93 Honda Civic VX horrible fuel economy

[imzjustplayin]

Another thing I'd like to point out... when was the last time you replaced the PCV valve? Apparently this too can be a doozy for fuel economy, I'm about to replace mine tomorrow as my fuel economy has plummeted and I've read some places that when replaced, people's fuel economy "skyrocketed"....

[benfrogg]

The PCV in the vx is just an open elbow.
I've had it out on multiple occasions, it's clear last time I knew. I'll peak at it again, but I suspect I'll have a similar result.
B

[imzjustplayin]

Originally Posted by benfrogg

The PCV in the vx is just an open elbow.
I've had it out on multiple occasions, it's clear last time I knew. I'll peak at it again, but I suspect I'll have a similar result.
B

It's not suppose to be an Elbow.. You should use an actual PCV valve because otherwise the car can get too much vacuum at the wrong time and or direct air back into the engine again, at the wrong time. PCV valve is design like the way it is for a reason and using a simple elbow makes no sense. The PCV valves are dirt cheap and there is absolutely no reason not to use the correct part. Funny that you mention it's an elbow because one parts guy at the store was about to sell me an elbow instead of an actual PCV valve.

FYI PCV valve is a ball and spring that is suppose to be a one way valve and the way to test is to blow and suck on the part that goes into the engine. If you can just as easily suck on it as you blow on it, the valve is defective, and if you can't easily blow air through it, it's also defective or clogged. Should only be able to blow air through the valve and the direction is from engine to intake. The valve should also make a good rattle or clicking noise when shaken. (off car)

---As an update for the replacement of my PCV valve, my preliminary fuel economy according to scan gauge jumped back up to where it was previous and I think I've noticed a bit of a power improvement and a more steady idle according to the scan gauge. As a point of reference, my fuel economy dropped from an average of 35mpg according to scan guage to 29mpg and when I replaced the valve, it went back up to 35mpg.

The GPH (Gallons Per Hour) at idle with an IAT of 70-110F was from .22 - .18 GPH (decrease at higher IAT), however I didn't detect much of a change in GPH at idle compared to previous but I did notice that now when I turn on the headlights, the GPH dropped from what I remember it be around .28-.32 GPH to .22-.25 GPH. Turning on the Climate Control Fan to the highest setting (4) didn't have as profound of an effect on the GPH as it did previous, even before I saw the drop in fuel economy. Even when testing with the A/C, I saw that the GPH was still lower than what I remember it to be.

[benfrogg]

http://www.gassavers.org/showthread.php?t=2518

We've hashed this one out before.
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[add|ct]

Yeah, I still have the 'valveless' PCV valve that came with this vehicle to my knowledge. I did buy a replacement because I thought I had some defective piece of garbage, but wound up using some cleaning spray into the original and put it back on.

I wonder if the 94/95 models came with one that included an actual moving part inside? I'd really like to know what a person from Honda's service department has to say about it.

[theholycow]

My Buick also has a PCV elbow instead of a valve. Some engines were designed to not use a valve for their PCV system.

[imzjustplayin]

Originally Posted by benfrogg

http://www.gassavers.org/showthread.php?t=2518

We've hashed this one out before.
B

Yeah well here is a really simple reason why I know it does not use an elbow. The Service manual for the '92-'95 civics mentions nothing of an elbow, look up a PCV valve and you'll see there is nothing mentioning d15z1. Instead, there is a description of the Positive Crank Ventilation system with no asterisk or anything of the sort. The reason for this is because PCV valves all behave the same. They're check valves that are designed to open after a certain amount of pressure, depending on the car. If there is an elbow instead of a PCV valve, it's because the last owner did not know what they were doing and instead put an elbow instead of the valve.

Originally Posted by theholycow

My Buick also has a PCV elbow instead of a valve. Some engines were designed to not use a valve for their PCV system.

no no no! That's not how the PCV system works! Did you buy that Buick new or used? The guy at the autoparts store tried doing the same thing to me! He tried to sell me an elbow instead of a PCV valve!!! I told him that an elbow is not a PCV valve and then he brought out a PCV valve instead. I think there is a serious issue of people not understanding the purpose of the PCV valve and so are replacing them with elbows..

[benfrogg]

I've had three vx engines so far. One in the car I have now, one in a parts car, and a spare motor I have for the car now. All three have had elbows and not pcv valves.

Everything I've read on the net says no pcv, just an elbow. There's never been any issue with using the elbow the car came with, that I'm aware of. I think it has something to do with lean burn, not sure of that though.
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[benfrogg]

http://ecomodder.com/forum/showthrea...vx-pcv-18.html

[imzjustplayin]

Originally Posted by benfrogg

I've had three vx engines so far. One in the car I have now, one in a parts car, and a spare motor I have for the car now. All three have had elbows and not pcv valves.

Everything I've read on the net says no pcv, just an elbow. There's never been any issue with using the elbow the car came with, that I'm aware of. I think it has something to do with lean burn, not sure of that though.
B

The Civic HX and the Insight both use lean-burn and both definitely use PCV valves. An elbow is completely contrary to how a PCV valve should operate. Why don't you just spend the $5 on the PCV valve and we can use this little experiment to show whether there is a difference in how the car runs between an Elbow and a PCV valve. Since none of those cars are the original car, it's still easily possible that someone could have used an elbow instead of a PCV valve because the PCV valve gets easily clogged. It's also possible that an elbow is used somewhere along the line and people are confusing the elbow with where the PCV valve goes or you keep checking the wrong part in the system. Like there could in fact be an elbow in the system and you inspect it to be ok, but you still end up not checking the actual PCV valve itself which could be somewhere else.

http://www.hondaautomotiveparts.com/...EATHER+CHAMBER

This diagram isn't the easiest to follow, and so it's certainly possible that where you're looking is suppose to be an elbow but you still end up not replacing the actual PCV valve itself which is somewhere else.. Now that I look at it carefully, you can see there are two PCV valve designs but the PCV valves are listed as being in two different places.. Check out where it says: "VALVE ASSY., PCV", it's listed in two different places.