i just finished my TPI to Carb swap and she starts up and idles quite nicely. but once i give it 1/3 throttle, all power seems to fade away. theres absolutely no power above 2300 RPMS. the exhaust makes this "clapping" noise. i checked for any exhaust leaks but could not find any. base timing is set at 12* and total timing is at 30* being that the weights and springs in the distributor remain unchanged. the wires are routed correctly to each cylinder and the distributor/coil are brand new. im still using the stock TPI fuel pump and a mallory return style afpr. it holds pressure at 5.5psi at WOT so pressure is ok. perhaps im not getting enough volume? so what do you guys think?

heres my current setup:

1989 trans am

355ci
9.3:1 CR
stock tpi fuel pump
mallory return style afpr
750CFM edelbrock carb
edelbrock performer rpm air gap intake
edelbrock performer rpm aluminum heads
hedman 1 5/8 shorty headers
zz4 cam - 208/221 @ .050
flowmaster 2 chamber muffler
no cats
700R4 w/shift kit, vette servos and vette stall
msd billet distributor
blaster 3 coil
accel 8mm wires

 

We all like to think we've covered everything, but it's VERY easy to overlook the obvious.

Did you check the float bowls in the carb?
Are you sure ALL the vacuum inlets are either used or plugged?
Do you have the vacuum advance on the distributor set to the full vacuum port (passenger side) or the off idle port (driver's side)?
Whichever it is, try switching it. Just an FYI, it should be on the driver's side port.
Is the choke working properly?
How's the fuel filter?


That's all I can think of right now. I know it sounds like stupid stuff to check, but you may feel even more stupid if it IS one of those. Lord knows I've done it numerous times.

 

im on my third carb in a year, and you sound like you have a carb problem, is it new and properly adjusted?

 

"Most carb problems aren't"

Plugged cat convertor is where I'd start. Then my ignition wires, then carb

 

damn stupid question time (and I'll preface this by saying I know NOTHING about egines)... could it be spark plug related too big/small a gap (have actually entered this question as a separate topic too)

 

What gear ratio are you running...

 

Quote:

no cats
700R4 w/shift kit, vette servos and vette stall
msd billet distributor
blaster 3 coil
accel 8mm wires

My bad. Did you try bumping up fuel pressure?

 

yea i tried bumping up fuel pressure but still no go. i was able to pickup a holley "blue" fuel pump for $98 from a local dealer so i couldnt resist. im taking a break right now as we speak. gonna head down there and resume the battle in a few minutes. i also backed down my base timing to 10* w/25* of advance for a total of 35*. gonna take it out as soon as im done and see if theres a difference.

so hopefully a new fuel pump and filter along with the timing changes will help things out. ill be back later to post the results. hopefully all goes well wish me luck!