88 GTU failed emissions
#1
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
88 GTU failed emissions
Here's my read out from 2 years ago:
15 mph:
RPM - 1817
%CO2 - 14.4
%O2 - 0.45
HC - 58 (118 max)
CO - 0.28 (0.75 max)
NO - 169 (799 max)
25 mph:
RPM - 1973
%CO2 - 14.39
%O2 - 0.48
HC - 62 (93 max)
CO - 0.30 (0.63 max)
NO - 193 (738 max)
Here's todays:
15 mph:
RPM - 1803
%CO2 - 14.2
%O2 - 1.0
HC - 91 (118 max)
CO - 0.49 (0.75 max)
NO - 94 (799 max)
25 mph:
RPM - 2041
%CO2 - 14.3
%O2 - 0.8
HC - 100 (93 max) FAILED
CO - 0.35 (0.63 max)
NO - 70 (738 max)
So the things that changed from 2 years ago....
Then:
Exhaust leak on edge of main cat
Pulling coolant into chambers
Pushing exhaust into coolant
Now:
Gutted pre-cats
Same main cat with leak on crimped edge
Freshly rebuilt motor with no leaks
Do you think it was the gutted pre-cats? I gutted them because the honeycomb melted and clogged them up. The main cat seems to have come uncrimped or something on an edge, so it leaks. Also the pre-cats have a hole in the bottom of each one?? It looks like a manufactured punched hole about 1/4" diameter.
Ideas?
15 mph:
RPM - 1817
%CO2 - 14.4
%O2 - 0.45
HC - 58 (118 max)
CO - 0.28 (0.75 max)
NO - 169 (799 max)
25 mph:
RPM - 1973
%CO2 - 14.39
%O2 - 0.48
HC - 62 (93 max)
CO - 0.30 (0.63 max)
NO - 193 (738 max)
Here's todays:
15 mph:
RPM - 1803
%CO2 - 14.2
%O2 - 1.0
HC - 91 (118 max)
CO - 0.49 (0.75 max)
NO - 94 (799 max)
25 mph:
RPM - 2041
%CO2 - 14.3
%O2 - 0.8
HC - 100 (93 max) FAILED
CO - 0.35 (0.63 max)
NO - 70 (738 max)
So the things that changed from 2 years ago....
Then:
Exhaust leak on edge of main cat
Pulling coolant into chambers
Pushing exhaust into coolant
Now:
Gutted pre-cats
Same main cat with leak on crimped edge
Freshly rebuilt motor with no leaks
Do you think it was the gutted pre-cats? I gutted them because the honeycomb melted and clogged them up. The main cat seems to have come uncrimped or something on an edge, so it leaks. Also the pre-cats have a hole in the bottom of each one?? It looks like a manufactured punched hole about 1/4" diameter.
Ideas?
#2
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Oh, it's also got a large streetport from the Pineapple template.
Gonna go test the O2 sensor with a multimeter on the green plug. If the O2 sensor is bad, that could be it.
This really sucks.
Gonna go test the O2 sensor with a multimeter on the green plug. If the O2 sensor is bad, that could be it.
This really sucks.
#3
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Well, O2 sensor is alternating what appears to be normally. It's only got about 10k miles on it anyways.
I took the main cat off and welded up the seam that was leaking.
I'm still getting a fffft ffffft sound from the cat at idle after warmed up.
I took the main cat off and welded up the seam that was leaking.
I'm still getting a fffft ffffft sound from the cat at idle after warmed up.
#5
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,948
Received 2,678 Likes
on
1,895 Posts
it still could be the o2 sensor. you may try playing with the AFM, or buy an SAFC or something too.
actually since NOX is so low, maybe advancing the timing would work, NOX WILL go up, but maybe the other two will go down enough, if you had a free retest i'd try that, if not SAFC
#7
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
since HC, CO and NOx are all still low, but HC and CO went up, but NOx went down, it might be a little lean.
it still could be the o2 sensor. you may try playing with the AFM, or buy an SAFC or something too.
actually since NOX is so low, maybe advancing the timing would work, NOX WILL go up, but maybe the other two will go down enough, if you had a free retest i'd try that, if not SAFC
it still could be the o2 sensor. you may try playing with the AFM, or buy an SAFC or something too.
actually since NOX is so low, maybe advancing the timing would work, NOX WILL go up, but maybe the other two will go down enough, if you had a free retest i'd try that, if not SAFC
I've been told that I need more miles on the rebuild (it's got about 30 miles on it now) and the HC will come down. Also, how would running 91 octane instead of 87 octane (currently 1/4 tank of 87) affect it? I also realized this morning that my air filter was still on the workbench and not in the car. Geez, how many different ways can I screw up this test?? lmao
Thanks for your input, guys!
Last edited by Jet-Lee; 05-04-12 at 09:32 AM.
Trending Topics
#11
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,948
Received 2,678 Likes
on
1,895 Posts
advancing the timing does get the combustion process started earlier, which SHOULD offer a more complete burn, which SHOULD lower HC and CO. NOX will go up about 200 for every 5 degrees of timing, but you have tons of room there, so it should be fine.
and actually you're so close you might just be able to get it hotter and pass
#14
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Turns out my TPS was horribly off (low). I adjusted it back up to ~1k ohm when hot at idle. I also advanced the ignition a tiny bit. It runs/idles sooo much smoother and stronger now!
Gonna have it re-sniffed tomorrow with premium (91) fuel.
Gonna have it re-sniffed tomorrow with premium (91) fuel.
#15
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,948
Received 2,678 Likes
on
1,895 Posts
good luck! the TPS runs the air control valve, so can make a big difference
#16
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Failed again.
CEL does not come on when the key is turned on.
It's not supposed to, it's an 88! Well, when I swapped in the dash from an S5, I musta put the S5 light cluster in as well, that would explain the fuel light coming on when the parking brake is set. Won't pass it despite documentation because the lens-icon-thingy is there "so it's supposed to light up".
The circuitry does not exist for it to light up!
Can't find my S4 light cluster.
FML.
CEL does not come on when the key is turned on.
It's not supposed to, it's an 88! Well, when I swapped in the dash from an S5, I musta put the S5 light cluster in as well, that would explain the fuel light coming on when the parking brake is set. Won't pass it despite documentation because the lens-icon-thingy is there "so it's supposed to light up".
The circuitry does not exist for it to light up!
Can't find my S4 light cluster.
FML.
#18
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Huge thanks to ROTARY POWERED for an S4 idiot light cluster!
#19
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
So....IAT....I hate you.
Found that it was disconnected, but car was running great. Once reconnected it ran like poo. It even died on the smog dyno and had to push the car out. It would NOT idle once warm.
Needless to say, I failed.
Managed to get it home, pulled the plug off the sensor, resistance seemed normal (~5k ohm). Left it unplugged, car improved. This is after fixing the TPS and advancing the CAS a little. I also had 91 in it. My HC's were in the 120's at both 15mph and 25mph.
Gonna go back today or tomorrow without the IAT (as I ran it originally) and with 87 (as I ran it originally) and see how it does then (after the TPS/CAS adjustment). It should pass just fine!
I'm thinking I need to reconnect the IAT at some point and adjust the CAS with a timing light. I just need a timing light. I'll bug someone local this weekend.
Found that it was disconnected, but car was running great. Once reconnected it ran like poo. It even died on the smog dyno and had to push the car out. It would NOT idle once warm.
Needless to say, I failed.
Managed to get it home, pulled the plug off the sensor, resistance seemed normal (~5k ohm). Left it unplugged, car improved. This is after fixing the TPS and advancing the CAS a little. I also had 91 in it. My HC's were in the 120's at both 15mph and 25mph.
Gonna go back today or tomorrow without the IAT (as I ran it originally) and with 87 (as I ran it originally) and see how it does then (after the TPS/CAS adjustment). It should pass just fine!
I'm thinking I need to reconnect the IAT at some point and adjust the CAS with a timing light. I just need a timing light. I'll bug someone local this weekend.
#20
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,948
Received 2,678 Likes
on
1,895 Posts
So....IAT....I hate you.
Found that it was disconnected, but car was running great. Once reconnected it ran like poo. It even died on the smog dyno and had to push the car out. It would NOT idle once warm.
Needless to say, I failed.
Managed to get it home, pulled the plug off the sensor, resistance seemed normal (~5k ohm). Left it unplugged, car improved. This is after fixing the TPS and advancing the CAS a little. I also had 91 in it. My HC's were in the 120's at both 15mph and 25mph.
Gonna go back today or tomorrow without the IAT (as I ran it originally) and with 87 (as I ran it originally) and see how it does then (after the TPS/CAS adjustment). It should pass just fine!
I'm thinking I need to reconnect the IAT at some point and adjust the CAS with a timing light. I just need a timing light. I'll bug someone local this weekend.
Found that it was disconnected, but car was running great. Once reconnected it ran like poo. It even died on the smog dyno and had to push the car out. It would NOT idle once warm.
Needless to say, I failed.
Managed to get it home, pulled the plug off the sensor, resistance seemed normal (~5k ohm). Left it unplugged, car improved. This is after fixing the TPS and advancing the CAS a little. I also had 91 in it. My HC's were in the 120's at both 15mph and 25mph.
Gonna go back today or tomorrow without the IAT (as I ran it originally) and with 87 (as I ran it originally) and see how it does then (after the TPS/CAS adjustment). It should pass just fine!
I'm thinking I need to reconnect the IAT at some point and adjust the CAS with a timing light. I just need a timing light. I'll bug someone local this weekend.
#21
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
So I grabbed an adjustable timing light from Harbor Freight.
I've got:
TPS set at 1k ohm at warm idle (was 400 ohm after first test)
CAS at 10 deg advanced (was 0 deg for first test)
IAT disconnected/hidden (same as first test)
1/4 tank of 87 octane (same as first test)
New air filter (same as first test)
It runs AWESOME! Hoping hoping hoping it passes tomorrow.
I've got:
TPS set at 1k ohm at warm idle (was 400 ohm after first test)
CAS at 10 deg advanced (was 0 deg for first test)
IAT disconnected/hidden (same as first test)
1/4 tank of 87 octane (same as first test)
New air filter (same as first test)
It runs AWESOME! Hoping hoping hoping it passes tomorrow.
#22
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
****!!!!
5/3/12:
15 mph:
RPM - 1803
%CO2 - 14.2
%O2 - 1.0
HC - 91 (118 max)
CO - 0.49 (0.75 max)
NO - 94 (799 max)
25 mph:
RPM - 2041
%CO2 - 14.3
%O2 - 0.8
HC - 100 (93 max) FAILED
CO - 0.35 (0.63 max)
NO - 70 (738 max)
5/9/12:
15 mph:
RPM - 1835
%CO2 - 14.3
%O2 - 0.6
HC - 149 (118 max) FAILED
CO - 0.27 (0.75 max)
NO - 145 (799 max)
25 mph:
RPM - 2047
%CO2 - 14.5
%O2 - 0.2
HC - 163 (93 max) FAILED
CO - 0.39 (0.63 max)
NO - 86 (738 max)
Today 5/11/12:
15 mph:
RPM - 1827
%CO2 - 14.2
%O2 - 0.7
HC - 61 (118 max)
CO - 0.35 (0.75 max)
NO - 94 (799 max)
25 mph:
RPM - 2049
%CO2 - 14.2
%O2 - 0.7
HC - 140 (93 max) FAILED
CO - 0.27 (0.63 max)
NO - 99 (738 max)
Differences between first (5/3) and last (5/11)...reset TPS from 400ohm to 1kohm and advanced the timing by 10 degrees.
Why did my HC's go UP?!
Do I just need a new damned cat??
5/3/12:
15 mph:
RPM - 1803
%CO2 - 14.2
%O2 - 1.0
HC - 91 (118 max)
CO - 0.49 (0.75 max)
NO - 94 (799 max)
25 mph:
RPM - 2041
%CO2 - 14.3
%O2 - 0.8
HC - 100 (93 max) FAILED
CO - 0.35 (0.63 max)
NO - 70 (738 max)
5/9/12:
15 mph:
RPM - 1835
%CO2 - 14.3
%O2 - 0.6
HC - 149 (118 max) FAILED
CO - 0.27 (0.75 max)
NO - 145 (799 max)
25 mph:
RPM - 2047
%CO2 - 14.5
%O2 - 0.2
HC - 163 (93 max) FAILED
CO - 0.39 (0.63 max)
NO - 86 (738 max)
Today 5/11/12:
15 mph:
RPM - 1827
%CO2 - 14.2
%O2 - 0.7
HC - 61 (118 max)
CO - 0.35 (0.75 max)
NO - 94 (799 max)
25 mph:
RPM - 2049
%CO2 - 14.2
%O2 - 0.7
HC - 140 (93 max) FAILED
CO - 0.27 (0.63 max)
NO - 99 (738 max)
Differences between first (5/3) and last (5/11)...reset TPS from 400ohm to 1kohm and advanced the timing by 10 degrees.
Why did my HC's go UP?!
Do I just need a new damned cat??
#23
Unconventional
Thread Starter
iTrader: (1)
Join Date: Apr 2010
Location: Visalia, CA
Posts: 329
Likes: 0
Received 0 Likes
on
0 Posts
Would that little variable resistor have an effect? Everything I can find indicates this is a lean condition, but all my vacuum lines are brand new, injectors are freshly cleaned. The variable resistor is turned all the way left (lean?).
Another $35, and the shop is closed this weekend. I'll find another one.
This is a FRESH rebuild, everything new. It shouldn't be doing this. It passed emissions with 4 coolant leaks before it locked up on me.
Another $35, and the shop is closed this weekend. I'll find another one.
This is a FRESH rebuild, everything new. It shouldn't be doing this. It passed emissions with 4 coolant leaks before it locked up on me.