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1989 7mgte swapped mk3
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Discussion Starter · #1 ·
well I failed today and i'm not sure what to do. I had the cat replaced a year ago so it's probably not that. The EGR valve is probably 3-4 years old along with the vacuum modulator. I only failed the nox with a 1479 with only 984 allowed. I also went inside the throttle body and cleaned out some of the ports before I went in today...thanks
 

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hmmm

we need more than NOx

we need HC and CO number also.
 

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1989 7mgte swapped mk3
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Discussion Starter · #3 · (Edited)
ok here all of them are...

25/25 test @ 2886 RPM

HC: 57 with 140 allowed
CO .14 with .89 allowed
NOX 1479 with 984 allowed
CO+CO 14.8 with 6.0 min.

50/15 test @ 1771 RPM
HC 59 with 144 allowed
CO .14 with .81 allowed
NOX 1007 with 1077 allowed
CO+CO 14.7 with 6.0 min
 

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1989 7mgte swapped mk3
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Discussion Starter · #5 ·
so the egr valve is not working correctly? Is that why nox passed at a lower RPM, but when it came up it failed?
 

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1989 7mgte swapped mk3
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Discussion Starter · #6 ·
is there anything to do to fix the EGR valve or should I just replace it...again...ugh
 

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Supras are never 'done'
1989 Toyota Supra
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Don't just replace it without doing some diagnosis. That's nothing but a waste of money. Use the TSRM and figure out specifically where the problem is. It could be something as simple as a vacuum line hooked up wrong.
 

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1989 7mgte swapped mk3
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Discussion Starter · #8 ·
alright...I do have a vacuum tester thing so i'll check all the lines then check vacuum on them...
 

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Supras are never 'done'
1989 Toyota Supra
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601 Posts
hornet7288 said:
alright...I do have a vacuum tester thing so i'll check all the lines then check vacuum on them...
Be sure to verify the routing against the TSRM as well. Also I believe they outline a test procedure for the modulator and the valve.
 

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sounds like it could be the cat. o and just to let you know on most smog tests your egr valve will only cause a problem if its stuck open. During a smog test the EGR isnt usually in operation. If the egr was the problem the HC would go up becuase itd be lean. My guess is your Three way cat has melted into a two way cat causing the nox to go up.
 

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o and the way to test an EGR for a leak is pull it off and put water on the pintle of the valve. If it leaks the water its bad, carbon fouled.
 

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damn sorry to steal the thread but i just got my can inspected and failed the HC, any suggestions?

NOx 920 out of 1077 allowed
HC 184 out of 144 allowed
CO .77 out of .81 allowed
 

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High HC is usually running rich. HC means raw fuel. If you lean it out expect the NOx to go up. Hmm you running a cat? Those numbers look damn high.
 

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HC doesnt really mean anything, if your lean HC is high, if your rich HC is high. You need to look at the CO. His CO is low, meaning that not much fuel got burned. My guess is check for a leaky egr or egr gasket. seems as if you running lean.


BTW im not making this up, just graduated wyotech. Advanced engine diagnostics. The last half was like a 7 month smog class
 

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so do you think HC has anything to do with me running higher octane and maybe old plugs? also should i just see if champion can get me a new egr or is that just not worth it
 

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no, your pretty close. Id do a tune-up (plugs, wires, filter, oil) and run some injector cleaner and see what happenes
 
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