DJKDL

Just wondering if there is any difference between a 2003 Auto Z and a 2004 Auto Z. The problem i ran into is, I owed both a 2003 and a 2004 Z both autos. This time last year my 2003 was Vandalized by some punks and insurance deemed it Salvaged. After buying the car back from insurance i decided to swap the motor out of my 2003 with only 34k on it, into my clean title 2004 Z with 187k. After the swap was done by a mechanic. During the swap of the motor. The Mechanic said the Harness seem to be different between the 2 so we pulled the harness out of the 2003 and ran it with the 2004 ECU. Car ran and idle find after the swap. Did a lot of around time driving and it runs like a dream like my 2003 did. I've recently started to see some issues. It all started about 2 weeks ago. heres what I've noticed ....

1. When the cooling fans turn on and I'm stopped. The car almost stalls. Ive check the Alternator and Battery and all test within spec so I've ruled out an electrical issue. So does anybody think this could be an ECU issue? maybe a pin out difference in the Harness? Maybe a Bad MAF?

2. When i get on it hard. Right around 3.600 - 4.0k when i believe the Variable Valve is suppose to kick in.. The car feels like it doesn't switch over. feels like a reduction in power when i get into the range at 80%-100% throttle. Again i wonder if this could be a ECU/Harness related or is my Theory of the MAF going bad.

The car at any other time runs fine. its just under these conditions the car is out of wack. Any suggestions?

dkmura

iTrader: (64)

No specific suggestions, but Nissan has been known to introduce small production changes into the line at times. There's no way to know for sure if there are any internal changes to the ECM or wiring harness unless you compare the pin-outs and FSM diagrams for each year. Tedious, at best.

Having been amazed at the changes between an '06 Z33 and an '07 HR swap for a racecar, nothing would surprise me.

Cux350z

iTrader: (162)

The only thing that changed in 04 was the 04.5 models had widebands in the upper locations which means they were 5 pin connectors.

Sounds more like a failing cam or crank sensor.

str8dum1

iTrader: (11)

the harnesses are different between the early 2003 and 2004 autos. you are going to have to go back and make sure everything was pinned correctly.

At this point it could be a million things causing your issues.