LI_Max_WOT

iTrader: (9)

Edit: MAF replaced.. 6th gen MAF install???

So this problem has been going on for about two weeks now, and I just replaced the spark plugs and checked resistance on coilpacks. Still the same symptoms. Cranks and cranks and cranks then finally starts, it never actually didn't start. The problems now are an apparent misfire and serious lag in any acceleration over about half throttle with basically no power over half throttle. At WOT, and any time over 4k rpm just about, the engine basically cuts out. It doesn't really stutter too much under light throttle up to about 3k-4k depending on the gear.

I was hoping the CEL would chime in and clue me in but no luck for me. Anyone have any ideas what the problem could be? I have a Walbro 255 (<6 months old) and 350z injectors, and am running on no tune. Everything was fine before, the only change has been my car seeing 87 (due to Sandy), then 87 + octane booster, 93, then 91 on a regular basis. I am so baffled I might even take it to a mechanic. If I do end up going, I don't want to go there with not even a remote idea what is wrong. My thoughts are either MAF or fuel pump/injector issue. Any one ever experience anything like this?

Rods03Max619

iTrader: (5)

Maybe get a friend or another Member so you can swap MAFs so you can decide on that...

LI_Max_WOT

iTrader: (9)

Haha why didn't I think of that?!?! I'm in Oklahoma City now and don't know any other maxima owners yet, but now it sounds like a good idea to

fishtale6spd

iTrader: (13)

What confuses me is that under WOT car doesnt read the maf it just dumps full fuel into the motor. Am I right in thinking this??

Donkeypunch

Hi.
Does the engine actually cut out like you say or is it more of a stops making power but still
is holding rpm?

My maf was BAD and never had a maf code. Cleaned it with MAF cleaner from pepboys
and that fixed that.

I would throw the stock fuel stuff back on. You have bigger injectors and big pump for
no reason at all. Who know if the ecu actually can even cope with that. Do you?

LI_Max_WOT

iTrader: (9)

I cleaned up the MAF, and replaced the filter which was pretty dirty.. no luck.. it still could be the MAF, right? This just means that its either too bad to clean or its not the MAF at all?

LI_Max_WOT

iTrader: (9)

I replaced the MAF sensor today. It made a huge difference in partial throttle and closed loop operation (back to normal). The max is still struggling at all rpm's in open loop (WOT), and still cuts out over 4k. By cut out I mean it basically just stops producing power whatsoever, and enters into a safety type mode. Idk, I've never seen this before. Actually, come to think of it, the only time I ever experienced something similar was when I took my VAFC II and without an a/f monitor just kept bumping up the fuel % until the fuel pump just quit. Don't ask me why, I don't even have an a/f monitor.

Aside from the used MAF I got (80k miles on it) being not completely functional or something, does anyone have any ideas what the problem could be? I doubt its the injectors they are low mileage and are cleaned every oil change. Could the fuel pump be on its way out? Or is it more likely that the MAF I got is not working 100%? I'm confused...

Is it possible it's running really lean and the engine just quits? This could be cause by the fuel pump going bad I would assume? Or possibly, could the MAF being bad have caused some other component to go bad? Should I reset the ECU after replacing the MAF??

At this point, I may just replace the wires to the fuel pump with larger gauges to increase the voltage to the FP... That's the only thing I can think of, I read a thread on here about that somewhere on here

Child_uv_KoRn

iTrader: (7)

I don't know that it would throw you into safe mode (b/c it's retarded), but the cats will cause the zero power problem and engine cutting out.
But you're right, it definitely sounds MAFy.

Clean both IVT sensors (lots of brake cleaner). That can cause rough running and I think even no start scenarios.

LI_Max_WOT

iTrader: (9)

I've got gutted cats and spaced secondary o2's, which have never caused a CEL in 2 years. Haha it does feel MAFy right? Those damn sensors are like the central nervous system of a car

If this doesn't work... I'll try cleaning the IVT sensors. This is me trying to take the lazy way out, cause play time is limited these days haha

There are a few open junkyards around, I'm gonna try to swap in a 350z/6thgen/G35 etc maf in there. Does this sound worth it? Any possible performance gains from this install? The sensor is so much slimmer. If it doesn't work splicing all those wires back will suck, cause I suck at splicing

Will the newer Nissan MAF sensor work with the 03' ecu? E.X.

2004-06 350Z 3.5L
2004-08 Altima 2.5L/3.5L
2004-08 Armada 5.6L
20045-06 Frontier 2.5L/4.0L
2004-08 Maxima 3.5L
2004-07 Murano 3.5L
2004-05 Pathfinder 3.5L
2006-08 Pathfinder 4.0L/5.6L
2004-08 Quest 3.5L
2007-08 Sentra 2.0L/2.5L
2004-08 Titan 5.6L
2007-08 Versa 1.8L
2005-08 Xterra 4.0L

VQ'rInWLA

iTrader: (83)

Try changing the fuel filter

Aviation005

failing fuel pump. it dies under load.

mine had the same issue kinds, i had random misfires, low acceleration at high RPM. Also had this terrible click which turned out to be preignition due to the failing pump.

in MY personal opinion, it sounds to be the pump from what you describe

I just re-read your post and noticed u had a new walbro and injectors. I still think its the pump, but it very well can be the injectors. When did the issue start, after installing which of those 2 items?

im running a 340LPH fuel pump, with stock injectors without a problem

litch

iTrader: (2)

Please do us a favor OP and use the thread search tool on this cat's name, make sure you take advice from the right person... ya catch what I am sayin?

http://forums.maxima.org/all-motor/6...-0-timing.html

I had a similar issue as you sir, except mine was running super insane rich. If I were in your shoes, I would clean out my MAF, then I would check the fuel filter... and if all else fails, and you really are looking to continue bolting on/ modding your car, I would get yourself a piggyback and get a tune done. Unless I have missed something, a custom tune would solve your problem.

LI_Max_WOT

iTrader: (9)

Yea, a tune is #1 on my priority list. I'm gonna get an A/F monitor asap cause no matter what I need one badly. I'll get to inspect the pump/filter next weekend.

Update: On a cold start, my max struggles to start after cranking and cranking. On most warm starts, it starts after about half the cranks. Could this narrow the problem down?

Litch, way OT but what centercaps are you using with your Rays? I wanted to use the 350z centercaps in mine but never got around to doing that yet and wasn't sure if they would fit.

Aviation005

yes dont take my advice. your engine and transmission may benefit.

litch

iTrader: (2)

I couldn't have said it any better myself.