Bradosaurus

Hello YotaTech forum!

Thank you everyone for posting and replying on the forums. This has been the best resource for help on my 4Runner that I can find.

I need help with my 4Runner. It's a 1995 with 3VZE engine. I bought it two months ago from a guy who said that it had, "no problems, head gasket is fine." The engine indeed ran fine. About two weeks after buying it, the alumiseal wore off and I started blowing water out of my tailpipe. I got a new head gasket set for it, and while taking the heads off, the #5 cylinder lower exhaust stud busted flush with the head. Long story short, no amount of penetrant oil/drilling/easy out would work on it, so I had to replace the head.

I bought the head from Cylinder Heads International, who had the lowest price for a remanufactured right head (~$200). They ended up putting the wrong shims into the exhaust lifters, so I re-shimmed the lifters on the 1,3,5 exhaust valves and measured the gap (0.011" on exhausts and 0.009" on intakes).

I reassembled the engine and started it up. The engine made some really awful throaty sound, which to me, sounds like blow-by on an intake valve. I did a dry compression check, and all of the cylinders (on a cold engine) came up with 155-165 psi. This is well within the FSM pressure spec (142-171 psi), and within the FSM pressure variance spec (14 psi).

The sound will change with advance/retard on the timing. The attached youtube video demonstrates the "throaty sound" as related to position of the distributor and position of throttle.

If the video is not available via this forum post, you can also see it via this link:

http://youtu.be/pGBQmxG5rWU

or

http://youtu.be/5QtLClk2c7w

<iframe width="420" height="315" src="http://www.youtube.com/embed/pGBQmxG5rWU" frameborder="0" allowfullscreen></iframe>

or

<iframe width="560" height="315" src="http://www.youtube.com/embed/5QtLClk2c7w" frameborder="0" allowfullscreen></iframe>

If you have any ideas, please help.

bmcghie

I hate to say it, but to me it sounds like something in airbox is loose. It seems to me you would hear the noise at any speed if it was valve related... I think I hear the noise when a specific amount of air/resonance for the airbox is reached.

Maybe try running it with just a sock over the VAMF for a little bit, and not clamped down to the rest of the airbox. See if your noise goes away.

One final thing: I also think your veezy gains and loses rpm slower than mine. I found after I did the ISR mod it really revs up faster, in addition to the oft-mentioned "more low end torque" (which wasn't much, but worth the cool new noise and $30)

Good luck.

ZARTT

Timing belt is off a tooth----or 2.

92dlxman

coming from a 22re guy, is your air-injection system proper? (if you have one) not sure how it could relate to timing but mine gurgles pretty good after a sharp off-throttle, which i noticed in your video. (diggin deep for that one lol)

ummmm otherwise, ummmmm, well, kinda stumped, is it easy to re-chech valve clearances? a new head, never torqued, ran, etc. possibility of something that shifted, bad valve-seat job? timing still doesn't make much sense though, unless it only quits making that noise when timing is RETARDED AFTER tdc, lowering combustion pressure substantially and thus eliminating intake valve blow-by, as you suspected. im intrigued

92dlxman

and, as previously stated, is it possible that when you replaced the head the belt was not properly aligned with that cam?

TNRabbit

I agree, sounds like the PAIR valve....how did you route it when you installed the "cold air" intake (what a joke...don't waste your time with those).

rlordjr

PAIR valve for sure. I just this weekend had same thing after HG replacement and found I had not put the hose back on the PAIR valve. Makes an awful sound.

93toyrunner2

3X on the Pair Valve not being connected correctly, check the hose to the upper plenum area.

Bradosaurus

Great advice, guys! The PAIR system was indeed allowing bypass. All hoses and vacuum tubes were connected properly. I measured voltage at the VSV connector with the engine on but not running, and it read 10.8 Volts. I fired up the engine with the VSV unplugged from the harness, and there was no blow-by on it. As soon as I reconnected it, the problem came back. This makes me wonder if there is a bad sensor/missed connection that is signaling the ECM improperly, thus the ECM is commanding the PAIR VSV open.

This problem didn't exist before I rebuilt the upper engine, which makes me think that I messed up on a sensor/vacuum hose somewhere. Any idea on sensors that may interact with/dictate PAIR valve position?

*Edit: note that the voltage is so low because I don't have my alternator connected.

Bradosaurus

Found the solution: Vacuum leak at EGR and #1 and #3 plugs with micro-cracks in them. Thanks for your help everyone!

yotasavg

good to know, i have chased many a vacuum issue as well