Well I FINALLY got my 68 running. Its got the Holley Commander 950 Multiport EFI on a 454 bored .125 over to make 481 cubes. I am not running an O2 sensor becuase I run race gas due to the 12.5:1 compression. I am having a severe stuttering at 2800-3100 RPM. When I nail it in first it just sitts there like its on a rev limiter at the above RPM then all the sudden it either snaps your neck back or blows the tires off. It does this in every gear, and it does NOT do it above or below those RPMS. It also does this at part throttle as well. It also ONLY does it while your driving, you cant get it to stutter without a load on the motor. It just seems to get SEVERELY worse once the engine gets up to running temp. I have been trying to make it richer to no avail. I have also tried making it leaner. I am beginning to think that something else is wrong. What could it be? Thank you very much for ANY help/advice.

 

Check the TPS and the MAP sensors.

Rich

 

what exactly would I be checking for? They seem to be functioning correctly. I will read the manual on how to check them but beyond that I dont know

 

Head over here and ask the question. The moderator Doug Flynn is a Holley EFI engineer.

Jody

 

i have a friend that is using the comander 950 and couldnt get his car tuned for nothing till he tried a different data logger and discovered his was bad

 

well this is all going to take me a few months to find out because at about 6800 rpm the motor dropped a valve and puked the guts out all over the track. THe only thing left is the intake manifold, timing cover, amazingly enough the oil pan, (and all the accessories etc). So its going to be a while before I can build a new long block. This time I am going to go bigger, like a 555 or 565 with about 10.5:1 compression and a more tame cam which should be able to let me use pretty much all of the fuel injections features. Thanks for the help.