AUYota

I got to replace the KS which means taking everything off including the injectors. Anything else I can do to justify the time and expense other that just replace the KS and associated wiring harness?

toyota_mdt_tech

Dont even think of doing it using the original pigtail wire. Replace the pigtail wire also! How about tossing in a new set of heargaskets? ;D Not much else in the area. Maybe upper timing belt idler?

suprathepeg

YEA for what you have to do once you get in there is really does suck.

AUYota

the pig tail wire, is that the basic wiring harness?

toyota_mdt_tech

No, there is a small piece that goes from the sensor to the harness. Runs under the intake. Always replace it

benwahballs

Every had your injectors cleaned? Sent mine away while doing the hg on 89 3.0L with 320k, the guy said that they were dribbling pretty bad. cleaned em up and they flow tested perfectly. cost around 200cad.

ChickenLover

X2 on having the injectors serviced.

Bumpin' Yota

x3 on having the injectors cleaned and befroe and after flow tested.

http://www.cruzinperformance.com did mine and i am a 100% satisfied customer!!

Optimus

I just put my '95's V6 back together yesterday after replacing failed headgaskets, so this is rather fresh in my mind.....

I think AUyota already planned on replacing the knock sensor's wire, seeing as he mentioned replacing the sensor and associated wire harness.

Were you actually getting a check engine code? Has any recent engine work been done? The knock sensor's 10" wire section is normally what fails. It gets quite crispy over the years. The jacket crisp-i-fies and falls off, then the wire corrodes.

As long as you are in this far, you might want to think about these other items if you don't know the age:

timing belt
upper idler pulley (between cam sprockets)
tensioner pulley and tensioner
injector cleaning
valve cover gaskets
valve clearance check
water pump
front main seal
idler pulley and bracket (false water pump)
new upper intake chamber to lower intake manifold gasket
intake manifold gaskets
new injector o-rings
plugs, wires
cap, rotor
checking the condition of the umpteen million vacuum hoses and coolant hoses
t-stat
new head bolts (if taking the heads off)

now, this list is rather extensive if you are just replacing the knock sensor, but some or all of it can be legitimate if you do not know the history of any of these parts. Some of them, such as the gaskets, are going to be needed regardless. And like someone else already mentioned, have the headgaskets ever been replaced (either under the special service campaign for free or other means)?

Just to get to the knock sensor is much of the work to take the heads off. The remaining work to get the heads off is taking off the alternator and upper bracket (easy), exhaust manifolds and bastard cross-over pipe, power steering reservoir and pump (easy), valve covers (easy), cams (easy), and some EGR piping on the passenger exhaust manifold.

I couldn't reach all of the exhaust manifold bolts (6) on the passenger manifold thanks to the birds nest of hoses and what-not on that side, so I left the manifold on (but unbolted the cross-over pipe) and pulled the passenger head with the manifold still attached.

A good assortment of tools really helps speed up the process. I have regular wrenchs, racheting wrenchs, stubby wrenches, stubby racheting wrenchs, short and deep well sockets, standard socket wrenches, compact folding socket wrenches, etc... and about 3 feet worth of socket extensions. I thinkk I used just about every type of these pieces of equipment for the job, particulary the stubby wrenches in tight spots.

There are some minor differences between your '90 V6 and my '95 V6, but most all of it applies. I think the t-belt tensioner is different between the two.