As mt_goat pointed out, your lowest compression readings are quite good, certainly nowhere near the point at which a rebuild would be called for. The difference between cylinders may be a concern, but you may as well run the motor for a week or so to let things settle out, then retest. See if there is still a big difference.

One thought I had, is that if you used the brake boost line to feed the water, you were probably not getting much in the two highest cyls, 1 and 3. Those are both in the front half of the intake manifold and the brake vac is way in the back. In fact there's no vacuum attachment in the front half. I think the best you could do is probably to remove the cold start injector and try to seal a vac hose to the opening, possibly with a couple inches of hose inside the plenum, angled toward the front. If after a week your 1 and 3 are still high, you might try that with another gallon.

I'm not getting the connection between valve adjustment and pinging. I mean, don't get me wrong, I think checking valve clearances on the 3veezy is always a good idea - I always find a few exhaust valves have tightened up, and my working theory is that the exhaust valves on this motor tend to stretch or tulip, leading eventually to the possibility of them not closing, if not checked every 80-90k or so. Adjusting valves on this motor is one of my least favorite jobs, and I've resolved never to attempt it again without a helper.

It's just that I don't see how a too tight or too loose valve could cause pinging. I'm willing to be educated...

As far as the high readings are concerned, perhaps if the heads were shaved enough, that could cause the compression to go up. If that were the case, the difference could be leakage from the lower cyls, rather than bulky carbon deposits in the high cyls. A leakdown test might shed some light.

Anyway, I certainly wouldn't rush to rebuild it, not based on what you've described here. I might try setting the timing to 10 deg btdc though, just to see how it handles it. You can always set it back. (You do set the jumper when you set timing, right?)

You might also hunt for a shop that has a fiber optic video inspection scope - they've come down to a couple-three hundred bucks, so maybe some shops have them. That way you could actually get a look at the pistons and valves to see if there are deposits there. HVAC guys also sometimes carry them, to look inside flues and such.
http://www.amazon.com/TESTO-318-V-Vi...dp/B0017O6V06/
http://www.automotive-diagnostic-too...ovs36-10ww.htm

 

As i said before check them cams!!!! See if theres scaring or chips!!! take a video of the motor running while pinging this may be helpful....to us.... you sure its nothing simple as a rattle of some kind...woobley pull hitting? motor mounts good engine rocking and hitting exhaust and ect. against truck....

 

OH WHILE THINKING ABOUT YOUR PROB I HAD A THOUGHT CHECK YOUR EGR!!!!!!!!!!! YOUR EGR VALVE MAY BE BAD OR RESTICTED!!!!!! THIS MAY VERY WELL BE IT CUASE I RECAL A BUDDYS RUNNER DOING THIS AND IT TURNED OUT TO BE THE EGR VALVE!!!!! CHECK EGR!!!!!! EGR valves on these trucks do not always throw a code do not be fooled into thinking the computer knows all....

 

Ok!!!!!!!

I ran another gallon of water through it this morning. Instead of using the brake booster hose - I used this vacuum port on the TB that was blocked off:


I have checked the EGR, but only applying vacuum directly to the EGR itself, raisng the rpm to around 2000 and applying vaccum to the EGR and stalling the engine. If there's anything else that I should do to check the EGR - please enlighten me!!! Or I could always check the FSM which is always in my list of recently opened documents...

As for checking the cams, was going to do it this past weekend, but ended up burning my hand while changing the oil... yeah - That has now been rescheduled for tomorrow or sunday. Although since changing the oil the little veeze has been running pretty well. I'm running pennzoil high mileage 10W-40 in it for the summer. I've got the timing back up to 10 degrees (w/ DLC jumped) and it isn't pinging all that bad, but I've still got 93 in the tank.

Kiroshu - I'll have an EGR and possibly Cam update for you this weekend

Edit: Oh, sb5walker: I did look through the plug holes with a borescope. The #1 piston did not look all that bad, although I could only see the top of the piston and not the valves/head...

 

Actually, I ended up rebuilding because I had blown a HG and the water in the oil had done some minor damage to the crank bearings, so I just did the entire rebuild. The cylinders themselves were incredibly clean when I pulled the heads, so I can only guess that when the factory HG recall was done (before I owned the truck) that a lot had to be taken off the heads/block. I'm still running @ 210 psi on each cylinder, all within a 5 psi variance. It's got pretty darned good torque~

I just finished putting in another HG after it sat for 20 months post-rebuild (blew HG 8k miles after rebuild). I was beginning to get the bad "drinking coolant" after only a tank of gas, so I put some Bar's HG/block repair crap in it to postpone the ineviitable & promptly clogged the crap out of my radiator today

...so now i have to flush it. If this thing doesn't last this time, I'm pulling the engine & selling it complete. Sorry to rant on your thread...

 

Are any of the vaccum hoses clogged up to the EGR? Is the passage throught the intake man where it meets the EGR plugged? Generally where the hot exhuast gases from EGR and the cool air from the intake man meet it clogs up there take your EGR valve off where it meets intake man and see if its clogged....

 

lol! everyone needs a place to rant every now and then... Yeah TNRabbit - now I remember your post on the second blown HG...

I do want to give you guys another update, while setting the timing back to stock the other day I noticed the idle did not change when I jumpered the DLC, however the timing did advance from 8 deg to 10 deg like it should. I'm going to check & adjust the TPS when I pull the plenum to check the valves this weekend. Don't know if I'll do it saturday or sunday. I'm also starting to hear timing belt noise - which is odd since I've only got about 10,000 miles on a new tbelt and both idler pulleys and waterpump were replaced at the time - prob the hydraulic tensioner since I didn't replace that - couldn't find one. Ok, now I'm off topic... lol

 

kiroshu - haven't pullled anything apart yet. I've got to special order an EGR gasket set... it did look nasty in there when I looked through the throttle body. haha - I should get to bed so I have energy to pull it tomorrow!!

^^^Scratch That^^^ the EGR gasket won't be in till Wednesday...

 

Ok - EGR system update. EGR is in perfect working order. The VSV is functioning, The vacuum modulator is fuctioning and the valve itself is functioning. I followed the FSM instructions for checking it. Additionally - with the engine off, I applied and released vaccum to the EGR valve and could hear it opening and closing. I still have yet to pull the EGR off (got the gasket set today) and since it's been raining all week here I've moved that project to Sunday. I've been running 89 octane with 4 degrees timing and it seems to be ok. I'm also going to replace the TPS since that will never stay adjusted right - and the resistance readings are all screwed up. Any good aftermarket TPS's - yes I could go OEM, but don't have $170 to blow on something that might fix the problem or not. If it does fix it - I'll return it and get an oem!!

 

Looks like 1sttoyotaparts.com wants only $73 for the OEM. You can pick up a Beck/Arnley from rockauto for $58, but for only $15 more for the Denso from Toyota, I would go for that.

 

didn't check 1st toyota - I'll go with that!

 

So - its been about a month on this - and I think i've got it narrowed down. The TPS didn't do anything. But, I have noticed the floorboard above my cat getting very hot. I'm beginning to think that my cat is no good - probably plugged up from burning oil and atf from the power steering idle up valve. (look at my post #40 on this thread at the #4 and #6 plugs to see how oil fouled they were) I'm going to do a backpressure test and see what kind of numbers I get from that. Might end up getting a whole new catback since the whole original exhaust system is falling apart anyway.

 

So, after much procrastination - I just replaced the TPS. Oh, after reading my last post I noticed I made a typo. I didn't replace the TPS, only adjusted it, and it would stay in spec for a couple days and then go out again, So I finally just got another one - OEM btw... Going to do some highway driving tomorrow, get her nice and hot and see what happens.

 

The build up on your spark plugs is just plain old sludge. Have you pulled the valve covers?

 

Haven't pulled the valve covers yet. I checked the plugs again the other day and after 4,000 miles they were starting to foul up again. Not as bad as in the pictures I had posted though.

Just got back from a test run - got a CEL - codes 14 and 41... Igniter and TPS, hopefully the TPS code is because something is out of adjustment. I don't think I got the IDL - E2 and VTA - E2 set right. Mostly because I didn't pull the TB off to change the TPS and I had a hard time getting a feeler gauge on the idle stop screw and holding the TPS while I tightened it...

 

Well, my head gasket finally blew , and I think it blew at the #1 cylinder by looking at the plugs, (and the EGR pipe was full of coolant) not sure yet. I wouldn't be suprised if it blew at #1 because of the compression being at 185...

 

I'm loving this thread, really.... I hope you get it figured. if it is a prob with the CAT a bit, believe it or not, Seafoam cleaning, two in a row after a warmup, will help break down, then pass out the chunks from inside that CAT...
Even to the point, where when you start revving it, you will get some sludge, goo, and moisture coming out your tailpipe.

 

Yeah, after I get the head gasket done, I'm putting a whole new catback exhaust in. I actually cut the dowpipe after the O2 sensor and before the cat, and you wouldn't believe how clogged the cat was.

 

 

Lol, I'm working on it. Gotta get a new Li-Ion Battery for my camera - and the thing isn't cheap. I'll see if I can get a cell phone pic.