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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#41
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Automotive emission controls
Eric Swanson wrote: You didn't mention the mileage on the engine. 27,100. No kidding. The car is hardly driven. One final point to check, if you haven't already done so, would be your PCV valve, I hadn't thought about that. Thanks. |
#42
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Automotive emission controls
Beloved Leader wrote:
Dave Plowman (News) wrote: Then presumably has an adjustment for the idle mixture? Yes, but they're sealed. Federal law and so forth. I mean, no one would ever know, but to get at the idle mixture adjustment screws, I'd have to take the carburetor off and drill out the sealing plugs. There are quite a few connections to the carburetor, so its removal is a major undertaking. I didn't have much trouble fixing my Toyota's carb and got only 2 of its 14 vacuum hoses wrong (taking clear photos or making sketches is a good idea). The instructions included with the aftermarket rebuild kit were better than those found in Chilton and Haynes manuals and almost equal to the factory manual (but there's a book specifically about Rochester carbs that's probably better than anything). OTOH aftermarket rebuild kits may be noticeably inferior in quality, and with my first kit, by Tomco, the rubber parts turned rock hard after five years, and the float valve clogged because it lacked a filter screen to trap the bits of rubber that flaked off the fuel line. The float valve clogged as a result, yet Tomco advertrised that its float valves were more clog resistant than others'. I was to told to not disassemble the carb any further than necessary. For example, the choke and throttle plates should be left alone, as should any adjustment screws, but if it's necessary to touch the latter, count the exact number of turns of their original settings because a lot of times there's no simple way to adjust them correctly, i.e., to set the idle mixture you may be instructed to use an exhaust gas analyzer. |
#43
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Automotive emission controls
Homer J Simpson wrote: wrote in message ups.com... By the way, run the air conditioner compressor for at least 10 minutes in a row each week, even during the winter, to keep the shaft seal from drying out. You have a Freon R-12 system and don't want any of that gas to leak out, and you don't want to convert to R-134a the wrong way (cheap, quick conversions don't perform well and have high failure rates). What about http://www.duracool.com/ ?? The web site says their R-12a substitute for Freon R-12 contains propane, and propane/butane blends are known to cool well in systems originally made for R-12. But I'd never try that since I don't like explosions in my car, and while Duracool downplays the danger, I doubt the refrigeration industry would have made such major efforts in the early 20th century to develop nontoxic, nonflammable refrigerants if the refrigerants available at the time had been reasonably safe. |
#44
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Automotive emission controls
wrote in message ups.com... What about http://www.duracool.com/ ?? The web site says their R-12a substitute for Freon R-12 contains propane, and propane/butane blends are known to cool well in systems originally made for R-12. But I'd never try that since I don't like explosions in my car, and while Duracool downplays the danger, I doubt the refrigeration industry would have made such major efforts in the early 20th century to develop nontoxic, nonflammable refrigerants if the refrigerants available at the time had been reasonably safe. Actually they were more concerned about poisoning the customer. Methyl Chloride and ammonia are pretty nasty. The stuff in Duracool is pretty much what is in a can of instant whipped cream - or anything else like that. With 12 gallons of gas under the car, 12 oz of butane in the engine compartment doesn't worry me. |
#45
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Automotive emission controls
Beloved Leader wrote:
wrote: Are you using only GM ignition parts -- AC plugs, wires, rotor, and distributor cap? No. At the very least, put in AC brand spark plugs. Regular copper-cored ACs are fine; there's no need for expensive platinum plugs.. The other parts, regardless fo brand, should be OK, except for any inductive supressive wires. If you have such wires (each measures only a few hundred ohms, some brands are Borg-Warner "Kool Wire" and Splitfire), replace them with regular resistive supressive wires (thousands of ohms per wire). Unless the distributor rotor or cap has developed hairline cracks from high voltage, there's no need to replace either, unless the rotor is shorter than the original (I've seen that). I mistakenly thought your idle speed was wavering, but since it's rock steady and the CO and NOx are low, I can't imagine there being a fuel system problem, and I doubt there are even vacuum leaks. So I have to believe the trouble lies with the ignition. Someone suggested the evaporative emissions system, but I believe it would also raise the CO since it vents the fuel vapors into the intake and makes the mixture richer. By the way, run the air conditioner compressor for at least 10 minutes in a row each week, even during the winter, to keep the shaft seal from drying out. You have a Freon R-12 system Ice cold, baby. The real deal. The good stuff. It's good you don't have a leaky Ford system or you could need a recharge every 2 years. I don't see the purpose of top engine cleaner here, and I'm surprised a dealer mechanic would recommend it, at least not without first reading out the CCC data stream during engine operation to find any abnormalities (temperatures, barometric and manifold pressures, oxygen sensor voltage, throttle position, fuel mixture solenoid duty cycle, etc.). The oldtimers like the stuff. Remember that the CCC system is ancient, being of the same vintage as 8088-based computers. It is way obsolete compared to OBD II. There is no such thing as a CCC data stream. It does not provide the sort of information you mention. Here's a web site for ALDL information from GM computers, and they say it was available as far back as 1982 with the CLCC system. I don't know if that's the same as CCC: www.ws6transam.org/ALDL.html www.ws6transam.org/aldl_28.html |
#46
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Automotive emission controls
Homer J Simpson wrote: wrote in message ups.com... What about http://www.duracool.com/ ?? The web site says their R-12a substitute for Freon R-12 contains propane, and propane/butane blends are known to cool well in systems originally made for R-12. But I'd never try that since I don't like explosions in my car, and while Duracool downplays the danger, I doubt the refrigeration industry would have made such major efforts in the early 20th century to develop nontoxic, nonflammable refrigerants if the refrigerants available at the time had been reasonably safe. Actually they were more concerned about poisoning the customer. Methyl Chloride and ammonia are pretty nasty. The stuff in Duracool is pretty much what is in a can of instant whipped cream - or anything else like that. With 12 gallons of gas under the car, 12 oz of butane in the engine compartment doesn't worry me. The propellant for whipped cream is usually nitrous oxide, as many people who've used it for cheap thrills have discovered. If propane/butane was so safe, why haven't any makers of autos, refrigerators, or air conditioners used it in the past several decades? |
#48
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Automotive emission controls
wrote: www.ws6transam.org/ALDL.html www.ws6transam.org/aldl_28.html I should add: when my car is tested, it is connected to the test equipment in three ways. 1) The rear (driving) tires are on the treadmill, providing speed information. 2) An exhaust gas analyzer probe is inserted into the tail pipe, providing exhaust gas information. 3) An inductive pickup is clipped over one of the spark plug wires, providing engine rpm information. There is no connection made between the ALDL port and the test equipment. |
#49
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Automotive emission controls
wrote in message oups.com... The propellant for whipped cream is usually nitrous oxide, as many people who've used it for cheap thrills have discovered. If propane/butane was so safe, why haven't any makers of autos, refrigerators, or air conditioners used it in the past several decades? "Today, almost all aerosol cans contain alternative propellants, such as liquefied petroleum gas, which do not pose as serious a threat to the environment". http://science.howstuffworks.com/aerosol-can3.htm The Plain Man's Guide to Aerosols http://www.yorks.karoo.net/aerosol/link4.htm As for what and why, there's a safety difference between what is used in a domicile and what is under the hood. It is possible that even the new refrigerants will wind up being banned in time. |
#50
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Automotive emission controls
Beloved Leader wrote: wrote: Here's a web site for ALDL information from GM computers, and they say it was available as far back as 1982 with the CLCC system. I don't know if that's the same as CCC: www.ws6transam.org/ALDL.html www.ws6transam.org/aldl_28.html Hey, I didn't know I could do that. My car is not at either of those links, so I will have to do some snooping to find a page right for me. I'm not sure how I process the data stream once I have it. I'm not very impressed with that Cadillac dealer because if you paid them they should have given a very specific diagnosis, like, "The problem is X, and the car will run right if Y is repaired/replaced," where Y isn't something like an entire new engine or car. What tests did the dealer perform? It's apparent that they didn't read out the ALDL data, but did they hook up an ignition oscilloscope, measure the exhaust emissions, check for vacuum leaks, or measure engine compression or leakage? Skill levels of mechanics can vary greatly. I once had a Chevy where the Chevy dealer that leased it couldn't solve a pinging problem, and after charging $240 (about $500 in today's dollars) they merely told me to run high octane gasoline. On the way home, on a whim I decided to stop at a Buick dealer, and they solved the problem in 20 minutes by changing a small restrictor or check valve in a vacuum line. That wasn't 20 minutes of repair time but 20 minutes from drive-in to drive-out. |
#51
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Automotive emission controls
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#52
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Automotive emission controls
wrote: Here's a web site for ALDL information from GM computers, and they say it was available as far back as 1982 with the CLCC system. I don't know if that's the same as CCC: www.ws6transam.org/ALDL.html www.ws6transam.org/aldl_28.html I think that all GMs from the early through the remainder of the decade used the CCC system, which just means that they had a computer managing certain aspects of the engine, transmission, and transmission. The CCC system then seems to be available in a variety of flavors. Some cars had throttle body injection, some had multi-port injection, and some used a carburetor. It seems to me that the cars with carburetors were referred to as being of the CLCC variety. http://www.ws6transam.org/aldl_28.html is the page that is probably so close to mine that I could use the information in provides directly. http://www.mitsi.com/Projects/types.htm Note that every system has an "I" in it somewhere other than the CLCC system. I believe the "I" stands for injection and the "C" for carburetor. |
#53
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Automotive emission controls -- The GOP wants to ask the voters one question: "what R U wearing -- R U naked"?
(Eric Swanson) wrote in
: In article .com, says... wrote: Try injecting propane or choke cleaner into the air intake (leave air filter and cover in place -- prevents fires in case of spit back) for a few seconds. If the idle (set to about 550 RPM) smooths out (injecting chemicals will make it speed up by as much as 200 RPM), suspect a vacuum leak or a carburetor problem. I can try that, using an unlit propane torch. Bear in mind that the idle's not rough, just low. Nonetheless, I find it hard to argue with such a sterling reading on my vacuum gauge. For the record, I'm getting my vacuum reading from a port that leads to the vacuum chamber for the car's vacuum-actuated cruise control. You didn't mention the mileage on the engine. Consider that older engines tend to have trouble with valve guide seals, which harden with age. A bit of extra oil will seep past into the intake and may add to your HC emissions, especially at low speeds when the throttle is almost closed. Also, your rings may be allowing some oil into the cylinders. One final point to check, if you haven't already done so, would be your PCV valve, which should close at high vacuum, but may be so dirty or worn that it is not doing so, thus allowing excessive amounts of gas into the intake manifold from the crankcase. The Dilapidated ****house Troll Swanson insisted that we need 50-60 years of data yet here he is pontificating without his 50-60 years of data. The GOP wants to ask the voters one question: "what R U wearing -- R U naked"? |
#54
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Automotive emission controls
Beloved Leader wrote: Dave Plowman (News) wrote: sound like the carb is faulty. Presumably being a late type it has electronically controlled mixture and idle speed? No. The Oldsmobile 5L/307 cid V8 is the last of the carbureted engines. The carburetor (US spelling) has a throttle position sensor, but everything about the carburetor's operation is mechanical, not electronic, unless there's something I'm overlooking. Thanks. Yikes. That's not right. The carburetor does indeed have a mixture control solenoid. Ten times per second, acting on readings from, among other sensors, the O2 sensor, it adjusts the air-fuel mixture. Wow, was that ever a wrong thing to say. I apologize for that. I got the instructions from a tech at the Cadillac dealer on how to use a dwell meter to check the operation of the mixture contol solenoid. I found a more appropriate port at which to measure my vacuum. It is about 19-20", but it is not steady. There is a vacuum leak somewhere in all those hoses. Those of you who said I had a vacuum leak, take a bow. I dread vacuum leaks. They can take forever to find. |
#55
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Automotive emission controls
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#56
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Automotive emission controls
In article . com,
Beloved Leader wrote: sound like the carb is faulty. Presumably being a late type it has electronically controlled mixture and idle speed? No. The Oldsmobile 5L/307 cid V8 is the last of the carbureted engines. The carburetor (US spelling) has a throttle position sensor, but everything about the carburetor's operation is mechanical, not electronic, unless there's something I'm overlooking. Thanks. Yikes. That's not right. The carburetor does indeed have a mixture control solenoid. Ten times per second, acting on readings from, among other sensors, the O2 sensor, it adjusts the air-fuel mixture. Right. I obviously don't know your car or carb being UK based, but SU in the UK produced electronically controlled carbs as a last ditch stand against injection before ceasing production. They used stepper motors for both idle and mixture control, and worked extremely well - while they worked, that is. Many have been converted back to 'manual' ;-) Wow, was that ever a wrong thing to say. I apologize for that. I got the instructions from a tech at the Cadillac dealer on how to use a dwell meter to check the operation of the mixture contol solenoid. I found a more appropriate port at which to measure my vacuum. It is about 19-20", but it is not steady. There is a vacuum leak somewhere in all those hoses. Those of you who said I had a vacuum leak, take a bow. I dread vacuum leaks. They can take forever to find. Spraying with something like WD40 can help while a helper observes the exhaust. If this gets drawn in and burnt, you'll get smoke. Is the heater/AC controlled anywhere by vacuum devices? The brake servo? Auto box? Remove all these feeds and blank off the outlets. But don't forget the engine crankcase breather system too when checking for leaks. -- *Sticks and stones may break my bones but whips and chains excite me* Dave Plowman London SW To e-mail, change noise into sound. |
#57
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Automotive emission controls
Dave Plowman (News) wrote: In article . com, Beloved Leader wrote: Yikes. That's not right. The carburetor does indeed have a mixture control solenoid. Ten times per second, acting on readings from, among other sensors, the O2 sensor, it adjusts the air-fuel mixture. Right. The Rochester Quadrajet on this car works, essentially, like all the other Rochester Quadrajets - venturis, float bowls, metering rods, idle circuits - same old stuff. The mixture control solenoid and throttle position sensor are different, though. Is the heater/AC controlled anywhere by vacuum devices? The brake servo? Auto box? Remove all these feeds and blank off the outlets. But don't forget the engine crankcase breather system too when checking for leaks. Yes, there are systems that run on vacuum signals. The cruise control is vacuum actuated, and the heater controls send a vacuum to motors that open or close doors to direct heated air to foot-level vents or face-level vents in the passenger compartment. I was getting an erroneous vacuum reading, because I had connected my vacuum gauge downstream of a check valve that sent vacuum to a storage tank that was part of the heater control system and cruise control. Even with the engine off, vacuum was present. That would have tipped me off right away, but I had disconnected my gauge with the engine running and did not note that effect. With the gauge connected upstream of the check valve (that is, between the intake manifold and valve), I now get a reading that better reflects the actual state of the vacuum. The vacuum is still at a good level, about 20", but the needle is twitching at about 10 Hertz, which is (incidentally?) the rate at which the mixture control solenoid is refreshed. Right now, I have the gauge on a long enough hose that I can sit in the driver's seat and watch it. The cruise control and heater controls are disconnected. Since this did not alter the stalling at idle, those circuits can be eliminated as a cause. |
#58
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Automotive emission controls
Dave Plowman (News) wrote: Is the heater/AC controlled anywhere by vacuum devices? The brake servo? Auto box? Remove all these feeds and blank off the outlets. But don't forget the engine crankcase breather system too when checking for leaks. I can't recall whether the TH200R4 transmission has a vacuum modulator or not. That's easily enough established. Thanks for writing. |
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