valve clearance? my car wants to die - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

banky · 07-08-2003, 06:01 PM

hey, i just finished a mission with my father. we changed out my pistons with pistons from another block we got at the local u-pick.. anyway, everythings put back and the car turns out for a few seconds then just dies. or it idles at 2000 rpms.. we lowered the idle and now it just does the former. my dad thinks it could be the valce clearance, because we dont exactly have the proper tools for that, but he rigged up something, just not sure what. anyway, he wants to know what happens when the valve clearance doesnt meet factory specs, does this problem occur? my check engine light doesnt turn on when the car starts, so i dont think theres an electrical problem. but when the car starts, if you keep revving, it'll stay alive and rev all it wants, it just dies if you dont keep giving it gas. anyway, any help would be greatly appreciated. thanks.

BTW: its a 92 S13, we got the block and the head from a 92 also. we used the new head, with the old block because the new block was from an auto 240. so we used the new pistons in the old block with the new head. sorry if any confusion.

banky

Bill Roberts · 07-08-2003, 07:27 PM

Did you do a full reset on your ECU?

If not, do a search for "resetting ECU" and do that.

It is located by the right passenger kick panel by the floor. Take the panel off, print the instructions and see what happens next.

I think with enough folks on this thread, you can get it right.

Also check all the ground wires and vaccum hoses. One Vac hose not there will cause this. Retorque the head also. Do compression check. Make sure all lines are connected.

banky · 07-08-2003, 07:39 PM

we've checked all the hoses and lines. everythings fine. anything that looked old we changed with a new hose.
right now the valve clearance is as follows; engine is hot.
intake valve, .016in hot
and exhaust valve, .017 hot

eh.. anymore input? thanks

banky

the engine starts but wont run.

Bill Roberts · 07-08-2003, 07:53 PM

Did you reset the computer?

Yes, No Maybe?

Stop. Repeat question one.

At this time is sounds like Mass air flow sensor, O2 sensor, throttle position sensor and fuel/air management computer problems.

All it takes to run right is Spark, timing, compression and Fuel/Air.

I sense the signals going to the computer are not coming back correctly.

Valve problems show up at 2000 to 3500 more than 1000.

If the valves are not touching the pistons (!!) and the spark plugs are not too long and touching the pistons, and you have compression...well, it should run. Valve clearence is a nasty knocking sound of your valves either being destroied by the top of the pistons or the cam slapping the hell out of them...no noise, no clearence problems.

If you have bad valve seats (not ground properly from valve seat to head seat) then yes, the compression loss would show up.

That is why I recommend the all elusive compression test.

your answer lies in Vaccum, fuel/air, computer problems in my most humble opinion.

07-08-2003, 06:01 PM	#1
banky Join Date: May 2003 Location: miami Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	valve clearance? my car wants to die hey, i just finished a mission with my father. we changed out my pistons with pistons from another block we got at the local u-pick.. anyway, everythings put back and the car turns out for a few seconds then just dies. or it idles at 2000 rpms.. we lowered the idle and now it just does the former. my dad thinks it could be the valce clearance, because we dont exactly have the proper tools for that, but he rigged up something, just not sure what. anyway, he wants to know what happens when the valve clearance doesnt meet factory specs, does this problem occur? my check engine light doesnt turn on when the car starts, so i dont think theres an electrical problem. but when the car starts, if you keep revving, it'll stay alive and rev all it wants, it just dies if you dont keep giving it gas. anyway, any help would be greatly appreciated. thanks. BTW: its a 92 S13, we got the block and the head from a 92 also. we used the new head, with the old block because the new block was from an auto 240. so we used the new pistons in the old block with the new head. sorry if any confusion. banky

07-08-2003, 07:53 PM	#4
Bill Roberts Zilvia FREAK! Join Date: May 2003 Location: S FL. Posts: 1,538 Trader Rating: (0) Feedback Score: 0 reviews	Did you reset the computer? Yes, No Maybe? Stop. Repeat question one. At this time is sounds like Mass air flow sensor, O2 sensor, throttle position sensor and fuel/air management computer problems. All it takes to run right is Spark, timing, compression and Fuel/Air. I sense the signals going to the computer are not coming back correctly. Valve problems show up at 2000 to 3500 more than 1000. If the valves are not touching the pistons (!!) and the spark plugs are not too long and touching the pistons, and you have compression...well, it should run. Valve clearence is a nasty knocking sound of your valves either being destroied by the top of the pistons or the cam slapping the hell out of them...no noise, no clearence problems. If you have bad valve seats (not ground properly from valve seat to head seat) then yes, the compression loss would show up. That is why I recommend the all elusive compression test. your answer lies in Vaccum, fuel/air, computer problems in my most humble opinion. Last edited by Bill Roberts; 07-08-2003 at 07:56 PM..

07-08-2003, 07:27 PM	#2
Bill Roberts Zilvia FREAK! Join Date: May 2003 Location: S FL. Posts: 1,538 Trader Rating: (0) Feedback Score: 0 reviews	Did you do a full reset on your ECU? If not, do a search for "resetting ECU" and do that. It is located by the right passenger kick panel by the floor. Take the panel off, print the instructions and see what happens next. I think with enough folks on this thread, you can get it right. Also check all the ground wires and vaccum hoses. One Vac hose not there will cause this. Retorque the head also. Do compression check. Make sure all lines are connected.

07-08-2003, 07:39 PM	#3
banky Join Date: May 2003 Location: miami Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	we've checked all the hoses and lines. everythings fine. anything that looked old we changed with a new hose. right now the valve clearance is as follows; engine is hot. intake valve, .016in hot and exhaust valve, .017 hot eh.. anymore input? thanks banky the engine starts but wont run.