1993 240SX : Hesitation at high speeds, rough/low idle, then no spark but cranks

[NotDave]

symptoms:

1) noticed car had hesitation at high speeds, felt a slight vibration when stepping on the pedal harder and acceleration at 55mph+ in 5th gear was apparently slower than it should be compared to another 240sx I have.

2) one day I started the car and the idle was really rough (almost like it was running on 3 cylinders). idle was low but the engine never stalled. i shut the car off and restarted it after peaking under the engine bay and making sure all the spark plug wires were in all the way and the problem went away for some reason. i do not know if i did anything at all.

3) one day i found that the clamp to the valve cover breather tube loose so i decided to re-clamp it while the motor was running. suddenly the engine stops and i could no longer start it. i did the spark plug wire to the valve cover test to see if it sparked when i tried to start the car and no spark came out.

i replaced the distributor with another running 240sx and still nothing happened. i only replaced the distributor that goes into the engine and the rotor that connects to it. the cap is the same because at the time i didnt want to disconnect and reconnect all the plug wires.

i replaced the what i think is the ignitor chip from another running 240sx and nothing happened. i dont know if i need to replace the other part too?

pic of what was replaced. do i need to replace other part too?

i know for a fact that both parts i replaced work because i just swapped them into my other 240sx and it runs fine.

clamp i was tightening when the motor died.

what should i check next? should i replace the other part near the ignitor chip too?

from searching i found some possible solutions:A) where is the tps sensor? is that a part of the cap/rotor? should i try swapping the cap/rotor?B) i plan to check the MAF and make sure it is plugged in and grounded properlyC) i plan to check the alternator ground and battery ground, what other grounds should i look for?D) i plan to check the tube from the clamp i was tightening and make sure its not clogged up.

Modified by NotDave at 10:01 PM 12/25/2006
Modified by NotDave at 10:04 PM 12/25/2006

[180fan]

those wires run to only a few things iirc. Sounds like you've got a bad connection at something crucial like your distributor though. Try to free up some slack on that and wiggle the connector, see if that helps.

[NotDave]

i checked the battery ground with an ohm meter and it was grounded properly.the wiring to the distributor isn't tight at all. i will try to wiggle it and have someone turn the key at the same time.

[NotDave]

im gonna try the coil near the ignitor next.

[dkdeleon68]

have you checked for moisture around the spark plugs?

[NotDave]

ecu connection wasn't good and/or ecu wasn't grounded enough. i took out an unplugged the ecu and plugged it back in and it worked. go figure.

[240on430]

i think the problem to the rough idling was due to a short on the tps. i unplugged it and then plugged the tps and it idled smooth thereafeter.

before doing that, i raised the idle and opened the throttle valve and it idled at almost 2000. but it still idled rough. when warm there's no rough idle. it start to roughen when the motor warms up.

...hope this helps.