Toyota stalling may be linked to on-board computers, electroniccontrol module
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From: Don Stauffer on 7 Dec 2009 09:23 dr_jeff wrote: > john wrote: > > Really. The ECUs definitely have problems, but please show us a better > way that doesn't involve electronics. Carbs worked well, but wasted > fuel. Without electronics, are air would be dirtier, we would use more > fuel. > Why did carbs "waste" fuel? They used enrichment at high manifold pressure, but so do FI systems. The last generation of carburetors were quite good. What really is the difference between a carb and a throttle body electronic injection system? One is controlled by a pneumatic computer, the other by an electronic one. Admittedly electronic computers can be miniaturized, and add more computation. Essentially the carbs of the seventies and eighties DID have computers. The amount of measurement of their environment and the amount of control was remarkable. There were even the deceleration controls that got rid of richness during trailing throttle. They were marvels of fluidic computing.
From: dsi1 on 7 Dec 2009 14:37 Don Stauffer wrote: > > Why did carbs "waste" fuel? They used enrichment at high manifold > pressure, but so do FI systems. The last generation of carburetors were > quite good. What really is the difference between a carb and a throttle > body electronic injection system? One is controlled by a pneumatic > computer, the other by an electronic one. Admittedly electronic > computers can be miniaturized, and add more computation. > > Essentially the carbs of the seventies and eighties DID have computers. > The amount of measurement of their environment and the amount of > control was remarkable. There were even the deceleration controls that > got rid of richness during trailing throttle. They were marvels of > fluidic computing. > > Carbs were pretty remarkable for what they did. I have a fondness for these devices and found working on them to be a relaxing pastime although I'd usually disconnect or adjust the little dashpot to not retard the throttle closing. :-) That said, going back to carbs would be a big step backwards.
From: sctvguy1 on 7 Dec 2009 17:34 On Mon, 07 Dec 2009 22:15:12 +0000, Tegger wrote: > "hls" <hls(a)nospam.nix> wrote in > news:DMGdnUC4lMmn6IDWnZ2dnUVZ_jidnZ2d(a)giganews.com: > > >> "m6onz5a" <corvair(a)comcast.net> wrote in message >> news:abb95d2a-529e-4ee4-9eac-90fed63d1117(a)z35g2000prh.googlegroups.com. >> .. On Dec 7, 11:46 am, "Jeff Strickland" <crwlrj...(a)yahoo.com> wrote: >>> The problem is that Toyota (and others) are using what is termed, fly >>> by wire. >>> >>> In fly by wire, the gas pedal is not mechanically connected to the >>> throttle >>> body. The gas pedal has a servo that tells the computer what the angle >>> is, and the computer then sets the throttle body with a stepper motor >>> to match the angle of the gas pedal. >> >> The throttle position sensor has been used for years in different >> embodiments, >> some essentially drive by wire. I know there are differences, but the >> technology >> is not totally new nor very experimental. >> >> I remember when total drive by wire came up in rec.autos.tech, a lot of >> us really didnt like where that was leading. I still dont. >> >> >> > > > You can thank emissions and CAFE regulations for throttle-by-wire. > > With all the easy gains long accomplished, it takes some serious > trickery to get the last little bit of blood out of that particular > stone. > > And, I learned today, it appears there is a liability-regulation issue > behind the "start button". > > My understanding is that the "start button" originally had a half-second > delay before it would shut off the engine. The problem was that people > were hitting it accidentally and causing unexpected shutdowns in > traffic, leading to a potential liability situation. Therefore, the > button was given a THREE SECOND delay. Apparently the drivers of at > least some of these "runaways" HAD pushed the "start button", but > panicked when the button did not shut the engine down immediately (three > seconds must seem like an eternity in such a situation). > > Source for above: Letter to the Editor in the Wall Street Journal, > Sat/Sun Dec5/6, page A20. Title of the letter: "Lawyers Shouldn't Be > Designing Cars". > The letter also mentions a previous article in the WSJ of Dec2 ("Bring > Back the 'Off' Switch"), which I missed reading. I like my 1941 Chrysler "starter button", it does exactly what is says it is supposed to do, start the damn engine. The key turns it off.
From: dr_jeff on 7 Dec 2009 18:32 Don Stauffer wrote: > dr_jeff wrote: >> john wrote: >> >> Really. The ECUs definitely have problems, but please show us a better >> way that doesn't involve electronics. Carbs worked well, but wasted >> fuel. Without electronics, are air would be dirtier, we would use more >> fuel. >> > > Why did carbs "waste" fuel? They used enrichment at high manifold > pressure, but so do FI systems. The last generation of carburetors were > quite good. What really is the difference between a carb and a throttle > body electronic injection system? One is controlled by a pneumatic > computer, the other by an electronic one. Admittedly electronic > computers can be miniaturized, and add more computation. > > Essentially the carbs of the seventies and eighties DID have computers. > The amount of measurement of their environment and the amount of > control was remarkable. There were even the deceleration controls that > got rid of richness during trailing throttle. They were marvels of > fluidic computing. They used more fuel than was needed.
From: dsi1 on 7 Dec 2009 19:07
Vic Smith wrote: > I'm stilling driving a '90 Corsica 2.2 with TB. Just recently it's > started bogging on heavy acceleration. Could be the TB, but likely > just needs a plenum cleaning. I'm about to give it away or junk it, > so I'll probably never find out. > Drove a '85 Cav 2.0 with TB for years and never had a problem with the > TB. My 84 Cavalier was a pretty good car too. I could never understand how it could get 27 MPG. All of my other cars since never get anything above 21. Weird. The cost of parts for that Chevy a mind-blower too. I could get repair parts so cheaply, you'd think they were stolen. How often does that happen? :-) > Never had an issue with port injection beyond replacing a few > injectors. > Never had a carb I didn't have to tinker with or rebuild. Mostly > Carters. That's all I know, > > |