Kaweh
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Re: Glowing Exhaust Manifolds
Gjac wrote: How hot does the engine get when climbing a hill? What is the temp reading on a flat? Engine is steady at 120 on flat land and once I climb and the manifolds get hot it slowly creeps up to maybe160, or 180. But it doesn't overheat. Fan clutch motor works great.433Views0likes0CommentsRe: Glowing Exhaust Manifolds
ddndoug wrote: kaweh - Have you tried "reading" the spark plugs to see if the air/fuel mixture is too lean? I'm guessing you already know this, but.... Are you disconnecting the timing advance wire while you are setting the base timing? Doug Yes exactly. timing is correct. I don't know about that spark plug reading. We have a snap on computer and so the GM shop foreman agreed to come on a test drive with me and do some data logging to what is happening at the moment they start to glow. At idle he said it was running a bit rich. not too much though he said. he wasn't worried about it. But I believe what is happening up a hill it's leaning out. we'll see early next week.433Views0likes0CommentsRe: Glowing Exhaust Manifolds
Does your fan clutch come one with a loud roar when climbing a hill on a hot day? What is your timing set at? Yeah Man, the fan works. 12 degrees advance. Everything works, no engine codes. great power in the city. Engine starts to drag up the hill, giving more fuel makes exhaust glow.433Views0likes0CommentsRe: Glowing Exhaust Manifolds
thanks for all the info everyone. The timing is correct because I even did it by ear and waited til it pings then backed it off. It is possible that they got a little red before but whey then all of a sudden after the backfire did my air line going to the air horns pop? That should have happened six years ago, the first time it climbed to Reno and I went up the grapevine to L.A.433Views0likes0CommentsRe: Glowing Exhaust Manifolds
Rickieblue wrote: I would say the timing marks you are using have changed and you are running the engine timing retarded. Chev harmonic balancers are known to shift due to 2 piece construction with the rubber between them deteriorating. I would advance the timing until it pings under heavy load and back it off a touch or put it on a chassis dyno and adjust it to get max horsepower. Just my 2 cents worth........ Thank you for that info. Remember this was happening before the rebuild and still. Also, I did just that. It is now at its maximum advanced timing before pinging.192Views0likes0CommentsGlowing Exhaust Manifolds
Hello, I've read a lot of posts here over the past 4 months and so I thought I'd chime in for some possible RVer insight. I drive a 34' Winnebago Elante year 1992 with a 7.4L Chevy. Five months ago I had a backfire that was caused by the injector wire grounding out to the throttle body. Ever since that was fixed I've noticed the exhaust manifolds glow under a load. Lots of testing led me to learn that the manifold vacuum was not steady and so I even went as far as rebuilding the engine. I left the camshaft alone but changed the lifters even though they were fine. The previous exhaust manifolds were cracked so I put on new ones and the heads were sent to the machine shop and came back looking brand new. Other things that were changed are the MAP sensor, O2 sensor, engine coolant sensor, water pump, timing chain, of course a full tune up and initially we thought the catalytic converter was clogged, which it wasn't so i put a new one in and checked the muffler too. So now it's rebuilt with a new computer, the right injectors and a new higher performance fuel pump. The fuel pressure now reads 12 psi. All cylinders were tested and show 150 psi, the fuel pressure regulator was rebuilt as well, The car fires right up and has great power in the city or straight a ways. The timing is advanced 12 degrees and I've ran it at 4 whites factory spec and at 6 degrees advanced and no matter what I've tried and tested it still makes the exhaust manifolds glow ridiculously red when i'm going up a hill. Giving it more gas just makes them glow more. So bad that at night you can see the both manifolds glow all the way past the Y pipe. Its scary!!! I've replaced all vacuum lines, tested for vacuum leaks (none found). Its bizarre, I've met some amazing mechanics over this past 6 months and they are all stomped! So i read a lot on here about how some folks put on headers and I know that this year 454 was prone to exhaust leaks, restrictions and manifold cracks. So I wonder did ya'll have this happen to you too or do you think it's normal for the manifolds to glow like crazy when on a hill? Is it somewhat normal for them to glow? If so to what degree? Cause this is scary bright red and even though i've had people say it's normal.... you're putting a lot of strain on this engine and 16,000 pounds blah blah blah, I don't buy it and here is why....... Some wise guy who owned it before me had put on air horns. Well the compressor for the horns was all the way in the back of the coach and the holding tank in the front by the radiator! Dumb design! nonetheless, i have owned this RV for six years and we went to Burning Man in it all six years and before this happened my air horn worked. It turns out when the manifolds started to glow, it cracked and melted the air line. the line was going along the frame and past the right exhaust manifold. And so if they were glowing before like this, the air horn air line would have bursted before. So that's how I know this is not normal. Any thoughts are appreciated. I'm considering changing the exhaust to duels and a chip upgrade from tbichips.com but the car has been fine since 1992 and I don't think i should have to upgrade stuff to stop it from burning up the exhaust manifolds. Ok, thats it for meow. Thanks for reading! Kaweh www.kaweh.com Spanish Guitarist San Francisco Bay Area.5.3KViews0likes23Comments
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