Runs for a second after prime shot
Hello all, new to fitech and have a situation that is driving me crazy. Finished the build (1972 GMC Jimmy with Chevy crate motor, MSD HEI) about a month ago and it ran fine. After a bit of driving the truck would just quit, it would re-start and go for a while and then do the same. It got progressively worse and now will only run on initial prime. The pump doesn’t run after crank position. If I turn the key back to off position the back on, it will prime and then nothing. Any thoughts?
To add to my question, I have a CDI box as well as the HEI. Should I dump the box and wire it with just the HEI and the fitech? I’ve found that the ECU is “hanging up” not receiving a tach signal. With some light taps yo the ECU area on the throttle body it will start and run until hot. Let it cool down, some more taps and it will start again. Help please.
I just started experiencing a similar issue. My unit has been installed for 4 summers now including this one. I never had any issues with starting or running in general. Suddenly on Tuesday last week it would not start after I got gas. eventually I got it started. once it was started it would run fine. if it sat for 10-15 minutes it would start back up and run. if i tried to start it immediately, it would fire off the prime shot and die. I think today I found that the ignition switch has a dead spot in it or possibly a wire is getting hot. every time I tried to verify 12 v at crank and the on position for the white wire, I had 12 volts, with a slight drop after prolonged cranking. I could see it on the handhled and could see it on the volt meter at the battery post. Today I started over and tried to verify the power was clean and 12v and saw no power at crank. I was trying to jumper the starter relay while holding the volt meter leads etc but I saw ver little voltage at the white wire in crank. I messed around with the connections and when I got help from someone to actually sit in the car and use the key, I could not reproduce the low volts issue and now the car stats and runs fine again. Long story buy I'm going to dig deeper into the ignition switch and wiring that provides the voltage to the White wire.