This is a heavily modified 350 w a custom chip. It will not rev above 3000 rpm. Stuck a Superchip for a 305 in it... same result. Any ideas on what to check?

 

Coil, distributor, or plugged catalytic converter.

 

if you have a catylitic converter you might want to check that. i had something similar happen to me and my cat was clogged

 

It does not have cats. Any troubleshooting meghods for checking coil or distributor?

 

Do you have the stock ignition/coil on it?

 

Yes, it has the stock Corvette stuff but I believe that the coil, cap, rotor, and module(thing in bottom of dist) are all new.

It will rev freely and sound good while parked, I only have this problem while driving but I don't get any codes.

 

Mine did that when my distributer was off a tooth.

 

make sure the EST wire on the pass side firewall is connected. Without that the CPU can't advance the timing which is required at the higher RPM's under load. It'll rev fine in neutral because there is no load but under load the lack of timing advance keeps it from getting into higher rpms.

There could also be a problem with the EST module/circuitry. I've never been that far into that aspect though.

But you should check for continuity in the EST wiring.

Hodge

 

mine did that bad for a couple of weeks... but not all the time... it would do it sometimes on the interstate when i was crusing... it would bog and not rev past 3000RPMS... fixed it when i changed the cap and rotor though... but my cap and rotor had 100,000+ miles on them... ORIGINAL GM PARTS!!!!

 

What is the EST? This is in a Jag so some of the wiring has been changed.

 

EST=Electronic Spark Timing.

When connected the computer is able to increase/decrease the timing. When setting the base timing you need to disconnect this wire and set the timing to 6* or whatever the correct timing is for your application. 6* is STOCK setting on most TPI motors. If you set the BASE timing without disconnecting this wire then you will have way to little timing and that will keep it from reving to higher RPM under load.

On F-cars there is a wire with a connector coming out of the wire loom on the pass side near the firewall. See the attached picture.

Again to reiterate... if you set the timing with-out disconnecting this wire the timing will be way too low. Also if this wire is not connected when trying to drive the car the computer cannot advance the timing and there will be no top end power just as you describe.

Hodge