comegetme

How many catalytic convertes does the Civic VX have? I am trying to verify my configuration, but getting conflicting information. The vx has a catalytic converter right below the exhaust manifold. Did it originally come with another catalytic converter in the exhaust pipe below the car?

comegetme

I just called Honda customer service to determine if the VX came with one or two catalytic converters. They put me 10 minutes on hold, only to say they are unable to determine it, and referred me to a dealer. Looking at the diagram https://www.hondaautomotiveparts.com...EXHAUST+SYSTEM , I am unable to determine if parts 9 and 11 are interchangeable or different configurations. If i interpret it right, part 9 seems to attach to part 5 which looks like a catalytic converter, while part 11 seems to attach to the exhaust pipe. What do you guys think?

eghatch9295

iTrader: (1)

one on the manifold.

comegetme

Thanks, eghatch!

Unfortunately, a mechanic welded a C.A.R.B. approved catalytic converter into my exhaust pipe for $150, in an effort to pass smog.

I do not know how he came to the conclusion that my VX had a cat in the exhaust pipe, but http://estore.honda.com/honda/parts/view-honda-parts-catalog-detail.asp?m=1992-civic-3-vx-5mt&b=B++02&dl=208728# shows a configuration with something that looks like a catalytic converter, doesn't it? The diagram is not quite clear to me.

O'Reilly and others sell aftermarket Catalytics for the exhaust pipe for the Civic VX that are C.A.R.B. approved: https://www.oreillyauto.com/shop/exh.../civic?q=catal

Question: Why would they be C.A.R.B. approved if the VX didn't have one in the exhaust pipe in the first place? I learned that since 2009, in CA catalytic converters may only be installed in the original location (i.e. below the manifold on the VX) - seems like a contradiction to me. Is it possible the OReilly's and other web sites wrongly categorized this part to match the VX? I studied the executive order https://arb.ca.gov/msprog/aftermkt/d.../D-193-117.pdf which list 1992 Hond Civic 1.5l, but not he model (VX, CX, etc.). Question: Are there other 1992 Civic's that have a cat in the exhaust pipe below the car?

To add insult to injury, the mechanic welded the cat at a location in the exhaust pipe where normally the resonator is located (further towards the back), not where the cat would be according to the diagram (behind the curved pipe that comes down from the first cat with a 90 degree bent). I do not know if he removed a resonator, or if it was missing.

Don't get me wrong, I'm not disputing the answer, but I'm trying to reconcile conflicting information, and figuring out if I have a case to have the mechanic remove the second cat and restore the exhaust pipe to it's original condition. I would imagine that having 2 cats on a car that is designed for 1 cat might affect other parameters in the exhaust system, or at the least be a complete waste of money. I never asked him to install anything not to spec, and I was never informed that anything would be installed off spec. Obviously, there are C.A.R.B. approved aftermarket replacements for the primary cat. Also, as I understand it, it would now be illegal and might prevent me from getting smogged in CA if a cat was installed at the wrong location (in the exhaust pipe vs. below the manifold in the engine bay), and/or if the wrong number of cats are in the exhaust system.

I don't know what to do. Your help is very appreciated.

comegetme

P.S.: The original reason why the second cat was added was because HC (hydrocarbon) at 25 mph was 280, which is many times as high as the max allowed. All other values were in range, including HC at 15mph.

After the second cat was installed, the value didn't drop.

Question: Even if the second cat should not be in the exhaust pipe on the VX, and even if there are other reasons for the high HC, shouldn't the second cat have at least reduced the HC by an amount more than the accuracy of measurement? Do catalytic converters in the exhaust pipe server a function different from the primary catalytic? Can other conclusision be drawn (vacuum leak in the exhaust after the converters)?? The car shows no check engine error code, and most components have just been replaced with high quality NGK etc. parts (EGR valve, throttle body, O2 sensor, PCV valve, air intake temperature sensor, rotor, spark plugs, wires).

eghatch9295

iTrader: (1)

are ignition and mechanical timing set correctly? in addition to severely restricting exhaust flow, i'd bet the second cat never gets hot enough to do its job. every 92-95 US civic EXCEPT cx/vx use a converter just after the exhaust downpipe. if the cat is as far back as you described, it would never properly work, even on a non cx/vx. 96-00 dx/lx/cx use a cat on manifold design as well, which is prone to failure due to cracking. a common work around is to install an oem (or aftermarket) exhaust manifold, and a stock converter in the location it would be on an ex model, which again is directly after the downpipe. in your case, this may be a solution, considering you already spent the money on the converter.

comegetme

Thanks again, eghatch. The more research I do and the more answers I get, the more evidence presents itself that the second cat was put in in error. The mechanic stated that "they" (a previous mechanic) replaced a cat with a straight pipe. He pointed out that the molding underneath the car is shaped to leave space for what he thought should be a cat, but according to the diagrams and pictures of aftermarket parts, should be the resonator. I hope he didn't remove my resonator thinking it was a piece of pipe!!! The mechanic has 30+ years of "experience"!!! Even if he was not specializing in Hondas, shouldn't he have realized that he put it in the wrong location?! I have 0 years experience, and a quick look at the diagrams shows me that something went wrong!

Regarding your proposed, possible solution: Yes I spent the $150, but I have a receipt and the work was done at a licensed and insured shop. I specifically told the mechanic to only use correct and legal parts, and not use any hacks or bandaids, as I plan on keeping this car for the long run. I see the following problem with your solution of moving the exhaust cat further to the front:
(1) He would need to welt another piece of pipe in the place where he put the cat. Don't the weld seams rust first? Will I have another potential point of failure? I'm a layman, but his welds on the cat already look ugly!
(2) Unfortunately I don't know if he removed the resonator believing it was a piece of straight pipe. With all the chaos and mess that he did, and given that he obviously was unaware that the place where he put the cat is for the resonator, maybe I should assume he did remove it?!
(3) I assume there was a reason why Honda put the cat on the manifold on the VX and CX models. I heard it may have to do with the lean burn, or any other parameters. I'm sure they didn't do it just for fun, as they surely incurred cost to vary from the other models. I would be concerned that having the cat in the exhaust instead, could alter any number of parameters, be it the efficiency of the cat, the engine backpressure dynamics, or anything else. I could also imagine the dealership might refuse to work on, or diagnose, the car, as many mechanics refuse to work on modified cars.
(4) I It is my understanding that the car would not pass the visual inspection portion of the smog test, as the cat in CA has to be in the original location and nowhere else.
(5) I see no evidence that the original manifold was defective. Why would I replace it.
(6) If the mechanic suspected the catalytic be defective, it would have been easy to replace the primary cat, to avoid all of the above problems. Since he used an aftermarket anyway, a bolt-on primary C.A.R.B. approved aftermarket cat for the VX would have been available for ca. $235 on Autozone, O'Reilly's, etc. with 50,000 miles warranty.

Frankly, based on the evidence, the mechanic clearly was not aware of the difference between the VX/CX and other EG's, misread his parts database, and put in the wrong part in the wrong location. The only option that I see is to make him restore the exhaust system to its condition before his change, and refund the $150. Why would I spend $150 (or any single cent) on having a car likely functionally defunct or at least out of spec (due to 2 cats in series), AND almost surely failing visual smog inspection? Frankly if my current understanding is right, I wouldn't even have it done for free, and not even if I had gotten $150 or $300 on top as a bonus!

After having the mechanic restore the exhaust, I plan on bringing the car to the dealership for a full diagnosis.

Your opinions and help are very appreciated. Please correct me if my conclusion and plan of action are wrong.

mk378

A cat needs heat for it to work. Installing one so far from the engine shows that the guy had no idea what he's doing. This is also why a typical factory system with the cat underneath the car has so many heat shields on the manifold and front pipe -- they keep the exhaust hot on its way to the cat.

Usually a bad cat will fail on all 3 pollutants. If it is only failing HC you may have a different problem.

94eg!

iTrader: (2)

The reason they do that is because the OEM or OEM style is either too expensive, unavailable, or they would simply work faster & make more money. The OEM manifold-cat is shaped really weird due to an angled outlet. If he wanted the job, he would have had to order parts and possibly loose you as a customer to the next guy. Instead they use an on-hand universal cat and simply leave the odd shaped OEM piece in place as dead weight and flow restriction. Yes it's lazy BS.

BTW: It looks like CARID sells two bolt-on versions of CARB compliant CX/VX converters from Magnaflow.

https://www.carid.com/1992-honda-civ...252960288.html

eghatch9295

iTrader: (1)

yes, your assertions seem correct to me. HC failure can be tricky. you said that you've already performed an ignition tune up, so the next steps are to verify timing, then a compression and leakdown test. a worn engine not working properly will also cause a major jump in HC emissions.

comegetme

Thanks to everybody. Thanks to eghatch!

The car is currently at the mechanic who is removing his "second catalytic" work. He stated that he had wanted to "save me money". Then he stated that he believed that the first cat was fine, but added this second in lieu of the resonator, mumbling that it "DOES THE SAME THING AS THE RESONATOR"!!! This doesn't make sense. I had told him 100 times that I planned to keep this car for the long run and want only the best parts at the right location, and find the root cause of the emissions problem. How can he do such a hack job. He wasted 2 days of my research time to identify his hack job, and 4 hours of shuttling to and from the mechanic and the smog stations. He didn't offer to refund my $150. I put in a stop order on the payment check for now.

Tomorrow, once the car is back to stock (minus the exhaust resonator), I will bring the car to a Honda dealer for a (hopefully) comprehensive diagnosis. I have never in my life been to a dealer! I'm scared Can I be assured that they test everything that can be tested, or should I insist, or verify, that they do certain tests? Will a compression test reveal a "worn engine", or should I have them do other tests or inspections on the engine? Will they do a so-called "VTEC test"?

The car has 190k miles and the engine bay looks very clean. The engine even still has the original black powder coating that I rarely see on EG's. No oil leaks. How likely is it that the engine is "worn"?
Also, can they identify a worn engine at the dealership?

Thanks in advance! This forum has helped me identify an unscrupulous mechanic attempting to turn my rare, near-100% stock VX that I loved, into a hack job that didn't fix a thing, that no serious mechanic would work on, let alone smog, and extracting $150 for it from an unsuspecting customer. Thanks, forum! THANKS, EGHATCH!!!

94eg!

iTrader: (2)

Can't answer your questions, but I can say it appears Honda still has your old VX B-pipe in stock if you want your old resonator back. You may have to order it locally though as most online parts dealers won't ship something so big. You can always contact them for details though.

18220-SR3-406
https://www.oemacuraparts.com/oem-pa...1hbnVhbA%3D%3D

#24 in image includes everything circled:

comegetme

Thanks. However, from what I read, my understanding is that the resonator is mainly to suppress certain frequencies, but has little to no effect on the combustion or exhaust dynamics. (Although some think that it might theoretically affect exhaust flow / back pressure and therefore combustion, but mostly in a scenario with no muffler or catalytic.).
If that is correct, then the resonator or pipe, whether stock of aftermarket, is the least of my problems. I hope that the dealership won't refuse to do their full diagnosis just because of the missing resonator.

comegetme

Do the dealerships all follow roughly the same protocol when diagnosing a car, or are there typically differences in the quality, depth or types of tests performed between dealerships? I'm in Los Angeles, so I have several dealerships in my area.

94eg!

iTrader: (2)

Yes the resonator is just a muffler. No the dealer won't care if it's missing.

eghatch9295

iTrader: (1)

a compression test is a simple, quick test to determine if the engine still makes compression within factory spec. should it fail, the diagnostics can begin there. weak or incomplete spark from failing distributor components can cause your issues, as can ignition or mechanical timing being out of spec.

TomCat39

One thing to note, you mentioned they used a C.A.R.B. compliant cat on your car. Are you in California?

The reason I ask is the California VX is different than the other 48 state VX's.

The California VX does not have lean burn capability nor the 5 wire wideband O2 sensor needed by the vtec-e.

There may be other differences I'm not intimately aware of. This will also give you mixed results in some of your research.

civic402lx

In his previous reply, he noted he is indeed in california. Los Angeles.

94eg!

iTrader: (2)

He is "in" California, but the car itself is not a California-spec-emissions vehicle. It's the 49-state version.

BTW: I compared the part numbers between the California & 49-state versions of the 92 VX, and the converters are indeed the same (18160-P07-A00). As mentioned previously, the o2 sensor is indeed different.

comegetme

The car is 49-state, and I am trying to smog it in Los Angeles, CA. According to the abundant discussions on related internet forums that I have been studying for years, this car "should" pass CA smog if all parts are working per spec. Otherwise I could have swapped in a CA ECU for the test, as I also have a CA VX, but I didn't because I want to find the actual defect and root cause. Also, there are exactly 3 (three) differences between 49-state and CA versions: (1) O2 sensor (EXCEPT for most 1992 CA VXs which have the 5-band also); (2) ECU; (3) wire harness. It has been discussed and confirmed over and over that everything else is exactly the same.

However, smog is not the only problem that this car has. It also has significantly less acceleration power than other VXs.

The hack job with the second cat has been reversed. It had near 0% chances of fixing anything, and 100% chance of making my car non-smoggable and non-serviceable in CA, both of which were known beforehand. It is also illegal to modify the exhaust system in CA. They reversed their job for free, but refused to refund my money (a contradiction in and by itself). I will write a demand letter and hire an attorney if I don't get my $150 back. Dropped the car off at the Honda dealer this morning. They just informed me that they need more time. They are swapping in another "mass airflow sensor" to test if this fixes the problems. The diagnosis is expensive ($300 just for the diagnosis, without parts or other labor), but they seem to be more thorough than regular mechanics. If they find the root cause, the money will be worth it to me.

I didn't know that such a thing "mass airflow sensor" existed, and not sure why it doesn't send an error code.

mk378

I don't know a lot about the VX but I thought they were all MAP controlled.

The OBD1 system doesn't have a lot of self-checks and there are thus quite a few things that can go wrong that don't set a code. Sensors that are out of calibration can cause runnability or smog problems without being far enough out to trip codes in the ECU. Especially the 5-wire O2 sensor.

Lack of power assuming it is running on 4 cylinders and not misfiring should first investigate for wrong timing or restricted flow in or out of the engine (mouse etc. in the intake, or melted / clogged cat).

comegetme

A search on Autozone and others confirms that the VX has a MAP, but no MAF sensor. I'm sure the Honda dealer representative said "mass airflow sensor" on the phone, but maybe he was just mixing up the two words, or using them interchangeably.

I'm sure the Honda dealer diagnosis will include checking misfiring, timing, and he said they would check the cat if necessary to trace down the problem. I will double-check that they checked the intake when I pick up the car, in the event they were not able to trace it down. Since the diagnosis includes at least a compression test, which in my understanding would eliminate the engine as root cause, I would think they "must" be able to trace it down - or not? I mean, if every part involved is either replaced or the functionality was checked by the dealership, then the system as a whole must work, right?

eghatch9295

iTrader: (1)

all of the above assumes a competent tech, or a tech who actually feels like performing/is capable of old school diagnostics. most newer "mechanics" are glorified parts changers who couldn't diagnose a misfire without a computer telling them what to do.

TomCat39

And to add to this, even with the old schooler's.... Some were more naturally talented at diagnostics than others.

My Honda Trained Technician buddy has been working on hondas for over 25 years, and runs his own personal shop. His buddy is the diagnostician, he even admits he's not as good at it like his buddy.

94eg!

iTrader: (2)

I was surprised to see an MAF on my new-to-me 2012 Odyssey. That generation of Honda is already 7 years old and replaced.

Also the person you talk with at the dealership is usually just a service rep. They always know little to nothing about the actual work being done, and really just function as an interpreter between mechanics and customers. They will always be a source of frustration and misinformation to a more technically advanced customer. Ask to talk directly with the mechanic actually performing the work and you should have a better understanding of what's being done.

Also be aware that mechanics these days spend most of their time in computer diagnostic and programming classes to learn how to work on the newest models. It's safe to assume that anybody who moved into the industry in the last 10 years probably has little to no experience with OBD1. Our cars are definitely moving into the realm of classic vehicles (weather muscle-car people like it or not).