Civic VX Emissions Failure - VTEC Malfunction, or Hopelessly Epic Melodrama? - Page 2 - Fuelly Forums

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Old 08-14-2009, 11:41 PM   #11
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The intermittent Check Engine Light that I was getting for the Spool Valve Oil Pressure Switch would go away whenever you turned off the ignition. That is, say if I went for a drive, and accelerated hard to get up to speed on a freeway, and the check engine light came on. If when I got home, and I jumpered the service connector, and then turned the engine off, and then turned the ignition back to ACC, it would blink the error code. However, if I just turned the car off, and came back the next day, it wouldn't blink the error code from the previous day. This makes sense, I guess, because the Back Up Fuse was basically not there, because it was blown.

I remember reading somewhere that the ECU stores a history of the driving performance, or something, and bases its operations on that somewhat. (some guy was saying on a forum that he took his recently reset ECU in his car to get his emissions checked and they said he had to come back, or something). Is that even remotely factual?

Hmm... this is perplexing. I wish there were some way to test to see if it this changed the engine's fuel mixture at all without taking it in to get smog-checked again.
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Old 08-15-2009, 07:35 AM   #12
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Well, I can't say for sure, but I failed emissions once because I forgot to remove the jumper from the service check connector. This was back when I was still running stock-ish OBD-0 engines/ECUs, which have no indicator that it's in service mode beyond the jumper itself.

Yes, I've read that some ECUs use cumulative fuel trim functions... OBD-2 ECUs definitely do, OBD-0 definitely do not. I'm not sure about OBD-1, but I'm leaning toward do... The fed. emissions VX ECU in particular with its additional processor and wide-band sensor.
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Old 08-19-2009, 09:08 PM   #13
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Just a thought...could it be that the catalytic converter is just plain worn out?

As for the mechanic being confused, that seems to be a common problem. When I take a car to a mechanic (a rare situation, usually happened when I was commuting 200 miles a day and working 70 hours a week, back in my former life as a retail store manager), about half the time I have to fix their "repair" so the car will run right.
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Old 08-19-2009, 09:33 PM   #14
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Quote:
Originally Posted by JoeBob View Post
Just a thought...could it be that the catalytic converter is just plain worn out?

As for the mechanic being confused, that seems to be a common problem. When I take a car to a mechanic (a rare situation, usually happened when I was commuting 200 miles a day and working 70 hours a week, back in my former life as a retail store manager), about half the time I have to fix their "repair" so the car will run right.
It is my understanding that the catalytic converter affects CO and NOx levels more than hydrocarbons. While those levels indicate that my Catalytic converter is relatively depleted, it still has enough life in it to pass the emissions test.

The failure is being caused only by abnormally high HC emissions only in 2nd gear at ~2300 rpm. This, along with the greatly changed %O2 and %CO2 readings indicate that the fuel mixture is changing drastically on the 25mph portion of the test, most likely because the VTEC is engaging.

But as for your comment about mechanics, I am definitely being very cautious, and saying "I have a VX, the only Honda with this particular VTEC-E engine sold in the USA. Are you sure you know how to fix it?". Mechanics are extremely optimistic before they get your money, I have discovered. I am also being very careful to find out exactly what things they do to the car.

I am taking it to another place tomorrow, which will hopefully have enough knowledge to troubleshoot the VTEC system's functioning and proper tuning.

Thanks for your comment!
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Old 08-20-2009, 07:00 AM   #15
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If it's only happening in 2nd gear...I wonder if you could hack in a 2nd gear lockout and stick a label on your shifter with a new shift pattern? You won't be fooling the guy doing the inspection, but you'll give him the excuses he needs to pass you; he'd be driving the car as you've modified it...

It's not like you cruise around in 2nd gear at 2300 RPM, so it's not like you'll be pumping out an inappropriate volume of pollution.
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Old 08-20-2009, 09:54 PM   #16
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Do you have a shop manual for your car, or barring that, a Haynes manual? (Don't get the large Chilton manual if you can help it, the information will probably be in there, but it'll take you hours to find it!)
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Old 08-20-2009, 10:02 PM   #17
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Do you have a shop manual for your car, or barring that, a Haynes manual? (Don't get the large Chilton manual if you can help it, the information will probably be in there, but it'll take you hours to find it!)
Hi,
I believe that the manual I linked to in my first post is the "official" shop manual. If you know this not to be the case, please correct me, and if you could, point me to the correct service/shop manual for for the Civic VX, if it exists on the internet.


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If it's only happening in 2nd gear...I wonder if you could hack in a 2nd gear lockout and stick a label on your shifter with a new shift pattern? You won't be fooling the guy doing the inspection, but you'll give him the excuses he needs to pass you; he'd be driving the car as you've modified it...

It's not like you cruise around in 2nd gear at 2300 RPM, so it's not like you'll be pumping out an inappropriate volume of pollution.
One of my first ideas was to just ask the Smog Technician to run the 25mph test in 1st gear, but when asked about that, they informed me that the RPMs for the test had to be between 2000-3000 rpm. Needless to say, with the VX transmissions, 1st gear @ 25mph is about 4000 rpm, and 3rd gear @ 25mph would be lugging the engine pretty significantly.

By 2nd Gear Lockout, you just mean essentially disabling 2nd gear right?
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Old 08-21-2009, 07:41 AM   #18
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If they do 25mph per the dyno and not per the speedo, just borrow some bigger wheels/tires to put on the front.
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Old 08-21-2009, 08:16 AM   #19
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Quote:
Originally Posted by badur View Post
By 2nd Gear Lockout, you just mean essentially disabling 2nd gear right?
Yes, that's exactly what I meant.

I just ran the numbers into a gear calculator and there's no way you're getting either 1st or 3rd into the 2000-3000 range for the test, but the point of my idea was to change your RPM.

RW's idea of using a different tire size might work; it will change the RPM of your engine at 25 if the speed is measured at the dyno, or the load if the speed is measured on your speedometer...either one of which may change the emissions.
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Old 08-21-2009, 04:33 PM   #20
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Here is the latest update in my epic sad tale of Civic VX emissions malfunction.

I took my car another mechanic shop that turned out to be a lot more competent with Honda engines than the previous place. They informed me of the following discoveries:
(this is the description of the problems I got on the invoice): "Lab Service - Diagnose for smog failure. Technician found no oil pressure to VTEC Solenoid even with power applied to it, EGR solenoid not ground by ECM, which cause higher NOX emission. Also notice cylinder head had been drill where VTEC solenoid go. Need new ECM and cylinder head tear down for further inspection since head gasket had been replaced."

So the spool valve (VTEC Solenoid) has no oil pressure, which is resulting in the VTEC mechanism not engaging. The Code 22 that the ECU is throwing every time I rev the engine under load is being thrown because the VTEC is trying to engage, and is not able to. The guy said he tested the spool valve and the oil pressure switch, and both are mechanically and electrically functional, and the screens are not clogged or obstructed (as I established when troubleshooting the problem myself). However, he says that they even tested the spool valve under load, and only a dribble of oil was coming out, where there should have been at least 57 psi.

The head gasket was replaced by Chevron Nisqually Automotive and Towing @ 132,000 miles (the car has 190,000 now). The tech thinks that they may have put the wrong head gasket in the engine, which might be missing the holes necessary for oil to get to the VTEC Solenoid, causing there to be no oil pressure there.

Additionally, the EGR Valves are not functioning as they should. The tech says that this is being caused by the ECU controller, and not by any fault with the valves themselves, or the wiring to the valves. He says a new ECU is necessary to fix that. He says that these problems are causing the engine to misfire, resulting in high NOx and high HC emissions levels.

He also mentioned something about a hole being drilled or enlarged in the cylinder head underneath the spool valve assembly. I have no idea what this is about... but it frightens me.

Even with all of these things wrong with the engine, I have still been getting around 40 MPG in mixed driving. I am excited to find out just how much better the car will drive when it is running properly! I am also kicking myself for paying as much as I did for the car, and for not finding out what was wrong with it from the seller (who I am pretty sure purposefully put a blown fuse in the ECU Reset fuse holder). I guess next time I buy a VX, I will know exactly what to look for.

So my plan (since I am poor, and can't afford to pay 800 dollars to have a mechanic take apart my engine and replace the head gasket) is to attempt to do it myself. My Dad (who lives nearby) has all the necessary tools, and a fair amount of experience with engines, and I think that this combined with a healthy amount of research into online tutorials, and having a couple shop manuals on hand will be enough for us to do it without breaking anything.

And I guess I am also in the market for a VX Federal ECU (P07-A00 [manual transmission] or P07-A01 [auto transmission, should still work with my manual trans, right?]), if anyone has one that they want to sell.
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