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Ok PRO'S what do you think?
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atcer1
New User
Nov 26, 2007, 9:37 AM
Post #1 of 10
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Ok PRO'S what do you think?
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K, heres the deal. I have a 2002 fuel injected V6 thats not burning oil, good compression, etc. with 70k miles and no warranty. The #1 rod is knocking. I don't have the money to rebuild it until this spring. I am considering removing the spark plug inserting a threaded pipe into the spark plug hole and attaching a hose. I'm going to attach the other end of the hose to a small muffler to reduce the noise and run it on 5 cylinders until spring. I know it will run rough, thats ok, its a stick shift and I can drive it easily. I need to drive it around 25 miles a day at low speeds. The question is, Will the damage to the rod and crank stop getting worse? I think that since the rod is effectively freespinning, it won't get worse. Also, would I incur other damage? if so, what kind of damage do you think it might be and how could I limit that damage until I have the money to rebuild it.
Thanks in advance,
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 26, 2007, 10:02 AM
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Re: Ok PRO'S what do you think?
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You'll have less money if you wait! Are you sure this is a rod bearing at all? ..............Searching mental archives here................... does this double knock go away when you cancel that plug?
None the less, waiting for a real mechanical engine repair like that and just muffling the noise of a missing spark plug will just throw the whole engine off balance, run poorly of course and about certainly will trash the converter(s) in the process with way too much improperly burned fuel.
By "K" 2002 do you mean the K series of GM trucks?
T
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atcer1
New User
Nov 26, 2007, 10:45 AM
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Re: Ok PRO'S what do you think?
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thanks for replying!
Its an Izuzu Rodeo. 2002 V6. Yes, when you unplug the injector to that cylinder, the noise goes away. I am pretty sure its a rod. It sounds like a rod knocking. I don't know how to tell for sure unless I take it apart. If you have a way to confirm its a rod without dismantling the engine. I would love to know how to do that.
Do you really think I would trash the converters? Since the injector is unplugged I wouldn't think the fuel mixture would change that much and its not burning oil.
I did wonder since the cylinder isnt firing, if somehow oil might bypass the rings and cause some kind of trouble.
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Tom Greenleaf
Ultimate Carjunky
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Nov 26, 2007, 1:47 PM
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Re: Ok PRO'S what do you think?
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Let's face it - you don't know what the noise is! I have to rely on your observations for a diagnosis. Forget using the fuel injector for now and cancel a spark plug instead - by that I mean prevent it from firing.
There are lots of different tell-tale sounds that peg a problem. You must rule out external noises like a loose spark plug, exhaust heat shield or part etc., I can't do that without being there, period.
These are the common groupings....
1. Valve and tappet noise.
2. Detonation.
3. Connecting-rod noises (more noticeable without a load on engine)
4. Piston-pin noise. (double knocking)
5. Piston slap. (muffled, hollow, bell-like sound) Usually gets better when warmed up.
6. Piston-ring noise. (similar to valve noise but will usually get quieter if you squirt oil in that cylinder thru plug and run for a minute)
7. Crankshaft knock. (heavy, dull metalic knock mostly or worse under load) Carbon build up can cause that slamming noise and fool you!!
Ok: Those are just basic. There are elusive noises with any and irregular noises. Observations on better or worse when cold, hot, idle, load, with and without spark and use of oil can help pin them down without tearing it apart. There are lots of moving parts to make noise. More than one mechanic has torn down an engine only to find out that a camshaft driven fuel pump or timing chain or belt was causing the noise.
History can help. Mileage, overheats, out of oil use, neglect etc. Valves can be funky with cracked springs. Many parts will look just fine in your hand and just a micron off make noise like crazy so it's best to have a good idea what's up.
Let's find out what the noise is,
T
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atcer1@aol.com
Nov 27, 2007, 7:34 AM
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Re: Ok PRO'S what do you think?
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Sorry for being so vague in my previous post. The injector and the coil are in the same plastic housing on this engine. There are 6 seperate injector/coil modules. When you remove the wiring harness to the injector, it disables the coil thereby canceling the plug. The knock goes away under load. when you put it in gear, hold the brake and bring the engine up to around 1800 RPM the noise not there. When you let off the gas it begins and continues until the engine idles and then it is still there but not as loud. I've disconnected the coil/injector wiring harness on each cylinder one at at time. The knock goes away when the #1 cylinder coil wire is off. It's still there after any of the other 5 injector/coil modules were unplugged. Heavy metallic and dull are perfect words to describe the sound. I haven't heard what carbon buildup sounds like so before go any farther, I will go buy a stethescope and find out whether the noise is higher or lower to rule out (or in) carbon build up before I do anything else.
Assuming it is a rod. and I am pretty certain it is, will I cause any additional damage by removing the plug and letting the #1 freewheel until I can afford to rebuild it?
Thanks again!
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Tom Greenleaf
Ultimate Carjunky
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Nov 27, 2007, 9:11 AM
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Re: Ok PRO'S what do you think?
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Ok: This is consistant with a connecting rod problem. By the book's description it will go away under load and reappear when engine is "floating" as when decellerating or when RPMs are up but no load for power or decellerating as in using the engine to slow down the vehicle. Carbon knock could behave like that but is pretty rare and was almost always a carbed engine, poke around town use, and leaded gasoline used but not always. That was such a problem way back when that folks just got used to pouring water down the carb of a hot engine to clear it out and if you didn't crack anything that worked just fine. There are distilate products to do that but that should only be considered if that is really thought to be the problem. I doubt it. You would see evidence of build up at the spark tip/electrodes of spark plug or your equivilant.
I'm not thrilled with the idea of eliminating this cylinder's spark and fuel and continuing to drive it because: 1. That mechanical problem is still there and if something broke it would probably take the whole engine out. 2. That cylinder would then be cold with a hot one right beside it which strains the metals/gaskets of head and block which would rather be the same or similar temps for expansion/contraction.
This problem does seem to be pin pointed enough and any more probably won't be found out without getting in there. Yes this is expensive no matter how you slice it.
Only you can decide on the approach now. If you think there's a chance to fix this later then try it. I don't. I would be scoping out the cost of a whole good replacement engine if I wanted to keep the vehicle at all. Just me - but I don't like the risks of machining a crankshaft if that's in the picture and probably is.
Just curious: Any ideas on why this happened??
T
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atcer1@aol.com
Nov 27, 2007, 12:11 PM
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Re: Ok PRO'S what do you think?
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I don't really know. Its a 2002 4WD Rodeo. I bought it that way for next to nothing. The dealer said there is a problem with that engine if you run it low on oil but thats all I know. It's in really nice shape otherwise and the owner was really mad at the car and just wanted it gone. I didn't think too much about the heat variation. that seems like it could turn into an expensive problem. Since I don't have much money in the car ( 400.00) I think I am going to experiment and pull the plug, vent the cylinder and see how it drives. I'll post after I see how it works for a week or tw.o
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atcer1@aol.com
Nov 27, 2007, 12:16 PM
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Re: Ok PRO'S what do you think?
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my last post seemed to imply I bought it from a dealer, I didn't, I bought it from an individual I work with. I called the ervice dept of a dealership
just clearing up
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Tom Greenleaf
Ultimate Carjunky
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Nov 27, 2007, 1:03 PM
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I understand the situation better now. It's great that you aren't into this for big bucks which you should be able to get if the motor blew up. Betcha the thing was run out of oil or too low for oil pressure probably by mistake with an oil filter or drain plug at a service along its life. If this had a history from new of using oil but behaved well for years then this could be just a bad batch of some part that caused this and could happen again to another cylinder.
Again, I'm not a big fan of reworking an engine. The precision of how they make them new just can't be duplicated. The exact line boring bit for that when made new was unique to that exact engine and the best you can do later is get close with unseen deviance in some bearinged parts just won't have the same life expectancy. You have a good deal with this so far price wise and I think I'd be looking for an awesome used whole exact matching engine for this. You would need to know what's available to you as I wouldn't like to ship one from far away as if it's no good it would be a nightmare.
There are two place I've used for whole engines and they are sharp at only keeping well known perfect originals and so far there have been NO surprises.
In light of this I kinda think you have nothing to lose to try your trick to keep using it. That because you really don't know if fixing that one cylinder will be permanant if done now anyway.
Good luck with it,
T
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atcer1@aol.com
Nov 27, 2007, 4:49 PM
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one last question,
What do you think about dismantaling the engine and having the one journal turned 10 under and then putting it back together. I am like you in that I don't think a rebuilt bottom end is anywhere close to being as good as the original engne. Used engines for this are very hard to find and run in the 3500.00 range.
Thanks for all you advice.
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