Serious Engine Trouble

[thedutchguy]

[nfpgasmask]

And this is totally safe for the VX?

Someone please educate me on what the purpose of the PCV Valve is, and why it can be safely taken out of the picture.

Bart

Sorry MASK..A wrong order of letters by me lol. I now have the PCV valve removed and a 90 degree piece of PVC in it's place in the valve cover w/a small air filter attatched to it to allow the engine to vent without any vacuum
support..

[nfpgasmask]

Nevermind my last post, this from Wikipedia:

"PCV system
The PCV valve is only one part of the PCV system, which is essentially a variable and calibrated air leak, whereby the engine returns its crankcase combustion gases. Instead of the gases being vented to the atmosphere, gases are fed back into the intake manifold, to re-enter the combustion chamber as part of a fresh charge of air and fuel. The PCV system is not a classical "vacuum leak." Remember that all the air collected by the air cleaner (and metered by the mass air flow sensor, on a fuel injected engine) goes through the intake manifold anyway. The PCV system just diverts a small percentage of this air via the breather to the crankcase before allowing it to be drawn back in to the intake tract again. It is an "open system" in that fresh exterior air is continuously used to flush contaminants from the crankcase and into the combustion chamber.

The system relies on the fact that, while the engine is running, the intake manifold's air pressure is always less than crankcase air pressure. The lower pressure of the intake manifold draws air towards it, pulling air from the breather through the crankcase (where it dilutes and mixes with combustion gases), through the PCV valve, and into the intake manifold.

The PCV system consists of: 1) The breather tube , and 2) The PCV valve. The breather tube connects the crankcase to a clean source of fresh air, such as the air cleaner body. Usually, clean air from the air cleaner flows in to this tube and in to the engine after passing through a screen, baffle, or other simple system to arrest a flame front, to prevent a potentially explosive atmosphere within the engine crank case from being ignited from a back-fire in to the intake manifold. The baffle, filter, or screen also traps oil mist, and keeps it inside the engine.

Once inside the engine, the air circulates around the interior of the engine, picking up and clearing away combustion byproduct gases, including a large amount of water vapor, then exits through a simple baffle, screen or mesh to trap oil droplets before being drawn out through the PCV valve, and into the intake manifold."

So, basically, what we are doing, is sort of bypassing the whole PCV system process? Is that correct? With the hose that leads back into the intake blocked off, does this cause any issues? Or is it ok for the main intake to be used fully?

My problem is that I am not understanding the point of the PCV system if it should just be vented off instead of fed back into the intake. Is this just a serious design flaw with this particular PCV system on Isuzu's part? Is it basically that the existing PCV configuration is not functioning properly (i.e. not venting or getting clogged)?

I have been changing my PCV with EVERY single oil change, and my oil consumption has not gotten any better....

Sorry for all these questions, just trying to learn this stuff so I have a solid understanding....

Thanks - Bart

[phant0m-je$ter]

I also thought Tone or maybe someone else mentioned at some point that the EGR is also a possible cause of oil leaking out and then vaporizing on the actual engine case due to the extreme heat...any thoughts on that...?

-Rob

[psychos2]

"My problem is that I am not understanding the point of the PCV system if it should just be vented off instead of fed back into the intake. Is this just a serious design flaw with this particular PCV system on Isuzu's part? Is it basically that the existing PCV configuration is not functioning properly (i.e. not venting or getting clogged)?

I have been changing my PCV with EVERY single oil change, and my oil consumption has not gotten any better....

Sorry for all these questions, just trying to learn this stuff so I have a solid understanding....

Thanks - Bart"

The pcv valve is used so that the gases in the crankcase get recycled (for emmision reasons). And the valve is supposed to close when there is vaccum,so it cannot suck oil from the valve cover. I cannot say that this will stop your oil consumption problem . I know that it stopped mine. I had changed my pcv valve did an oil change and within 1000 miles or so used 2 qts of oil. So it failed that quickly. The problem is more from poor design of the valve cover. I have not seen the underside of the valve cover but would guess that there is no baffle or too small a baffle to prevent the oil from being sucked up when there is a failure of the pcv valve. If I were you I would try it. I have looked at the chart in the vx manual and a pcv valve failure will cause excessive oil consumption. It will not harm your engine to try this. shawn

[psychos2]

I also thought Tone or maybe someone else mentioned at some point that the EGR is also a possible cause of oil leaking out and then vaporizing on the actual engine case due to the extreme heat...any thoughts on that...?

-Rob

It is not listed under exsesive oil consumption in the manual.So I do not think so. But do not know for sure. shawn

[Anita]

I talked with my isuzu mechanic (a good one) about this problem happening with so many owners. Through the years he has noticed two culprits showing up again and again. The EGR and the PCV both linked to oil consumption. Bob (Green Dragon) has an old post talking about the hazards caused by a faulty EGR.

I have been lucky that my VX doesnt use a drop of oil between changes. I do discuss with my mechanic what's going on with forum members VX's. He once made the point of saying for owners to be very careful about buying aftermarket PCV's.

[psychos2]

I talked with my isuzu mechanic (a good one) about this problem happening with so many owners. Through the years he has noticed two culprits showing up again and again. The EGR and the PCV both linked to oil consumption. Bob (Green Dragon) has an old post talking about the hazards caused by a faulty EGR.

I have been lucky that my VX doesnt use a drop of oil between changes. I do discuss with my mechanic what's going on with forum members VX's. He once made the point of saying for owners to be very careful about buying aftermarket PCV's.

Thanks Anita, So I would try the pcv fix first and if that does not work try cleaning or replacing the egr valve. shawn

[MoonRaker]

The way its set up isnt to my liking, I wouldnt vent it as the vapors are pretty harsh, almost made me pass out on my last road trip. Id say run a hose from the location of the PCV valve to the top of the intake an down to the airbox if anything, you have alot less vacume and the vapors are still going out the tail. Plug the manifold. If your still on warrenty take it to ISUZU and tell them that your going to get it emmisions tested if they dont replace your motor. Tell them you already have it on paper you telling them its on the way out and out of spec, date and time. Also throw in how they tryed pushing you out the door. Even if your not in a state that dosnt have emmisions tell them your going out of state to prove the point. When you have it on paper you can get them fined $10,000 to $50,000 for a corprate emmisions violation, they dont want that. Most people would just walk away like I did because I didnt have the knowledge I have now.

[MoonRaker]

I now that because unless a RX-7 or RX-8 comes to our shop with the emmisions bypassed or removed. It leaves with it. If its already gone its not our problem. We dont remove it our selves.

[psychos2]

The way its set up isnt to my liking, I wouldnt vent it as the vapors are pretty harsh, almost made me pass out on my last road trip. Id say run a hose from the location of the PCV valve to the top of the intake an down to the airbox if anything, you have alot less vacume and the vapors are still going out the tail. Plug the manifold.

The vapors are not an issue. I have not smelt a thing. Any high performance boat motors we build are vented from the valve covers . We have never had a problem with harsh vapors. Even in the dyno room. shawn

[MoonRaker]

Guess my motor was to far gone, atleast it didnt lock up or spin a bearing. Ive seen those vents before many times but mostly on motors with a low vapor output. Guess it just depends on the causes. Ive gotten down to opening my valve cover, id post a pic but I cant without subscribing. Its really brown and cooked in, kinda like a worn out T-bird I rebuilt while I was in the army. Needles to say ive spooken with a few people and all say the same thing there VX didnt do it in early miles of ownership. Ive only spooken with one guy and hes a very anal mechanic. He said he changed the oil between 2500 and 3000 miles. He has 180,000 miles and no problems, he really babys it, never seen dirt, dam shame.

[craigmm]

I have a 99 Ironman with roughly 100k and mine has had the same problem for about the last 20k. I found out mine was leaking oil due to a cracked rear main seal, which only costs about 150 bucks to replace. Instead I just put a quart of oil in every once and a while as it slowly leaked. Well I took to long the last time and ran it dry while driving in town, so like a good little engine it seized up, and now my VX is sitting in the back yard gaining dust.

I have been looking for an engine but their to expensive, so im going to just take it somewhere and have them rebuild it, probably for a couple thousand, there is no way I could do it myself.

So anyways mine was the cracked rear main seal.

[craigmm]

...oh yeah my tire blew out at the same time. go figure...

[twistedsymphony]

bad luck.. thanks for bumping this thread though good read

I was thinking about trashing the PVC now I'll be doing it for sure... I hate unnecessary crap like that.

It might be interesting to see how the JDM version has theirs setup, IIRC they aren't required to use a PVC system as part of their emissions laws so the Isuzu engineers would have likely gone the rout that makes the most sense for performance and reliability.