Hesitation/lack of power
 

Looking for some ideas on the cause. Car is leaving very lazy and has a hesitation at the hit of the throttle. It cleans up and runs strong after about 4,500 in first gear. Tried a spare carb, but unsure if it was good or not, and had the same results. Swapped converters to a known good one and replaced the ignition coil. The fuel pressure is staying steady at 7 1/4. The car is a 72 454 Corvette running in C/SA. The motor is fresh/new and was dynoed. Neither my carb or igntion were part of the dyno testing. Both sat for about a year without usage. Let me know if you have any ideas on what to look for/test. Thanks

Norm Webber

Re: Hesitation/lack of power
 

Try the fuel pressure at 6 psi for starters. Trans oil level is OK? If you use a 2 step change the 2 step module. Had one go bad when we had our Malibu stocker causing same grief.

Re: Hesitation/lack of power
 

Fuel sloshlng over?

Re: Hesitation/lack of power
 

No on the fuel sloshing as it will act similar in park stabbing the gas. Checked the fluid and it is ok. I tried leaving without the two step and had the same results. I will try the fuel pressure on the next run. Thanks for the ideas

Re: Hesitation/lack of power
 

Squiters doing as they should? Good flow out of both sides? Rear air flap OK?

Re: Hesitation/lack of power
 

Check the accelerator pump gasket, they dry out from sitting especially after using VP fuels. Chased that for a while once.

Re: Hesitation/lack of power
 

Described hesitation is usually too much or too little fuel. Too much and you'd get a black puff when it finally picked up. Too little and it's just a dead spot. I'd bet too little. I'd start by dissembling carb and cleaning thoroughly.
What carb does it have?

Re: Hesitation/lack of power
 

X2.............Sound like Carb.

Re: Hesitation/lack of power
 

how much timing are you using? where is your total set at ?what rpm? just curious

Re: Hesitation/lack of power
 

Change the coil wire!

Re: Hesitation/lack of power
 

accelerator pump. they shrink after sitting up for a while.

Re: Hesitation/lack of power
 

x2

Re: Hesitation/lack of power
 

I will be replacing the coil wires and going through both carbs. I have 38 degrees of timing in a locked distributor. Thanks for the replies

Re: Hesitation/lack of power
 

Verify TDC and "0" on the timing mark.

Re: Hesitation/lack of power
 

Change the coil wire!

???

explain?

Re: Hesitation/lack of power
 

What one wire in the ignition system causes the most resistance when it wears out or becomes ineffective at passing electrical current? It is the one wire that passes all 8 electrical impulses of the engine firing cycle. That one wire is used 8 times more than the normal spark plug wire. When that wire breaks down it is very similar to having a coil that goes bad. The spark energy is used up jumping inside the wire, just like a large gap resistor plug. If you ever find a bad one split it open and you can usually pour out the carbon/graphite that has turned to a powder or burned up. Test the resistance and you will see the bad coil wire is way up in resistance per foot than one of the other plug wires.
Coil wires should be replaced frequently.
He did mention that it came back alive after a higher RPM. If it had low spark energy getting to the plugs at low RPM the coil wire can cause that.
Oh, Low spark energy will make you think it is carb related because it shows up as rich at the plugs.

Re: Hesitation/lack of power
 

^^
interesting. thanks. now I got something else to check.....
chasing a power issue. when I let the transbrake go, rpm's fall 4-500 before starting to climb back up. Killing my 60 ft. Have swapped trans, convertor, carbs, ignition....
If I had any hair i'dve pulled it out....
(327-250 PG SS combo)