EGR Delete and CO levels
12-14-2015 | 02:13 PM
#1
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From: Portland, OR
EGR Delete and CO levels
I failed my OR smog test over the weekend. I deleted my EGR over the summer and wondering if replacing it will help. Here are some data points:
-TPS is currently slightly out of adjustment - I always struggle to get these right even with a multimeter. It runs great but when braking hard or revving high and then letting off the gas, the idle drops too low before recovering (have a wideband 02 sensor hooked up and know that it goes too rich when this happens)
-running slightly rich - 12.5-13.0 Air/Fuel ratio at idle
-02 sensor is new, OE and functioning
-EGR has been deleted
-Emissions results - CO2 and NOx are within tolerances, but CO is 5x the limit
I understand that EGR reduces NOx but have also read that high CO reduces NOx. I know I need to get the TPS and mixture in check. Wondering if that might do the trick or if I should spring for putting the EGR back on. I don't have much time to work on it right now, so I need to get any parts and do it all in one day.
Thanks in advance for your thoughts!
-TPS is currently slightly out of adjustment - I always struggle to get these right even with a multimeter. It runs great but when braking hard or revving high and then letting off the gas, the idle drops too low before recovering (have a wideband 02 sensor hooked up and know that it goes too rich when this happens)
-running slightly rich - 12.5-13.0 Air/Fuel ratio at idle
-02 sensor is new, OE and functioning
-EGR has been deleted
-Emissions results - CO2 and NOx are within tolerances, but CO is 5x the limit
I understand that EGR reduces NOx but have also read that high CO reduces NOx. I know I need to get the TPS and mixture in check. Wondering if that might do the trick or if I should spring for putting the EGR back on. I don't have much time to work on it right now, so I need to get any parts and do it all in one day.
Thanks in advance for your thoughts!
12-14-2015 | 03:40 PM
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I'm not easily able to find out "what is tested" (I don't know if you're in Portland, Medford, or where ever). In California, if ANY part of the emissions system has been altered you fail. No matter what the tail pipe emissions are. So an EGR delete means no California registration.
You don't provide any numbers, but I really doubt Oregon has a CO2 limit. Usually, there is an HC, CO, and NOx limit. Very generally, high CO is coupled to running rich (too little oxygen to convert the CO to CO2)
You don't provide any numbers, but I really doubt Oregon has a CO2 limit. Usually, there is an HC, CO, and NOx limit. Very generally, high CO is coupled to running rich (too little oxygen to convert the CO to CO2)
12-14-2015 | 04:25 PM
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I'm not easily able to find out "what is tested" (I don't know if you're in Portland, Medford, or where ever). In California, if ANY part of the emissions system has been altered you fail. No matter what the tail pipe emissions are. So an EGR delete means no California registration.
You don't provide any numbers, but I really doubt Oregon has a CO2 limit. Usually, there is an HC, CO, and NOx limit. Very generally, high CO is coupled to running rich (too little oxygen to convert the CO to CO2)
You don't provide any numbers, but I really doubt Oregon has a CO2 limit. Usually, there is an HC, CO, and NOx limit. Very generally, high CO is coupled to running rich (too little oxygen to convert the CO to CO2)
12-14-2015 | 11:24 PM
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What do you guys think? Is this a MAF/TPS adjustment or do you think it will take putting an EGR on to bring the numbers down.
Forgot to mention. I had a local Toyota shop rebuild my MAF and they've tinkered with the mixture screw. Neither they, nor anyone else in town seems to have smog test equipment in their shop since the state does the testing. They all say they can't tell me how rich or lean it, which is why I bought a wideband setup and wired it for temporarty install using a cigarette lighter plug.
Forgot to mention. I had a local Toyota shop rebuild my MAF and they've tinkered with the mixture screw. Neither they, nor anyone else in town seems to have smog test equipment in their shop since the state does the testing. They all say they can't tell me how rich or lean it, which is why I bought a wideband setup and wired it for temporarty install using a cigarette lighter plug.
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12-15-2015 | 02:49 AM
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Here's some instruction on emission analysis:
http://www.cygnusx1.net/Media/Supra/...taTech/h56.pdf
As you can see, this simple chart predicts that with Air/Fuel around 12.5-13, you'll get the way-too-high HC and CO numbers you have.
I doubt it's the EGR; while everything affects everything else, the purpose of the EGR is to reduce NOx and keep your truck from poisoning everyone. NOx is its reason for being.
The TPS has the idle switch, so I would re-test that part of the TPS to make sure the idle switch is closing at idle.
The O2 sensor should adjust mixture to get it up to 14.7 (or so) at all times. I'm not sure what diagnostic connector you have, but you could run the O2 sensor check. It looks to see the voltage flop back and forth at least 8 times in 10 seconds; if it isn't doing that at idle you might have a bad heater (the sensor doesn't work cool, so the heater keeps it working at idle) or just a weak sensor.
Let us know what you get.
http://www.cygnusx1.net/Media/Supra/...taTech/h56.pdf
As you can see, this simple chart predicts that with Air/Fuel around 12.5-13, you'll get the way-too-high HC and CO numbers you have.
I doubt it's the EGR; while everything affects everything else, the purpose of the EGR is to reduce NOx and keep your truck from poisoning everyone. NOx is its reason for being.
The TPS has the idle switch, so I would re-test that part of the TPS to make sure the idle switch is closing at idle.
The O2 sensor should adjust mixture to get it up to 14.7 (or so) at all times. I'm not sure what diagnostic connector you have, but you could run the O2 sensor check. It looks to see the voltage flop back and forth at least 8 times in 10 seconds; if it isn't doing that at idle you might have a bad heater (the sensor doesn't work cool, so the heater keeps it working at idle) or just a weak sensor.
Let us know what you get.
Last edited by scope103; 12-17-2015 at 06:16 PM.
12-15-2015 | 03:15 AM
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From: Springfield, Orygun
Having never dealt with smogging a vehicle, I can't really speak as to what does what, resulting in what. But, the EGR valve is closed at idle, meaning non-functional, same as blocked off or removed. If it's open at idle, your truck will run like doo-doo. Now it will show a result at cruise or whatever rpm they may rest at, but at idle, your EGR should have no effect on emissions. So I'd find a non-adjusted VAFM, and then try. Got a friend you can swap with for a day?
12-15-2015 | 10:58 PM
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Your lucky your not in California. I'd get you for Missing EGR = Fail (Tampered System)
Anyway putting the EGR back on wont help if all they are testing is emissions at idle. Looks like its too rich at idle which could mean a few things but basically too much fuel or not enough air. With that much CO and from what you said I would look at adjusting the TPS and adjusting the MAF back to stock maybe a little leaner but this can be difficult unless the gear was marked when the shop tinkered with it. Plugs and wires can be ruled out unless its misfiring and you say the o2 sensor is new so that's out (unless you got a bad one) Other things that can cause this are vacuum leaks which the o2 will see as lean and richen the mixture. Leaking injectors , blocked fuel return line, bad pressure regulator, Coolant temp sensor, Low compression, Exhaust leak before o2 sensor - The list goes on and at the bottom of the list is the Catalytic Converter. I would start with adjusting the TPS and MAF sensor this is more then likely the problem.
Anyway putting the EGR back on wont help if all they are testing is emissions at idle. Looks like its too rich at idle which could mean a few things but basically too much fuel or not enough air. With that much CO and from what you said I would look at adjusting the TPS and adjusting the MAF back to stock maybe a little leaner but this can be difficult unless the gear was marked when the shop tinkered with it. Plugs and wires can be ruled out unless its misfiring and you say the o2 sensor is new so that's out (unless you got a bad one) Other things that can cause this are vacuum leaks which the o2 will see as lean and richen the mixture. Leaking injectors , blocked fuel return line, bad pressure regulator, Coolant temp sensor, Low compression, Exhaust leak before o2 sensor - The list goes on and at the bottom of the list is the Catalytic Converter. I would start with adjusting the TPS and MAF sensor this is more then likely the problem.
Last edited by 854x4; 12-15-2015 at 11:00 PM.
12-15-2015 | 11:21 PM
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Your lucky your not in California. I'd get you for Missing EGR = Fail (Tampered System)
Anyway putting the EGR back on wont help if all they are testing is emissions at idle. Looks like its too rich at idle which could mean a few things but basically too much fuel or not enough air. With that much CO and from what you said I would look at adjusting the TPS and adjusting the MAF back to stock maybe a little leaner but this can be difficult unless the gear was marked when the shop tinkered with it. Plugs and wires can be ruled out unless its misfiring and you say the o2 sensor is new so that's out (unless you got a bad one) Other things that can cause this are vacuum leaks which the o2 will see as lean and richen the mixture. Leaking injectors , blocked fuel return line, bad pressure regulator, Coolant temp sensor, Low compression, Exhaust leak before o2 sensor - The list goes on and at the bottom of the list is the Catalytic Converter. I would start with adjusting the TPS and MAF sensor this is more then likely the problem.
Anyway putting the EGR back on wont help if all they are testing is emissions at idle. Looks like its too rich at idle which could mean a few things but basically too much fuel or not enough air. With that much CO and from what you said I would look at adjusting the TPS and adjusting the MAF back to stock maybe a little leaner but this can be difficult unless the gear was marked when the shop tinkered with it. Plugs and wires can be ruled out unless its misfiring and you say the o2 sensor is new so that's out (unless you got a bad one) Other things that can cause this are vacuum leaks which the o2 will see as lean and richen the mixture. Leaking injectors , blocked fuel return line, bad pressure regulator, Coolant temp sensor, Low compression, Exhaust leak before o2 sensor - The list goes on and at the bottom of the list is the Catalytic Converter. I would start with adjusting the TPS and MAF sensor this is more then likely the problem.
I had a few bugs and went all out replacing everything external to the block. I had a bad AFM and got two bum 'reman' AFMs from two different suppliers - I learned that they don't seem to rebuild them, just clean them up -- one had a completely worn out carbon sweep, the other a bad air temp sensor. I had a local shop take the working parts from both and combine into a single unit. In the process, the factory mixture was lost.
I recently did a late model plenum/throttle body swap. I recorded the TPS settings pre-tear down and set it back to the same in the swap. It seems to run great but it was likely running rich before the swap.
I will mess with the TPS and AFM this weekend. Thanks!
12-16-2015 | 03:33 AM
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I did the egr and pair delete, and can pass a smog no problem. It's important to make sure all codes are cleared. If you have no codes, and the TPS is calibrated and the truck still won't pass, it could be a compression issue.
12-16-2015 | 06:28 AM
#13
I have learned on getting a used AFM to take my manual or specifications on the AFM and a meter and test them in the yard. AFMs seldom if ever throw a code.
As far a the TPS, I have cleaned them and got them working better and will pass test, and they can still cause problems, but from now on if I have or suspect a TPS, I just replace them. Look at the number of times you are on and off the throttle in a single mile. A truck with 100k miles litterally can have millions of cycles on the TPS.
Dealing with emissions test can be frustrating but it can help figure out what is not operatng properly and when you eventually pass will have a much better running truck.
As far a the TPS, I have cleaned them and got them working better and will pass test, and they can still cause problems, but from now on if I have or suspect a TPS, I just replace them. Look at the number of times you are on and off the throttle in a single mile. A truck with 100k miles litterally can have millions of cycles on the TPS.
Dealing with emissions test can be frustrating but it can help figure out what is not operatng properly and when you eventually pass will have a much better running truck.
12-16-2015 | 07:41 AM
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I have learned on getting a used AFM to take my manual or specifications on the AFM and a meter and test them in the yard. AFMs seldom if ever throw a code.
As far a the TPS, I have cleaned them and got them working better and will pass test, and they can still cause problems, but from now on if I have or suspect a TPS, I just replace them. Look at the number of times you are on and off the throttle in a single mile. A truck with 100k miles litterally can have millions of cycles on the TPS.
Dealing with emissions test can be frustrating but it can help figure out what is not operatng properly and when you eventually pass will have a much better running truck.
As far a the TPS, I have cleaned them and got them working better and will pass test, and they can still cause problems, but from now on if I have or suspect a TPS, I just replace them. Look at the number of times you are on and off the throttle in a single mile. A truck with 100k miles litterally can have millions of cycles on the TPS.
Dealing with emissions test can be frustrating but it can help figure out what is not operatng properly and when you eventually pass will have a much better running truck.
I'm not great with a multimeter and have always had difficulty getting the TPS adjusted just right on my own. I know that's part of the issue on top of the mixture at the AFM being a wildcard.
12-16-2015 | 10:00 AM
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So why not trip the diagnostic connector and check for stored codes. If there's something wrong with the TPS or afm or o2 it will show up. Additionally You can easily check the condition of the sensors by using the procedures in the FSM. True, the afm may not throw a code but if it's damaged you'll be able to find out with an ohm meter and the FSM. It's very easy using an Ohm meter by following toyotas directions. I go the extra mile and run a wideband in my truck to keep tabs on air fuel and operating condition. Recommended!
But if you still can't pass, after everything is dialed in, it's the rings. Sucks but what can you expect on 30 yr old car. in that case it's time to start from scratch and do it right.
But if you still can't pass, after everything is dialed in, it's the rings. Sucks but what can you expect on 30 yr old car. in that case it's time to start from scratch and do it right.
12-16-2015 | 10:12 AM
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So why not trip the diagnostic connector and check for stored codes. If there's something wrong with the TPS or afm or o2 it will show up. Additionally You can easily check the condition of the sensors by using the procedures in the FSM. True, the afm may not throw a code but if it's damaged you'll be able to find out with an ohm meter and the FSM. It's very easy using an Ohm meter by following toyotas directions. I go the extra mile and run a wideband in my truck to keep tabs on air fuel and operating condition. Recommended!
But if you still can't pass, after everything is dialed in, it's the rings. Sucks but what can you expect on 30 yr old car. in that case it's time to start from scratch and do it right.
But if you still can't pass, after everything is dialed in, it's the rings. Sucks but what can you expect on 30 yr old car. in that case it's time to start from scratch and do it right.
I've historically had a challenge getting the TPS dialed in correctly. I usually get 3 out of the 5 readings dialed and seem to lose them when attempting to hit the other two -- tends to be due to my limited experience with multimeters more than a defect with the part.
Will let you know what the weekend brings.
12-16-2015 | 09:22 PM
#18
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From: Springfield, Orygun
Well, the TPS setup is just getting the right readings at closed throttle, and making sure others are in spec. Have you used 4crawler's writeup? Made it simple for me. I only verify closed throttle, .57mm, and .85mm checks. Then make sure it's a clean sweep, with no dropouts, from closed to wide open.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
If you hit the closed reading, then the .57mm reading, unless your TPS is failing the others should be in spec. I overthought it the first time, chased ohms all over the place.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
If you hit the closed reading, then the .57mm reading, unless your TPS is failing the others should be in spec. I overthought it the first time, chased ohms all over the place.
12-17-2015 | 05:47 PM
#19
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Update: I readjusted the TPS tonight and adjusted the idle mixture screw on the AFM -- it was as tight as it would go. I backed it out almost 4 turns and got the Air/Fuel ratio to hover between 14.6 - 14.8 at idle. I drove it around the neighborhood a few times and it seems to drive fine.
I'm anxious to get it re-smogged on Saturday to see how it goes. I also have new Denso spark plugs I'll be installing before the test - pretty sure my current ones are less than optimal with running rich.
Thanks for all of your assistance! Fingers crossed!
I'm anxious to get it re-smogged on Saturday to see how it goes. I also have new Denso spark plugs I'll be installing before the test - pretty sure my current ones are less than optimal with running rich.
Thanks for all of your assistance! Fingers crossed!
12-17-2015 | 08:34 PM
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From: Columbia County, Oregon
Seafoam?
I live in the West Portland area and I just passed at the Sunset/Cornelius Pass DEQ back in November. I have a 94’ 4runner 22re w/280k that I bought 2 months ago. The PO had deleted the EGR and punched the cat. I was curious how each part would affect the emissions so I replaced them one item at a time. I considered buying an EGR and putting it back on, but in the end I was able to avoid it. It took me 3 attempts due to high CO and I think I failed at around 8% C0’s my first run. Short story is I put on a new cat and failed at like 5% CO, then I replaced the 02 sensor and cleaned the carbon out of the throttle body and got even closer at roughly 2-3%CO, then I put a full bottle of seafoam with a full tank of Chevron+ and ran it down to a ¼ tank. After a pretty hard 30 minute drive to DEQ I passed at .84% CO’s( my understanding is a hotter engine will produce less CO but feel free to correct me if I am wrong). It certainly isn’t along term fix, but I guess it depends on how desperate you are to get through DEQJ
Not sure that this is much help from the troubleshooting perspective, but I thought it was rather similar to my scenario. It also might help support the idea that the deleted EGR isn't problematic?? I dunno...
Also, are you throwing any codes? Mine throws the EGR code…
The good news is the guy told me you can test as many times as you want and as you know it is free until you pass so that’s a relief. Someone once told me that they force you to take it to a smog tech after you fail a bunch of times.
Good luck!!!
I live in the West Portland area and I just passed at the Sunset/Cornelius Pass DEQ back in November. I have a 94’ 4runner 22re w/280k that I bought 2 months ago. The PO had deleted the EGR and punched the cat. I was curious how each part would affect the emissions so I replaced them one item at a time. I considered buying an EGR and putting it back on, but in the end I was able to avoid it. It took me 3 attempts due to high CO and I think I failed at around 8% C0’s my first run. Short story is I put on a new cat and failed at like 5% CO, then I replaced the 02 sensor and cleaned the carbon out of the throttle body and got even closer at roughly 2-3%CO, then I put a full bottle of seafoam with a full tank of Chevron+ and ran it down to a ¼ tank. After a pretty hard 30 minute drive to DEQ I passed at .84% CO’s( my understanding is a hotter engine will produce less CO but feel free to correct me if I am wrong). It certainly isn’t along term fix, but I guess it depends on how desperate you are to get through DEQJ
Not sure that this is much help from the troubleshooting perspective, but I thought it was rather similar to my scenario. It also might help support the idea that the deleted EGR isn't problematic?? I dunno...
Also, are you throwing any codes? Mine throws the EGR code…
The good news is the guy told me you can test as many times as you want and as you know it is free until you pass so that’s a relief. Someone once told me that they force you to take it to a smog tech after you fail a bunch of times.
Good luck!!!
