Hi all, Just got my carb back from having a full rebuild and they replaced the choke heater. Installed the carb and everything seemed fine while in the driveway. I went for a drive and now the choke light is staying on and the rpms stay at 1800 rpm when parked and I cant seem to kick it down. I checked the voltage at the Alt and I am getting 14.2V. I am also now getting a buzzing noise from the green relay under the dash at the relay pack. Car is all original including the carb. Any ideas ? Thanks in advance.

 

The buzzing is the Choke Heater relay. Either there's a problem with the relay, or the choke...

 

Found the 20 amp C/H fuse blown. Replaced fuse and all was good until the car warmed up and I kicked it down to regular idle, then fuse blew again and choke light came on. All wiring looks visually good and undisturbed. Anyone had this problem ?? Seems to be an intermittent shorts ??

I verified all voltages at Alt and battery 14.2V, Brown wire at Alt only is power when car is running.

 

The "Choke" light isn't what it says it is. Or at least, that's only 1 small part of what it is. It's actually the "Alternator" light.

Your alternator is bad.

The alt is a 3-phase generator, with a 6-diode array referred to as "rectifier" to convert the AC to DC. Additionally there is an array of 3 diodes, called the "diode trio", that is involved with operating the voltage regulator, the warning light, the choke relay, etc. There's a more detailed explanation here.

https://www.thirdgen.org/forums/elec...nals-drop.html

The buzzing is caused by one phase of the 3-phase not making it through the diode trio. So, as the alt spins, and the 3 phases follow one another, 2 phases work, and one doesn't. The relay operates during the 1/3 of the time that the alt isn't working, and drops out the other 2/3. This is why you still have nominal charging voltage; the 2/3 of the time that it works, is enough to keep the batt charged up. And of course, the buzzing that's correlated to engine (alternator) RPM.

The part going bad that causes all this is the diode trio. You can swap out just that one thing, if the alt is fairly new and in good shape, as it's not too $$$$ and eeeeezzzzy enough to get to; butt if the alt is old and in an unknown state of wear-out anyway, then the odds are pretty good that it's getting around to needing more than just that, to renew it. It'll be one of those states where you fix one thing and 2 weeks on down the road something else in there breaks. Best to just get a new alt.

 

Thanks for the reply. I found the C-H fuse blown, replaced the fuse and all was good until I kicked it down to normal Idle then it blew again and the light came on and relay buzzing again. All voltages at Alt and battery are 14.2V and the brown wire is only powered when the car is running. It appears to be the original Alt. My Alt wiring has a jumper from the back terminal to the red plug wire, it looks factory. See pic.

 

The red wire jumping the 2 alt terminals is factory, as described in the post I referred you to.

There may be a connection from the choke heater circuit to the idle stop solenoid relay to power the solenoid. I don't recall for sure and I'm not sure where that is in the car, might be in the "convenience center". Seems possible that if blowing the fuse is related to idle, then it may be something to do with that solenoid.

The solenoid is on the driver's side of the carb. Should have a dk grn wire going to it. Try unplugging that wire and see if it makes a difference.

 

Appreciate your help. I know exactly what you referring to about the solenoid but mine does not have that and it appears to never had one because there is no bracket or evidence of one unless someone removed it years ago. There is two wiring harnesses there that were loosely taped sitting on top of the intake manifold so I retaped then and zip tied them away from the carb. See pic

 

You have the export model, not US. It's quite a bit different. No ECM among MANY other things. Would have helped to mention that earlier.

I don't have much info on that, can't help much further.

 

So maybe not the alternator?

I think I would be tracing wires and looking for anything that is changed or not reinstalled exactly how it was right before you took it apart for carburetor rebuild (assuming you did not have this problem before the rebuild). The fuse blowing when kicking down to regular idle seems like a significant clue.

Edit to add: The next thing I would do is find out everything that is powered through that fuse that keeps blowing. Pretty sure your solution lies there.

Numquam ponenda est pluralitas sine necessitate.

 

Yes, looking at that now.

 

When he said he had 14.2 volts from the alternator, I ASSumed the alt was not the problem...