California smog/emissions issues (bogging at 15Mph, HC and CO at 25Mph)
12-12-16, 07:07 PM
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California smog/emissions issues (bogging at 15Mph, HC and CO at 25Mph)
Hello i have a 1988 rx-7 vert that i have been trying to get to pass California emissions/smog for the past few weeks i've so far replaced a lot of parts and retested 5 times with no pass and am starting to get frustrated and confused.
The car is a 1988 vert s4 n/a engine that has been rebuilt by me less than 1000 miles ago due to a blown coolant seal while i had it apart i did some light cleanup on the runners and intake ports no changes at all to the primary or second ports and only light touch up on the auxiliary ports. the car got a oil pellet from Atkins and Atkins auxiliary port sleeves i also slightly raised the oil pressure. the intake manifold and throttle body were ported and i did the secondary throttle plate delete. most of the seals were left as is only soft seals were replaced as well as both front and rear irons due to cracking at the point of the coolant seal failure.
The car always had problems with cold idle due to removal of the thermowax after this but, warm idle always seemed fine. and recently we decided to sell the car as it was not being driven much and we have my rx-8 as a daily driver.
The first smog session we failed at the start of the test due to a lumpy idle as well as at 15Mph the carr would bod down and slow below what was allowed and then it would speed back up to test speed only to have the smog computer abort the test due to "acceleration violation". I assumed it was due to the throttle body being ported and modified and replaced the throttle body and BAC with good used ones from Ebay.
The second time it went to smog it ran good and on the dyno made it through both tests onlyto have the results come back a bad failure only at 25Mph with allowed HC being 67 and the car producing 630 and CO max being .8 and the car producing 4.2 the nox was a pass with allowed being 550 and the car producing 9 at 15Mph the car passed with flying colors producing less than a quarter of allowed values on all tested numbers. I thought the car was probably running even richer than it should and replaced the O2 sensor.
The third test was a slight improvement of the HC number to 550 and of CO to 3.8 with a slight increase of NOX to 15. After reading a bit on this website i decided to replace the ACV with one off ebay as well as the plugs and wires for good measure. I also decided to add some denatured alchohol to the tank to make it run leaner and hopefully decrease the HC and CO numbers at 25Mph. also a vacuum line was put from the intake manifold nipple that is usually capped straight to the nipple on the ACV that is closest to the firewall to try and force the ACV into port air mode.
The fourth test was a fail in a similar manner to the first except the idle was stable. the car would drive on the dyno at 15Mph and then suddenly bog down and re-accelerate to 15 causing the test to be aborted. i decided that i had added too much alchohol to the tank and added 5 more gallons of 91.
The fifth test was identical to the fourth. I am pretty much stumped at this point as almost everything is different from the first attempt yet the issue has come back. I was thinking that maybe t could be ignition coils/igniters but, i don't feel or hear any missing. its also worth noting that i cant seem to replicate the issue on the street. the car is definitely running better than it was but, it just wont pass no matter what i try. I have a feeling that i will pass assuming i can get the bogging issue to stop.
Thank you for all the help in advance,
Gage
The car is a 1988 vert s4 n/a engine that has been rebuilt by me less than 1000 miles ago due to a blown coolant seal while i had it apart i did some light cleanup on the runners and intake ports no changes at all to the primary or second ports and only light touch up on the auxiliary ports. the car got a oil pellet from Atkins and Atkins auxiliary port sleeves i also slightly raised the oil pressure. the intake manifold and throttle body were ported and i did the secondary throttle plate delete. most of the seals were left as is only soft seals were replaced as well as both front and rear irons due to cracking at the point of the coolant seal failure.
The car always had problems with cold idle due to removal of the thermowax after this but, warm idle always seemed fine. and recently we decided to sell the car as it was not being driven much and we have my rx-8 as a daily driver.
The first smog session we failed at the start of the test due to a lumpy idle as well as at 15Mph the carr would bod down and slow below what was allowed and then it would speed back up to test speed only to have the smog computer abort the test due to "acceleration violation". I assumed it was due to the throttle body being ported and modified and replaced the throttle body and BAC with good used ones from Ebay.
The second time it went to smog it ran good and on the dyno made it through both tests onlyto have the results come back a bad failure only at 25Mph with allowed HC being 67 and the car producing 630 and CO max being .8 and the car producing 4.2 the nox was a pass with allowed being 550 and the car producing 9 at 15Mph the car passed with flying colors producing less than a quarter of allowed values on all tested numbers. I thought the car was probably running even richer than it should and replaced the O2 sensor.
The third test was a slight improvement of the HC number to 550 and of CO to 3.8 with a slight increase of NOX to 15. After reading a bit on this website i decided to replace the ACV with one off ebay as well as the plugs and wires for good measure. I also decided to add some denatured alchohol to the tank to make it run leaner and hopefully decrease the HC and CO numbers at 25Mph. also a vacuum line was put from the intake manifold nipple that is usually capped straight to the nipple on the ACV that is closest to the firewall to try and force the ACV into port air mode.
The fourth test was a fail in a similar manner to the first except the idle was stable. the car would drive on the dyno at 15Mph and then suddenly bog down and re-accelerate to 15 causing the test to be aborted. i decided that i had added too much alchohol to the tank and added 5 more gallons of 91.
The fifth test was identical to the fourth. I am pretty much stumped at this point as almost everything is different from the first attempt yet the issue has come back. I was thinking that maybe t could be ignition coils/igniters but, i don't feel or hear any missing. its also worth noting that i cant seem to replicate the issue on the street. the car is definitely running better than it was but, it just wont pass no matter what i try. I have a feeling that i will pass assuming i can get the bogging issue to stop.
Thank you for all the help in advance,
Gage
Last edited by GageSilveira; 12-12-16 at 07:08 PM. Reason: typo in title
12-12-16, 07:22 PM
#2
If all else fails, replace the cat.
My car (SF Bay Area) never went on a dynamometer to pass smog. There was an idle test and a test at...2500 or 3000RPMs. I don't remember exactly, but no dyno pulls.
If you bite the bullet and buy a cat, I'll bet you pass, especially if the car's been running rich.
EDIT: Here's a link that kinda opened my eyes. Apparently you live in the city and I live in the suburbs and we're both right. If you have a family member or trustworthy friend with an address in a town with a lower population...
How to Pass The Smog Inspection - SmogTips.com. Pass the Smog Check. Pass the smog test. Emissions NO, HC, CO, Hydrocarbon,Carbon Monoxide, Nitrogen Oxide are the three smog forming chemicals. passing the smog, passing smog, ignition timing. pass smo
My car (SF Bay Area) never went on a dynamometer to pass smog. There was an idle test and a test at...2500 or 3000RPMs. I don't remember exactly, but no dyno pulls.
If you bite the bullet and buy a cat, I'll bet you pass, especially if the car's been running rich.
EDIT: Here's a link that kinda opened my eyes. Apparently you live in the city and I live in the suburbs and we're both right. If you have a family member or trustworthy friend with an address in a town with a lower population...
How to Pass The Smog Inspection - SmogTips.com. Pass the Smog Check. Pass the smog test. Emissions NO, HC, CO, Hydrocarbon,Carbon Monoxide, Nitrogen Oxide are the three smog forming chemicals. passing the smog, passing smog, ignition timing. pass smo
12-12-16, 07:28 PM
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If all else fails, replace the cat.
My car (SF Bay Area) never went on a dynamometer to pass smog. There was an idle test and a test at...2500 or 3000RPMs. I don't remember exactly, but no dyno pulls.
If you bite the bullet and buy a cat, I'll bet you pass, especially if the car's been running rich.
EDIT: Here's a link that kinda opened my eyes. Apparently you live in the city and I live in the suburbs and we're both right. If you have a family member or trustworthy friend with an address in a town with a lower population...
How to Pass The Smog Inspection - SmogTips.com. Pass the Smog Check. Pass the smog test. Emissions NO, HC, CO, Hydrocarbon,Carbon Monoxide, Nitrogen Oxide are the three smog forming chemicals. passing the smog, passing smog, ignition timing. pass smo
My car (SF Bay Area) never went on a dynamometer to pass smog. There was an idle test and a test at...2500 or 3000RPMs. I don't remember exactly, but no dyno pulls.
If you bite the bullet and buy a cat, I'll bet you pass, especially if the car's been running rich.
EDIT: Here's a link that kinda opened my eyes. Apparently you live in the city and I live in the suburbs and we're both right. If you have a family member or trustworthy friend with an address in a town with a lower population...
How to Pass The Smog Inspection - SmogTips.com. Pass the Smog Check. Pass the smog test. Emissions NO, HC, CO, Hydrocarbon,Carbon Monoxide, Nitrogen Oxide are the three smog forming chemicals. passing the smog, passing smog, ignition timing. pass smo
12-12-16, 10:11 PM
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12-13-16, 12:01 PM
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The fourth test was a fail in a similar manner to the first except the idle was stable. the car would drive on the dyno at 15Mph and then suddenly bog down and re-accelerate to 15 causing the test to be aborted. i decided that i had added too much alchohol to the tank and added 5 more gallons of 91.
The fifth test was identical to the fourth. I am pretty much stumped at this point as almost everything is different from the first attempt yet the issue has come back. I was thinking that maybe t could be ignition coils/igniters but, i don't feel or hear any missing. its also worth noting that i cant seem to replicate the issue on the street. the car is definitely running better than it was but, it just wont pass no matter what i try. I have a feeling that i will pass assuming i can get the bogging issue to stop.
Thank you for all the help in advance,
Gage
The fifth test was identical to the fourth. I am pretty much stumped at this point as almost everything is different from the first attempt yet the issue has come back. I was thinking that maybe t could be ignition coils/igniters but, i don't feel or hear any missing. its also worth noting that i cant seem to replicate the issue on the street. the car is definitely running better than it was but, it just wont pass no matter what i try. I have a feeling that i will pass assuming i can get the bogging issue to stop.
Thank you for all the help in advance,
Gage