capframe

iTrader: (1)

Poor acceleration after warming up (2003 Maxima)

For the past year I have had a problem with my 2003 Maxima as I've lost a huge amount of acceleration power.

I tried many of this forum's suggestions with no luck.

I don't usually FLOOR my car when it is COLD but this morning I pulled out of my garage and into the street and just FLOORED IT! ...and WOW!... the car accelerated extremely STRONG. The engine just blasted off, felt like a new car again.

Sadly, as I watched the temperature gauge climb up I found that my newly found performance quickly disappear as engine reached operating temperature.

I let the car cool down for 3 hours and tried it again with the same results.

Basically, my car runs like a dream in the first minute it is cold then runs like crap when it is fully warmed up.

I quickly ran to the dealer and got them to replace the Coolant Temp Sensor but that didn't fix it, should I have replaced the thermostat too?

Kind of excited because it seems like I'm close to discovering the cure but I'm not sure where else to look.

I would appreciate your help in piecing this puzzle together. Thank you.

Some of the parts already replaced for other reasons or to troubleshoot this particular issue:
* Coolant Temp Sensor
* MAF
* Spark plugs
* Transmission
* Throttle Body
* Pre-Cat
* Rear O2 Sensor

UPDATED: (The following were replaced for troubleshooting purposes per advice from YOU after this thread was started)
* Fuel Filter
* PVC Valve

Reizy

iTrader: (48)

Something to do with closed loop vs open loop. Any codes? Possibly O2 sensor?

capframe

iTrader: (1)

Hello Reizy,
Pre-cat O2 sensor has been replaced although I'm not saying it wouldn't be bad again but no helpful codes at all ever.

Stormzusmc

iTrader: (17)

I get the same issue. My car even sounds a lot different when she is cold. I know engines run better when they are cold, but this is a huge difference.

capframe

iTrader: (1)

Exactly!... way too huge of a difference in performance. When I FLOOR it when cold, my Cold Air Intake absolutely SCREAMS sounding almost like a damn fighter jet but as soon as the car is all warmed up the Cold Air Intake sounds very weak like it's not even there.

Clearly, there's some kind of sensor or something that is messed up in our car that is incorrectly telling the ECU/engine to slow down and under-perform after the car is warmed up for whatever reason.

jasonmax

iTrader: (2)

where did you place your intake, maybe it's sucking up hot air.

have you cleaned your MAF? try to clean it see if the power gets better.

Stormzusmc

iTrader: (17)

^I have the injen cai, which is a great location for cold air (not near the block). I am looking into replacing my MAF because I heard cleaning it really doesnt do a thing.... Its either get the 80 dollar 00-01 MAF or the 400 dollar MAF for the 3.5....Already talked to Dave about it as well...not sure what I want to do...or if this will even fix the issue.

daredevil514

iTrader: (1)

Hey Man,

i'm not sure if you still have your pre-cats, but I had the same thing when my center precat was blocked. I had the dealer change it recently this week, all power has been restored.

Progress

iTrader: (26)

The Injen is located behind the radiator, right? How is that possibly a good location for cold air?

jasonmax

iTrader: (2)

you havent tried it and you already know it doenst do a thing?http://forums.maxima.org/5th-generat...10-w-pics.html

capframe

iTrader: (1)

My CAI is an Injen and is placed in the standard place and I've had the CAI a year before the issue even existed and so I know that's now it.

Also I cleaned my old MAF then also got a brand new MAF last week and same thing.

capframe

iTrader: (1)

Well, I replaced my MAF with the $80 then with the $400 and still didn't fix the issue but if you have $80 to spare It wouldn't hurt to have a new MAF

I was mad at the $tealer$hip for charging me $400 for a part that is really worth only <$80 so I returned the $80 one with my $400 MAF receipt and got my $400 back so now I have a $400 MAF for $80. Greedy stealerships, trying to charging hundreds of dollars more for the same part.

capframe

iTrader: (1)

jasonmax is right, if the MAF is the problem then cleaning it maybe might help but if the MAF wasn't the problem in the first place then of course it won't make a difference at all, as in my case.

Stormzusmc

iTrader: (17)

Its not by the block, and its way down there, but im assuming you know that already.....

Yes I am well aware of this thread and how to clean the maf...I spoke with Dave B on the phone and after speaking with him he said its pretty much useless...I highly doubt he was just trying to get me to buy a new maf from him...I know this part regulates the air to fuel ratio, and it is found behind air filter and can be cleaned although is very sensitive and can sometimes make things worse.

Progress

iTrader: (26)

What does the block have to do with anything? All the heat from the motor is displaced at the radiator. There are tons of threads that say the Injen is a joke when it comes to intakes for our cars because it pulls in the hottest air. That and it's overpriced.

Stormzusmc

iTrader: (17)

Yes I'm aware that all the heat is dissipated at the radiator, with that, the radiator needs a purpose, if the motor was cool then there would be no need for a radiator. The motor is hot so it radiates heat just like the radiator does. I'm aware most of these intakes if not all are jokes (they sound cool though...lol)..I highly doubt that a intake is part of our issue. To test however I can put my stock box back on and see.

modenaf1

iTrader: (3)

I would definitely say the MAF is ruled out. Now what about the fuel you are using? A hot engine is more likely to knock. If you have lower grade/watered down gas it might not be knocking when it is cold, but it may start to when warmed up causing the knock sensor to pull ignition timing thus your poor performance.

Also, you mention the intake not being as loud when it is warmed up? The only thing that affects the amount of noise coming from the intake is the throttle opening. Since you are VQ35, the computer controls the opening of the throttle body electronically. Perhaps this goes back to the fuel issue or whatever, but perhaps the computer isn't opening your throttle body 100% for some reason.





As for intakes, do you 5th gen guys have no space in the fenderwell? For my 4th gen I bought an intake and filter off of Ebay for 30 dollars and all I had to do was cut away some sheetmetal behind/underneath the battery and my filter is in the fenderwell behind the drivers side foglight and it gets NO hot air from the engine or radiator whatsoever.

Stormzusmc

iTrader: (17)

I'm only using 92-93. I only hear a "sucking" noise when I rev it up. Otherwise my exhaust is to loud to hear the intake itself unless I have the hood open. I'm not knocking when its cold, but it sounds like its running a lot better. I have my intake installed as the directions called for and did not look further. I can check it out this weekend. I may put the stock airbox back on for giggles and craps....My CEL is not on, but I may run a diagnostic test to see whats going on.

capframe

iTrader: (1)

I don't think that's the problem because I had my Injen CAI for over a year before any of this was even an issue.

Stormzusmc

iTrader: (17)

^ Yeah I'm not saying it is, but I would like to see the difference.

Progress

iTrader: (26)

Sorry for going off-topic. My comment was in regards to the post I quoted and not the thread in general. Sorry, folks.

LA02MAX

iTrader: (3)

I think it's something to do with fuel...when my BMW's fuel filter got really old/clogged it was doing the exact same thing...car ran great when cold, and it was really slow once it warmed up. During open loop operation the car runs very rich, which means more fuel is being injected per cycle. If there is clogging going on, the vacuum system that your fuel runs on will be able to push the fuel more efficiently through the lines/injectors, giving your car a better combustion. When it switches to closed loop, it starts to pull fuel in order to lower emissions. By doing this, the amount of vacuum pushing the fuel through the lines is decreased and can't easily get by whatever is blocking the line, and you'll get less fuel to burn, which means the car will run like crap.

That's at least my theory...what I would start with if I were you would be replacing the fuel filter (it's about $25 and not difficult at all to replace) then getting the nissan fuel injector service done. I believe it's around $110 and they hook up a high pressure system to clean out everything leading to the injectors.

And just a little correction: engines are actually more efficient when they're warmed up, which is why the running temperature of modern engines is higher than old engines as we find new ways of keeping the engine as resistant to wear as possible (ie: the development of new materials). Your engine should not run better when your oil is cold, so there is definitely an issue that needs to be solved. Good luck!

capframe

iTrader: (1)

LA02MAX,
Thank you, this sounds like a very good theory. The only problem I have is that I heard the fuel filter is in the fuel tank and so I don't know how you would think that is easy at all? I've called the dealer before and asked about the fuel filter and they go crazy saying how it's not replaceable, too hard to get to, etc...

Stormzusmc

iTrader: (17)

All I know is I will be taking mine to the dealer to see if they can run some tests and the injector service may be a good idea. I recently replaced the plugs and ignition coil due to leaking valve cover seal.....

LA02MAX

iTrader: (3)

The fuel filter literally took me 15 minutes to do. The bottom of the rear seat just snaps off (there's a little lever in the center that you push and the seat bottom just pulls off) then the fuel sending unit is exposed. Remove a couple bolts and the sending unit comes out, and a couple of snaps later, you have your fuel filter off. Dealer's are just lazy, but several people have taken apart their used filters and seen things that should NEVER be labeled "lifetime". haha.

Here's an extremely detailed write-up on how to do it: http://www.shiftice.com/fuel_filter.html And definitely check the rest of that site out good. He's a member on the .org and his write-ups are excellent.

Yeah definitely try the injector service. My car was running fine and I did it, and noticed a definite improvement. It idled much smoother than before and it seemed like I got more of my low end power back. Just MAKE SURE that you tell them you want the fuel system FLUSH, where they hook up the machine; not just the crappy fuel injector liquid they pour into the gas tank.

capframe

iTrader: (1)

I didn't do the injector service but the dealer did claim that they checked the " fuel line pressure... " or something like that and they said it's fine. But then again they don't really troubleshoot for performance they just micky mouse things and if the car starts and no codes they send you away.

Stormzusmc

iTrader: (17)

Ill pick a fuel filter up today and do this tomorrow then hopefully I will have time to take it to the dealer to do the flush. Then post later with what happens.
Yeah you gotta be specific if you want them to do something when you have no codes.....

capframe

iTrader: (1)

I think I'll do the fuel filter replacement too and report back with the results.

How about that large piece that the fuel filter goes into, is that the fuel pump? If that is the fuel pump can I just replace the whole fuel pump if not too expensive in case it is to weak to pump or something?

capframe

iTrader: (1)

Call Dave Bournette(Parts Dep.) @ SouthPoint Nissan (866-941-2048) to order these parts: (Price quotes as of 4/2/2009)
Fuel Filter - 164002Y505 - $11.19
O-Ring - 1734201A00 - $7.34

Stormzusmc

iTrader: (17)

Yeah I'm going tomorrow to pick my fuel filter up and do the fuel system flush

Reizy

iTrader: (48)

Are there any pending codes? You need a code reader. See if this helps, or confuses you.

capframe

iTrader: (1)

No pending codes or check engine light or anything ever.

Derrick2k2SE

iTrader: (3)

Dave B. does a lot for the org and its members. He also works on comission. Unless you are in desperate need of a part today he's the guy to buy from. We need to take care of the people who take care of us, not figure out ways to get around them.

capframe

iTrader: (1)

UPDATE: Installed the new fuel filter myself and that did NOT fix the issue.
I still have lack of power but the lack of power that I do have is very smooth thanks to the new fuel filter.

What should I replace next? Thermostat? Does the Thermostat do anything that could affect? Can someone elaborate on the Thermostat, what exactly it does, how easy it is to replace, can I do it myself and is it even at all relevant to our symptoms here? Thank you.

Stormzusmc

iTrader: (17)

Hmm well I'm still doing my fuel filter and flush as well...and see what happens. Before and after that I'm going to check for pending codes and see what I can find.

capframe

iTrader: (1)

Oh yeah I'd do the fuel filter even if it is not the issue because it is actually a lot of fun for under $20.

It was pretty cool to see an open oasis of gasoline in the middle of the back seat.
I actually thought about just driving like that with open access to the gas tank so my back-seat passengers can use the round gasoline puddle as an ash tray. I don't see any problem with that at all because if the filter gets clogged with ashes I'll just replace it because now I know how.

Maxgig

iTrader: (5)

My gut told me from the beginning that it was your thermostat. Glad you put in a new filter but try the thermostat next.

Stormzusmc

iTrader: (17)

I had also found all these threads and have been sifting through them to see what I should do.

http://forums.maxima.org/5th-generat...m-i-think.html

http://forums.maxima.org/5th-generat...ower-loss.html

http://forums.maxima.org/5th-generat...uld-wrong.html

http://forums.maxima.org/5th-generat...ower-loss.html

RR5

iTrader: (6)

Give this product a shot http://www.seafoamsales.com/motorTuneUpTechGas.htm

I have a 2002 and I'll pull the vac line going to the brake booster which comes off the intake manifold. Dunk the hose with the engine on into a cup with a small amount of the seafoam, allow the suction to pick up the liquid, then immediately shut off the engine. Wait about 5-10 minutes with the engine off. Start engine and rev the engine a few times, you'll get smoke out of the tail pipe but your injectors/cylinders are clean(er) haha.

capframe

iTrader: (1)

UPDATE: I just replaced the PVC Valve with my bare hands while engine was HOT ...but the issue of lack of VQ-fighter-jet type power/acceleration still exists.

What should I replace next?

Thank you.