Ok I pulled my rear bank plugs to see how they are burning now, and one is a cream. One is like brown and the other is blsck but not wet. what could be causing them to burn differant on the same bank?

 

show us pics of the spark plugs. any number of things could be causing the differences.

 

le t me know if the pic works.

 

the left one looks normal
the mid one looks very lean possibly clogged/bad injector
right one looks rich or weak spark

i would put the left one back where it came from and then switch the mid and right ones then go for a drive and see what they look like after that

also pull the other bank of plugs and inspect those to see if theres a trend

 

The VG is prone to issues like that due to the poor intake manifold design. the way the runners are, the first cylinder will run about stoich, the second one will run rich, and the last one in the line of the intake will run very lean, because it's at the end of the intake line, basically all the air comes down the intake tube and goes straight into the last cylinder because it's at the end of the line.

or something to that effect. there was another VG guy on the forum (I think MTcookson??) that had done some more research on that and had found some of that stuff out. you might talk to him and see what he said.

but yeah, you definitely have some issues there you need to fix.

 

I know that Scott (boostedmaxima) has done alot of work to his manifold, including flowtesting and modifying it so that it flowed evenly.

 

okay, cool. I hoped someone else would remember those issues. the IM design on these cars sucks.
I wonder what going to a Z31 manifold would do and if it would fit under the hood?

 

In my reading, it has been indicated that the Maxima manifold was higher flow and better performance as compared to the z31 intake. I have never heard of the z31 being better and as a guess, would tend to have the same problems as the air flow design is from one end of engine to the other, just as in max, only the max intake is split in two to feed each bank.

 

I bet the Z31 intake would fit since they used a similar design on the 2nd gen Maximas. I have some Z31 intakes laying around that I could mess with but the design of them do really suck. A guy from Z31.com modified them and made them flow quite well but I'm not sure if he's doing it anymore or not.

 

I've not tried to swap, yet looking at both the z31 and Max intake manifold, I'm not certain that they are interchangeable without also swapping out fuel rails. The z31 turbo injectors are an upgrade to stock Max units though. As I recall, the rail is lower flow. Max is 3 bar versus z31. I don't recall what z31 bar rate is (2.0 - 2.5 ?).

 

Send the injectors out to www.witchhunter.com for cleaning and flow for 12.00 a injector. Killer deal sent back next day.
I'm betting it's the used injectors your using. He'll give you before and after numbers. I got mine done before I even installed them in the car just for this reason.
Intake manifold is a huge issue on these cars but won't cause near the condition you've got going on. My plugs usto read different in almost every cyl. Now they are even across the board.
Waiting for a ECU...
~Scott

 

Brad... that new pic of your car is Kick A$$ !!!!!

 

Thanks! We are gonna have to meet up soon before this snow gets any worse.... 9psi is awesome! Although my fuel system is completely maxxed out now...

 

dam double post by mistake

 

I cant wait to get the new intake manifold and ill ship you the ecu on monday.

 

Nice to talk to you the other day Brad... Sorry the weather didn't agree more for going for a ride!

I'd definatly slide the bigger injectors in your car and commence to tuneing with the regular FPR and the FMU. I'll bet you'll be able to come prity close with just those adjustments with out hitting 90+psi fuel pressure

93, Definatly get the injectors cleaned and flowed. At least you'll have peace of mind that they all are good and flow right so your not fighting a tuneing problem when it's the injectors.
~Scott