300zx running on 4 cylinders
 

i had posted this in another forum location here but i think that this page is more appropriate, sorry mods!

hi I recently bought a 1990 300zx N/A 2 seater w/ t tops. i have just recently done the resistor trick and had deactivated the code 34 and found that it was the wire from the ECU. the car was low on power and since that has been fixed some power is still gone, actually A LOT of power as it seems. when the car is running it sounds like a damn VW beetle it misses and it back fires if you shift at a higher rpm. it also smells like fuel, its running very rich. there are no codes since I’ve cleared 34. i didn’t have a code 21 once but i think its because my ECU wiring clip wasn’t screwed in good enough since then i haven’t ever had another code.
so here is what i have found.
I’ve changed the wires with new OEM Nissan coil wires, still runs like crap. i have un plugged all the coil wires one at a time, and noticed that 2 didn’t make a differences so i know I’m facing 2 dead cylinders. i have tested all coil wire clips and i get 12v from the middle connector on all. I had swapped one of the good coil pack with on of the bad coil packs thinking maybe id have a new dead cylinder but the car seemed to just run worse so i swapped them back. no i checked the PTU and it is the series one. i have read they are crap and that they go out all the time and that there is a recall. so i unplugged both sides and tested every pin and i got .5 volts on every pin on one side and i got 9 volts from the 'e" pin? not sure what that is, however i read that I’m supposed to get 12v readings or its not doing its job, my thing is if they were all reading so low wouldn’t all the cylinders be pretty dead rather than just two. and also if it was bad i shouldn’t have received a 12 volt reading from the coil pack wire clips? i herd of a trick of testing the injectors with a screw driver i have yet to check, is there anything else i can do does anyone have any tips? i think there may be a special way to test the ptu? because i didn’t get anything close to 12v!

Make sure you are not going off the plug order, as you found it, I would verify the wire order per the manual, if you have a few wires reversed, it would run like a VW !

So the coils can go to any cylinder but the wires must be connected to the proper cylinder. Is that what you are saying? If so il check that to. However that wouldn't cause a dead cylinder would it?