Author Topic: Carb not kicking down anymore  (Read 4799 times)

Offline Autonutz

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Carb not kicking down anymore
« on: August 18, 2015, 02:35:08 pm »
I eliminated some extra wiring that the electric choke was fed from and it seems that ever since the carb won't kick down unless I manually push the lever behind the choke.

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Online bd

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Re: Carb not kicking down anymore
« Reply #1 on: August 18, 2015, 03:05:16 pm »
I eliminated some extra wiring that the electric choke was fed from and it seems that ever since the carb won't kick down...

Ooops!

Clip a test light to a clean, bare ground and probe the battery positive terminal to make sure the test light works.  With the test light still grounded, probe the two terminals on the choke thermostat with the ignition switched on.  Do either or both terminals illuminate the test light?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Autonutz

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Re: Carb not kicking down anymore
« Reply #2 on: August 18, 2015, 03:06:28 pm »
Yep its a full circuit, I tested prior to minimizing the wiring, it gets a full 12v

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Offline Autonutz

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Re: Carb not kicking down anymore
« Reply #3 on: August 18, 2015, 03:11:54 pm »
The little red tab in behind the choke is where I have to press in order to kick it down after its running for a few minutes.

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Online bd

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Re: Carb not kicking down anymore
« Reply #4 on: August 18, 2015, 03:19:42 pm »
Yep its a full circuit, I tested prior to minimizing the wiring, it gets a full 12v

Did you determine that using a voltmeter or did you use a test light?  Did you probe both wires while both wires were connected to the choke?  Did both terminals show/measure '12 volts?'

Have you tried cleaning the choke linkage with B12 or other carb spray?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Autonutz

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Re: Carb not kicking down anymore
« Reply #5 on: August 18, 2015, 03:45:57 pm »
Yep its a full circuit, I tested prior to minimizing the wiring, it gets a full 12v

Did you determine that using a voltmeter or did you use a test light?  Did you probe both wires while both wires were connected to the choke?  Did both terminals show/measure '12 volts?'

Have you tried cleaning the choke linkage with B12 or other carb spray?
I used my voltmeter, if I recall the front terminal showed 12 volts and the rear was the ground.
Also tried lubricating everything up and it didn't seem to help.
I'll see about taking a short video of it.

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Online bd

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Re: Carb not kicking down anymore
« Reply #6 on: August 18, 2015, 04:15:36 pm »
If the choke plate opens all the way by itself w/o you having to push it open, thoroughly wash down all the linkages on the choke side of the carburetor using a good carb spray.  If you have a compressor, blow it all dry and make sure the linkages move freely with the throttle held slightly open.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Autonutz

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Re: Carb not kicking down anymore
« Reply #7 on: August 20, 2015, 12:45:08 am »
It sits partially open after initial start, after hitting the throttle the plate sits open more and that's when it won't kick down unless I press that red mechanism on the passenger side. I took a video but this app keeps shutting down when trying to upload lol

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Online bd

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Re: Carb not kicking down anymore
« Reply #8 on: August 20, 2015, 01:01:22 am »
To see if the choke stat works, with the engine off, disconnect the two wires from it then jumper one terminal to ground and the other terminal to B+.  See if the choke plate relaxes and opens all the way within two or three minutes.  If the choke plate doesn't open completely, either the thermostat is adjusted too rich or its faulty.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Autonutz

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Re: Carb not kicking down anymore
« Reply #9 on: August 20, 2015, 02:01:54 pm »
Jumping worked, it definetely opened up all the way

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Online bd

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Re: Carb not kicking down anymore
« Reply #10 on: August 20, 2015, 03:15:39 pm »
You need to troubleshoot the wiring.  I recommend a test light.  Although a voltmeter will work, it requires more skill and is easy to misinterpret. 

Hook both wires back up to the choke stat.  Probe the ground wire both with ignition on engine off and ignition on engine running.  It should test consistently dead.  Does it?

Now, probe the hot wire with ignition on engine off and ignition on engine running.  It should test dead with engine off and battery voltage with engine running.  Does it?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)