Just failed IM240
Thread Starter
Advanced
Joined: Apr 2001
Posts: 89
Likes: 0
From: Romeoville IL
Just failed IM240
I just got back from emmissions,not good,CO standard(15),mine(25.7),HC standard(.80),mine(.86). When I got back I pulled the codes and found a code 32(EGR problem), no driveability problems, do you think I should replace the EGR and try again or just go with the methanol in the tank?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Just failed IM240 (91Yellow1)
I just returned with my IROC LB9 from the Ohio E-Check. It failed on the first pass with high HC and very high CO due to a bad O2 sensor. With a new O2 sensor and 16oz of Methanol in the tank it passed HC and CO was barely present.
I would serivce the EGR first. Reset the ECM and see when the code returns. If at idle it is likely the valve or solenoid; if above 2,000rpm driving check the temperature sw too.
If you want to try as is, add a can or two of methanol and hold the idle at about 1,200rpm while waiting to be tested; this will assure the O2 sensor and cat are heated properly as they tend to cool off a little during a long 600rpm idle.
I would serivce the EGR first. Reset the ECM and see when the code returns. If at idle it is likely the valve or solenoid; if above 2,000rpm driving check the temperature sw too.
If you want to try as is, add a can or two of methanol and hold the idle at about 1,200rpm while waiting to be tested; this will assure the O2 sensor and cat are heated properly as they tend to cool off a little during a long 600rpm idle.
Race Director
Joined: Mar 1999
Posts: 12,597
Likes: 237
From: Bartlett Illinois
Re: Just failed IM240 (91Yellow1)
how long did your run the car before going through the E-Check?
I think if you FIX the EGR it should pass.. if you have an AFPR you might want to lean it a bit and that may help...
I think if you FIX the EGR it should pass.. if you have an AFPR you might want to lean it a bit and that may help...
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Just failed IM240 (91Yellow1)
91Yellow1, that's the same sympom my Vette had the first time I had it on the highway. The Chevy dealer in Mesa, AZ put in a new EGR valve.
Sorry for my misquote above, I should have said Isopropyl (the major component in dry gas), not Methanol. My Mr. Goodwrench friend in Barberton, OH told me to use about 16oz of Isopropyl in a tank of gas, or more if CO is realy bad. I think you could get by with 16 oz in 1/2 tank of fuel (take the level up to about 1/2 tank with 93 octane).
[Modified by 65Z01, 2:54 PM 1/28/2002]
Sorry for my misquote above, I should have said Isopropyl (the major component in dry gas), not Methanol. My Mr. Goodwrench friend in Barberton, OH told me to use about 16oz of Isopropyl in a tank of gas, or more if CO is realy bad. I think you could get by with 16 oz in 1/2 tank of fuel (take the level up to about 1/2 tank with 93 octane).
[Modified by 65Z01, 2:54 PM 1/28/2002]
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Just failed IM240 (91Yellow1)
We don't have to pass those the only # I have is for nox 530.5
So you are running a little rich, but was the car cold and what rpm did they take it to on the treadmill? If you get the car to lean out a little your NOx will go up, but it seems you may have some room.
EGR is there to control NOx, so right now it's not a problem as they either botched the test or the rich mix was keeping it cool. Did you go in with the SES light on?
What are the mods on the car?
Engine must be fully warmed up then testing!
Good Luck,
Pete
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Mar 2000
Posts: 1,630
Likes: 1
From: Woodstock GA
Re: Just failed IM240 (91Yellow1)
Do you still have the factory cat on the car? It just sounds like you have removed the cat It is possible the O2 sensor is getting slow but I see you have a dual exhaust need to know what has been done. An IM240 test both NOX and weather the Cat is still there and working. I have seen L98s almost pass with out the cats. Now if the EGR is not working you could fail for NOX and seeing how you have a code 32 I suspect the EGR is not working, now the engine may have been running cool enough not to fail the NOX but if you retard the timing to try to pass HC and CO you just may fail NOX. But first need to know if the factory cat is still on the car.
David Fulcher
David Fulcher
Advanced
Joined: Jan 2002
Posts: 87
Likes: 0
From: Belleville Illinois
Re: Just failed IM240 (David-F)
I also thought that the point of running them on the dyno was to check nox, but in Illinois, they have im240 and don't give any readings on nox.
High co's is caused by rich mixture, need to check your o2 sensor, maybe it's sluggish. My Firebird they had to run it on the dyno twice back to back to get it to pass. How about your air filter, look for things that will cause it to be rich. I bet if you get the co's down the hc's will come down some too. I was told by my dealer that the alcohol and retarded timing was good for lowering HC's.
Good Luck!
High co's is caused by rich mixture, need to check your o2 sensor, maybe it's sluggish. My Firebird they had to run it on the dyno twice back to back to get it to pass. How about your air filter, look for things that will cause it to be rich. I bet if you get the co's down the hc's will come down some too. I was told by my dealer that the alcohol and retarded timing was good for lowering HC's.
Good Luck!
Burning Brakes
Joined: Nov 2000
Posts: 855
Likes: 0
Re: Just failed IM240 (CFI-EFI)
Where does one buy isopropyl? I've seen it refered to as "dry gas" here on the forum. What type of store sells it? Ask for it as anything else?
Thread Starter
Advanced
Joined: Apr 2001
Posts: 89
Likes: 0
From: Romeoville IL
Re: Just failed IM240 (CFI-EFI)
Sorry guys the #'s I posted before(530.5) was CO2 not nox ,we only have to pass HC and CO tests.To answer some more questions:My cat is M.I.A.,I have a new K&N with open lid,air foil, and elims. that is the only mods I have. I tried going back through with alcohol in the tank and here is what happened, HC:Standard.80,mine:4.24(got worse) CO:standard 15.0,mine 11.4(much better than before).I guess I will have to get some cheese and try to catch a cat :lol: Wait I guess I have to catch the mouse then the cat :D
[Modified by 91Yellow1, 7:03 AM 1/29/2002]
[Modified by 91Yellow1, 7:03 AM 1/29/2002]
Le Mans Master
Joined: Nov 1999
Posts: 8,512
Likes: 3
From: Memphis, Tn
Re: Just failed IM240 (Rick86)
Where does one buy isopropyl? I've seen it refered to as "dry gas" here on the forum. What type of store sells it? Ask for it as anything else? It's rubbing alcohol, but parts stores sell it for twice as much as drug store and its marketed as water remover for gas tank.
Le Mans Master
Joined: Dec 1999
Posts: 8,540
Likes: 1
From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Just failed IM240 (91Yellow1)
I tried going back through with alcohol in the tank and here is what happened, HC:Standard.80,mine:4.24(got worse) CO:standard 15.0,mine 11.4(much better than before).
Also CO2 is usually measured in %. 530.5 does sound like a NOx measurement, as in ppm. 530 does not make sense as a CO2 measurement.
What was actual HC measurement this time?