I bought my '89 4runner two weeks ago and dove right in... See this thread:

https://www.yotatech.com/forums/f116...nation-267263/

While the top is pulled apart waiting on injectors I decided to see what else I could check/take care of. This led to a lot of reading on valve shim clearance and adjustment. Seems that if the valves are close, it's not worth the hassle to tear into it further.

Here's my numbers:
5: I-.010 E-.012
3: I-.012 E-.010
1: I-.010 E-.010

6: I-.011 E-.009 loose but a .010 just won't go
4: I-.011 E-.012
2: I-.012 E-.011

All of my intakes are over except 1 & 5 and they are the high side of the range. All the exhaust are in range except #6 and its just under and the .009 is pretty loose.

From my understanding the valve clearance will tighten up over time. Should the intakes be ok where they are? The exhaust valves are getting to the bottom of their range with 6 already being under. Am I risking it big time by not adjusting these at this time? Is there something I can look for or tell tale signs of damage or wear the is noticeable from the cam area?

Truck is sitting at 240k and I have to idea the maintenance records. The title says mileage exempt so I really don't know how many miles are on the motor.
Thoughts please.

 

I wouldn't be overly concerned about those valve clearances at this time. I would do a compression test prior to doing anything else. Blown head gaskets are more common than failed injectors. If your compression is good and you proceed with sending out the injectors, it only makes sense to adjust your valve clearances. I always adjust the exhaust valves closer to the high side of the spec and the intakes to the middle of the allowable range

 

Is it possible to do a compression test with the valve covers, plenum, t/b, and such off? Never done one this deep into a motor. Thanks for the help!

 

You can. Disable the ignition by pulling the EFI fuse, and disable the fuel pump. I think that truck has a circuit opening relay behind the glove box, but not 100% sure. Circuit opening relay supplies voltage to the fuel pump. And be very careful not to drop anything into the intake ports. Might not be a bad idea to at least set the plenum back in place with a bolt or 2 to so nothing falls into the intake

 

Here's the comp test #'s:
2 = 175
4 = 160
6 = 165
1 = 190
3 = 200
5 = 175

Head gaskets seem to be ok, I think. lol
With these comp #'s, is it worth it to tear in to the valve adj?

 

I don't like those numbers. A cylinder leak down test will be the most conclusive way to tell where you are losing compression. Could be rings and/or burnt valves but I would suspect blown head gasket between those 2 cylinders(4 and 6). If its a head gasket or valves, I'd pull the heads and send them to a reputable machine shop for an inspection and valve job. They should also adjust the valves as part of the job.

 

Of course this doesn't explain your #5 misfire. You have compression and if you have good spark at the right time, it's probably fuel. But not necessarily a bad injector. Could be a wiring issue as well.

 

Not what I wanted to hear on the compression numbers. Lol. Was hoping to not have to yank the heads. I guess it's time to read up on that.

#5 misfire may be a wiring issue. The wires on this thing are very brittle. Going to replace the injector plugs. May just look in to a new harness.