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Car Forum / Toyota / Toyota Cars / August 200788 corolla emissions, high HO level.
I recently acquired 88 corolla with 4FAFE carburetor Canadian emissions specifications. The car drives fine and very decent gas mileage. The car failed Ontario Drive Clean with following numbers. ASM2525 Test. (Driving at 40 kmh or 25 mph) HC ppm - Limit (78) Reading - 124 (FAIL) <<<<<<<<<<<< CO% - Limit (.44) Reading - 0.10 (Pass) NO ppm - Limit (907) Reading - 469 (Pass) RPM - 1830 (Valid) Dilution - 13.4 (Valid) Curb Idle Test. HO ppm - Limit (200) Reading - 78 (Pass) CO % - Limit (1.0) Reading 0.01 (Pass) NO ppm - N/A N/A RPM - 1130 (Valid) Dilution - 11.4 (Valid). Prior to the test. I changed spark plugs(champion from canadian tire), air cleaner, distributor caps/rotor and wires. Ran the car with 91 High octane gas for 30 minutes on highway and did not shut off the prior to the test. The Drive Clean shop wanted $70 to diagnose the problem. After talking to my mechanic friend, I decided to change O2 sensor ( I was planning to change it anyway). And retarted the timing by 3 degrees. The following was the result on my 2nd test which increased HC and CO (2 FAILs) ASM2525 Test. (Driving at 40 kmh or 25 mph) HC ppm - Limit (78) Reading - 207 (FAIL) <<<<<<<<<<<< CO% - Limit (.44) Reading - 0.49 (FAIL) <<<<<<<<<<<<<< NO ppm - Limit (907) Reading - 431 (Pass) RPM - 1815 (Valid) Dilution - 13.8 (Valid) Curb Idle Test. HO ppm - Limit (200) Reading - 78 (Pass) CO % - Limit (1.0) Reading 0.01 (Pass) NO ppm - N/A N/A RPM - 841 (Valid) Dilution - 12.0 (Valid). It seems my Dilution went up from 13.4 to 13.8 and new 2 tests failed. One Drive Clean facility told me it's my carburetor. My mechanic friend does not agree. It does not make sense to me as NOx gas is very low for both tests. There are 2 things that bother me.. 1 - I did not use toyota spark plugs.. used champion. 2 nd point that might be contributing to the problem is that the secondary heated air intake (from manifold) is not connected. Recently the manifold was changed and old screws are rusted and breaking when I tried to take them off. I do have the cover for the manifold. I understand this cover is to help the heated air circulating for better burning of the fuel during winter. But now it's summer. ??? I am mechanically inclined and do most of my own work (except for oil chages). I thought the car would pass for sure after I changed the O2 sensor, but it's getting worse. Called Drive Clean 1-800 and they were absolutely no help. Need a second opinion as I have a 3 way converter that costs big bucks before I go ahead and replace it. Sorry for the long post. Will take any suggestions.. thanks.. Typo.. One Drive Clean facility told me it's my carburetor.. should read "Catalytic Converter" towoodmaster <desmond@rogers.com> wrote in news:1186594999.122471.325460 @b79g2000hse.googlegroups.com: > I recently acquired 88 corolla with 4FAFE carburetor Canadian > emissions specifications. The car drives fine and very decent gas > mileage. The car failed Ontario Drive Clean with following numbers. Is the air pipe still present which runs from the air cleaner to the cat? Or has it rusted off?  SignatureTegger > Is the air pipe still present which runs from the air cleaner to the cat? > Or has it rusted off? > Tegger Hi Tegger, thanks for the reply. The intake pipe from air cleaner - manifold cover is still present, but it is not hooked up as old manifold cover is in the trunk. The bolts from the doner manifold are so rusted I broke one. If it will reduce the (HO) unburned gas then I can drill the bolts and put back the manifold cover. Anyways I was going to put the cover back, might as well do it sooner. Tegger, You may be on to something.!! >> Is the air pipe still present which runs from the air cleaner to the >> cat? Or has it rusted off? [quoted text clipped - 7 lines] > as well do it sooner. > Tegger, You may be on to something.!! The point of that pipe is to supply the oxidation side of the cat with supplemental oxygen to prevent the cat from becoming depleted. No oxygen on the cat, no conversion. The pipe rusts off and people have a tendency to just plug the hole in the cat so it won't make the exhaust noisy. If yours is capped off, you'll need to open it up and find a way to reconnect it to the air cleaner again. By the way...At night or in a dark garage, check for spark quality. Get a cheap spark plug from a parts place, pull a plug wire, insert the spare plug into it, and hold the threads against a ground. Now run the engine and observe the color of the spark. If it's anything other than bright purply- blue, you have a weak spark, which also contributes to high HC. A weak spark is usually a weak coil. SignatureTegger > Prior to the test. I changed spark plugs(champion This was your first mistaje. Use NGK or ND. Champs SUCK in foreign cars > from canadian tire) This was your second mistake... ;) > Prior to the test. I changed spark plugs(champion from canadian tire), > air cleaner, distributor caps/rotor and wires. Replace these parts with OEM parts, not aftermarket crap. >I recently acquired 88 corolla with 4FAFE carburetor Canadian > emissions specifications. The car drives fine and very decent gas [quoted text clipped - 63 lines] > before I go ahead and replace it. Sorry for the long post. Will take > any suggestions.. thanks.. Sorry this will not help but... Wow your smog laws sure must be lax compared to ours here in California. 8/ "the secondary heated air intake (from manifold) is not connected". Fails visual inspection here. "retarded the timing by 3 degrees". Incorrect timing fails here. Heck they even take the gas cap off my car and test the damm cap here. Dan >I recently acquired 88 corolla with 4FAFE carburetor Canadian > emissions specifications. The car drives fine and very decent gas [quoted text clipped - 63 lines] > before I go ahead and replace it. Sorry for the long post. Will take > any suggestions.. thanks.. The clue is that HC and CO went up after your changed the spark plugs. Stick to OEM ignition parts - plugs, wires, cap, rotor, and fix the pipe between the air cleaner and cat. SignatureRay O (correct punctuation to reply) >The point of that pipe is to supply the oxidation side of the cat with >supplemental oxygen to prevent the cat from becoming depleted. No >oxygen on the cat, no conversion. >The pipe rusts off and people have a tendency to just plug the hole in >the cat so it won't make the exhaust noisy. Thanks for all your reply.. I checked last night for the air cleaner to cat pipe. It is plastic until the firewall area then metal. It connects to the driver side of the catalytic converter. The metal and plastic pipe is in very good condition. The forefront pipe from manifold to cat also seems to be brand new. The one I was talking about may be a Canadian thing for cold weather. This is probably to help heat up the car better by supplying heated air from a cover on top of manifold to the air cleaner. Obviously US model does not have this. Things in order for today are .. . I am going to Toyota dealership to get spark plugs. I also could not find the spark plug gap anywhere on the car. So I did not gap the champion plugs. >The clue is that HC and CO went up after your changed the spark >plugs. Stick to OEM ignition parts - plugs, wires, cap, rotor, and fix > the pipe between the air cleaner and cat. Actually, The spark plugs were done prior to the first test. Both HC and CO went up on 2nd test after I changed the O2 sensor and retarded the timing. ( I expected it to pass as it was only off by limit 78 - measure 124) Does anyone think it is the catalytic converter that I need to change? I am going to spray the cab again with cab cleaner.. just in case the float is sticking.. that might have caused excessive gas during running? Also if anyone had a similar HC CO fail during their emissions? What did you do besides changing cat that made a difference.? All your responses are very helpful. thank you .. Ohh .. by the way they do check the gas caps in Ontario for pressure test. I had a similar problem with a '91 PASEO. When I regapped the new OEM plugs to the specied gap, it passed. You need to buy the OEM plugs. I would also set the ignition timing to the most advance I could get without pinging under load. Please let us know how you made out. Marvin ----------------------------------------------- >>The point of that pipe is to supply the oxidation side of the cat with >>supplemental oxygen to prevent the cat from becoming depleted. No >oxygen on the cat, no conversion. [quoted text clipped - 27 lines] >All your responses are very helpful. thank you .. Ohh .. by the way >they do check the gas caps in Ontario for pressure test. > Actually, The spark plugs were done prior to the first test. Both HC > and CO went up on 2nd test after I changed the O2 sensor and retarded > the timing. ( I expected it to pass as it was only off by limit 78 - > measure 124) I don't think retarding the timing was a good idea on a car that was failing HC -CO. I'd reset the timing back to normal. I think the timing had a good bit to do with it getting worse.. Retarding the timing will lower NOX scores, but probably make the HC scores worse. Your NOX score will probably go up by setting the timing back to stock, but according to your scores, you have a bit of leeway there. Note how the NOX dropped on the 2nd go... That was from the timing change. > Does anyone think it is the catalytic converter that I need to change? Doubt it very seriously. You are misfiring or running too rich. I guess it is possible the cat could be fuel polluted, etc if the car has been running rich, but I'd only go to that as a last resort. I think if you get it burning cleaner, it'll pass with the cat it has. > I am going to spray the cab again with cab cleaner.. just in case the > float is sticking.. that might have caused excessive gas during > running? Also if anyone had a similar HC CO fail during their > emissions? What did you do besides changing cat that made a > difference.? If the float sticks, you should smell gas, and usually some gas will run out the sides/base of the carb. If you run rich, the exhaust will be black and sooty. If you have a decent digital meter, you can measure the voltage off the O2 sensor and get an idea how you are burning. A near perfect burn should give a voltage of about .45 volts or so. If it's lower, you are lean. If it's higher, it's running rich. The usual range of the sensor will be about .1-.9 volts as far as the usable range. The car has to be warmed up for it to give off a voltage. Doesn't take too long though.. Being you have an O2 sensor, and a carb, that is a feedback carb system. Make sure the puter is working, no codes, etc.. You want to make sure it's actually going into closed loop when hot. Something as simple as a flaky temp sensor can cause the problem you have. The car thinks it's cold all the time, stays in open loop, and runs too rich. You gotta diagnose the problem on those deals. The O2 sensor can be handy to get an idea where you are at as far as mixture. You don't have all the fancy gear the shops and dealers have, so you have to make do with what ya got. MK > Note how the NOX dropped on the 2nd go... That was from the timing > change. [quoted text clipped - 18 lines] > have, so you have to make do with what ya got. > MK Thanks MK .. I found 2 problems.. This morning I got toyota spark plugs.. when I took out the old spark plugs 3/4 cylinders had white dust. . (Overheat ?) When I checked the gap, it was .35. The ones from the dealerships were .44 I put the dealer plugs in a heart beat. 2) I checked the O2 sensor voltage reading as suggested. 0.38 V after about 2-3 minutes of idling. car cool. 0.09 - 0.11 after about 15 minutes of running the car. (hot) I suspect a cooling system problem. The car never ran hot or cold. Temperature rises normally as the car warms up. During highway driving the temperature dips just a bit. If idled in one spot the fan would kick in every 3-4 minutes or so. > Make sure the puter is working, no codes, etc.. > You want to make sure it's actually going into closed loop > when hot. Something as simple as a flaky temp sensor > can cause the problem you have. The car thinks it's cold all > the time, stays in open loop, and runs too rich. > You gotta diagnose the problem on those deals. could you explain what is a "puter"? how can I verify if the temp sensor is working? I will get a new thermostat tomorrow. thanks for your help again... >> Note how the NOX dropped on the 2nd go... That was from the timing >> change. [quoted text clipped - 26 lines] > gap, it was .35. The ones from the dealerships were .44 > I put the dealer plugs in a heart beat. The white dust can also result from improper spark plug heat range. Replacing the plugs with the Toyota spark plugs may have cured the problem. > 2) I checked the O2 sensor voltage reading as suggested. > 0.38 V after about 2-3 minutes of idling. car cool. > 0.09 - 0.11 after about 15 minutes of running the car. (hot) Is the voltage from the O2 sensor fluctuating after it is warmed up? How much is it fluctuating and how quickly? > I suspect a cooling system problem. The car never ran hot or cold. > Temperature rises normally as the car warms up. During highway > driving the temperature dips just a bit. If idled in one spot the fan > would kick in every 3-4 minutes or so. This sounds like the cooling system is working normally. >> Make sure the puter is working, no codes, etc.. >> You want to make sure it's actually going into closed loop [quoted text clipped - 7 lines] > thermostat tomorrow. > thanks for your help again... "Puter" = computer. Put a volt meter on the temp sensor - voltage should rise as coolant temperature rises, or you can unplug it form the wiring harness and resistance should go down as coolant temp rises. I don't think a thermostat will cure the problem since the cooling system seems to be working normally. SignatureRay O (correct punctuation to reply) > Thanks MK .. I found 2 problems.. > This morning I got toyota spark plugs.. when I took out the old spark > plugs 3/4 cylinders had white dust. . (Overheat ?) When I checked the > gap, it was .35. The ones from the dealerships were .44 > I put the dealer plugs in a heart beat. That could be from lean running mixture. heck, you may have a lean misfire instead of rich.. Both increase HC.. > 2) I checked the O2 sensor voltage reading as suggested. > 0.38 V after about 2-3 minutes of idling. car cool. > 0.09 - 0.11 after about 15 minutes of running the car. (hot) Yep, you are running very lean once warmed up. Your mixture at idle is about what it should be at speed. > I suspect a cooling system problem. The car never ran hot or cold. > Temperature rises normally as the car warms up. During highway > driving the temperature dips just a bit. If idled in one spot the fan > would kick in every 3-4 minutes or so. Well, if the temp gauge is in the appx middle, and it's always been in the same place, your cooling system sounds fine. But....It's still possible to have a bad temp sensor. > > Make sure the puter is working, no codes, etc.. > > You want to make sure it's actually going into closed loop [quoted text clipped - 4 lines] > > could you explain what is a "puter"? The computer which controls the feedback carb.. It's probably under the dash somewhere. Most older feedback systems like that can be read with no extra tools needed. > how can I verify if the temp sensor is working? Well, you would measure the resistance, or if open/closed. I don't have a manual for that car, so I don't know the specs of the temp sensor. You need a service manual of some type. It's almost impossible to work on any modern car without a manual. I would never think of it. I buy a manual for every car I get. >I will get a new > thermostat tomorrow. > thanks for your help again... Why???? Don't throw money away on guesses!!! So far, I've heard no real indication that you have a cooling problem. If you needed a stat, you would either be overheating, or running way too cold. You need to find out why your mixture is so far off. It could be a number of things. The feedback computer might not be working. The solenoid in the carb could be bad and stuck at one position. You could be all carboned up in the combustion chambers, intake valves. That will cause lean running. The carbon soaks up fuel vapors.. You might have a mis-adjusted carb.. The list can run for hours... You need to get a good manual, and then go down the list in an organized manner. At this point, you are just going helter -skelter, which is just going to cost you a load of parts you don't need. And.. You will need a bit of test gear to check that system. At the least , a good VOM. But without a manual, you will have no idea what specs to check for.. A manual is a must.. I wouldn't be half surprised if you feedback carb/computer system is flaked out.. Those puters are pretty hard to kill, but it can happen. If after testing, the computer is bad, you can get one at a junkyard for a half decent price. You may have a bad carb. In most of those the mix is controlled by a solenoid, which adjusts the mixture several times a second, using data from the puter, which gets it's data from all the sensors. MK BTW, it's also possible the mix is controlled "honda" style by regulating the air, instead of the fuel.. But I dunno.. You need a manual.. MK n...@wt.net wrote: >BTW, it's also possible the mix is controlled "honda" style by >regulating the air, instead of the fuel.. It is. Toyota called it the EBCV- External Bleed Control Valve BTW, also make totally sure you have no vacuum leaks.. Check all the rubber hoses from all sides, carb base, make sure carb is not loose, etc.. If it has any vacuum valves, make sure the diaphrams are not leaking.. That was a common problem on some of the carbed hondas. Vac leaks will have you running lean, and if bad enough, the feedback system can't correct it. MK > >The point of that pipe is to supply the oxidation side of the cat with >>supplemental oxygen to prevent the cat from becoming depleted. No >oxygen [quoted text clipped - 31 lines] > All your responses are very helpful. thank you .. Ohh .. by the way > they do check the gas caps in Ontario for pressure test. Put the ignition timing back to factory specs, or at least where it was. Make sure the temp gauge is working and the car warms up - if not, check the temp sender. As far as the tube from the top of the exhaust manifold to the air cleaner, a missing one should not cause the problems you are having. That tube helps drivability during warm up and should be closed off after the car warms up. Spraying the car with carb cleaner will not fix a sticking float, and if the float is sticking, you will probably see fuel outside the carb or smell fuel. You can try fuel injector cleaner that you add to the tank during fillup, but I doubt if it will fix the problem. If you look into the carb, you should see a fine mist and no dribbles. If you see a fine mist, the jets and floats are probably OK. I doubt if the cat is bad - that vintage cat was pretty trouble-free. SignatureRay O (correct punctuation to reply) > I checked last night for the air cleaner > to cat pipe. It is plastic until the firewall area then metal. It [quoted text clipped - 5 lines] > air from a cover on top of manifold to the air cleaner. Obviously US > model does not have this. Are you sure? It was an almost universally common item on US cars from the mid-70s until carbs were replaced with FI, and my '87 US Corolla had it. I remember this because a careless shop tore its hot air intake duct and patched it with muffler cement and gauze because they couldn't find a replacement of the right diameter.. Tegger wrote: > > Is the air pipe still present which runs from the air cleaner to the cat? > > Or has it rusted off? [quoted text clipped - 6 lines] > reduce the (HO) unburned gas then I can drill the bolts and put back > the manifold cover. Tegger is referring to the air suction system for the catalytic converter, but the thing you just described instead seems to be the hot air intake system, which is designed to prevent the air-fuel mixture from leaning out in cold weather, when the air is denser. AFAIK it's the only device that attaches to a cover on the exhaust manifold. BTW while you have access to the exhaust manifold, clean the pivots for the heat riser (has a wind-up spring on one side) with choke cleaner (no oil) so it moves freely and doesn't overheat the air in the intake manifold, which can make the mixture too rich (can make CO and HC go up, NOx go down). The air suction systems on the few Toyotas I've seen had a reed valve attached to the side of the air filter housing, and attached to that valve was a steel pipe that went to either the exhaust manifold or to a fitting on the side of the catalytic converter. The reed valve may also have a thin vacuum hose that goes to a carburetor port to prevent air suction at idle. If there's no such hose, then the air suction works all the time. You should be able to hear a low pitched buzz (like a tuba) from the reed valve. A very rough check of the catalytic converter can be made by removing the rubber hose and smelling the exhaust coming from it, then reattaching it and smelling the exhaust at the tail pipe while the engine is idled fast. If there's much less gasoline smell at the tail pipe, the cat is probably OK. Don't confuse that smell with sulfur smell, which is also a sign of a working cat (but maybe another problem). > I am going to Toyota dealership to get spark plugs. No need to pay dealer prices when identical Denso brand plugs are cheaper at discounters. Gap is 0.043" NGKs will also work perfectly. > I am going to spray the cab again with cab cleaner.. just in case the > float is sticking.. that might have caused excessive gas during > running? Also if anyone had a similar HC CO fail during their > emissions? What did you do besides changing cat that made a > difference.? I'm familiar with only one type of carb for Toyotas, a 2-barrel Aisin with a sight glass on one side. I don't think it's possible for its float to stick unless something is wrong with the float valve, but there's probably nothign wrong with it if the engine starts and runs normally. OTOH a high float level can cause a rich mixture, but you can check that through the sight glass (foam floats can gradually absorb gasoline and become too heavy). The fuel level should be approximately in the middle of the glass, between the 2 horizontal markers. There should be an electrical connector for checking the oxygen sensor without disconnecting it. Unlike the sensor, this connector puts out hefty pulses and can be read safely even with a cheap analog meter (can overload an oxygen sensor if connected directly). Hi All.. I am taking the car to my mechanic(friend). We are going to set the timing on it using the light. He is going to check the book, I read somewhere that it should be 5-10 degrees somewhere around 7degrees ???. ( factory settings.) >But without a manual, you will have no idea what specs to check for.. > A manual is a must.. I wouldn't be half surprised if you feedback >carb/computer system is flaked out.. I am going to get a manual on my way home today. I will start off with the temperature sensor, then work my way to see if I can get codes off the computer. One other thing about the diagnosis. I jumped E1 and T on my car got no engine light at all. All I get is the Brake light and battery light. Pulled the Diagnostic cap to see if there was any wires going to E1 and T.. No wires to T. only 3 wires. 1) E1, 2) Vox? 3) O2 Tried connecting the E1 and Vox .. no engine light. Is there a different way to get engine codes off 88 corolla carb car? >Well, if the temp gauge is in the appx middle, and it's always been >in the same place, your cooling system sounds fine. >But....It's still possible to have a bad temp sensor. This morning while I was driving after about 30 minutes, turned the heat dial all the way and got VERY hot air through the vents. Also I noticed that the temperature dial dropped to 1/4 level on instrument cluster. After I turned off the heater, it went back up to 1/2 way point. It was 23 degrees this morning in Toronto. Not sure if it is supposed to drop that much.? > There should be an electrical connector for checking the oxygen >sensor without disconnecting it. Unlike the sensor, this connector >puts out hefty pulses and can be read safely even with a cheap > analog meter (can overload an oxygen sensor if connected directly). I took the reading of 0.1 Volts from the wire that connects the O2 sensor to the male/female plug. Not sure if that's what you meant. When I changed the original plug about a month ago, there was no white deposit.. beside me putting 94 Octane on a carb car..(darn emissions) I did not do anything different. So toyota Denso plugs should be better for the car. Again, I have learned so much within the last 2 days. I thank you all .. Once I figure it out.. I will post my emissions results so, others can learn from it. Des. > Hi All.. > I am taking the car to my mechanic(friend). We are going to set the [quoted text clipped - 16 lines] > Tried connecting the E1 and Vox .. no engine light. Is there a > different way to get engine codes off 88 corolla carb car? If the check engine light is not illuminated, it is unlikely that there will be any codes stored in the computer. To get codes, jump wires E1 and TE1. >>Well, if the temp gauge is in the appx middle, and it's always been >>in the same place, your cooling system sounds fine. [quoted text clipped - 6 lines] > point. It was 23 degrees this morning in Toronto. > Not sure if it is supposed to drop that much.? You are describing normal operation of the cooling system. It is probably OK. >> There should be an electrical connector for checking the oxygen >sensor >> without disconnecting it. Unlike the sensor, this connector >puts out [quoted text clipped - 13 lines] > learn from it. > Des. SignatureRay O (correct punctuation to reply)> |
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