75 scamp 318 engine problems

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75 plymouth scamp

75 plymouth scamp

Sold the scamp ....still got the duster tho
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Jul 30, 2020
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West Central Indiana
brand new distributor and new avs2 600 carb. i can rev this engine to the moon just fine...if i put it down in drive and stab the gas hard it dies. starts back up idles like a dream . new tune up on everything new carb and hei distributor. still having issues. at a loss chasing things down any help appreciated. also new fuel pump mechanical. mild cam not sure on specs, headers , weind intake . stock heads and stock bore. thanks ! (automatic car)
 
75 plymouth scamp said:
brand new distributor and new avs2 600 carb. i can rev this engine to the moon just fine...if i put it down in drive and stab the gas hard it dies. starts back up idles like a dream . new tune up on everything new carb and hei distributor. still having issues. at a loss chasing things down any help appreciated. also new fuel pump mechanical. mild cam not sure on specs, headers , weind intake . stock heads and stock bore. thanks ! (automatic car)
Click to expand...
Sounds fuel/carb related. Sounds like your secondaries are killing it. You can unhook your linkage that actuate the secondaries mechanically and see if it still dies off the front barrels. If it doesn't, now you know where the problem is. If it still does it, then look at the accelerator pump and perhaps pump shot nozzle.
 
I have a new AVS2 but have not used it yet. The air valve from the factory seems really loose. I wont be surprised if mine does the same thing. Do like 318will run says or tighten up the adjustable spring on the air valve.
 
New HEI distributor?
How did you hook it up (electrically)? Did you bypass/eliminate the ballast resistor?
What did you set your initial at? It may need a bit more static timing.
 
Actuate your throttle from closed to fully open (engine off) while looking down the primary throttle bore and make sure your getting a full accelerator pump shot. This test is no cost and a bad accelerator pump can cause the motor to fall on its face under load. Secondaries opening too soon, as mentioned above, can also cause the engine to bog under load.
 
What kind of diagnosis have you done so far? Have you double checked the tuneup?
 
AVS 2 is a 650 cfm carb they are too much for the 318s, have tried this.

We took the same AVS 2 carb and put it on a stock build 360, and it ran perfectly, no adjustments, no tuning needed.

Need more displacement for the AVS 2 to work properly.

Put on an Edelbrock 1406 600 cfm carburetor. Your 318 will run perfect with it right out of the box.

20230705_103321.jpg


1406 on a 318, yep runs perfect.


☆☆☆☆☆
 
George Jets said:
AVS 2 is a 650 cfm carb they are too much for the 318s, have tried this.

We took the same AVS 2 carb and put it on a stock build 360, and it ran perfectly, no adjustments, no tuning needed.

Need more displacement for the AVS 2 to work properly.

Put on an Edelbrock 1406 600 cfm carburetor. Your 318 will run perfect with it right out of the box.

View attachment 1716340688

1406 on a 318, yep runs perfect.


☆☆☆☆☆
Click to expand...

He could adjust the carb he has first before getting a whole other one. I have an AVS2 I've tuned on my stock 360 after running a 1406. AVS2 is more sensitive to the idle and light throttle cruise mixture being too lean and causing an off-idle stumble. Could also be a bunch of other things, we need more details on exactly what it's doing. "Stab the gas hard" does that mean WOT from a stop or just giving the gas pedal a small sharp jab? How does it drive if the pedal is pressed gently?
 
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