dem0nk1d

So yesterday I’ve noticed that my engine has had a massive loss in power, and gas mileage due to cylinder 6. I’ve done the compression test and it’s 5psi. The two other cylinders 2and 4 on the driver side are 150PSI each. I’m think I either bent a valve on cylinder 6 as it’s not conclusive to be a bad head gasket, due to the other cylinders showing 150psi compression. What’s your idea’s of what could be wrong. I say valves.

Also I’m looking into the 3.4 swap as if this engine would get better all around power and mileage.

OutlawMike

If you have near zero compression, most likely valve related, or, a hole in a piston. Rings tend to be more gradual and give you low compression, not zero.

I had zero compression on #6 in my 3VZE. My avatar shows a picture of why. The valve seat fell out of the head and caused the valve to stick open.

Either way, time to pop the heads off, or get a new motor.

Good luck.

dem0nk1d

well this is going to be my first go around with pulling the intake off, to get into the heads. this will be a good learning experience. any tips on pulling the intake off, i hate all the damn vac lines. LOL. If i didn't live in california everything would have been taken off and capped off.

OutlawMike

Pictures, pictures, and more pictures. Also, masking tape with a Sharpie to identify each line. Every time you remove something, take a picture of where it went.

Some have done this without removing the vacuum lines, at least, the majority of them. You can flip the plenum over onto the passenger side fender and leave it there.

But, since these are EGR motors, that things is most likely full of carbon, and a top end rebuild would be a good time to clean it up. I removed all of thel ines off of mine and popped out the plugs on the front/back to get inside and clean it up.

Somethings to replace while you are in there:

The knock sensor pigtail from the harness to the knock sensor.

Have the injectors serviced at Witchhunter Performance, so some other injector servicing house.

New thermostat, idler pulley, tensioner pulley, and tensioner spring (if it has one of those), T-belt, water pump, etc, etc.

It might be easier to remove both heads together, with the exhaust manifolds and crossover pipe attached. I did it that way, it takes two people. You can then remove all of the exhaust on a bench, which is far easier.

I did headers while mine was out, but, they are not a dramatic improvement. Mostly I did it to keep #6 cool, as that is the cylinder that runs hot on these motors, due to the exhaust configuration.

Or, consider a 3.4 swap. I do not regret rebuilding my 3.0, but, given a different time in my life and availability of funds, I would have done the 3.4 swap.

Good luck.

dem0nk1d

i got a quote for 1400 long block, with all accessories include ac / power steering / the works, wiring harness and ecu. i might be heading this route. i think the only thing else i would need is the 3.4 clutch and other misc items.

OutlawMike

Do it, you will spend that much on the 3.0. Of course, you will have to deal with the wiring, but from what I have seen and heard, the 3.4 is a huge improvement.

dem0nk1d

might as well go for broke.

HAWAIIANSTYLE

im having the same problem with gas mileage and loss of power. i have a 94 4runner 3.0 on which i recently did the head gaskets this past april. it ran fine till about a month ago it began to run very weak. havent done a compression test on it yet. im throwing a code 12 (rpm signal/ knock sensor signal). getting out of 1st and 2nd sometime can be a PITA.