Pulsing transmission???

[67dart_drop_top]

I did a couple of things that may have lead to my troubles, so I am hoping someone will be able to point to something that I can check. I did these things in this oder.

1. Dropped the fuel tank, cleaned it out, painted, replaced.
2. Newly rebuilt carbuerator.
3. Dropped 904 transmission connected to a 273 and replaced all seals, filter and oil.

I noticed a "pulse" before dropping the transmission. What I mean by that is the car seems to lose and regain a few rpms in about one second intervals. This only happens when I am at a stready speed. The shifts between gears are great, and there are no problems when I am accelerating or decelerating. It is just when I am at crusie speed.

I would have suspected a vaccuum line from the carb, but I do not remember there ever being a connection between the two???

Anyone have any ideas?

 

[wjajr]

2. Newly rebuilt carburetor.
Do you mean purchased a rebuilt carburetor, or did you rebuild your old carburetor?

Auto parts store rebuilt carburetors often do not perform well as they are a collection of parts “point five rear-ended” (half-assed that is) together, and are no longer dedicated to a particular application. One is better off rebuilding their original carburetor.

I noticed a "pulse" before dropping the transmission. What I mean by that is the car seems to lose and regain a few rpms in about one second intervals. This only happens when I am at a stready speed.

Do you mean the pulse was there before making repairs, or did the pulse start after repairs were made? Could you describe the pulse as a surging? If so surging at constant throttle opening on flat ground or up a slight grade is often a sign that the air fuel mixture lean. Did you change the jetting? Did you use a vacuum gage to adjust the idle mixture screws to attain the highest in-gear vacuum if car is an automatic?
2. Newly rebuilt carburetor.
Do you mean purchased a rebuilt carburetor, or did you rebuild your old carburetor?

Auto parts store rebuilt carburetors often do not perform well as they are a collection of parts “point five rear-ended” (half-assed that is) together, and are no longer dedicated to a particular application. One is better off rebuilding their original carburetor.

I noticed a "pulse" before dropping the transmission. What I mean by that is the car seems to lose and regain a few rpms in about one second intervals. This only happens when I am at a stready speed.

Do you mean the pulse was there before making repairs, or did the pulse start after repairs were made? Could you describe the pulse as a surging? If so surging at constant throttle opening on flat ground or up a slight grade is often a sign that the air fuel mixture lean. Did you change the jetting? Did you use a vacuum gage to adjust the idle mixture screws to attain the highest in-gear vacuum if car is an automatic?

A big vacuum leak can cause lean running at small constant throttle openings. Check for vacuum leak between carburetor and intake.

 

[67dart_drop_top]

Do you mean purchased a rebuilt carburetor, or did you rebuild your old carburetor?

It was rebuilt by a sompanyh that specializes in carb rebuilds.

Do you mean the pulse was there before making repairs, or did the pulse start after repairs were made?

I noticed the pulse after the carb replace and before pulling transmission.

Surging at constant throttle opening on flat ground or up a slight grade is often a sign that the air fuel mixture lean. Did you change the jetting? Did you use a vacuum gage to adjust the idle mixture screws to attain the highest in-gear vacuum if car is an automatic?

I have not but will do that as my first step.



A big vacuum leak can cause lean running at small constant throttle openings. Check for vacuum leak between carburetor and intake.

Would be shocked but will check.

Thanks. I am kinda surprised there was only one repsonse. Yours musta been real good to not have any other guesses.

Thanks again. I really do appreciate it, and I will let you know how it turns out.
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