Correct D15Z1 leanburn info
 

I finally got my vtec-e up and running. This was an hmotors jap engine so I had to round up the oil cooler and throttle body to make it a real, complete d15z1. No doubt this is a neat little engine.


This is a low mileage engine, but the O2 sensor has about 130k so it may be slightly out of calibration, but it is the original L1H1.

I've found so much false information about the leanburn operating parameters on this site and many others that I'm going to post my own recorded data in this thread.

Here's a little data I've observed from my previously-turbo car setup (hence all the gauges) :

- EGT's are roughly 250 degrees F cooler in leanburn mode

- Air fuel is 22-23.5 while in leanburn mode (measured with a new Innovate XD16 and LC1)

- Engine will stay in leanburn up to approx 4 in.Hg (which is nearly ambient manifold pressure) in all gears but 1st

- leanburn engages only between idle speed and 2650 rpm. When in any gear (including neutral) other than 1st, a manifold pressure of approx 4 in.Hg can be a achieved in leanburn until 2500 rpm, over that rpm manifold pressure must be ramped down as RPM increases to 2650.

- car must be moving a certain speed for leanburn to activate, it will activate in neutral if over idle speed and vehicle speed over 5 mph???

- Closed loop remains active under all conditions except for on a cold startup, it is possible to fully load the engine at stoichiometric fuel ratios up to 3000 rpm. Under 3000 rpm fueling richens in stages, not gradually, this is based on load and it appears to be based on throttle position at its richest and final stage. So fueling ratios go from 14.7 then steps to 13-13.5 then steps to 12.3-12.5/full rich at WOT. After 3000 rpm air/fuel continues to run 12.3-12.5 up to rev limit (regardless of throttle position) when coolant temp under approx 197* F. if temp is over 197* air/fuel richens to 11.5. Needless to say, stay under 3000 and don't let the radiator fan come of if you have to hammer down on it.

- oil temp seems to be very well regulated with this engine due to the oil heater/cooler. Even coming up the mountain and full throttle for 5 minutes I have yet to see oil temps over 210 degrees at 85* ambient temps.


Here are the parameters, very close to what the ecu requires for leanburn:

- NO Leanburn in 1st gear

- 2nd-5th gear:
rpm: 800-2400 manifold pressure ~4 in.Hg max. / 2400 rpm 5in.Hg tapering off to 8 in.Hg @ 2650. Over 2650 - no leanburn
(Seems best to shift at 2500 max with VX gearing)

- Coolant temp: Unsure of exact temps, but leanburn will activate in 5th gear or neutral before full operating temps, probably about 140*F. All other gears require full temps before engaging leanburn.

- After engine restart, even at normal operating temps, leanburn will not reactivate until after 10 seconds or so



VTEC parameters -

Low load engage - 3000 rpm
High load engage - 2250 rpm
High load disengage - 2000 rpm

Note: No leanburn while vtec active.



The leanburn difference? I drive a lot of miles per week with my D15Z1 and have done a bit of testing. The difference between ignoring leanburn/normal burn and trying to stay in leanburn whenever possible seems to be only about 3 mpg. What I have found to make the most difference is keeping the rpm under 2800.




Hope this clears some of the mis-info up, may be back to add or edit.




Link to maximizing lean burn thread (leanburn at idle and ambient manifold pressure)

http://ecomodder.com/forum/showthrea...nda-23288.html

This thread is old but I have something to add. In another lean burn post it was mentioned that the cat needs to warm up to temperature in order for lean-burn to activate. I know for a fact (for the HX atleast) that you do not even need a cat in order to use lean burn. You dont even need the secondary o2 sensor. After I swapped my engine with a new one I had to replace the exhaust manifold. Long story short, I needed to wait until I got a new direct fit cat for another model to have it cut and welded in to my exhaust. I drove without a cat or secondary o2 sensor (check engine light on) and was still able to go into lean burn. Just thought someone might want to know that cat temperature or emissions past the first o2 sensor have nothing to do with lean burn.

It seems intake temperatures have a huge impact on lean burn. Or atleast for me. Its been about 60 degress or less this week and my car does not want to stay in lean burn for long. No matter how careful I am to keep throttle position low. On monday it was above 75 degrees and I stayed in lean burn the entire trip on the highway with no problems. So it would appear that colder air intake temps can keep you out of lean burn. Can anyone else confirm this?

this is REALLY good info.

I missed this too. Really great stuff. Thanks for posting. Nice to the AFR confirmed by someone with a gauge.

I can confirm the vx does not need a working cat either. I get leanburn in cold temps but not as much. I just figured it may be do to the car moving thru denser air , colder fluids, higher alt load etc.

With the P07-A01 ecu (probably all 92-95's) intake air temps are not a factor in switching to leanburn - at least down to ambient air temps of 20 degrees F

As long as manifold pressure does not pass that threshold of 4"hg it will stay in leanburn if the other abovementioned conditions are met.

Unfortunately, the later generations are severely emissions restricted.

That was going to be my question, you did these tests with a stock ECU, not a JDM part, right? because it's the ECU that controls lean burn, the sensors on the engine are just telling it what the engine is doing.
For those of us who are a little fuzzy on what the different amounts of vacuum are, could you expand on the vacuum gauge readings and how that translates for those of us without a vacuum gauge.

there is absolute pressure, and vacuum. if you are interested, go read about it on Wiki.

4 inches of mercury vacuum is dang close to WOT.

You could use a vacuum gauge or scanguage and they both tell you engine load. 0 vacuum on a vacuum gauge would be 100% load on a scangauge. Most people say around 22 in vacuum is idle. So basically as you go from 30 to 0 that is basically engine load that you would see on a scangauge.

Thats odd that they would add in IAT for HX. I have seen a few other people talk about IAT affecting lean burn on the HX so I know its not just me. Must be emissions, like you said. During those nights after it took me out of LB it would not let me back in. I had to do some EOC and then about a minute after turning on the engine it would go into LB for a short amount of time before kicking me out. When it kicked me out I was following all the parameters that allow lean burn on warmer days and for seemingly no reason it would just kick me out. Last night I tried various ways to "reset" the LB so that I could get back in without shutting the engine off. I found that if I went WOT for a few seconds and then went back to regular cruising LB would kick back in within a few seconds. I wonder if that is because the engine heated up a bit more, or if going WOT resets some function of LB.

Leanburn engines have been a challenge to automakers from the beginning with NOx levels being difficult to control, and as each year goes on the emissions restrictions become more aggressive. Now we have NOx converting catalysts, but with a cost.

If you '96+ vtec-e guys have determined the IAT's are the culprit, bluffing the ecu into staying in that critical window may not be that difficult. Since resistance of the thermistor goes down with increasing temps, using a fixed resistance "simulator" with a SPDT switch may be an option. I doubt there are any appreciable ignition corrections that would cause a problem for the intended application, and since we ecomodders tend to live in closed loop, fuel would correct itself.


And 4 In.Hg. is nearly full throttle, where mine stays 90% of the time, and even has the throaty intake tone to go with it. A vacuum gauge is a powerful tool with LB engines.

rather then fooling the sensor, just make a hot air intake.

So I wonder if the WAI actually gives better gas mileage because of the warmer air, or because the engine reads "INCOMING WARM AIR". If the later is the reason, then why not feed it a incoming air is warm signal like all the time?

@cbaber: I just read this now, but here's a thought for you: Do you have OEM wheel size? I had large prelude tires/wheels on my VX for about 2 weeks waiting for a chance to get winters put on them. This was a whopping 9.7% increase in outside diameter, plus much heavier wheels to boot. The car struggled much more to stay in lean-burn with those wheels on, b/c the gearing was too tall and had to struggle, and the extra reciprocating mass, etc, meant more work too. So this is just a thought: you cant' diverge much from OEM wheel size for gearing's sake.

Also, I just put a warm air intake on my VX, but it's too early to see if it works much yet...haven't had a chance to drive it yet. I'll let you know if it helps much that I can notice as winter is setting in here soon.

@greasemonkey: thank you very much for taking the time to give actual air-fuel ratios while running! Outstanding. :thumbup: You manged to keep the meter in the exhaust pipe while driving down the road? Did the 22:1 to 23.5:1 ratios hold steady all throughout the lean-burn operation, or was that just the most common averages?

John

The tallest tire I've ran was a 185/65/14. I saw an improvement over the 195/50/15 - probably because of the width. Yes, it bumps up the effective final drive, but only minor changes were necessary in driving technique. My car has Integra brakes so original tires are not an option.

The wideband O2 is a permanent mount.

http://i12.photobucket.com/albums/a2..._/DSC01385.jpg

The factory wideband is very stable, nothing short of impressive. The air/fuel usually stays within one point while cruising, but it really depends on the conditions whether it runs in the low 22's or high 23's - not sure why.


Perhaps this will answer your other questions -

http://ecomodder.com/forum/showthrea...nda-23288.html

thanks for the info on the rpms and when lean burn kicks in and when it doesnt. Ive just installed my D15z1 about a month ago and just installed a Hf tranny two days ago. My 02 is in the wrong spot thats for sure. Make sense thats why it has been acting up. ive installed it right below the firewall and this was after i didnt know that the 02 needs to be really hot to work. I had a Dx tranny before the swap and I got 41 mpgs kinda of curious what i would get with the HF.

I've not been able to confirm that O2 sensor position is a factor. As I posted earlier, I swapped my stock exhaust manifold for another Civic setup, which the O2 is at the back of the manifold near the firewall. Even with that setup I could still engage lean burn. My problem is the O2 sensor. Shortly after making my earlier posts my factory sensor went bad, and I bought a cheap replacement. After buying the replacement I can no longer engage lean burn without the engine hesitating and stumbling when it tries to engage.

I've bought another manifold that moves the O2 sensor back up next to the exhaust ports, but have yet to install it. If that solves my problem then I will report back. If not, it's my cheap O2 sensor that cannot handle the lean burn.

Mine engine light turns on when its cold outside, especially in the morning or when i leave it outside in the cold. Lean burn doesn't turn on at all or not for a while. Now that its colder i have to drive 15 or 20 miles of driving doing whatever. If i turn the car off and leave it sitting and start it up Ive got a 50/50 chance of it coming on again. When i did this swap last month same set up it was 75 plus degrees and my engine light never came on. Soon as the weather changed the 02 light came on. I am going to make a jumper harness hopefully soon and put it in the front near my engine and HOPE that will correct the issue of the engine light coming on.

This does pose a concern to me now this issue is mentioned. As seen in the pic, mine is a few more inches away from the exhaust ports than the original config. Since day 1 the MIL would come on if I hit fuel cut right after startup - as if it had to be preheated before it would work properly. I've gotten use to the quirk and hadn't paid it any attention for some time, but after a quarter million miles, she's starting to jerk. That's probably a reasonable lifespan. Unfortunately, a sensor costs as much as the engine so it won't be getting replaced anytime soon.

In relation to the brief discussion of tire size, there is a super tire sizing chart I found on another thread somewhere that is the best I've ever seen, found here: Custom rims, wheel tire packages for your ride - RIMSnTIRES.com

As to warm air intake, it is definitely better to make a warm air intake then to trick the computer by telling it the air is warmer than it really is. I used a warm air intake last winter, but it didn't seem to do much for me, but then again, I had tires/wheels on that were way too big for the VX and that hurt mileage so it was impossible to tell. I had to change an engine mount this summer and in the process had to remove some intake plumbing, and while at it just removed the whole resonator, etc, and put on a premium Amsoil EaA air filter with pre filter over it, so I had to lose the warm air. Maybe this winter I'll try again with proper tire sizes.

Greasemonkee, how many miles on your VX now? You got a quarter million miles out of your 02 sensor??? If this helps, I have an 02 sensor for my VX that I bought as a spare in January, as I had some mild stumbling issues too. A month ago I put it in the VX for one full tank of gas, and it made absolutely no difference for mileage or the stumbling, so I put the original sensor back in. The spare I got is a Denso, which is one of the OE Japanese companies Honda uses for its' components. I can sell the spare 02 sensor for 200 bucks or so, if interested: it's basically brand new, and clean. I just called a local Honda dealer here by me in Ontario, (Image Honda in Stony Creek), and they charge 380 dollars for that sensor before tax. I understand you have no reason to trust me to be telling the truth, but I can send pictures if that helps. I would keep if but I'm so tight for money 200 bucks would help me a lot. If your 5 wire 02 sensor is actually bad, a new sensor will do wonders for your mileage, and maybe clear up stumbling too.

(As a side note, if you're not going to keep your car up but let it go to waste, so to speak, let me know if you are ever going to sell it. :) I keep my cars up, and with a car like a VX it's totally worth the money.)

Lastly, who here has a good ECU for the VX, from a 94 or 95 model years for a hundred bucks? I'm looking. Thanks.

Thanks for the offer! I'll be heavily pondering that.

Mine was originally a CX which I converted and modified to get the most that can be had from the leanburn system - there should be a link to that on the first page.


I try my best to keep the vx top shape - lot of irons in the fire lately, but because it's no longer a dedicated route car and only gets driven 45 miles/day; it would be years before a $390 sensor paid for itself. Every inch of this one is modified (ITR suspension, ect) and this one will probably be with me from now on.

Greasemonkee...

I tried looking for a link you may have left when you converted your car, but couldn't find one. Would be interested to see all you did.

Mine's just bone stock, so far.

thanks

Fixed, sorry. Recently deleted all of my NSA spy (google) accounts and it wiped out the youtube links.

It's at the bottom of the first post.

You had to delete all your NSA spy accounts! Lol!

I saw your vids finally...lot of gauges floating around the cockpit. If I were driving your car I'd have a hard time resisting the urge to flip a few switches and start the countdown to blast off. In other words...very cool.

Noticed your vacuum gauge showed 21 inches of mercury at idle. That's very good...and makes me wonder about mine. My car idles with about 18 inches of Mercury. I *think* my engine is still very sound and tight, and I can't find any vacuum leaks anywhere. I just have a cheap Chinese gauge though...can't comment too much on it's accuracy, but I think it's pretty good. Would 18 inches of vacuum bother you? Hopefully I can find a way to get a compression test done on it.

Also, when almost WOT going up that hill at 13.5 Air Fuel Ratio, did you ever encounter anything close to detonation?

Also, since you seem to know what you're doing...what are your thoughts on this. The idle air control valve has gone to pot on Ed, and has a mind of it's own...sometimes dropping down to 500 rpm, other times it won't go down when you let off the throttle, it actually continues to rise. (no, not stuck throttle cable.) It's a cheap aftermarket part that worked perfect at first, but is already crapped out after one year. Basically, as I see it, the iacv functions almost as a kind of choke, even though that might not be it's primary function. And when it's acting up, the faulty iacv could actually be enrichening the mixture unduly, right? So I'm thinking, once I get the new OEM Honda valve in place in a couple weeks, that theoretically could improve mileage. Thoughts?

I would like to do your mod where you widened the parameters for lean-burn initiation, but that procedure is a bit above my skill level maybe. I am trying to figure out if you're a mechanic or engineer by trade. Or both? I'm a little worried about long-term longevity with such mods, but lean-burn extension seems like a relatively risk free mod, so long as it's done right. It's not like you're adding 20 pounds of boost. How much extra torque would you guestimate the mod gave you? Any downsides in driveability? And you think it gave you an extra 2 mpg?

What I would like to do is rig up a small led light that glows green when lean burn is active...but scared to splice wires into the ECU harness.

Nice work on the car. Ever break your magical 60 mpg barrier yet? I just today, got my best tank ever, at 56.74 mpg, and I think there is still quite a bit of room for improvement, if only my finances would improve first...

few more things greasemonkee...

I just now found your photos of your civic and van...and had to comment. This is uncanny...not only do we have the same car, but we also have a navy blue 98 odyssey! I once got, on our best tank, 930 kms on 60 liters of fuel, or, 36 mpg. That was with low rolling resistance Ecopia tires, top tier Amsoil fluids in everything, and air-tabs on the rear of the vehicle, and not other mods.

Few more questions...sorry to keep nailing you with emails like this. But what is that canister in the front fender area of the odyssey? Also, what did you do to the PCV canister on the VX with the extra thick tubing? Also, I saw metal threaded plugs...did you clean out the intake manifold on your car and plug it with those?

what kinds of headlights are on the odyssey? And what on earth did you do to the exhaust on the...odyssey? (two divergent pipes.) Lots of curiosity going around here!

Initially I had a problem with the EGR valve. The valve itself was moving properly, but the old, hardened grease in the sensor was holding that part of it in the open position. The ecu saw this as the valve being open, thus adding a LOAD of timing, finally resulting in detonation that couldn't be remedied even with 93 fuel. After cleaning and regreasing the sensor the problem went away. The fuel controller artificially changes the map signal which changes timing - adding timing in this case. Without having a timing light and watching it under a load (impossible without a dyno) the best I could do was make an educated guess. Ultimately removing a few degrees from the distributor was enough to offset the ecu timing change.

So to answer the question directly, there was no detonation at 13.5 AFR, however it may become more sensitive with too much lead timing at those AFR's. Nevertheless, sure beats 11.8 AFR.











The iac valve is nothing more than a bypass valve to let air around the throttle plate that operates on duty cycle (pulses sent from the ecu). This shouldn't effect economy unless you're really idling high; it has no way of changing the fueling directly. There are a lot of these around - the same on most all D series engines I think. If you want , I may have one on the shelf.




The fuel controllr did give me an increase of about 2 mpg, not from leanburn expansion alone, but leaning the wasteful WOT maps and target lambda. This is a neat system btw, always remains in closed loop when at operating temp.

A light would need a little circuitry I believe, but possible.



Not sure what you speak of on the diverging pipes on the odyssey - haven't touched it - the civic, yes, it's got a DX exhaust manifold. The metal plugs and hose is probably the train horn. Eventually I had enough of people running me off the road because they could see the car. There is only one vacuum tank in place to prolong the power braking during coast.


Metal plugs - ahh, you must be talking about the magnetic oil drain plugs? I make those.


With skinny 185 tires, the car was kissing 60, but difficult. The mountainous terrain require a lot of hard braking - 1000' to 4000' back down to 1000' up and down up and down. On flat road 60 would have been easy. These days I opt for the handling rather than that extra mpg and run the 195-50-15's. The extra speed carried through the curves without having to brake compensates a little.


Haven't really modified the odyssey other than the aero. Just bought a CNG Ram Van to haul my cargo, the odyssey will be sold. At $1.69 a gallon, I'll go for extra cargo space.

And no sir, I'm technically not an engineer or mechanic. I run a route through western NC. I suppose what your title is and what you're good at are two different things.

Thanks once again for the reply.

I figured since the idle air control valve bypasses air, the computer reads that in the exhaust stream and add more fuel. I thought it would act the same way as a vacuum leak that way. Whatever the case, it sure is annoying! I'll see if the new one helps. Give me details on your idle air control valve please...esp. what car did it come from? Also, mileage and price? I just purchased one from Majestic Honda though, it's been shipped but I have to pick it up and it's still unopened. The CX and VX have a different IACV than most Honda's, partly because those two models don't have fast idle valves, just a iacv. Most other similar Honda engines have both a iacv and a fast idle valve just under the throttle body, so on the VX the one valve performs double duty somehow.

the plugs had holes in the middle...so was guessing not used as magnetic drain bolts. How much does a descent fuel controller cost? I'm not too up to speed on them. Do you have to splice it into the wiring harness, or is there a more plug and play way to do it...this is OBD1 or zero, not sure which. I am a little nervous about altering fuel ratios though...there is a reason they richen ratios under load, although sometimes Honda does over-engineer things. It could compromise longevity if nothing else...unless you have extremely robust oil in there. Didn't you have an exhaust gas temp gauge? Did it alter the EG temps at all by leaning out the mixture while still under load (going up that mountain)? It should have.

I wasn't sure what I was talking about with divergent pipes either! I don't now which vehicle it was on...but there was a long pipe on the underside that wasn't the exhaust, but looked like another exhaust pipe that ended in what looked like a conical air filter??? I am still baffled by it.

Lastly, didn't mean to pry into your occupation or anything...you just seemed pretty handy so I took a guess. Don't know what I'm good at...got a master's degree that got me nowhere due to the "market," and am now in sales. On top of Amsoil, they also make really good natural fertilizers, but out here getting farmers to consider a more sustainable way to crop than just laying chemicals down is like going through a brick wall. So I guess what I do and what I am good at are sometimes different.

I'll take info on your idle air control valve if you don't mind. Is there a way to personal message me? Thanks again for your time.

A picture is worth... a lot! I think you're talking about this one?
http://mob12.photobucket.com/albums/..._/100_2026.jpg

So... what is it? :)

Thank you NachtRitter, that's the one. Perhaps Greasemonkee could offer prize money to the one who guesses correctly? :D

crankcase evacuation?

And we have a winner!



Note the 3" exhaust pipe....

It really pains me to look at these old pics. Losing 300 hp hurts.
http://i12.photobucket.com/albums/a2...psa6305fab.jpg




VxonFumes, I'll see what I've got in the way of iacv's, however there's no way to tell what they go to. What I do know is the obd2 iacv's had a longer bolt pattern. I believe these may have been revised internally to allow more airflow. Again, to my knowledge, all odb1 iacv's were the same on the D's - could be wrong, but I've yet to come upon an issue with interchanging them. I'll pm you if I find something.

Ahhh, yes, a slowly decaying economy as the powers-that-be slowly choke the breath out of it's victim - the python preparing for the feast. I am a certified aircraft mechanic... that never was. No offense taken at all on the inquiry. These days a man must be talented over the broad spectrum.

Without previous tuning experience I would have feared the fuel controller, these range in price according to what you want. One of the older apexi units would have worked for my app. Keep in mind that I was driving 1500 miles a week to justify the fiat currency spent on these gizmos - unless you anticipate fuel prices getting out of hand. A 600 mile range is nice though, for a non-basjoosed chassis.

Is ur evacuation on the performance engine or the lean burn one? I often thought about doing an evacuation like I did on my gremlin drag car. From the crankcase into the exhaust downstream with an anti backfire valve. Does it make a noticeable difference the way you ran it? I've only ever see crankcase evacuations run into the exhaust

greasemonkee

WOW killer post!!!!!:thumbup:

For forced induction
As the internal combustion engine evolved it was realized that blowby gasses and particulates were corrosive and a fresh air ventilation system must be incorporated, better known as the PCV system today. My contraption may have been overkill but fulfilled the objective - force fresh air in, but the gasses were dumped overboard rather than burned. Better to suck and have negative crankcase pressure, but the pump oil logged; this was the original, double benefit concept.

There is a lot of pressure once you get past a bend or two in the exhaust (from the outlet), a venturi with may have dropped the pressure enough for crankcase gasses, but increasing the post turbine pressure, might defeat the purpose. Seems like I've already experimented with this.

Oil contamination and boost don't work well together. That block was nearing the end of its life. Carrying a bed pan around to catch the oil waste wasn't highly desirable.

Ohhh ok. I didn't really think about the exhaust pressures with a turbo setup as compared to say a v8 drag car or circle track car where they just headers and collectors. I think the main thing that stopped me from trying it on my lean burn engine was the "pcv valve" from the factory d15z1 wasn't a valve at all. They were gutted intentionally to create that effect of full engine vaccum in the crankcase to make the engine work less. Or so I theorize :/

Who knows maybe its worth a try on a lean burn engine. I like the way you welded the pipe onto the oil baffle. Fantastic lookin welds.

@ slownugly:

the leanburn engine (on the VX anyways) does have a PCV valve, it's just in a funny place. There is a strange canister that plugs right into the block at the back, by the oil filter. From there a tube goes up towards the intake manifold. Down by the canister is what *looks* like a PCV valve but it's not, it's just a connector. But there is a PCV valve right by/in the intake manifold that is an elbow shape, and from there directs piping to the intake where it vents. It's a really strange system...I wonder why it's not "normal." I also wonder why they used a canister below. I have a theory, but it not be worth much. What I wouldn't give to be able to talk to one of the original lead Honda engineers that designed the VX back in the day, and just pick his brain for 2 days straight.

greasemonkee...about the iacv: if you can't be certain it came from a 92-95 model year CX or VX, then I think I want to pass. There is a difference between those two models and the other civics of that time. The fact that the other models also simultaneously had a fast idle valve but the VX/CX didn't is substantive. If you go to Majestic Honda and plug in the right info, you will get the fiche pictures that show it. If you do have one from a CX or VX though, let me know...although I'm running out of time for it. Also, if you or anyone else is interested in a 5 wire 02 censor for the VX used for only one tank of gas, let me know.

Thanks

Nope that elbow that goes through the intake looks exactly like a pcv but the vxs were open from the factory. No guts in them. The story is people would take their vxs to a mechanic, the mechanic would do the old shake test to the pcv valve not knowing they were empty. It would fail the shake test so they would install a pcv valve that had the guts. This is what I've read on this site. I cleaned the guts out of both my lean burn engines. Maybe someone has a known original to confirm. I have 2 spare z1s laying around I'll have to look when I get to work.

Also I believe all civics this generation had that black oil baffle in the back as well as the pcv going up the intake. Only difference was the open pcv valve.

I was going to upload a fiche picture from Majestic Honda for you, but the biggest .doc file I can upload is 19.5 KB. How useless is that? That's enough for maybe a blank sheet.

Anyways, go to Majestic Honda, punch in Civic, 1992, VX, KL5MT for tranny option, and then choose *breather chamber* for system name/component. A diagram with corresponding part list will show up. Illustration #6 is the elbow, and described there by Honda as "VALVE ASSY., PCV." I don't know who's telling the story you're referring to, but it's not correct. My own civic had a PCV valve in it as well, and pretty sure it was original by the condition. Besides, wouldn't make any sense to not have a valve: you don't want those gasses going back into the crankcase. Anyways, Majestic Honda is a great site.

Not sure what you refer to when you say "black oil baffle." If it's the black canister type box the PCV tubing comes out of (Illustration #1) it's the "CHAMBER SET, BREATHER." Not to be filled with oil, presumably. Would get in the way of the breathing part. :) Hope this helps.