blown formula

Last weekend I was cruisin' in my 312 Fastec w/twin 454 efi's & one engine dies. 3100 rpm & it just shut off like turning a key.
Found no spark thru distributor, weak spark out of coil. Replaced the coil, same thing. replaced the ecm, same thing.....
I suspect the optical trigger in distributor or the crank trigger. Any ideas???
& yes, this happened 3 times. Just the last time, it would not restart at all, not even a backfire!! ???

eyezlee

hey blown, had the same type of deal happen last weekend. turns out that the thunderbolt IV module was just loose enough to kill the engine. Squeezed it and it snapped in place, fired right up. Did your tach bounce around before it died? Mine was bouncing from 3200 (the rpms I was running) to 36-3800.

blown formula

Hi Paul
I don't have thunderbolt ignition on this boat. It is ECM for fuel injection. I swapped out the ecm & coil & no help. I'm stuck here!!

Bayley

I had the exact same thing happen this past weekend on a '99 454 Mag EFI. Cruising along, everything looks fine. Then suddenly, the right motor just died. It turned out that my distributor gear got eaten up (badly). If your gear is missing a tooth or has one worn, it might skip forward, stall, then skip back and start up fine.

Easy way to check for this, pop the cap off and see if you can turn the rotor by hand. One degree of gear lash is about nominal... I had about sixty!!! Not sure why the gear failed. My cam gear looks great, distributor feels great, and the oil pump is smooth as it ever was. However, if you look around, you will find quite a few people with spontaneous gear destruction for no apparent reason.

Good luck and keep us informed.

-Bayley

blown formula

Yeh, I saw the post about the gear failures, but did not think it applied here, due to the multiple fails described. I will post whatever the trouble was when it gets repaired......

B.R.S.

I don't know if this will apply here but the same thing happened to me last Sept. Turns out the timing chain gear on the crank broke into 9 pieces. There were no forgien parts anywhere the gear just failed. When it broke the distributor stopped turning and it was like someone turned the key off. DON'T BUY ANYTHING FROM COMP CAMS!