74AMC Gremlin dying

amc
gremlin

#21

Only dies coasting around left hand turns when I go to accelerate after the turn I have no power and the alternator and oil light come on.


#22

An AMC Gremlin went 90 miles without breaking down? … lol …

Just kidding. I had a friend in college who bought a new one. Even in the first year of ownership it was in a the shop more than parked at her dorm parking lot. But it sounds like you are up for the challenge, good for you.

Suggest to approach this problem scientifically. First off, do some tests to determine if the problem is spark or fuel. Do you have a good healthy visible spark at each spark plug during cranking? You can use a spare spark plug to easily do that test, put it on each wire one by one. Good idea to do a basic battery/charging system test too. The battery should measure 12.6 volts before first start of the day, then after starting the engine, 13.5 - 15.5 volts. Does it? Do you have battery voltage at the + terminal of the coil when the ignition is on? That’d be a good time to clean & renew the battery connections too. If it isn’t spark, fuel is next on the list. You should be able to remove the air cleaner and look into the throat of the carb (where the air flows in) and verify fuel gets squirted out in that area when you press on the accelerator pedal. If no fuel is coming out, probably the fuel bowl is empty, due to a faulty inlet valve. You can also test that the fuel pump is pumping fluid ok, by disconnecting at the carb and placing the line in a container and measuring how much gas gets pumped in 15 seconds of cranking. (Fuel work safety precautions apply here). Well, you get the idea, it’s just a series of tests until everything works …

On an unknown car like that, good idea to do all the basic engine tune-up stuff

  • replace spark plugs, spark plug wires, distributor cap, and rotor
  • replace ignition points
  • replace fuel filter
  • replace engine air filter
  • fuel pump volume flow test
  • check base ignition timing, and timing advance curve, both vacuum and centrifugal , and dwell
  • valve clearances
  • replace pcv valve
  • replace all rubber vacuum hoses and fittings that look at all suspect, followed by a complete vacuum system test
  • cylinder compression test, wet/dry
  • expect that a complete carb rebuild will be required, but dont’ do that until you’ve verified the pump works, and the gas tank isn’t in need of a cleaning.
  • change engine oil and filter
  • make sure engine is securely grounded to chassis, and chassis to battery ground.

#23

That reminds me of vehicles with a failing ignition switch


#24

@74AMCGrem This sounds more and more to me like a problem with the ignition system and the fact that it is only on left hand turns that the engine dies still makes me think it is in the primary side of the ignition system. As you turn the engine shifts on the motor mounts. As the engine shifts, a primary ignition wire may be touching the engine and thus grounding out the ignition. Look for wires near the engine. You may want to wrap tape around the wires or find a way with a piece of string to tie these wires away from the engine.
AMC made some interesting cars back in the 1960s and 1970s. I preferred the AMC 6 cylinder engines to the 250 cu in 6 that was in my 1971 Ford Maverick.


#25

Looking at the engine I didn’t see any wires that were even close to the block and if they were they were insolated by rubber.


#26

If the engine stalls when you briskly apply the accelerator, the accelerator pump in the carburetor may not be working.


#27

Personally I like Gremlins and I am assuming this is a hobby car for you, not a daily driver.
Along with all the above comments ( I too suspect points and primary wires)
The fuel delivery system needs to be upgraded to work with ethanol gas or if not, use ethanol free gas if available in your area. The ethanol, which is present in all grades of pump gas unless otherwise stated, does all sorts of nasty things on older vehicles.


#28

I had a 1972 Toyota Carina that experienced the exact same problem. The issue turned out to be the fuel filter. One time it clogged up and the car died just as I reached Echo Summit coming home from Lake Tahoe. It was snowing and I was the last car over the pass before chain requirements were put into place (I didn’t have chains). It took about 2 minutes to remove the fuel filter (it was inside the engine bay and right by the right fender well so was extremely accessible), blow it out (yuck!) and reinstall it. Problem solved. If the IP’s problem is with the fuel system, it might be worth it to drain the gas tank and all the fuel lines completely and have the tank cleaned.


#29

After replacing fuel filter replacing pcv valve and gasket plus running sea foam thru carb and tank the problem is still happening…


#30

Still only happens on left turns? Check motor mounts.


#31

Is that AMC guy you mentioned not willing to help you ?


#32

Since the previous owner used ethanol gas, if you are get the correct pressure and volume of gas going to the carburetor I would definitely consider rebuilding the carburetor Or buying a rebuilt carb.


#33

AMC guy had no ideas. Motor mounts are good. And the previous owner used only ethanol free gas.


#34

Many keys on the keychain? Possible ignition switch hiccup? Try using just the key ?


#35

@Barkydog may have hit on something. The ignition switch was a weakness on the 1965 Rambler that I owned. I replaced that switch at least twice in the 8 years I owned the car. I think I had to replace the ignition switch on my 1968 AMC Javelin as well. In neither car did I have more than just the car keys on my key ring
Back then, the ignition switch was on the dashboard–there was no locking steering column. Your 1974 Gremlin may have the steering column lock combined with the ignition lock, but this may still be a possibility.


#36

Could I Hotwire the battery directly to the coil to see if the problem persists? That would reduce the number of possibilities drastically.


#37

If you run a hot wire between the battery and coil, you’ll eliminate the ballast wire from the ignition switch to the plus side of the coil.

Then when the engine is started and the charging system comes on line, the higher voltage from the charging system will fry the coil. points, and maybe the plug wires.

Tester


#38

Couldnt I just disconnect my alternator?


#39

I owned a 1979 Jeep CJ 5 that would start and run perfectly, then randomly die, but would immediately fire back up and run as normal. At the suggestion of a friend of mine, I replaced the ignition control module. He had one laying around anyway since he’d swapped a vortec 350 into his 81 Scrambler. That fixed my issue, and sounds similar to what you’re describing. I don’t know if your model Gremlin has the same part (probably), or how much an ignition control module costs, but it might be worth a shot if you haven’t resolved your issue. There might be a way to test the module, but someone more knowledgeable would have to chime in there - and in my case it was so random it would’ve been near impossible to test anyway.


#40

I believe AMC began using electronic ignition in 1975, if this car has electronic ignition it was converted.