Engine idles fine and runs in 1st, but dogs and shakes the car in 2nd!?

This one is new to me. Brand new Holley 2bbl carb, Pertronix goodies in the distributor, and correct gap on plugs.

The Olds starts/idles beautifully, and takes off fine in first. Once I hit 2nd, it's like Chitty Chitty Bang Bang! I haven't taken it to 3rd - too scared!

The timing seems right, although I'll admit backfiring thru the carb when it's happening.

What the poop is going on?

- Shane

 

Check to see if the advance is working correctly in the dizzy. Backfiring thru the carb could be an issue with the valves.

 

I don't know everything but it sounds like you may have a lobe wore off the camshaft...alot of times they will run great until you put a load on the engine then all h--l breaks loose.popin back through the carb...Pull the valve covers,unplug coil wire,have some turn engine over..watch the rockers..if you have a wore cam lobe you will see it..

 

That's how it aaaallllll starts! It ran "ok" with the Rochester, but when I rebuilt that, there was a checkball frozen in its hole. Don't tell anyone, but I left it there - it had run decent before. LOL Ahem

Anyway, now that I'm trying to do right by the '62...."all hell breaks loose"! I just...want it...to run....like it did...but better!

 

Don't know what year engine it is, but Olds had trouble with soft cams. Check firing order, did you take the distriburtor out, if you did make sure you put it back where it is supposed to be, might be off a few teeth.

 

Start with the simple things. Check the firing order, cap and rotor. As you put more load on the motor the spark has to be hotter to fire the plugs and it will find any weak point in the cap or rotor and fire the wrong plug.

Check the fuel filter and float level as a motor running lean will pop back through the carb. You might have to change jets in the carburetor as it may need to be tuned to this engine. When you use an OEM carb, the engineering has been done to tune it to the motor it's on.

 

The old "It ran good before I fixed it".

 

Lol Well it did!
I will check the mixture of fuel....I did lean it back a hair bc it smelled WAY too rich while it ran. This is a 394ci w/new Holley 2bbl, besides the Pertronix, the rest is stock.
The dist has never been out, and the plugs are new and gapped good. Wires are in order.
I think I'll get home and play with the air/fuel mix a little.......

 

check the fuel pump while your at it.

 

Pertronix sucks.

 

Unless Holley has changed their carbs, the only things you can adjust are idle mixture and float level. To change the mixture off idle, I think you need to change jets inside the carb or change a metering plate.

 

Put the points back in then adjust the gap, dwell, and timing properly.

 

I agree with GUNNO1. The SBC in my roadster had the same symptoms. Ended being the cam with two flat lobes. Popped & backfired thru the center carb.

 

Fuel filter? you need more flow at speed than at idle. One way i've diagnosed is to get up to the speed where it starts bucking. pop it in neutral for a short wile. The bowl will fill while your coasting..then back into gear while you still have some speed and see if it takes a while to start sputtering. If it runs good for a few seconds, fuel delivery. If not, keep searching
I did this to diagnose some gelled diesel which clogged a filter on me two days after replacing

 

what they said

 

I would have to agree with checking the fuel filter first. You may have a restriction in the fuel system.

 

Maybe you hooked the vacuum advance to the wrong port when you put the Holly on.
It may have been hooked to full vacuum before,and ported vacuum now.

Also,with the motor off,look inside the throat of the carb,and make sure the accelerator pump squirts fuel with even the slightest movement of the throttle.