Suzuki Sierra Carby Troubleshooting
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Ookie the zuke
- Posts: 12
- Joined: Tue 20 Dec, 2022 12:54 pm
Suzuki Sierra Carby Troubleshooting
Hi guys. Wondering if anyone has any experience troubleshooting carby issues. I have a G13a with an Asian carb. I am havi by issues with the engine wanting to idle high. Can’t tune it below 1500 rpm. Engine also appears to be running extremely rich, will pop splutter and backfire under both acceleration and deceleration. Engine will also flood out and die following deceleration going back to idle. Plugs are black and sooty. Unsure of choke operation or how to verify or adjust. Also not sure if carb is original to motor as the plug from the fuel solenoid has 3 pins while the plug from the loom is a single spade. Also a few vacuum hoses pluggged off floating in No man’s land.
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Cheers Callum
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gwagensteve
- Financial Member
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- Joined: Mon 13 Aug, 2007 5:20 pm
Re: Suzuki Sierra Carby Troubleshooting
There's really too many variables here.
In general, the best advice is to get hold of a factory service manual, it explains how to correctly setup the carb, especially the choke. Despite what everyone says, these are not very complex carbs (in terms of external adjustment) and aren't "full of emissions controls" - what they do suffer from are is many hands thinking they can "tune" them (you can't) by fiddling with every adjustment. It's impossible to work out what has been done until everything is put back to factory specs, then you can troubleshoot the carb.
Disconnected and plugged vacuum lines are an issue. Again, people see a nest of hoses and think "pointless complexity" but there aren't many hoses and they do things. Again, the FSM explains their routing and function.
All the sierras I recall have a three pin plug to the carb, are you sure the single terminal on the loom is definitely for the fuel cut?
High idle issues will generally be the choke stuck partially on, a vacuum leak, the throttle being misadjusted so it's cracked open at "idle" or the idle up control for the headlights/blower fan/rear demister misadjusted.
Does the idle speed change when you put the headlights on?
In general, the best advice is to get hold of a factory service manual, it explains how to correctly setup the carb, especially the choke. Despite what everyone says, these are not very complex carbs (in terms of external adjustment) and aren't "full of emissions controls" - what they do suffer from are is many hands thinking they can "tune" them (you can't) by fiddling with every adjustment. It's impossible to work out what has been done until everything is put back to factory specs, then you can troubleshoot the carb.
Disconnected and plugged vacuum lines are an issue. Again, people see a nest of hoses and think "pointless complexity" but there aren't many hoses and they do things. Again, the FSM explains their routing and function.
All the sierras I recall have a three pin plug to the carb, are you sure the single terminal on the loom is definitely for the fuel cut?
High idle issues will generally be the choke stuck partially on, a vacuum leak, the throttle being misadjusted so it's cracked open at "idle" or the idle up control for the headlights/blower fan/rear demister misadjusted.
Does the idle speed change when you put the headlights on?
michaelpiranha2000 wrote: The rear is in great condition. but has a broken crown wheel and pinon