72 Duster Resurrection

moparmat2000 said
Ok. Just an FYI, if your fuel gage and water temp gage ever are both pegging or going to empty/cold. Then the instrument voltage regulator is on the fritz. The gages you have run on 5V except the ammeter and speedometer. They use a little vibrating points regulator on the back the gage cluster to drop 12v to 5v if it sticks closed they peg, if it sticks open they drop to empty or cold.

I would use a point n shoot digital thermometer to see if the engine is getting too hot. Its a possibility the sending unit for the gage is bad, pegging it out. The sender is on the front of the cylinder head, with a purple wire going to it. The water temp sender is dirt cheap, i think the same part number was used up thru the 90s on chrysler 2.2 and 2.5 4 cylinder and 3.0 V6 engines.

Ok, while the engine has been gently idling for a minute, the instruments settle to this state:

Voltage staying at a negative current draw position when the engine is not running and jumps to what the pic shows when the engine is idling.

temp immediately and steadily increases from cold peg to hot peg as soon as the engine starts. I absolutely refuse to believe this is correct. From a dead cold engine to pegged out temp after 2 mins of idle? no way. I'm ordering a replacement temp sender.

Fuel has never moved from empty even with 5 gals of fresh gas added.

Could these problems be the gage voltage regulator you mentioned?

moparmat2000 said
Yes probably. I'd ohm out the wire to the neutral safety switch to eliminate an internal break in the wiring. The neutral safety switch on that year is a multifunction switch. Its used for park and neutral starting, and for turning on the reverse lights. Also make sure you have a good body to engine ground at the firewall. Not having this causes all sorts of weird problems. I think mopar went to this switch about 1968 and continued to use it on all RWD automatic transmissions at least thru the early 1980s. Should look similar to pic below. It will be on the left side of the trans near shifter linkage input to the trans. Put a bucket or pan under it when you swap it out.

I would recommend rock auto for most of what you will need. I use em and they are great. Especially when stuff goes on closeout. Just checked rockauto. They got a neutral safety switch. airtex/wells PN# 9A6 for $6.35. For 1972 duster slant 6 automatic. I try to round up a bunch of stuff i need from em being shipped from the same location so i only get hit with 1 shipping cost. Way cheaper than local stores like vatozone. On this old stuff they would have to special order it anyway.

View attachment 1715092898

Yeah I love rock auto, probably the best site organization, pictures, and selection out there. Im putting together an order for this project now, including the NSS you recommended there, thanks for looking that up for me.

moparmat2000 said
Right now i am recuperating from lower back surgery i had yesterday to remove a bulge from one of my discs. So i'm bored as heck for the next 2 weeks. I'm hoping all the info i am sending your way is going to help you.

I think you mentioned you messed with chevys before you got the duster. I think over time working on this car to get it running you will find out that Chrysler did some pretty solid engineering on these cars. Also the unibody on these is pretty strong and also pretty light compared to a full frame car.

Sorry to hear about your back my friend, I hope your recovery goes well. I definitely appreciate all your input, I still need to re-read your posts about the instrument panels, amp meter bypass, etc.

Keep it coming!

slantsixdan said
More Slant-6 specific info at the HEI upgrade article. The headlamp relay diagram posted above is from this page on my site.

Dan, I definitely plan on doing a HEI upgrade and the headlamps for sure need some work, so thanks for the great info as usual!

Questions for the experts:

-The engine will start perfectly and run happily with someone manually spraying gas into the carb. The fuel feed line pumps a strong stream of gas out when the engine is running so I know the fuel pump and lines are functional.

However, when the gas feed line is attached to the carb, the engine will not start. So I need to break the carb down, clean, inspect, and possibly rebuild. No surprise there.

But I am going nuts trying to find the right rebuild kit. I have done my research for Holley 1920 identification help via
1920 1 Barrel

and the video here Holley 1920 Carburetor Kits

and threads like this Holley 1920 carburetor identification HELP!!

I just can. not. find. a 4 digit "list number" that any site has a rebuild kit for.

Here are my carb pics:

I know that third pic with the numbers 0509 and 4164 are supposed to be the ones I need, but Im just running into a wall finding a kit.

Any advice?.....