Author Topic: Choke light stays on and volts gauge not working  (Read 11410 times)

Offline swilliams

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Choke light stays on and volts gauge not working
« on: January 08, 2014, 07:30:14 PM »
Hello new to posting but have watched and read for awhile. Very impressed with the knowledge here.   
I have a 86 c10 slowly improving to my taste. The truck came with a crate 350 edelbrock intake performer I believe, edelbrock 1406 carb everything else stock down to it is still running smog controls. I removed the smog (not necessary in my state) removed a/c (still works but has a leak) water pump replaced. I put it all back together and now my choke light stays on all the time and my volts gauge is not working. I have read what I can find on here about oil pressure switch and choke working together but I am not having oil press gauge problems. I have the sending unit by cylinder 1 chased the wire it runs in to harness behind dist and I cant really see the choke and oil press unit down by dist I am changing out dist with MSD 8262 and MSD 5520 so I figure I can get a better look at that time. I just don't believe the problem goes that deep I think I may have not hooked something back up right or something. Just remembered that volts gauge worked when I first put things back together truck almost didn't start at the store later that day when I got it home checked it out I had forgot to reattach neg battery cable but choke light has been on since smog removal. Any comments or suggestions or advice would be helpful. Thanks

Offline bd

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Re: Choke light stays on and volts gauge not working
« Reply #1 on: January 08, 2014, 09:38:12 PM »
Welcome from Central California!

The oil pressure gauge and choke use separate pressure switches.  The gauge sender is single-prong; the choke switch is double-prong.  Common switch locations are at the back of the intake, next to the distributor and right above the oil filter.  Check the choke and ignition fuses - a wire may have arced to ground, popping a fuse.
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 dvdswan

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Re: Choke light stays on and volts gauge not working
« Reply #2 on: January 09, 2014, 02:02:04 PM »
welcome from the PNW.

Offline Venton

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Re: Choke light stays on and volts gauge not working
« Reply #3 on: January 09, 2014, 05:27:54 PM »
Welcome from Southern Maryland.

Offline bake74

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Re: Choke light stays on and volts gauge not working
« Reply #4 on: January 09, 2014, 08:24:11 PM »
     Welcome from California.
#1: The easiest and most obvious solution to any problem is 99% of the time correct.
#2: There is no such thing as impossible, it just takes longer.
  74 k10, 77k10    Tom

Online zieg85

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Re: Choke light stays on and volts gauge not working
« Reply #5 on: January 09, 2014, 08:51:03 PM »
Welcome from NW Indiana
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline swilliams

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Re: Choke light stays on and volts gauge not working
« Reply #6 on: January 10, 2014, 06:17:33 PM »
I will have to check on what you say I hope its that simple. seems like every time I go 1 step forward end up 2 steps back nothing bad just annoying. Thanks for the greetings and advice.
 8)

Offline 1979C20

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Re: Choke light stays on and volts gauge not working
« Reply #7 on: January 30, 2014, 09:29:47 AM »
On your fuse box you will find a fuse named "gauge/idle" or something along those lines, check that fuse. Had it pop on me, list my temp, fuel, and volt gauges and my service engine light wouldnt turn off.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline swilliams

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Re: Choke light stays on and volts gauge not working
« Reply #8 on: January 30, 2014, 09:42:17 AM »
I have pulled fuse for spot labeled choke and light was out. Now have finished ignition update now choke light is back on without fuse??? I have good  oil pressure so I don't know what is up. I have been told to check in to changing dist module from current 5 pin to a 4 pin.

Offline bd

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Re: Choke light stays on and volts gauge not working
« Reply #9 on: January 31, 2014, 01:57:36 AM »
That's because the CHOKE fuse does not power the choke light.  The CHOKE fuse powers the choke thermostat, via the 2-prong oil pressure switch (OPS).  The dash choke light is powered by the GAUGES fuse that feeds the instrument cluster. 

When ignition is switched on, 12 volts is supplied to the instrument cluster including the choke light.  The choke light 'grounds' through the choke thermostat and remains illuminated as long as the engine isn't running.  When the engine starts, oil pressure closes the 2-prong OPS.  Consequently, 12 volts from the CHOKE fuse is supplied through the OPS directly to the choke thermostat.  Since the dash choke light is also connected to the choke thermostat, 12 volts is supplied to one side of the choke light by the GAUGES fuse while being supplied to the opposite side of the choke light by the CHOKE fuse.  Since 12 volts is applied to both sides of the choke light with the engine running, voltage is balanced and the light extinguishes.

Incidentally, the ignition module you use (4-pin vs 5-pin) has no bearing on the function of the choke light.  If you remove the GAUGES fuse, the choke light should go out.  If you remove the CHOKE fuse, the choke thermostat will take exceedingly long to open, and the choke may not open fully.
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 swilliams

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Re: Choke light stays on and volts gauge not working
« Reply #10 on: January 31, 2014, 02:21:38 PM »
Thank you for that I will put the choke fuse back in.