Dave Jr

Okay I know that this is in the Sticky for how to's and all but I need to express my problem specifically. I love my 2k3 and it has great power. But it seems to have better power at times. For instance. It's an auto so I have it locked into first at about 4500 RPMS sometimes I can nail it and the tires will break loose and others they don't do anything. The car still seems to move but not as much.

Same thing with just driving around sometimes she feels great and other times she seems to hold back a little.

With an open intake should you be able to hear the VIAS say like the Honda's and their VTEC there is a distingused intake note when it reaches a certain point. Should I be able to hear this??

Because I can't tell a difference anywhere in the RPM band the intake noise stays the same.

The reason I ask is because I was racing an SE-R and it got to a certain point and his intake kicked it up a notch sounded just like the honda's VTEC. With my open intake mine makes no noise. So the big question is should it have that second level of sound after 5000RPM ??

Any suggestions would be greatly appreciated.

Thanks

MannyNJ2k2max

iTrader: (3)

you should be able to hear it even if your car is
stock climbing from 4k-6krpm- I believe WOT kicks
around 4200-4300rpm A frankencar intake
will definitly increase that sound and give you a few ponies up top-

Dave Jr

I printed off some instructions amd I can't find the damn thing. I have this little brass actuator on the passanger side but I can't see underneath anything on the drivers side. Is this the same on the 2003 I have an automatic I can't find it please help.

SteVTEC

The variable intake manifold on the 02-03's switches over at 3800rpm. It dips from peak torque just before that, and then raises back to peak torque just after. You should be able to feel and hear that with an aftermarket (louder) intake.

Dave Jr

Looking at my car I can't find the Variable Intake box that everyone is talking about. Can anyone tell me were the VIAS is on the 02-03 because I can't find it on the drivers side but do see something directly on the side of the intake manifold on the passanger side.

Your replies are greatly appreciated..

spirilis

iTrader: (2)

On my 2K I don't think I hear any significant intake difference above 5K RPM... my VIAS L-shaped rod does operate... either it's broken inside the manifold or it's working properly and I just can't hear it
Never dyno'ed or raced another 2K 5spd to compare though...

Shogunsc4

iTrader: (2)

I know what you mean b'coz I have the same problem. I have an '03 auto...sometimes it pulls good and sometimes it lags a bit. When I nail the gas on the roll, it seems like there was some kinds of resistant. As for the sound...I have a frankencar, when i punch it on the get-go...the intake is "loud" up to about 4k rpm...then after that it screams! Last time on the track in 100 F temperature, i'd only trapped 89.9mph @ 15.7.

Dave Jr

Yeah its funny punch it sometimes it hauls other times its just okay. My best at the track not sure temp outside at the time but 15.0 @ 94 I want to go back soon to run in colder weather see what she can pull off.

gkstar

iTrader: (1)

Don't the 02+ have drive by wire throttle? Since your computer would be sending the throttle signal it might be more laggy from time to time.

Dave Jr

It's funny that you mention that. I was looking at the drivers side for the VIAS which I still don't know where it is. I think that on the 02+ it's on the passenger side. But anyway. On the throttle body there is a block box with a connector. I unplugged it and started the car to see what this was as I thought that it was the VIAS but then the car would idle and when the gas was pressed it would raise to maybe 1000 or 1500RPMS and thats it. It also threw a code right away. I then **** the car off and plugged it back in. Started it and the check engine light stayed on for awhile and then went off eventually. But ever since I unplugged this plug from the Throttle body I swear she is lots more responsive. First gear brings the tire spin no matter what the RPM and she pulls hard all gears. Somehting changed and it just so happened after I did this. What are your thoughts.

gkstar

iTrader: (1)

You might have reset the the drive-by wire system. Or there could have been a loose connection. After unplugging you are experiencing the throttle response and pwr that you would on a good day. Correct? If this pwr all the time stays the same then cool, if the heisatiation comes back look into getting a hesiatation TSB done. Your ECU program might need alittle update. Have fun smokin your tires in the mean time.

Dave Jr

Right she is having a good day all day now. So far so good and if she stays this way I will be happy. If you don't mind I would like to ask you a question. I have read on the list that guys are reseting there computers and this is helping the car perform better? Is this possible? I mean wont the stock programming take over? Or is there some sort of learning curve built in for this stuff ?

spirilis

iTrader: (2)

Resetting the computer will make it run a little better, for a short while. After the ECU's had enough time in Closed Loop mode with the O2 sensors providing feedback, and the ECU's seen enough weather conditions (cold, warm, etc.), it'll be back to normal.
The main reason it runs nicer after a reset is because it usually runs richer... until it's adjusted the long term fuel trim to something leaner (learned over time from raw data accumulated by driving in closed loop)

gkstar

iTrader: (1)

Once any performance mod is added, intake, y-pipe, headers etc. are added it is recommended that you detach the neg battery cable. This returns the ecu to almost a blank slate for it to relearn the increase air-fuel etc. There is a curve to an extent that most basic bolt-ons can be accomadated for, but overall the stock ECU program will regain control of the mods. The ECU will not conteract the mods entirely, but the biggest gains are felt right after install.

A friend of mine with an 02 had some issues with the Injen intake after install. It was recomended to him by fellow org members to disconnect the battery for 24hrs to fully clear the ECU, it worked and he has had no problems since.

One of the most popular threads recently has been on the TS ECU, that is a totally different story. Technosquare is re-flashing the ECU to a new program with higher rev limiter. Hope this helps.

2001SE

how can you reset the ECU on the 2k2+?

gkstar

iTrader: (1)

http://forums.maxima.org/showthread.php?t=249106

IceY2K1

iTrader: (3)

I'm not too sure I notice anymore with the stock intake DEFINITELY hear it with a pop charger.

If it's working properly, you can't mistake the surge in power after 5Krpms.

Cutler

iTrader: (3)

hmm at 5k is when I felt it on my 2k

spirilis

iTrader: (2)

hmmm I don't hit 5K RPM much but I should do a few experiments to try...

FYI, I remember doing a VIAS experiment where I hooked my hand vacuum pump up to the fresh air inlet on the VIAS box, applied vacuum, tucked the pump under the hood, closed the hood and took it for a drive... it drove a little differently (sounded slightly more "throaty"), so I believe my VIAS butterfly valves work... I should toy with that some more.

IceY2K1

iTrader: (3)

Check for kinks or cracks on the vacuum lines just incase.

spirilis

iTrader: (2)

I always thought the PowerValve received vacuum internally through the vacuum tank it was bolted to... (is this not correct?)
There is a hose going into the front of the VIAS box, but that is the fresh air vent (and that's not kinked)... if there is indeed a VACUUM hose I missed (i.e. something underneath the VIAS box), I'll have to check deeper!

IceY2K1

iTrader: (3)

I'm not sure now. Maybe there are two.

PM me your email addy and I'll send you a PDF of the FSM if you don't have it, since it's 80K and I can only attach 50K.

IceY2K1

iTrader: (3)

Now that I look at it...you're right.

Scratch that.

panda_1

iTrader: (4)

question where the hell is the VIAS box on a 2k max?

NYC2SD

The VIAS is located with in the intake plenum

spirilis

iTrader: (2)

It's this thingie on the 2K:

jgibson146

Probably a stupid suggestion, but is your A/C off, it robs alot of power. Question for Max master, does the compressor kick off when applying full throttle?

spirilis

iTrader: (2)

Fun with VIAS!

I did some fun little experiments just a half hour ago.
1. Disconnected Swirl Control valve harness. Car didn't necessarily run any better. Took it out for a spin... didn't run any differently. Eventually the SES light came on with code P1131 (pulled using my scantool). Cleared it, the code reappeared as a ghost code ("Pending code").

2. Disconnected VIAS control harness. Took it out for a spin, revved it up in 2nd gear all the way to 6K RPM. Engine sounded a little more tame, more consistent sound throughout the whole RPM range.
Reconnected the VIAS harness. Engine sounds a very tiny bit more raspy/louder, can't say I feel any extra "jolt" of power though. Both high-RPM runs were performed going uphill.

Conclusion: There's no point in disconnecting the Swirl control valve harness, unless you really want to have a staring contest with the SES light. Turns out, after reading the shop manual, that the Swirl control valve only closes at <3200RPM with engine coolant temperature between 10C and 55C, so once it's up to operating temperature, the Swirl control valve stays open all the time.

VIAS I'll have to do some more experimentation with. Especially once I break out the vacuum pump and start manually actuating the VIAS (wanna drive with the VIAS open all the time to compare...)

spirilis

iTrader: (2)

Yeah, climate control/defrosters were off.

spirilis

iTrader: (2)

A thought. What if the vacuum check valve in the vacuum tank supplying vacuum to the VIAS Power Valve became stuck open? Suppose as a result, the Power Valve could not receive enough vacuum at high RPM, WOT conditions to open. That would cause a condition where the VIAS appears to work, it opens fine when you rev it up at idle (revving it with minimal load should produce more vacuum than revving it up under maximum load), the solenoid works, everything works... but when you take it out for a test-drive, it feels like the VIAS just isn't opening. That would produce a condition similar to the VIAS valves inside the intake manifold being damaged.

Dave Jr

Can someone post a mesage of the VIAS box on a 2002 or 2003 because I beleive it is different as I can't find anything that appears to be even remotely the same as in the picture of the 2K.

Thanks