LT4 swap into a 1972 camaro

[mxb401]

long time member - not a big poster. cant believe ill be the first on the ltx forum, i appreciate everyones suggestions.

so i bought a crate lt4 motor from GM and the ecu kit (the one w/ the pedal etc)

everything is installed, all wires are connected, primed the motor, new battery, and grounds separated, have fuel pressure, and oil pressure,
engine will crank but not turn over
when i turn the key to one click the red LED light on the 'fuse box' blinks...and when i turn to start it shuts off.

hooked up to a scanner
no spark
no injector pulse

cant seem to figure out whats going on. anyone that has any suggestions im open to anything at this point. i realize this has a lot of technical specifications and questions, even if someone would have a number to call or contact info on more in depth trouble shooting it would be great. i reached out to GM performance and went thru their suggestions and didn't get any closer.

thanks in advance.

[andrewb70]

long time member - not a big poster. cant believe ill be the first on the ltx forum, i appreciate everyones suggestions.

so i bought a crate lt4 motor from GM and the ecu kit (the one w/ the pedal etc)

everything is installed, all wires are connected, primed the motor, new battery, and grounds separated, have fuel pressure, and oil pressure,
engine will crank but not turn over
when i turn the key to one click the red LED light on the 'fuse box' blinks...and when i turn to start it shuts off.

hooked up to a scanner
no spark
no injector pulse

cant seem to figure out whats going on. anyone that has any suggestions im open to anything at this point. i realize this has a lot of technical specifications and questions, even if someone would have a number to call or contact info on more in depth trouble shooting it would be great. i reached out to GM performance and went thru their suggestions and didn't get any closer.

thanks in advance.

Where ever you hooked up the ECU "power on" wire (whichever it is in the GM harness) is not connected to the proper source. It needs to be connected to a switched source that is hot in both RUN and CRANK. So when you go to crank it over, the starter spins, but the ECU shuts off.

Andrew

[dhutton]

X2. You should have tapped into a pink wire.

Don

[mxb401]

thanks to both of you...fired right up. runs great!! cheers!

[kcarter13]

I made this exact same mistake when I did my lS3. Doing an lt4 swap now on another car. Can't wait to fire it up

[badazz81z28]

Curious to see pics? What did you do for the accessory drive?

[Takid455]

Curious to see pics? What did you do for the accessory drive?



Building a 77 TA with LT1. Using the Holley high mount. This uses the LS water pump. Wanted to run the CVF or Kwik setups but with retaining the factory AC guts, not sure if the peanut 7176 compressor can fill that volume. Needed a Sanden 508/709. Haven't tried to fit it yet, but I am told the LT water pump interferes with the frame/ control arms .