tacurt

This is a great forum, my first post. I just bought my second 4runner, first was an 87 and i loved it. I just bought a 94 v6 sr5 4x4 w/ 110k. I got suckered, the check engine light had been disconnected. Turns out they didn't feel like replacing the knock sensor wire, it pulled completely out from under the manifold. I did a compression test just for the hell of it #2 was around 120 all otheres 160+. I put a leak down tester on it, couldn't figure out how to read the leak % but I could hear air escaping from the oil cap. I guess that means the rings? I assume the truck has been running in "safe" mode with cel on for a long time by the way the plugs looked, could this have caused ring damage. Strange thing is it doesn't smoke at all. Should I start looking for a remanufactured engine or fix the knock sensor wire and drive it? I don't drive the truck daily, I only put about 5-6k a year on my cars since I have a take home police car with free gas. Thanks.

kenwoodrunner

120 is more than enough for ignition. fix the knock sensor and drive it and save for a motor down the road. also i forgot fix the cel also.

tacurt

Fixed the cel already, ks wire is on order. Planning on starting on that next week. Also doing valve covers while i'm in there.

toytech76

I can say almost 99% positve that you have a burned exhaust valve. They burn valves almost as much as they blow head gaskets. Too bad you don't live near me in cali. lol I can do those things in my sleep. I only charge $1000 to do them minus parts

tacurt

Wouldn't a bad exhaust valve would cause me to hear air leaking from the exhaust or egr instead of the oil cap?

toytech76

Seeing its not a severe loss of compression, maybe not. Trust me...I work on these damn things every day and do at least a couple valve jobs a month on them. The bottom ends of those are pretty damn strong and it would take alot of abuse to ruin them. I would put money on it being a burnt exhaust valve

tacurt

Whats the best way to check the valves? Remove the head while I'm doing the knock sensor?

tacurt

I guess from the lack of other suggestions the burnt valve is probably correct. How would I find out for sure, remove the head?

toytech76

remove both heads and do a valve job. Don't grind the exhaust valves. Replace them with toyota valves. Intakes you can grind

mattches

Yes, it does sound like a valve prob. If it has been running in limp because of the non-connected or bad knock sensor it could have been running to lean thereby burning the valve.

But, seeing as how you have got to this point of diagnosing valve problems, because you ran a comp test "just for the hell of it" and the result is not to terrible, and this is not your daily driver (you get to drive around for free on your communities' tax money ). I would simply replace the sensor and wire put it all back together, reset the ecu and drive it. The cost of having your heads removed, machined, valve job will run you around 1300 or so. Unless you do the disassembly and reassembly of the head yourself. A nice new reman with all the sensors, plugs, belts and hoses will run you 2500-3000 or so (assuming you do the install yourself). If you just have it to be a weekend warrior 4x4, the keep it simple.

Not saying that replacing your knock sensor is a breeze, but so long as you pay attention and label it all (so it goes back to together correctly) it should only take a day to do.

Good Luck!