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What vehicle are you working on?
Does it sound like its back firing through the intake (timing issue) or through the exhaust? (rich condition)?
Beefy and Yarddog who are also forum members here are much more experienced with Carbs than me. Hopefully they will chime in soon as all my training is all EFI.
Is my Suzuki Swift, 1995, C:P (exactly like the Geo Metro but 5 doors but with a 1.6L engine, 16 valves) and actually is from the exhaust. Around noon today I loosened the screw a bit and the coughing was gone, also it.
http://img190.imagevenue.com/img.php?im … _444lo.jpg
http://img228.imagevenue.com/img.php?im … _514lo.jpg
http://img183.imagevenue.com/img.php?im … 2_42lo.jpgIs odd, ugly and damm to many vacuums, but when it behaves, it rocks C:P
Also if you need more info, this carb is the same as the one used by the Mitsubishi Lancer of the same year. Funny thing is it?
Have you put any carb cleaner to it? The fact that the A/C actuates the accelerator pump and makes it run normally suggests to me at least that it might be running lean at idle normally. I would look into rebuilding the little bugger, since it wasn’t touched since it was rebuilt. You could have some clogged tunnels in your idle circuits. I imagine that carb wouldn’t be terribly complicated, and a good soak in a carb cleaner tank could do wonders for it. Just make sure you follow the rebuild kit’s instructions closely to set the idle/accelerator pump etc. I don’t see one on there, but a car of that vintage with a carb should have an idle metering solenoid (I think), that could be malfunctioning as well. Although I just noticed you are from Venezuela. That might not apply at all. I would however suggest a good rebuild/cleaning like i mentioned.
You also might want to post this in the ‘service and repair questions’ section as there are many guys better than carbs than me. I am still learning the technique, which is pretty backwards here in the states.
I did a little research through Google. It seems Suzuki used carbs and two FI systems in the 1990s. As I recall Suziki was the only manufacturer to use a carb in the US in the 1990s. I could be wrong, but it’s possible almost nobody in this country knows much about that carb. It appears to be a dirt simple carb with some exotic devices added, electronic controls and many vacuum operated systems running off it. If the engine was rebuilt a few weeks ago, someone may have hooked up a vacuum line incorrectly and there could be a vacuum leak somewhere. It could be very hard to find one as you have to take the air cleaner off and disable so many lines.
In that you hesitate to pull the spark plugs, I doubt you want to dive into a job that would a pain even for a Suzuki mechanic. In the US, we say, “You’re diving into the deep water.” You might be diving into the deep water in the Amazon with the Piranha. 😉
It looks like that carb is very very clean as if someone just cleaned it to install it on the new engine. I think you need to go back to the shop that installed it, tell them the problem and see what they think.
I read that Suzuki carbs from the 1990s are often called “carb-jectors” by Suzuki folks and they have complex electronic metering systems. If you eliminate all the other problem areas, you would need a book and a digital multimeter to check and adjust the controls.
The first thing to do would be to check the spark plugs. If you a carb problem, all of the plugs will have evidence of it. If just one or two plugs show evidence of a problem, that could be ignition or an internal engine problem. Do you want one of us to post a video about how to remove and replace spark plugs?Thanks Dreamer. Let’s hope our friend found someone who knows something about Venezuelan Suzukis.
I tempted to write something in the “How To” about Carburetors just for grins.Quoted From yarddog1950:
Thanks Dreamer. Let’s hope our friend found someone who knows something about Venezuelan Suzukis.
I tempted to write something in the “How To” about Carburetors just for grins.I would say go for it!
All my training and education is all EFI. Being able to tune a carburetor seems like its a dieing art.
Id love to read your work.Yeh man, I’d love to see some refreshers on say, the Quadrajet. The holley 4150 and 4160 are super easy. The Q-jet is an artform.
Quoted From yarddog1950:
I did a little research through Google. It seems Suzuki used carbs and two FI systems in the 1990s. As I recall Suziki was the only manufacturer to use a carb in the US in the 1990s. I could be wrong, but it’s possible almost nobody in this country knows much about that carb. It appears to be a dirt simple carb with some exotic devices added, electronic controls and many vacuum operated systems running off it. If the engine was rebuilt a few weeks ago, someone may have hooked up a vacuum line incorrectly and there could be a vacuum leak somewhere. It could be very hard to find one as you have to take the air cleaner off and disable so many lines.
In that you hesitate to pull the spark plugs, I doubt you want to dive into a job that would a pain even for a Suzuki mechanic. In the US, we say, “You’re diving into the deep water.” You might be diving into the deep water in the Amazon with the Piranha. 😉
It looks like that carb is very very clean as if someone just cleaned it to install it on the new engine. I think you need to go back to the shop that installed it, tell them the problem and see what they think.
I read that Suzuki carbs from the 1990s are often called “carb-jectors” by Suzuki folks and they have complex electronic metering systems. If you eliminate all the other problem areas, you would need a book and a digital multimeter to check and adjust the controls.
The first thing to do would be to check the spark plugs. If you a carb problem, all of the plugs will have evidence of it. If just one or two plugs show evidence of a problem, that could be ignition or an internal engine problem. Do you want one of us to post a video about how to remove and replace spark plugs?Well I was going to post at the “Service and Repair Questions ” section but lets continue here. Actually the carb is quite rare, and yes is it kinda of semi-injector-not quite-but kinda injected type of carb. The thing is I got it adjusted (yeee me, yeeee) by just turning a little the metering needle. Now there are no burps or coughing, the engine idles super smoothly and the powaaa is amazing. Acually the engine has a little story about it.
Let
If I understand you correctly, you no longer have the problem with noise and your Suzuki now runs great.
If you have no black smoke from the exhaust and no black soot at the end of the exhaust pipe, this indicates the carb adjustments and condition are fine.
If your gas mileage drops, you might suspect a problem with carb adjustment (or ignition), but if your gas mileage meets expectations, your carb is probably adjusted near perfect. If you want to confirm this, it would be best to get a good look at the spark plugs because they will tell you a lot more than looking at the exhaust. I watch my gas mileage in the vehicles I’ve owned. If the gas mileage drops or the power drops, I look at the spark plugs.
If you want the carb adjusted “perfectly”, you would need to have it tested for HC (unburned hydrocarbons or fuel) and for CO (Carbon monoxide). You would need a shop with an exhaust analyser.
When an exhaust system cools down, moisture condenses inside the tailpipe. When the car is started in the morning, you may see steam or droplets coming from the tailpipe especially in winter or in a climate with high humidity. An older car with no catalytic converter might collect quite a bit of water in its exhaust.
I suspect your car collects enough moisture to see droplets and steam.
I’m not sure but I think your car is different from Suzukis sold in the US with different emissions requirements and probably a different carburetor.When I first looked at the photos of that carburetor, I thought, “What the heck is that thing on the front that looks like a dash pot?” I looked again today and noticed that as you look down the throat, that’s no conventional choke. That’s a piston. I’ve never seen nor heard of a downdraft carb with a piston and a dash pot so I guess I might be excused for not seeing what was there in front of me.
Carbs with pistons go back to 1900 or 1905 depending upon whom you believe. They were invented by a Brit named Skinner and produced by his company Skinner’s Union or SU. I like to call them SU type carbs, but the Brits called them “Constant Depression” because they maintain a constant vacuum by means of a variable venturi. I have no explanation why they call a vacuum a “depression”. I checked a few websites for info about these carbs and Wikipedia claimed there were a handful of downdraft SU carbs used on cars before WWII.
I imagine Suzuki chose a downdraft carb to make it easier to service on a front wheel drive car and because they are familiar with the sidedraft type of this carb on motorcycles.
The piston retracts into the dash pot (a cylinder found on top of sidedraft SU type carbs and this varies the size of the venturi as well as the mixture by means of a tapered needle that sticks out of the bottom of the piston and into the main jet. In typical SU carbs, the main jet can move away from the piston to provide more enrichment such as might be needed for cold starting eliminating the conventional choke. I think the cold start function on this Suzuki carb is controlled by electrics.
Here’s a video showing a pair of SU carbs that might be off a circa 1960 British or Swedish 4 cylinder >>>
http://www.youtube.com/watch?v=YH6306zM-UgWell ye is a variable venturi type of carb. Also yes, is running great, and well alright, I will check the spark plugs C:P The rule of thumb would be is they look brownish is good, white is too lean and black too rich, right?
These are the best photos of spark plugs in different conditions that I could find. The first two photos show very clean plugs from engines in excellent condition. You can ignore the slight difference between the two because it pertains to heat range and racing conditions not carb adjustment. The next two photos show slight carbon fouling and significant carbon fouling.
Not shown is oil fouling which is black and wet.
http://members.uia.net/pkelley2/sparkplugreading.html
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