New car, new problems; 76 Duster 318

You always say get a manual to people first,ya they help but what the HELL is FABO for? its all about our hobby and helping each outer out.

No, Snake, I don't always say that, and I think you know that. Very helpful answer by the way. But a factory manual IS important, most especially to someone not familiar with these cars. Furthermore, I've posted SEVERAL times that if "you guys" who have later manuals could post them, it would be a huge help.

1. A quite prominent vibration that comes up during acceleration (higher speeds, why I didn't notice it when test-driving), and goes away when you let off the gas...- CK

I still would check U joints, regardless of opinion. Pull the tires and inspect for bumps, loss of tread, just as a general check. Are all the lug bolts tightened properly? Then PULL the driveshaft. You can not check U joints with the shaft in the car. Pull the two rear caps, inspect for grease and smoothness, and gently move the joint in the shaft, while "feeling" for roughness or smooth action. Move the front one/ slip yoke same way, feeling for roughness, looseness, etc.

Slip the yoke into the trans and feel for side--side movement, to get some idea of the rear bushing.

Try to move the rear axle yoke side-side and wiggle left/ right to get some idea of trouble with pinion bearings. Move the yoke in rotation both directions, feeling for roughness, looseness. This can be VERY subjective, as all rear gears have some slack in the ring/ pinion.

2. Backfiring and chugging, seems like a cyl isn't firing right. Happens under heavier acceleration, but doesn't happen during normal acceleration. After the trip to post, I noticed this didn't go away. The sound was noticeable at the back by the tailpipe. Almost sounded like something in the exhaust was plugged? No noticeable noise under the hood. Sounded like a healthy V8 chugging away. When I got to the back of the car, though, it sounded like it had dual exhaust and one pipe had a potato stuck in it...- CK

First pull the plugs and look them over. Oil / fuel fouled? damaged? Gaps look OK?

Then do a "backyard balance test." You "hear" people speak of "pulling plug wires," but you do NOT want to do this. This is because the spark will "go high" when a plug wire is removed, and cross fire to other cylinders. Not only can this damage the ignition system, but it gives you false results.

So set up to SHORT each cylinder. One way to do this is to work the dist cap boots up, and slide very small thin brads/ nails down beside each plug wire. Hook up a tach or vacuum gauge, or just critically listen to the engine. Get it warmed up and at "best idle." One at a time, short each cylinder, watch the tach and or vacuum, and LISTEN. EVERY cylinder should drop the same amount, and SOUND the same. A lesser or just slight change means something wrong in a cylinder, as does "no" change, which means it's not firing at all.

There could be many causes, including valve problems, worn rings, or problems in the ignition system, bad wire(s), plug(s) and as others mentioned, dirty, wet, carbon tracked cap and rotor.


3. Speedometer doesn't work, starts at 80 and moves up with acceleration. Anyone know any sort of fix for this aside from chucking the speedo? - CK

Do you mean that the speedo is stuck at 80, works OK up to 80? Need more details. Offhand this sounds like a speedo problem, IE not cable or drive gear

speedo gauge light doesn't work. Fuses? Temp gauge doesn't work. Light pullswitch knob is loose, pulls right off... Anyone got an extra light switch and temp gauge from a '76 Duster?- CK



Dashes have a habit of having multiple problems. If it's only the speedo illumination that doesn't work, most likely a couple of burned out bulbs. If NONE of the cluster illuminates, this gets a little deeper. Post back with what lighting does/ does not work, and whether turning the light switch shaft makes them brighter/ dimmer "smoothly"

TEMP GAUGE. Are you sure the FUEL gauge works? They are supplied power by the "voltage limiter" sometimes called by other names, which chops up 12-14V power to effectively 5V. If this device is bad, neither gauge will work. There can be other problems. A quick first check is to unhook the temp sender wire, and clip it to ground. Go in and turn the key to "run." watching the gauge. It should very quickly move to "hot." Don't leave the key on any longer than needed to test.

SWITCH KNOB. Someone probably didn't know the "trick." Normally, your remove the knob AND SHAFT as a unit. Unhook the battery ground, pull the shaft all the way out to "headlights," and reach up under. There's a button on the switch which mechanically releases the shaft. Pull the shaft out. Then you can JB weld (epoxy) the knob back onto the shaft.



Also, does anyone happen to have even an idiot book for this car? Hate not having one of those.- CK

You can download the 72 factory shop manual from this link. There ARE differences in your car, and only use the wiring diagrams as a rough guide. Most of the mechanical "stuff" is the same.

You can thank AbodyJoe for this

[ame]http://www.abodyjoe.com/pictures/Misc.%20car%20info/1972%20Plymouth%20Chassis%20Serv%20Man.pdf[/ame]