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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / September 2006help exhaust glowing
HI everyone my misses just got back from the shop and says the car is running sluggish. Also loss of power and when i looked underneith because i thought i could here the exhaust blowing god damn the exhaust at the front end of the car is glowing red hot is this normal i think not but can anyone tell us what it could be. gratefully yours simon sihen Wrote: > HI everyone my misses just got back from the shop and says the car is > running [quoted text clipped - 6 lines] > gratefully yours > simon Catalytic convertor or muffler's hogged up, exhaust can't get out...  Signaturejeffcoslacker http://www.automotiveforums.com Holy night fighters looking for glowing exhaust stacks to find the bombers! This is not normal unless an engine has been running very hard for a long time. I am guessing that you may have roached a turbocharger (if so equipped) or are running so horribly overrich that a lot of fuel is actually burning within the exhaust manifold. I'd actually consider having this one towed to a reputable mechanic. Best of luck, --Joe > HI everyone my misses just got back from the shop and says the car is > running [quoted text clipped - 6 lines] > gratefully yours > simon Ad absurdum per aspera Wrote: > or are running so horribly overrich that > a lot of fuel is actually burning within the exhaust manifold. I'd > actually consider having this one towed to a reputable mechanic. I have a problem with this...and I'm not trying to start a fight or imply that you don't know what you are talking about...because you obviously do...BUT.. A rich mixture cools combustion. It CAN make the area near the exhaust port run somewhat hotter than normal due to continued burning after the exhaust stroke IF...there is a supply of oxygen available to the hot mixture inside the exhaust system. This is usually not the case, however. It would happen sometimes on the old early emissions control equipped motors that had active or passive air injection into the manifolds...the idea being that any unburned mixture would spontaneously reignite after being expelled from the cylinder, saving the cat from having to deal with it if possible. In the instance of an extemely rich condition, you would sometimes see them with manifolds glowing hot, feeding afterburn with injected fresh air... But in gereral (no more A.I.R. systems), if you want to see a manifold turn red, an extremely LEAN mix is the way to go about it...a lean mix ignites earlier, burns way hotter and is still hot leaving the cylinder, and at the manifold you'll see temps as much as 300F hotter than normal...hot enough to completely blue chrome on motorcycle pipes, where an over rich mix will just tint them slightly gold, if it discolors them at all... I could demonstrate this to you if you lived near me, if you point a infrared remote pyrometer at the turn where the pipe leaves the cylinder on a bike, you'll see 500-600F on a well tuned bike, maybe 650-700F on one that runs rich, and as high as 900F on a lean running motor... Another thing...the cat. It gets hotter the more unburned fuel it has to digest. At a certain point, it becomes too much, and it will begin to overheat, glow, and the interior structures will begin to fall apart, sometimes ending in a complete blockage with burn-through like I believe this person is seeing...so if it turns out that is the case, it would be wise to consider the car's state of tune and correct any problem that might have led to this point... Signaturejeffcoslacker http://www.automotiveforums.com > Another thing...the cat. It gets hotter the more unburned fuel it has > to digest. At a certain point, it becomes too much, and it will begin > to overheat, glow, I once saw this exact thing on an '80s Lada Riva (Russian 4WD). It later turned out the carb float had sunk and tons of fuel was being dumped into the engine to the point that the engine eventually stalled and would not restart. By the time I got to see it, the cat was glowing literally orange and the rubber hanger rings were on fire. Good thing there was snow beside the road. By throwing snow at the cat, we were able to extinguish the fires before the vehicle itself went up. That was a night to remember, let me tell you. SignatureTeGGeR® > I once saw this exact thing on an '80s Lada Riva (Russian 4WD). > By the time I got to see it, the cat was glowing literally orange When did Lada ever fit cats ? dingbat@codesmiths.com wrote in news:1157715455.446907.8530 @d34g2000cwd.googlegroups.com: >> I once saw this exact thing on an '80s Lada Riva (Russian 4WD). > >> By the time I got to see it, the cat was glowing literally orange > > When did Lada ever fit cats ? In Canada in the '80s. SignatureTeGGeR® I've just had this exact thing with my VW. Had to have a brand new exhaust system and the catalytic converter had completely crumbled, so effectively the car couldn't breathe. I had severe loss of power (couldn't go over 70) and it sounded like the exhaust was going. Apparently I was lucky the car didn't catch light. Hope you've got a wad of cash to hand... > dingbat@codesmiths.com wrote in news:1157715455.446907.8530 > @d34g2000cwd.googlegroups.com: [quoted text clipped - 6 lines] > > In Canada in the '80s. TeGGeR® Wrote: > I once saw this exact thing on an '80s Lada Riva (Russian 4WD). It > later [quoted text clipped - 15 lines] > -- > TeGGeR® The Russian cars of the 80s had cats? Signaturesilicon212 http://www.automotiveforums.com > The Russian cars of the 80s had cats? In Canada they did after a certain point. SignatureTeGGeR® >> The Russian cars of the 80s had cats? > >In Canada they did after a certain point. Until they fell off, anyway. Like everything else on the Lada. --scott Signature"C'est un Nagra. C'est suisse, et tres, tres precis." > > The Russian cars of the 80s had cats? > > In Canada they did after a certain point. > > -- > TeGGeR® My 86 Jeep CJ7 didn't come with a cat, the 87's did though. Maybe that's the cut off year? Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590 (More Off Road album links at bottom of the view page) >> > The Russian cars of the 80s had cats? >> [quoted text clipped - 3 lines] > > Maybe that's the cut off year? Could be. Leaded gas was banned in Canada around about 1987. Some cars had cats earlier. The Mazda RX-7 had one for 1981. In that case, it enabled Mazda to get rid of the trouble-prone thermal reactor. SignatureTeGGeR® > Ad absurdum per aspera Wrote: > [quoted text clipped - 14 lines] > old early emissions control equipped motors that had active or passive > air injection into the manifolds... Most vehicles still have at least passive air aspiration systems. You can't make a catalyst work without some added air in the exhaust stream. Much LESS air is added now than in the days of big air pumps on carbureted engines, but its still added. > if you want to see a > manifold turn red, an extremely LEAN mix is the way to go about it... Or run with a severe misfire. A misfire causes perfectly-mixed ready-to-burn air/fuel to be dumped into the exhaust plumbing. A dead cylinder or two will melt down an exhaust system pretty easily, which is why for 30 years now its been against recommended service procedure to pull a spark plug wire, even briefly, for diagnostic purposes. > Another thing...the cat. It gets hotter the more unburned fuel it has > to digest. At a certain point, it becomes too much, and it will begin > to overheat, glow, and the interior structures will begin to fall > apart Not without that oxygen you claim isn't available in an over-rich mixture. A catalyst FACILITATES combustion, but it can't create combustion without both fuel and oxygen to combine. Steve Wrote: > , which is > why for 30 years now its been against recommended service procedure to > pull a spark plug wire, even briefly, for diagnostic purposes. Actually it's to keep raw HC out of the Cat, for the reason I explained before. > Not without that oxygen you claim isn't available in an over-rich > mixture. A catalyst FACILITATES combustion, but it can't create > combustion without both fuel and oxygen to combine. There is no combustion occuring in the cat. If there is, it destroys it, as I said. Check your understanding of a cat's job. You have some wrong assumption going. Also explain where this air is admitted to the exhaust stream. Haven't seen an air pipe on a cat since the mid 90's...an OBD II system with up- and downstream O2 sensors couldn't provide any useful info in an open system with air being admitted post-combustion... Signaturejeffcoslacker http://www.automotiveforums.com jeffcoslacker Wrote: > Actually it's to keep raw HC out of the Cat, for the reason I explained > before. [quoted text clipped - 7 lines] > up- and downstream O2 sensors couldn't provide any useful info in an > open system with air being admitted post-combustion... OXYGEN STORAGE In order to oxidize CO and HC, the catalytic converter also has the capability of storing the oxygen from the exhaust gas steam, usually when the air fuel ratio goes lean. When insufficient oxygen is available from the exhaust stream the stored oxygen is released and consumed. This happens either when oxygen derived from NOx reduction is unavailable or certain maneuvers such as hard acceleration enrich the mixture beyond the ability of the converter to compensate. Signaturejeffcoslacker http://www.automotiveforums.com > Steve Wrote: >> , which is [quoted text clipped - 16 lines] > up- and downstream O2 sensors couldn't provide any useful info in an > open system with air being admitted post-combustion... If you would bother to check almost every eng still has a air pump. and air passages are intragel with the head, not external. air is still added post combustion as has been since the adoption of cats. SignatureThunder Snake #9 "Protect" your rights or "lose" them. Kevin Bottorff Wrote: > If you would bother to check almost every eng still has a air pump. > and air passages are intragel with the head, not external. air is still > added post combustion as has been since the adoption of cats. > . Really? As a state liscenced emissions tech since 1991, that's the first I've heard of it, outside of the active and passive systems I've already described, which are obsolete now. Where is this pump located? I'll have to go check it out. Wanna explain how a closed loop feedback system with multiple o2 sensors can create an accurate reading of o2 levels in combustion gases if external air is admitted before sensing? I'm fascinated. Please quote some sources, because I've been looking since you posted this, and can't find a thing about it... Signaturejeffcoslacker http://www.automotiveforums.com Well, one of the things that's limited us to handwaving in this diagnosis is that the original poster didn't really specify anything about make, model, year, engine... Leaks can also admit external air where and when the designers didn't mean to, under some conditions. Anyway, he and friends have evidently established internal clogment of the cat as the problem. So... what caused that? Did it just get old and/or rusty and collapse internally, or was this a meltdown from excess fuel? I think that car needs more diagnosis before it gets a clean bill of health... and in particular, throwing a new cat into a car that tends to plug the things by puking oil and/or macroscopic amounts of unburned gas into them could be an expensive waste of parts. Cheers, --Joe > Kevin Bottorff Wrote: >> If you would bother to check almost every eng still has a air pump. [quoted text clipped - 14 lines] > Please quote some sources, because I've been looking since you posted > this, and can't find a thing about it... ok then, explain how they ever did it. They have had O2 sensors since before FI and were using air pumps then too, and not just to blow into the cat as some now do. (not an answer just a question) I am going to recheck some newer ones to see about the air pump and head air injection thing to be sure. KB SignatureThunder Snake #9 "Protect" your rights or "lose" them. Kevin Bottorff Wrote: > > Kevin Bottorff Wrote: > >> If you would bother to check almost every eng still has a air pump. [quoted text clipped - 28 lines] > Thunder Snake #9 > "Protect" your rights or "lose" them. Early O2 sensor systems used air pumped into the forward portion of the cat, that and the O2 sensor resided upstream of that point, so it was monitoring pre-air injection gases. As soon as pre and post cat sensor setups and full closed loop became the rule, air injection had to be abandoned...not neccessary with the fine control of mixture that dual sensors and faster processing offered... some real early ones had an O2 sensor right up next to the engine in the manifold, with air injected slightly downstream, those manifolds has a big "plenum" shape to them...the sensor still monitored mixture ahead of the incoming air... Carbed engines with O2 sensors were very crude feedback systems, made to try to maintain an "overall" quality of mixture, rather than moment by moment control... Signaturejeffcoslacker http://www.automotiveforums.com > Kevin Bottorff Wrote: > > [quoted text clipped - 33 lines] > Early O2 sensor systems used air pumped into the forward portion of the > cat, That would render the NOx bed inoperative. > that and the O2 sensor resided upstream of that point, so it was > monitoring pre-air injection gases. As soon as pre and post cat sensor > setups and full closed loop became the rule, air injection had to be > abandoned...not neccessary with the fine control of mixture that dual > sensors and faster processing offered... Mid 90s GM OBD2 systems used an electric air pump that pumped into the exhaust manifolds. An example would be a 1996 Pontiac Grand Prix with a 3400 engine. Worked on a late 90s Audi a while back that had a secondary electric air pump also. > some real early ones had an O2 sensor right up next to the engine in > the manifold, with air injected slightly downstream, those manifolds [quoted text clipped - 4 lines] > to try to maintain an "overall" quality of mixture, rather than moment > by moment control... The original GM feedback system introduced in 1980 was called CCCC (Computer Controlled Catalytic Convertor) it controlled whether the air pump switched upstream to the manifolds, downstream to the cat or dumped to atmosphere. The CCCC moniker was changed in 1981 to CCC Computer Command Control, it was a bit more refined, a bit more powerful but still controlled whether the air pump switched upstream, downstream or atmospheric. On cold start open loop, it's no special trick to pump air into an exhaust manifold, on warm engine closed loop, it's no special trick to pump air downstream to an oxidizing bed of a catalytic convertor or to atmosphere, or in the case of an electric air pump, simply shut it off. aarcuda69062 Wrote: > That would render the NOx bed inoperative. > [quoted text clipped - 4 lines] > Grand Prix with a 3400 engine. Worked on a late 90s Audi a while > back that had a secondary electric air pump also. A 1996 Pontiac would still be OBD I... > The original GM feedback system introduced in 1980 was called CCCC > (Computer Controlled Catalytic Convertor) it controlled whether [quoted text clipped - 8 lines] > convertor or to atmosphere, or in the case of an electric air > pump, simply shut it off. These I never had to have any real reason to understand, was not doing emissions control work when they were still rolling in numbers, so thanks for that, it was interesting. Signaturejeffcoslacker http://www.automotiveforums.com > aarcuda69062 Wrote: > > > > That would render the NOx bed inoperative. > > > > Early 2 way cats didn't deal with NOx... Well, yeah, by definition, a two way cat wouldn't be reducing NOx. Bulldozers don't float either. Define "early." You claim having a smog license since 1991. > > Mid 90s GM OBD2 systems used an electric air pump that pumped > > into the exhaust manifolds. An example would be a 1996 Pontiac > > Grand Prix with a 3400 engine. Worked on a late 90s Audi a while > > back that had a secondary electric air pump also. > > A 1996 Pontiac would still be OBD I... It most certainly would not. Hell there were 'pull ahead' 94s and 95s that were OBD2. > > The original GM feedback system introduced in 1980 was called CCCC > > (Computer Controlled Catalytic Convertor) it controlled whether [quoted text clipped - 12 lines] > emissions control work when they were still rolling in numbers, so > thanks for that, it was interesting. Glad to help. aarcuda69062 Wrote: > > aarcuda69062 Wrote: > > > [quoted text clipped - 7 lines] > > Glad to help. I know there were some that didn't fully incoporarte all the OBDII equipment but could be scanned as OBDII, they were called OBD 1.5 or something like that, never ran across one *with a reason for me to note that aspect of it anyway) I meant real early. Back in the dark ages. Smog pumps. 2 way cats. Big block motors that couldn't pass a 1.5L Toyota Tercel with a rolling start...when did diagnostic connectors and check engine lights start showing up on everything, about 1981? That's the age I'm talking. Signaturejeffcoslacker http://www.automotiveforums.com > about 1981? That's the age I'm talking. In 198O and later, there certainly was a preponderance of three way NOx reducing cats. That was the whole point of having the PCM control where the air pump introduced the O2 (either upstream into the exhaust manifold or downstream into the second bed of the cat). On cold start with a rich mixture, there isn't much NOx production but there is excess CO and HC, so the air pump pumped O2 into the exhaust manifolds to aid oxidization of CO and HC before it could overload the cat. On warm running with the PCM in closed loop, the air pump was switched to downstream where it pumped O2 to the rear oxidizing bed for final clean up of CO and HC, the NOx reducing bed was forward located in the cat ahead of the air pump inlet because O2 hinders the reduction of NOx. At some point into closed loop, the air pump -might- have been switched to dump to atmosphere if the NOx bed was reducing sufficiently to supply the rear oxidizing bed with the O2 it needed to work properly. Nowdays, with really efficient NOx reduction, there is enough O2 split off of the NOx molecules to feed the rear oxidizing bed the O2 supply that it needs, thus making air pumps somewhat less necessary but not totally extinct. >>Kevin Bottorff Wrote: >> [quoted text clipped - 15 lines] >>sensors can create an accurate reading of o2 levels in combustion gases >>if external air is admitted before sensing? I'm fascinated. Ever heard of "upstream sensor" and "downstream sensor?" Steve Wrote: > >>Kevin Bottorff Wrote: > >> [quoted text clipped - 19 lines] > > Ever heard of "upstream sensor" and "downstream sensor?" You misread everything I post, and then throw it back at me without comprehension as if you are making a point, when you are saying exactly what I just said....What did you think I meant by multiple sensors? Signaturejeffcoslacker http://www.automotiveforums.com > Steve Wrote: > >>>jeffcoslacker <jeffcoslacker.2du58n@no-mx.nodomain.com> wrote in <snip> >>>>if external air is admitted before sensing? I'm fascinated. <snip> >What did you think I meant by multiple sensors? My bad- I missed the "before sensing" clause. Indeed the whole point of multiple O2 sensors is to have at least one of them always able to sense the raw O2 content of the exhaust coming out of the engine before its either corrupted by the reduction catalyst or by air injection. The downstream sensor measures how well everything works as a system, and enables OBD-II level diagnostics. IOW, the upstream sensor controls the fuel trim, the downstream sensor tells if the emission controls are working. But the whole point is that, even today, air injection is still used to make the oxidation catalyst perform better. LESS air is used, and the big belt-driven air pump is indeed almost (if not) extinct. But air injection lives on. But getting back to the ORIGINAL post- I still say that a glowing exhaust is most likely the result of a misfiring cylinder (or several) since that is the process that dumps ready-to-burn air/fuel mix into the exhaust stream. Steve Wrote: > > Steve Wrote: > > [quoted text clipped - 27 lines] > the > exhaust stream. It could be...I just figured that most people would notice something strange and the post would be like "My car has been running like crap and now..." or "I've been getting terrible gas mileage, and now my manifold is glowing..."...but perhaps I assume too much... Anyways, you got me on that secondary injection...wasn't part of my understanding of the system, and I apologize for doubting you. Signaturejeffcoslacker http://www.automotiveforums.com Keep driving it like that, and you'll torch the exhast valves and head gasket, if you don't catch something on fire first... Tow truck time, if you're smart... Signaturejeffcoslacker http://www.automotiveforums.com Unburned fuel in the exhaust will cause the exhaust to glow even without AIR. Retarded timing or crossed plug wires will leave unburned fuel in the exhaust. jeffcoslacker and his pyrometer are also accurate as far as combustion temp and fuel ratio. What you have is a fire inside the exhaust. AIR will make the exhaust even hotter becuase of fresh O2 supplied to the unburned fuel in the exhaust. After all, that is exactly what AIR is designed to accomplish. SignatureJustSayGo http://www.automotiveforums.com what are you using for fuel? are you adding any octane? That does that. > Unburned fuel in the exhaust will cause the exhaust to glow even without > AIR. Retarded timing or crossed plug wires will leave unburned fuel in [quoted text clipped - 3 lines] > supplied to the unburned fuel in the exhaust. After all, that is > exactly what AIR is designed to accomplish. ed Wrote: > what are you using for fuel? are you adding any octane? That does that. > [quoted text clipped - 18 lines] > > > > http://www.automotiveforums.com Whaaa?:screwy: Signaturejeffcoslacker http://www.automotiveforums.com Hi everyone just an update Had the car checked at work luckly i work for bus company so thers lots of mechinics about. Pretty much every one was right the cat died. Gotta do lots of overtime to get it fixed. Thought about just putting a staight pipe on there but i far to concerned about the environment to do that so looks like i gotta get the p[ushbike out the shed. Thanks for all the reply's Si... Bristol England > Hi everyone just an update > Had the car checked at work luckly i work for bus company so thers lots [quoted text clipped - 6 lines] > Thanks for all the reply's > Si... Just gut the cat, it's toast anyway... > Bristol > England Ulf jeffcoslacker Wrote: > Sorry, you were right, a 1996 Pontiac could have been OBDII, depending > on model and build date. hey, tell me more about this system, please. Apperas I have a huge hole in my knowlege (apologies to any I led to believe they were wrong)...never run across trouble with it, but I did a little looking and it seems it's a quite common issue on some S Model GM trucks... Signaturejeffcoslacker http://www.automotiveforums.com jeffcoslacker Wrote: > Sorry, you were right, a 1996 Pontiac could have been OBDII, depending > on model and build date. Wasn't OBDII government-mandated for all cars beginning in 1996? Signaturesilicon212 http://www.automotiveforums.com So very likely the exhaust system or at least the converter(s) are already damaged. Excessive fuel from cyl miss-fire; most likely multiple miss-fire is the likely cause. Rising combustion temps will increase exhaust temp. Excessive exhaust temp that hinders combustion will in most cases lower combustion temp. SignatureJustSayGo http://www.automotiveforums.com |
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