mxracer0486

I think you got ripped off on your head job. Last time I had a pair of heads machined with surfacing and 3 angle valve job it was only $200....

HondaTec521

Yo Trunner,didn't mean to flame you .I just see cars brought in all the time with severe damage from neglect/stupidity.Cars run with no oil or overheating until they lock-up.You took it to 4 "mechanics"and they didn't have a clue?Were they Dealership technicians?If any car comes in our shop we always have to come up with some kind of answers or a direction to continue diagonseing the problem.(we also have Tech-Line)a manufactures help line for the most difficult problems.
So good luck(really)with solving your problems.As noted before by someone else you probably need some ring work to go along with your valve work(major oil consumption).

Ted Bundy

TAke this for what it is worth. My son's 94 4Runner got a rather loud clackity sound about 2 weeks ago. I had it in the garage and every night started it up and tried to figure out where the sound came from. I have a couple of friends that work on domestic engines for a living. They both stopped by and agreed with me that the sound, sounded like it was coming from the top of the engine. I also pulled the valve cover on the driver's side and even tried some "Top Engine Cleaner". Nothing worked, but I was sure driving myself nuts trying to find the problem. Finally I got it to one of my mechanic friends house and we pulled the pan off the engine. Takes about an hour for a couple of guys to get it off. We found that the very rear rod bearing is rattling. I would have argued that the sound had to be coming from the top of the motor, but I was wrong. My plans are to pull the engine, have the crank built up, and then turned back down. I priced a new crank at the local dealer ship and it has a cost of $985.78. No way am I gonna put that kind of money in a crank. This truck is only to get my son back and forth to school so I am just gonna work on the crank and stop.

TRunner

Not so much you doing the flamming....

As for the rings, I think you are right.

The previous diagnoses or lack thereof was probably because mechanics had wasted two days trying to figure it out with no avail and didn't want to do any more "free" work. The one place that would have had more a clue, I was not able to leave it with for a long enough period. They were the last crew to see it prior to this last event which was not that long ago. And no none of these were dealers. The dealer ships around here seem to triple charge you for everything and claim they will not reasmble vehicles and let it go without replacing this and that no matter its condition or age. The last time I went there they hit me up with a $3500 for a radiator, timing belt, and water pump. Not cool.

DavidA

Those were the symptoms I had when I screwed up the MAF. Replaced it and now it runs great. Mine was running so lean the header was glowing red.

Just a thought...you might want to check it out.

TRunner

Was it actually running lean or could you smell fumes out the tail pipe? Mine stinks of gas. I did check that out in the begining as that is what code 14 tells you to check, but all looked clean and well. How would one actually test it other then swapping it out and crossing fingers?

JohnStra

Ted Bundy - How did you figure out the rod bearing was making the noise? You must have removed the baffle too, hu? Did you just rotate the engine and listen?

Thanks-
john

TRunner

I was wondering this myself.....

DavidA

I actually was cleaning it and pushed the airflow "gate" too hard and pushed the sensing mechanism under the top plastic plate beyond its' limits. So I opened it up to see why I could not get the engine to run after that...and lo I had bent the little resistor pin that travels back and forth telling the engine how much airflow was coming through. I got it semi-working...but the engine ran just like you describe...very lean, would not accelerate above like 3-4k...and was extremely rough. The MAF was so messed up that my mechanic found a used one for $120 and we put it in. It is running better than ever now.
Because of the similarity of the symptoms I thought you might be having an issue with your MAF.

TRunner

I was toying around with that as a scenario for a while, but gave up on it. The only disimilar trate is the fact that my engine is not running lean at all. It stinks of gas fumes and is sucking down gas. It just thinks it is running lean. Which tells me it has to be someing with the ECU or O2 sensor.

Ted Bundy

Sorry fellers, been gone for a few days. A friend and mine took the front end apart and removed the oil pan. It took the two of us about an hour to do this. It is not hard at all. After removing the pan we still could not find anything lose, so I bumped the starter, with the coil wire off, and he kept checking the bearings. As soon as a little pressure was eased on one of the rod arms, that bearing could be wiggled with your hand. It was bad enough that we could rattle it.
We are going to pull the engine this weekend, take out the crank and probable have it turned down. Sure won't buy a new one with the prices of those things. I am hoping tha this is all I will find wrong. We will probably replace the oil pump and all the seals. I am not wanting to take off the heads unless I have to.

JohnStra

Ted - Can you try to describe your knock sound? My truck sounds like a little diesel... steady tap/knock in synch with RPM. I hear it best at low RPM when the engine is good and hot. I've spent so much time listening with a scope, but I still don't have it pinned down. I hear it best with my scope pressed firmly against the head right next to the driver's side exhaust manifold. I can also hear it really well if I put my scope right on the exhaust underneath the truck.

Thanks,
-john

Ted Bundy

On my son's 4Runner, he had no odd sounds at all, and then all at once he brought it to me and said that he had a knocking under the hood. I stated it up, and it had a rather loud knock. If it would have been a Chevy engine, I would have thought it sounded like a busted rocker arm. The noise was real strange. Some times, at idle, it would just go away. I was convinced that it was on top of the motor. When I put a scope to it, it sounded like it came form the back of the engine, on the drivers side. I had two local friends/mechanics and they did not guess it was a bearing. We finally pulled the pan, and it was still a little tough to fine. We turned the engine over a couple of times, and when the pressure on that piston was just right, we could rattle the bearing very easily. This was odd because it did not have any odd noise and the knocking started all at once.
Hope this helps

TRunner

Did it knock at idle? Or only during a certain scenario?

HondaTec521

You can remove the plug wires one at a time with the engine running(at the rpm the knock is the loudest).If the knock goes away on the disconnected cyl.then youv'e isolated it to either a rod brg. or wrist pin problem.If the noise is still there then you could have a cam/valve problem or main brg problem.

TRunner

Unfortunately, I pulled the heads this last weekend. If I would have only tried this two weeks ago when the engine was still in one piece!!!

Anyhoo, thanks for the advice. I got the heads removed and need to find a good valve guy. I would like to get a vavle job done regardless. There was a lot of sparkle in the oil in the heads. Also the bearings themselves looked a little worn. I think it was probabbly the cam bearings, but i am going to check the main bearings as well. I droped a 14mm socket down there that I need to fish out anyways. :pat:

934rnr

Is the sparkled flakes copper in color? 99.9% it is your rod end bearings when you drop the oil pan it will be full of copper colored oil like mine was. It seems when your engine overheats it takes out the rod beaings first.

I would pull your engine out and replace the rod bearings. It's not hard to do even easier if you pull the engine. I also found when I tore my engine down the crank bearings were in relatively good shape probably not needing to be replaced. Putting the rings on is easy but make sure you clean the piston ring grooves out first you can use a old ring to do so if you don't have a ring groove cleaning tool to clean off the carbon deposits.
Also buy a cylinder honeing tool and a ring install tool as well as a ring compressor.

HondaTec521

Yeah , sparkle for fire works -good . sparkle in engine oil -BAD.You need to completely disassemble your motor and remove all the sparkle.It still might not be all that costly.I agree w/ 934rnr.rod brg's usually go first.Main's are pretty hardy.Check rod journals on the crank closely.If ok ,hone cylinders(wash out residue w/hot soapy water)re-ring,replace rod brg's,clean up the heads and reassemble.