my carburettor seeks freedom from its computer control (electronic enslavement)

[psychopathicdude]

I own a faded blue 87 GL sedan. It has the electronic feedback carburettor (slap the engineer that thought THAT was a good idea). Its a little low on the options list, it doesn't even have power steering....or power windows, or power locks....but it DOES have power mirrors!! woohoo!! Anyway, it does the basic transportation bit pretty well, and has even survived a few off road excursions (or as I prefer to call it, "prairie surfing"). This car has run solid for the 3+ years that I have owned it, except for some annoying issues with the computer-controlled part of the intake system.

The car had no muffler when I bought it (rusted up and fell off). So I put on a simple flow-through glasspack muffler. Wasn't loud anymore, but you could still hear a good tone, and I figured it was a good idea for the exhaust pipe to exit behind the car, not under the back seat. Every so often, the car would adopt a rough idle, back-fire more, and the ECS (emissions control system) light would come on. This meant that the poor computer could no longer adequately "fix" the imperfect air/fuel ratio from the carburettor (probably crap built up in the "duty solenoids" that mess around with the carb). Blast some carb cleaner through it, drive it a bit, and it would clear right up.

Everything was fine...until a few days ago, when little pieces of my catalytic converter came flying out my tailpipe. Then big pieces, and the more pieces that came flying out, the louder the car got! It now has quite a rumble at idle and roar at full-tilt-boogie (WOT). Anyway, i'm not complaining, i rather like it loud (haven't listened to radio since....just roll down the window and listen to the "engine music").

Yesterday, the ECS light started coming on again. Now, the only reason the computer was screwing with the air/fuel ratio was to keep the Catyl'verter happy (whole lot 'o' good THAT did). With no more 'kitty-Cat', whats the point? I think the car would run stronger (and be simpler) without all the computerized shenanigans going on in the intake manifold. The plan is to: (A). either remove all extraneous solenoids and valves from intake manifold and plug the holes, or swap the carb onto an efi manifold. (B). Remove ECS light (C). Tell the computer to go to hell.

If anyone's done this and has wisdom to share (or is simply smart enough to know something I don't already) please let me know. Don't tell me not to bother, I shall not be swayed...so don't bother. If you think I'm crazy for undertaking this project, you don't know the half of it. After the carburetor is liberated from its electronic restraints, I plan to mount it at the mouth of a turbo.....draw-through style! But that's a project for another day. One step at a time....

p.s. i realize that driving a car with no cat and removed/disabled emission controls is illegal...it will be for OFF-ROAD USE.

[TheSilentChamber]

I would convert it to fuel injection. Even a batch fire system such as Megasquirt would be easier and cheeper than trying to fuck with that carb system.

[UncleBob]

the subaru carbs had major problems. Even when the entire system was stock, they can be very hard to get to pass emissions, they like running rich at cruise. I've never bothered disecting why exactly, because I don't "do" carbs....I just diagnose problems.

Your goal of removing the feedback portion of the system isn't worth while. What you need is a better carberator (or fuel metering system in general). Your problem is, I doubt you have a whole lot of bolt-on options that are cheap. You could, of course, swap out the entire engine with a more modern EFI setup. Not cheap. You could convert to megasquirt. Not only would it require a decent chunk of money, but requires quite a bit of learning, knowledge and fabrication.

If it was me, and I was being a cheap bastard, I would bastardize it to accept a better carb. Maybe a CV carb off of a Vtwin motorcycle. Plenty of carberation for your car, already downdraft config, and would take hardly any fabrication to make it work. Simply need a round tube to mate it to. Tuning it would require a little trial and error....but that would be a given no matter what you went with.

and...you could completely remove all the emissions crap these cars are infested with (I absolutely hate feed back carb systems too)

But then, I'm also very familiar with tuning carbs, and bike carbs....so thats the first angle I look at. Its probably not a very practical suggestion for most people....but I'd bet it could be made to work well if someone had the time to kill.

[Moppie]

Is this car an 97 Subaru Leone???


As for feed back carb systems the one in my 89 Honda works very well, its not quite as good as proper programed fuel injection, but its better than a mechanical fuel injection system.

[UncleBob]

Originally Posted by Moppie

As for feed back carb systems the one in my 89 Honda works very well, its not quite as good as proper programed fuel injection, but its better than a mechanical fuel injection system.

until something goes wrong.

Trying to find the source of a problem on a honda feed back system is a nightmare! Must be 30 vacuum lines, at least 10 vacuum valves, meters etc....and nothing is easy to get to, or easy to find info on.

I did like the short-lived prelude twin carb setup, because they used Mikuni CV carbs right off a Honda motorcycle....until they added all the feed back stuff anyway

[Moppie]

Originally Posted by UncleBob

I did like the short-lived prelude twin carb setup, because they used Mikuni CV carbs right off a Honda motorcycle....until they added all the feed back stuff anyway

Now I know why they sound so good on a cold winters morning
The mass of vacuum lines does look bad, but if you take a logical approach to it, and read the diagram on the lid of the control box, it's actualy quite simple to understand and trouble shoot.
Iv never had to do it on my car, but Iv done it a few times on others.

[psychopathicdude]

I have a question for "TheSilentChamber": How is converting to a completely different Fuel Injection System (megasquirt or otherwise) "easier and cheeper [sic]" than tweaking the system already in place? Me turning wrenches is free; buying new systems, adapting them to work in this application, probably a little custom fab involved.....definitely not free. maybe i'm just not following your logic; care to elaborate?

UncleBob, I realize that my carb might not be all that great, but it seems as though it could work better without all the emissions carp. Besides, the Carburettor Liberation Movement is only the beginning. And yes, I do have "the time to kill."

Moppie, where did 97 Leone come from? look at the top of the page....the post that started it all, i believe it says: "faded blue 87 GL sedan". which is indeed the car in question.

Feedback systems suck...this we know. Removing "all that crap under the hood that doesn't make it go any faster" won't necessarily fix all the problems, but carb diagnosis and adjustment will be much easier without "all that crap" constantly changing settings and messing things up. And it'll look alot prettier. I might actually be able to see the engine; without tubes, hoses and "vacuum solenoids" blocking the view.

It will also simplify the conversion process to A: a different carb, B: an EFI or throttle body setup, or C: a turbocharged form of induction (draw-thru carb, blow-thru carb, EFI, Throttle Body, or otherwise)

p.s. don't worry, this isn't my daily driver...it's the car i wrench on when i'm bored.

[psychopathicdude]

if i wanted to poke around an engine bay crammed with a myriad assortment of vaccuum lines, i'd buy a twin-turbo RX-7....well, i want to buy one anyway, they're just a bit pricey (especially on a 20-something's insurance). and its getting harder to find examples that someone hasn't blown up.

whatever i do to my Suby, be it custom-fabbing, carb-swapping, or just carb-fixing, that feedback carp is coming out.

[TheSilentChamber]

Originally Posted by psychopathicdude

I have a question for "TheSilentChamber": How is converting to a completely different Fuel Injection System (megasquirt or otherwise) "easier and cheeper [sic]" than tweaking the system already in place? Me turning wrenches is free; buying new systems, adapting them to work in this application, probably a little custom fab involved.....definitely not free. maybe i'm just not following your logic; care to elaborate?

I'm not sure if what your wanting to do is a matter of tweaking rather than an act of reconstructive surgury. Logic behind my responce was if you replace the carb with one thats not electronically controled, your looking at probably $200, and you still have a carb (I have a profound hate for carborators, but thats a differnt story). Now say you wanted to do a megasquirt system, thats $100ish, plus say $50 in parts from the junk yard- intake manifold, fuel rail, injectors, and a few sensors. Now you have a fuel injection system (primative, but still fuel injection) that is alot more tuneable than that carb, and easier to tune once you turbo. Draw through turbo has allways been a bad idea in my mind, your mixing air and fuel, adding heat and compression... if something goes wrong you have a whole charge pipe thats essentually now a pipe bomb.

[Moppie]

Originally Posted by psychopathicdude

Moppie, where did 97 Leone come from? look at the top of the page....the post that started it all, i believe it says: "faded blue 87 GL sedan". which is indeed the car in question.

Faded Blue 87 GL dosn't tell me shit about what sort of car it is.
In 1987 I can think of half a dozen manufactors who used the GL tag any number of their different models.

Uncle bob said something about it being a Subaru, but you have a Nissan listed in your profile, and a photo of a Nissan Pulsar EXA (one of the worst cars ever made) in your Avatar.

If its a US spec small 1600 or 1800 Subaru then it was sold else where in the world as a Leone, and I might have some ideas, as my brother used to own one.
If its a US spec Nissan Pulsar EXA then I deffinitly know how to solve your problem.

[psychopathicdude]

Sorry Moppie, I had originally posted this in the Subaru/Nonspecific category...(which received few views and no response) I then reposted it here without specifying it's Subaru nature. The car is a blue US-market (California spec) 1986 Subaru GL sedan, which in later years was called the Loyale, and my service manual mentions the 1600, 1800 name. My other car is a US-market 1987 Nissan Pulsar NX SE which appears identical to my profile pic (stolen from nissanexa.com or somewhere...i don't remember) which is immaterial to this discussion. I realize now the confusion potential of having a car-picture for my Avatar and asking automotive questions without exactly specifying which car I have. oops. my bad.

SilentChamber, my intentions at present (they may change without notice) are to keep the current carb and to simply remove or disable all who would seek to hinder its operation (all the valves and hoses and crap that masquerade as an emmissions control system). Where I go from there all depends on when I get there, and how much money is in my wallet then.

[TheSilentChamber]

Realze that that stuff doesnt just hinder its operation, it makes it operate.

[Moppie]

TSC is right, with out all the extra crap the carb won't function correctly.
This means replacing the carb.

Fortunatly, I happen to know the Japanese market version of that car didn't have a feed back system on it, like wise the NZ market version.
So if your clever you maybe able to get hold of a carb from overseas, here from a wrecker here in NZ, or Japan, and then retro fit it.

Or, since Subaru are very good at useing everyone elses parts, and building very few of thier own, find out what brand of carb it is, and see if a replacement is easily obtained.
What I think you will find however is the carb thats on there bolts to a manifold with a standard choke size and bolt pattern. Likly to be the same as used by Webber and Dellortto etc.
This makes it really easy to find a replacement, and your biggest cost will be a little time on a dyno getting it tuned.

[UncleBob]

I like how this thread has gone full circle

TSC, I'd like to see you build a MS system with $150.....Thats one very mighty friendly junkyard you go to that has a really awesome selection of parts! And where are you getting the MS for that cheap??

draw thru's do suck....no reason you have to do it that way though. Blow thru carb systems work very well.

And not that its all that important, the avenue I was suggesting would probably cost around $50. Maybe $100. Depends on Ebay.

[UncleBob]

Originally Posted by TheSilentChamber

Realze that that stuff doesnt just hinder its operation, it makes it operate.

this is very true. Its the biggest reason I wouldn't use the carb. You will not get it tuned properly without doing some pretty serious modifications to it. IE, re-engineering it.

Granted, it'll run without the feedback stuff. But not nearly as well as it could.