have you tried replacing your MAF sensor?

 

UPDATE. Just cahnged MAFS. and it still does it.... wow. at a loss of words. i honestly dont know whats up with this car. i feel like setting it on fire....

 

i have another idea of what it might be, let me know if it sounds correct. Could my heads be bad, specifically bank 1? if the exhaust valves are not opening all the way, that would explain my terrible sounding exhaust note at WOT, the missfiring spudder sound, and the fact that the drivers side muffler ONLY picks up an AFR readings correctly. The passender side muffler picks up a reading but reads lean. honeslty i think it is the only thing that it could be at this point. is there any way to diagnose the issue? anyone know of some place in my area that could help me?

 

UPDATE. Today, i went to speak with the machinist that worked on my motor. I explained everything to him. from the time of the build to the day of tuning. Also told him what i have done to ttry and rectify the issue from replacing plugs, coils, MAF, fuel pump.. ETC... including the engine code i keep getting, p2a03 and the occasional p2a00. So the verdict is....The car is off timing! hence the sputtering exhaust nore and major lack of power. i suspect it is off by one tooth or maybe even two. It makes comlete sense, especially how he described it to me. the valves are not opening all the way to let the exhaust gases out creating a sputtering sound. also, this is the reason why the wide band on the dyno always read lean after certain RPM. load levels. So, im going to rip it all off again and redo the timing AGAIN.... wow.

 

Sounds accurate. Take pictures of the timing and compare. Before you put the front cover back on, you should be able to verify that all timing marks are lined up accurately.

Yesterday we did the timing on my friends built motor. Once you have the secondaries on and can ensure that they are lined up correctly the primary is easy. We had slack on the left side (drivers side) and needed to adjust the cams counter-clockwise for the crank sprocket to line up properly with the timing.

If you have questions, just post. My friend created a thread on here with his questions as well. Pics are good to verify accuracy as well.

 

thanks for your reply, yea i had my freind whom is a nissna tech do it... he must of messed up...i want to just do it myself but wish i had a reliable hand to verify.. i will post pics when i dive into it.

 

update: went to confirm today that it was in fact the timing before ripping it apart. i went to a friends shop who uses a motis computer to check the cam phase on both exhaust and intake for bank 1 and 2, everything matched except the exhaust cam on bank 1!!! so it was the timing the whole time. this explains why im having the p2a03 code which is for bank 1! the exhaust valves on that side are not opening at the right time. well, im going to start ripping it aprt this weekend and redo the timing. "(

 

update?

 

update: well, i have been nit picking everything and its coming down to the timing as you know. i have someone else doing it for me becasue i am over dealing with this car. last night he ran some diagnostics last night and found that the timing was so far off, according to the computer, that it wouldnt make sense that it is even running. -64 +64 WAY OFF! supposed to be 8-12 +-. The past 100-200 miles i had a few more issues arrise including; coolant all over garage floor for no apparant reason, also, very rough idle and raondom multple misfire ONLY AT IDLE. once i drive it does away, at a light engine light flashes. WTF! ive never seen, heard of any car doing any of this for any reason. The mechanic is going to verify if it is infact the timing tomorrow. if it is not, then i think im going to sell the car, im sick of it. At this point, the only thing it can be is a cursed car....ive never seen a car that cant be diagnosed.... any last recomendations?

 

Yeah ...........stay positive ,it will all sort out , I totally feel ur pain been in similar situations with my G , When ur finally putting the power down in your beast it will all be worth it ..........TRUST!

 

Yea I hope. I just see no end. I talked to the tech doing my timing. And he said he didnt see the timing was off because he had to rotate it to many times to see if it would line up. But he noticed a sticking tensioner... He cleaned it and made sure it is working. Timing is back on but won't know if that resolves th problem until tomorrow night.... God please let that fix her!!!!!!!!

 

Keep us posted

 

ok here the update. tech called me and everything is back together, i wish he had better news for me but it wasnt the timing. its doing the exactally same thing. ok, this is gone on way to long. im obviously missing something. something that is absolutely impossible to detect. WTF! random misfires all of a sudden? coolant leak all over the garage? P2a03 P2a00 p0187 p0300 WTF is happening to my car! 285whp on the dyno, car sounds like its shitting itself, something has got to be wrong with my heads, bad computer, or bad A/F sensors, all this money wasting trying to figure this problem out and im not getting anywhere.... wow the worst christmas gift ever.....

 

he just called me... ive never felt so lost. he is saying that it is a 1) bad ECU, 2) bad intake sprocket? WTF? highly doubt it becasue those were just replaced!!!!! 3) bad intake seliniod Yea right... dont even have a code for that!!! to make it even more confusing, he completely dimisses the idea that the problem can infact be the A/F sensor, which i have a code for??? p2a03!!!!!!!!!!!!! The best advice he gave me was "the only thing left to do is start throwing parts at it"... ie. ECU, Sprocket, IVT selanoid. why is everyone that touches my car so &#$(@$* Incompetent... does anyone know who i can take it to that in s. florida?

 

Post a link to this on my 350Z.....way more FI guys on that forum. More guys =more information. I'd try that