Black sooty tailpipe.
10-18-2010, 05:07 PM
#1
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Black sooty tailpipe.
I had a new exhaust pipe and muffler installed about a year ago. The inside of the pipe is already black and sooty. I can rub my finger inside it and its very black, but not oily or wet. Is this normal or does this mean i am running rich?
10-18-2010, 05:17 PM
#4
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Too rich, then.
engine isn't getting hot enough to combust everything, leaving you with a nice dark sooty carbon buildup.
have you done a valve adjustment recently?
engine isn't getting hot enough to combust everything, leaving you with a nice dark sooty carbon buildup.
have you done a valve adjustment recently?
10-18-2010, 10:54 PM
#5
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Too rich. Common causes of rich running include tired O2 sensor or corroded O2 sensor connector, leaking injector(s), including possibly the cold start injector, exhaust leak upstream of the O2 sensor (allows air/oxygen to be drawn into exhaust stream - fooling sensor), out-of-range air meter, bad engine coolant temp sensor (so it never runs in closed loop), high fuel pressure (rare, could be caused by obstructed fuel return line or bad pressure regulator). Possibly the PAIR (Pulsed Air Injection) system is malfunctioning, but that's not real likely either. There are simple instructions for troubleshooting the PAIR system in the factory manual.
There may be other possible causes of rich running but those are all that come to mind at the moment.
There may be other possible causes of rich running but those are all that come to mind at the moment.
10-19-2010, 02:45 AM
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Too rich. Common causes of rich running include tired O2 sensor or corroded O2 sensor connector, leaking injector(s), including possibly the cold start injector, exhaust leak upstream of the O2 sensor (allows air/oxygen to be drawn into exhaust stream - fooling sensor), out-of-range air meter, bad engine coolant temp sensor (so it never runs in closed loop), high fuel pressure (rare, could be caused by obstructed fuel return line or bad pressure regulator). Possibly the PAIR (Pulsed Air Injection) system is malfunctioning, but that's not real likely either. There are simple instructions for troubleshooting the PAIR system in the factory manual.
There may be other possible causes of rich running but those are all that come to mind at the moment.
There may be other possible causes of rich running but those are all that come to mind at the moment.
10-19-2010, 09:20 AM
#7
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For starters, when was the O2 sensor last changed? If over 90k miles, it probably needs to be replaced. Getting a direct-fit Denso is the best bet by far. Cheaper either from sparkplugs dot com or get the part # from there & search for denso and the part # on amazon - often cheap there.
If you're not sure about the sensor, you can check its switching rate, which, if too slow, tells you the sensor is "lazy" and should be replaced. Testing procedures are in the MFI System - Oxygen Sensor section of the fsm. You'll need a multimeter. http://personal.utulsa.edu/~nathan-b...42oxygense.pdf
You should pull the O2 sensor connector and clean it up, whether you replace the sensor, or not. Best stuff for cleaning that is Caig Deoxit: http://www.amazon.com/Hosa-Contact-R...dp/B0014F110I/
As to trouble codes, it certainly would be good to check, and to address any issues highlighted by codes. But codes usually only come up if a circuit is either open or shorted; for the most part, the computer has no way of knowing if the signals it receives from sensors are inaccurate, so not having any codes is no guarantee that everything's okay.
It's a challenge to find a leaking injector, since you have to remove them and hook them up to the fuel rail & pressurize it. But you can at least check the cold start fairly easily. Remove it, still hooked up to the fuel line, then pressurize by jumping +B and FP in the check connector and turning ignition on (but not starting). Easiest thing to do with the injectors is to ship them off to witchhunter.com. They do a great job cleaning & flow testing them, will provide new o-rings and turnaround is real fast. Excellent prices for what they provide.
To check for an exhaust leak, check exhaust manifold closely for any cracks or blackened areas. Listen along the manifold and front pipe with a length of hose.
See the fsm for instructions and specs on checking the air meter. Best check is to look at the volts directly on the ecu terminals when ignition is on. Terminal map is near the beginning of the MFI System - Troubleshooting section, and specs for the meter are on page EG1–129: you're mainly interested in the VS volts (measure between E2 (ground) and VS terminal) - that's what tells the computer how open the vane is. But you should also check VC - if VC is off, you may have a bad or corroded connection somewhere, but if VC is good and VS is off, the air meter needs to be adjusted or replaced. THA, the temp signal, should be measured by checking resistance directly on the air meter terminals; see the VAF Meter section: http://personal.utulsa.edu/~nathan-b...33volumeai.pdf (Unless the outside temp just happens to be 68 deg F, in which case you can use the volt range in the Troubleshooting section.) To check volts on ecu terminals, use backprobe adapters for your multimeter, or, if you don't have, push needles into the connectors and hold test leads against them.
To check the ECT (engine coolant temp sensor), check the volts between E2 and THW on the ecu when ignition is on and engine at operating temp. Should be .2 to 1 volts.
To check the PAIR system, see instructions in the Emissions PAIR System section of the fsm, as mentioned.
For fuel pressure, see the MFI System - Fuel Pump section for specs. Probably easiest to have a shop do that for you, but if you want to do it yourself, see these posts:
https://www.yotatech.com/forums/f116.../#post51210586
http://www.toyotanation.com/forum/sh...76#post3022876
As mentioned, too-high fuel pressure is rare. You could at least check that the return line is free by removing the fuel filler cap, then removing the lower, larger rubber hose from the side of the fuel pressure regulator (that's the return line), give it a few minutes for most of the gas to drain into tank, then try to blow into the return line. At first you'll be pushing the fuel remaining in the back part of the line up into the tank, but after that, the line should be clear and it should be easy to blow into it. Obviously, you'll want to avoid getting any fuel or fumes into your body.
If you're not sure about the sensor, you can check its switching rate, which, if too slow, tells you the sensor is "lazy" and should be replaced. Testing procedures are in the MFI System - Oxygen Sensor section of the fsm. You'll need a multimeter. http://personal.utulsa.edu/~nathan-b...42oxygense.pdf
You should pull the O2 sensor connector and clean it up, whether you replace the sensor, or not. Best stuff for cleaning that is Caig Deoxit: http://www.amazon.com/Hosa-Contact-R...dp/B0014F110I/
As to trouble codes, it certainly would be good to check, and to address any issues highlighted by codes. But codes usually only come up if a circuit is either open or shorted; for the most part, the computer has no way of knowing if the signals it receives from sensors are inaccurate, so not having any codes is no guarantee that everything's okay.
It's a challenge to find a leaking injector, since you have to remove them and hook them up to the fuel rail & pressurize it. But you can at least check the cold start fairly easily. Remove it, still hooked up to the fuel line, then pressurize by jumping +B and FP in the check connector and turning ignition on (but not starting). Easiest thing to do with the injectors is to ship them off to witchhunter.com. They do a great job cleaning & flow testing them, will provide new o-rings and turnaround is real fast. Excellent prices for what they provide.
To check for an exhaust leak, check exhaust manifold closely for any cracks or blackened areas. Listen along the manifold and front pipe with a length of hose.
See the fsm for instructions and specs on checking the air meter. Best check is to look at the volts directly on the ecu terminals when ignition is on. Terminal map is near the beginning of the MFI System - Troubleshooting section, and specs for the meter are on page EG1–129: you're mainly interested in the VS volts (measure between E2 (ground) and VS terminal) - that's what tells the computer how open the vane is. But you should also check VC - if VC is off, you may have a bad or corroded connection somewhere, but if VC is good and VS is off, the air meter needs to be adjusted or replaced. THA, the temp signal, should be measured by checking resistance directly on the air meter terminals; see the VAF Meter section: http://personal.utulsa.edu/~nathan-b...33volumeai.pdf (Unless the outside temp just happens to be 68 deg F, in which case you can use the volt range in the Troubleshooting section.) To check volts on ecu terminals, use backprobe adapters for your multimeter, or, if you don't have, push needles into the connectors and hold test leads against them.
To check the ECT (engine coolant temp sensor), check the volts between E2 and THW on the ecu when ignition is on and engine at operating temp. Should be .2 to 1 volts.
To check the PAIR system, see instructions in the Emissions PAIR System section of the fsm, as mentioned.
For fuel pressure, see the MFI System - Fuel Pump section for specs. Probably easiest to have a shop do that for you, but if you want to do it yourself, see these posts:
https://www.yotatech.com/forums/f116.../#post51210586
http://www.toyotanation.com/forum/sh...76#post3022876
As mentioned, too-high fuel pressure is rare. You could at least check that the return line is free by removing the fuel filler cap, then removing the lower, larger rubber hose from the side of the fuel pressure regulator (that's the return line), give it a few minutes for most of the gas to drain into tank, then try to blow into the return line. At first you'll be pushing the fuel remaining in the back part of the line up into the tank, but after that, the line should be clear and it should be easy to blow into it. Obviously, you'll want to avoid getting any fuel or fumes into your body.
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10-19-2010, 04:55 PM
#10
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not a problem with an engine that is pre 1996. I don't have a cat on mine. however.... depending on where your at, it's probably not a good idea.
10-19-2010, 05:07 PM
#11
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Wouldn't hurt anything. You could also eliminate the PAIR system to since it's only purpose is to inject fresh air into the exhause to help catalyzation of the exhaust gases. But sombody recently stole the cat off my Girlfriends '91 P/U so I just replaced it with a straight pipe. Every night for the first week she came home telling my how her truck smells like a lawn-mower. And people following you won't appreciate it either. If it isn't clogged I would just leave it as it causes little to no power loss.
10-19-2010, 05:09 PM
#12
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But Magnaflow cats are cheap and work well - no restriction of exhaust. Part # from here: http://www.car-sound.com/ and search ebay for magnaflow and the part # for a good price.
10-19-2010, 05:20 PM
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10-19-2010, 06:25 PM
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Only problem would be if it were a California truck. Way to tell is that CA trucks have two O2 sensors: one in front of the cat, and the other one behind it.
But Magnaflow cats are cheap and work well - no restriction of exhaust. Part # from here: http://www.car-sound.com/ and search ebay for magnaflow and the part # for a good price.
But Magnaflow cats are cheap and work well - no restriction of exhaust. Part # from here: http://www.car-sound.com/ and search ebay for magnaflow and the part # for a good price.
10-19-2010, 07:11 PM
#16
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Would you recommend the direct fit over the universal fit? Found one for $97 bucks on ebay. Still $97 bucks more than just chpooing it off...lol I'll have to think about the pro's vs con's of chopping it. I'm not worried about the law or emmisions around here. Besides this is not an everyday use truck, just a hunting truck used primarily in the winter.
If you do use the direct fit, you'll need two donut shaped cat gaskets. I also bought new bolts, nuts and a hangar from the dealer.
I've read reports where folks had better performance with a cat than with a straight pipe, but I have no way of knowing if those reports are reliable.
10-20-2010, 04:04 PM
#18
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First, what was out of spec and what were the numbers? There's a spring that can be adjusted to richen or lean out the mixture. I've not done it but search the forum because I've read of a number of people adjusting it.
If you do need a replacement, I would try to find one at a junkyard or on craigslist, but bring a multimeter and the specs so you can check it out before laying down any cash. As for price, I've seen anywhere from $40 to $165. You can usually find them on ebay, but you take the chance that it may be out of spec. There are some remanufactured units available; presumably those are okay but they're more $$.
If you do need a replacement, I would try to find one at a junkyard or on craigslist, but bring a multimeter and the specs so you can check it out before laying down any cash. As for price, I've seen anywhere from $40 to $165. You can usually find them on ebay, but you take the chance that it may be out of spec. There are some remanufactured units available; presumably those are okay but they're more $$.
10-20-2010, 04:20 PM
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E2-Vs was reading over 1000 ohms when closed. It should be 20-400 ohms.
