I did some searches on this, but I still have some questions I was hoping some more experienced people might be able to help with.
I tested my 1994 Civic VX this last weekend and it failed the NO portion of the test. From what I read the EGR is the main culprit for these types of failures. I found a guide for cleaning the EGR passages which involved removing these plugs in the EGR rail, but my intake does not appear to have these plugs. About a year or two ago I pulled my EGR valve off and inspected it do to an intermittent EGR code that would come and go, usually on the freeway, 5th gear at a steady rpm. The EGR was clean and not frozen.
I guess what I'm looking for is a VX specific EGR system troubleshooting guide. Also, how can i verify that my cat is in good shape? I've owned the car since Sept 2006 and have never personally replaced it. Car has the proper VX plugs, gapped properly, clean air filter.
Here are the results.
TEST RPM %CO2 %O2 HC ppm CO % NO ppm
me me me max ave me max ave me max ave me
15mph 2686 11.5 4.5 97 21 15 .59 .06 0.00 731 150 1146
25mph 2382 11.6 4.2 62 13 11 .59 .05 0.00 798 136 1288
How's the catalytic converter? I've failed the NOx test a couple times and a new cat fixed it. Usually this is the case when the car just barely fails the NOx test. Also, was the car cool or warmed up when you took it in? One time, I had a car fail, the smog guy told me to take it out on the freeway for about half an hour, and come back. Lo and behold, it passed. Seems that catalytic converters work better when they are good and hot.
All this is assuming that your EGR is working properly.
__________________ "We are forces of chaos and anarchy. Everything they say we are we are, and we are very proud of ourselves!" -- Jefferson Airplane
Dick Naugle says: 1. Prepare food fresh. 2. Serve customers fast. 3. Keep place clean.
i usually drive my car quite a bit also right before the test. when i had trouble passing smog it ended up being my ecu was not sending signal to egr solenoid. if u idle your car and activate the egr the car should stall.
can you separate out each measurement a little? I'm having issues figuring out the columns. I'm asking cause even if the other measurements pass, they can help indicate problems.
a bandaid converter fix is to (and I've done this to a car with before/after OBDII cat test and sniffer test successfully):
*warning: you can finish off the cat this way too. it is very much a do at your own risk thing to do. I'm sure if you try hard enough you can cause all sorts of unpleasant things to happen. do this only as a last resort and of your own violation. YOU HAVE BEEN WARNED*
1. warm up the engine and converter. drive around some. pull over and open the hood.
2. disconnect one spark plug and rev up the engine a little... purpose being to dump unburnt fuel into the cat while it's nice and toasty, making it much more toasty.
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
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"You don't get to judge me for how I fix what you break"
Ok found the FSM, went through the EGR pages and followed the troubleshooting flow chart. Found that the EGR diaphragm would not hold vacuum. So looked into a new valve, ~$240. A little more then i was looking to spend. I went to the local auto yard, found a earlier civic, i'd guess it was a 88-90 era 4 door. It had a EGR valve that was close enough to work. Everything was the same except for the EGR vac hose was on the other side of the valve.
Retested yesterday. All values remained the same (passing) except for the NOX, which dropped to 418 and 602.