Trying to pass smog. 8 months of failing
#26
HAILERS
Join Date: May 2001
Location: FORT WORTH, TEXAS,USA
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88NON TURBO...........Fully warm up the engine. Idle the car. Pull the large black hose off the bottom of the ACV. Feel for air. There should be only a minor amount of air coming out that large nipple.
Now pull the BLUE electrical plug off the relief solenoid on the other side of the engine. Now a Large amount of air should come out the large nipple on the bottom of the ACV. Proves the solenoid is working and part of the ACV is working.
Put the elect plug back on. Now at idle, pull the two vacuum lines that are just above the ACV off. One at a time. Both vacuum hose should have a vacuum on them. Feel for it with your fingers. IF both have a vacuum, that is good. Put the hoses back on.
Now at idle feel for the air coming out the bottom large nipple. Rev the engine over 3800rpms. At approx 3800rpm the air coming out the large nipple should really blow out hard, proving the relief solenoid is working and the ECU is operating the swtching and relief solenod and acv right.
What you also might do, is look at the voltage coming from the 02 sensor at idle. It should be close to zero. Now pull the plug off the blue relief sonenoid. Now the 02 sensor should read rich. Like 0.7 or 0.8vdc. Because NOW there is no air going to the exhaust ports located prior to the 02 sensor and the airpump air is now being sent overboard into the right fenders silencer.
If the ACV works as above, then it is the catalytic converter gone kaput or a seriously malfunctioning engine running too rich. You know there is a variable resistor on your car? It controls idle mixture. It has a R and L screw that mean just what you think. Turn to L til the engine starts stumbling a touch and then back til the engine is steadier at idle. Might help. Might not. Just a main cat should do the job if things are right with the engine..
Now pull the BLUE electrical plug off the relief solenoid on the other side of the engine. Now a Large amount of air should come out the large nipple on the bottom of the ACV. Proves the solenoid is working and part of the ACV is working.
Put the elect plug back on. Now at idle, pull the two vacuum lines that are just above the ACV off. One at a time. Both vacuum hose should have a vacuum on them. Feel for it with your fingers. IF both have a vacuum, that is good. Put the hoses back on.
Now at idle feel for the air coming out the bottom large nipple. Rev the engine over 3800rpms. At approx 3800rpm the air coming out the large nipple should really blow out hard, proving the relief solenoid is working and the ECU is operating the swtching and relief solenod and acv right.
What you also might do, is look at the voltage coming from the 02 sensor at idle. It should be close to zero. Now pull the plug off the blue relief sonenoid. Now the 02 sensor should read rich. Like 0.7 or 0.8vdc. Because NOW there is no air going to the exhaust ports located prior to the 02 sensor and the airpump air is now being sent overboard into the right fenders silencer.
If the ACV works as above, then it is the catalytic converter gone kaput or a seriously malfunctioning engine running too rich. You know there is a variable resistor on your car? It controls idle mixture. It has a R and L screw that mean just what you think. Turn to L til the engine starts stumbling a touch and then back til the engine is steadier at idle. Might help. Might not. Just a main cat should do the job if things are right with the engine..
#28
Rotary $ > AMG $
iTrader: (7)
your thread has been helpful.
you seem to me that your running really lean, getting 24 mpg is crazy to me, i get 18 on the freeway at best, 14 in the city.
oh and i would pass in texas, my car could pass under those #'s
so do i need the two pre cats to be functional?
the first one is empty, the second is intact but useless...
this is the cat that i bought, that has been on the car. is this is correct part?
http://www.performancepeddler.com/de...CT_ID=MAG23688
you seem to me that your running really lean, getting 24 mpg is crazy to me, i get 18 on the freeway at best, 14 in the city.
oh and i would pass in texas, my car could pass under those #'s
so do i need the two pre cats to be functional?
the first one is empty, the second is intact but useless...
this is the cat that i bought, that has been on the car. is this is correct part?
http://www.performancepeddler.com/de...CT_ID=MAG23688
At what stage of your odyssey did you replace the cat? I am afraid that if you replaced it prior to all your other fixes, you may have cooked it.
I have trouble believing the cat is working because the NOx numbers would be very very low. Rotaries are inherently low NOx producers. My front brick, the one that reduces NOx was completely crumbled and still my NOx was a pass. Your NOx numbers look like the cat is not working at all.
The two front pre-cats are intended to heat up and light off very quickly after startup, reducing emissions during a cold start. You do not need them to function to pass a sniffer test. You do need them to pass the visual portion of the test. Just remove them and completely gut the housings, then reinstall.
The cat I used is universal and was sized for a very large V8 engine and a large vehicle, 7.4 L (460 ci) and 7000 lb.
http://www.autozone.com/selectedZip,.../selectZip.htm
The theory was told to me by Jerry at Jerry's Muffler in Lewisville, TX. Jerry is a stand-up high performance exhaust guy (He also does a helluva good job with high performance 4 wheel alignments) Jerry told me that ALL modern brick type cats are by default high-flow design. He said that what I needed for my Rotary was a high flow and HIGH CAPACITY cat-that way the bricks would be larger and beefier spreading the reduction and oxidation reactions over a larger surface area. This would effectively reduce the surface temperature on the bricks, thereby extending the life of the cat. It was good advice. I am on my third test with the same cat, 2nd year of actually running on the car.
BTW, in case i hurt your feelings, Santa doesn't really hate you.
#29
Rotary Gearhead
iTrader: (6)
It's best to check it with a lab scope, and since most people don't own one, it is usually checked with a multimeter. You can do a resistance check or a voltage check, either one will do. Since you're local I can check it with my lab scope if you like. Send me a pm if you're interested. I can also show you how to check your coolant sensor and both IAT sensors
#30
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thanks everyone
alright, well i guess i need to slap some money down on a big beefy cat then....
ill let you know what the results are, thanks for the help
honestly i could care less about an rx7, i just love the motor. look at my avatar, i deal with a v8 enough already
ill let you know what the results are, thanks for the help
honestly i could care less about an rx7, i just love the motor. look at my avatar, i deal with a v8 enough already
#32
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once again
Alright i cot another cat and welded it in front of the main cat.
Problem is it didn’t really change the number that much.
i still feel that my motor is consuming to much fuel, and that is why my hydrocarbons are way too high.
After running my new setup the new cat, which im going to cal a pre cat. got very hot, to point of glowing red, i dont want to destroy this cat.
basically im looking to run leaner so i can pass smog, any suggestion on this would help.
pictures of my new setup
(the first pre cat is still on the car, but it has no brick in it)
Problem is it didn’t really change the number that much.
i still feel that my motor is consuming to much fuel, and that is why my hydrocarbons are way too high.
After running my new setup the new cat, which im going to cal a pre cat. got very hot, to point of glowing red, i dont want to destroy this cat.
basically im looking to run leaner so i can pass smog, any suggestion on this would help.
pictures of my new setup
(the first pre cat is still on the car, but it has no brick in it)
#33
Meoff Jack
Join Date: Mar 2007
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i failed smog 2 times the 3rd time i passed...what i did was get new cats....(2 new cats)....it made a huge difference on my numbers...hope this helps.
[edit]
oh wait you already did that...hahaah..sorry i was too slow..
[edit]
oh wait you already did that...hahaah..sorry i was too slow..
#37
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How I Passed
this is what I did
8 gallons of gasoline
2 gallons of methanol mixed in the tank
results
15mph HC 10 CO .03 NO 49
25mph HC 17 CO .12 NO 29
passed with no problem
PS. the ratio is critical, I first showed up with 4 gall of gasoline and 2 gall of methanol, the car ran like **** and wouldn’t run stable on the dyno
As for anyone who wants to try this method just remember that Methanol is corrosive to aluminum and should not be left in the car for any long period of time.
8 gallons of gasoline
2 gallons of methanol mixed in the tank
results
15mph HC 10 CO .03 NO 49
25mph HC 17 CO .12 NO 29
passed with no problem
PS. the ratio is critical, I first showed up with 4 gall of gasoline and 2 gall of methanol, the car ran like **** and wouldn’t run stable on the dyno
As for anyone who wants to try this method just remember that Methanol is corrosive to aluminum and should not be left in the car for any long period of time.
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