TDC, fuel pressure

[EVOclipse]

ok the haynes manuals got me confused once again. first question is it REALLY that important to make sure my #1 piston is at TDC, when removeing the timing belt. also the order of everything seems REALLY off, it says to relieve fuel system pressure but when you do that, the TDC u just set goes right out the window. so is it a big deal when taking everything apart or can i just worry about it when i put it back to gether. oh and details its a 96 eclipse RS nonturbo of course,god i hate it

[gthompson97]

for the piston to be at TDC, the crankshaft pulley (not accessory belt pully, behind that) for the timing belt must have the arrow lined up vertically with the one on the block. your #1 (and #4) pistons are now at TDC. releiving the fuel pressure is just a safety precaution. i normally don't do it, just when you undo the bolts for the fuel line, let it sit there for a min and let all the fuel run out. it's not gonna spray all over or anything.

[EVOclipse]

thanks thats mostly what i was worried about. cause in the book its all talkin about HIGH pressure fuel line and crap. also dont u mean the 1 and 3 cylinders? and in all actuallity i thought only 1 cylindr at a time would be tdc, plus when i was spraying out my engine i noticed as the air crossed the exhausts, only the 4th sounded open and the other 3 were closed. (dont ask...but i had alot of rust i wanted to blow out with the compressed air)

[gthompson97]

nope, pistons 1 and 4 run together and 2 and 3 run together. they're called "buddy" pistons

[kjewer1]

To further elaborate, only one of the two paired pistons will be at TDC on the compression/power cycle, the other is on the exhaust/intake stroke. So while one piston is compressing the mixture, the other is forcing the exhaust out.