed from its fuel supply. Those washers see a smaller torque value of 15 ft-lbs as the banjo is a bit smaller. I have not replaced any of them ever. That is not a maybe! It is my reality and my experience. The key here is applying the correct tension in the banjo bolt and certainly inspecting these pesky washers for damage and replacement should the need arise. My apology for stepping on your thread in a questioning manner. Our collective knowledge is the best part of YotaTech.
ATGP

cabledawgrunner

Scope, you are one of the most knowledgeable users of this forum...but you can really be a dick sometimes.