Anyone know what could make a perfectly healthy motor lose compression all at once while you're cruising at 45mph and just shut off and not start again?

 

yeah, if for some reason it's not cranking at ALL. that is about the only way i could see you losing compression on all 4 cylinders at the same time on a motor that was running perfectly fine just moments earlier.

 

oh yeah and if you havent already, check to make sure the timing belt isn't broken...

 

Nope not timing belt... that was the first thing i checked. I'm really stumped here. I guess I'm going to have to break into the motor. It's cranking just fine, just has 0 psi compression across the board. The motors only got like 60k on it and i just installed it 2-3 weeks ago. Never been driven hard. I'm thinking head gasket, maybe floated valves since the head is dx wired for 7200 rpm. I only took it that high maybe 3 times though. Odd.

 

i dont think it sounds like a headgasket. car smokes like fuck until they totally go. have you cranked the car and sat there and watched the timing belt/cam gears to make sure everything is moving?

 

Yes, everything is rotating properly. I even checked to make sure that all the valves are on time. I honestly can't figure out what else it could possibly be... if i broke a rod or something then i would still have compression in at least one other cylinder i would think. I dunno.

 

yeah, something is very fishy about that.

 

I can't think of what would make all cylinders do that simulateously, unless you somehow had a really lean condition and melted/puched holes through all the pistons.. Most things would cause headgasket-like symptoms, coolant leaks, etc.. Broken rods are usually very audible, and the other cylinders will behave fine. Valvetrain stuff is usually easy to spot,and will happen when it's being abused. Valves won't suddenly get bent or stuck at normal RPM, etc is what I'm trying to say.. If the timing belt is fine, not broken, and not off a few teeth, then that's strange.
If you haven't had the head off recently, this is really a stumper.

 

check ur dizzy and make sure your getting spark, if thats good check and make sure your getting fuel and run a fuel pressure test if all thats good swap out a known good ecu and see if that helps

 

you are stupid. stop posting, really. he did a compression test and the motor gets no compression. NO SPARK WONT MAKE THE MOTOR NOT HAVE COMPRESSION.


i'm thinking you suddenly jumped like 4 or 5 teeth on the Tbelt somehow. i'd reset the timing belt back to TDC for sure and go from there.