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-   -   94 Civic VX smog troubles (https://www.fuelly.com/forums/f10/94-civic-vx-smog-troubles-12807.html)

mcc6 08-03-2010 12:02 AM

Re: 94 Civic VX smog troubles
I decided to do the valve adjustment, change of spark plugs, and EGR cleaning since those are good maintenances things to do anyway, and he only charged $50. After doing them, he said it appeared necessary for all three. He also opened up the cat and said it looked fine. Also, I hear no misfiring while listening at idle, nor do I feel it while driving. Mechanic said it would be obvious if I have any misfiring.
Day before my last day to do smog retest I filled up tank with premium and did an oil change. Did the test at 9am after driving for 45 min, but still failed the test (worse than original).

One thing I recently noticed is that the car idles above 1000rpm when I first start it up. But then as I drive around, it gets lower at each stop light. After about 10min of driving it goes down to where it should be.
BTW, I'm going to take the car to a Honda master tech to get a definitive answer in regards to the new distributor/wires/timing. Those were put in recently, but the O2 sensor was put in 2 years ago.

Here' are my questions. If the O2 sensor is not the correct NGK replacement, should I assume that's my problem and just buy one?
If not, how do I check if I the one I have is working? First I have to buy a DMM. :)
I've tried to find threads about testing the O2 sensor, but I only seem to come across info relating to converting from CA to Fed VX. Should I be testing voltage right at the ECU, or should I be directly testing the wires from the sensor?
Step by step instructions is what I'm after. Maybe I'm asking for too much help and don't know enough to make use of these forums. :(

add|ct 08-07-2010 01:46 PM

Re: 94 Civic VX smog troubles
Any updates?

You have a fed VX getting tested in CA, right?

It looks like you may need to bite on the sensor. I'd still run a can of top end engine cleaner before you install a new sensor, but only a foam like the Mopar CCC or Amsoil's Power Foam. Both are still available either at the dealership(Chrysler/Dodge/Jeeps for the Mopar) or online(Amsoil website for the Power Foam) and are fairly easy to do for less than $10 in either case.

Just an idea so that a new sensor may not get clogged as quickly. These won't last but 2-3 years, it seems, in a high mileage VX.

Here's something that may be helpful from the forums here, I suggest reading all of the posts:


mcc6 08-08-2010 01:59 AM

Re: 94 Civic VX smog troubles
Yup, fed VX in CA. Still need to see what Honda master tech has to say about the distributor. What are the correct spark plug wires, btw? I found a guy that's selling a TD-42U distributor and NGK wires for $100 total. I shouldn't buy them if they are used, right?
With the helmes manual in tow, I plan to check the o2 sensor through the ECU with a DMM. The manual says to connect the "test harness" to the ECU. Is that already there in the same place as the ECU, or do I have to go out and buy one? I suppose I'll find out once I dive in.

add|ct 08-08-2010 08:31 AM

Re: 94 Civic VX smog troubles
I have no experience doing that personally, so I'd check around the forums here or over at honda-tech via a search to see if anyone has a walk-through for testing voltage at the ECU and hopefully it will at least explain the terminology.

I wouldn't buy a used distributor or pack of wires. Like the thread linked above brought out, the VX is very picky about having the right wires.

I wouldn't use Bosch or AC Delco. Get the NGK, or Sumitomo wires from the dealer/the Honda tech you found; he should be able to buy them. They are the Sumitomo, but will probably cost more than even NGK. I got them and they work great.

As for the distributor itself, it would cost you more than $100 new alone, but with anything used you are putting your money at risk, let alone your car. I doubt he'd be selling them for anything more than 'as is'. Make sure the part number for the NGK is the right one if you go that route instead of the Sumitomo.

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