Have you tried checking your fuel pressure or changing that awesome lifetime fuel filter nissan used in these cars?

 

No i haven't done anything as of yet, collecting thoughts and ideas at thing point then checking what i can...if my diy doesnt work, then i will take it into a shop

 

Meh no time, got a good guy looking at the car tomorrow during the day....out of town now, flying back to MSP soon...then getting drunk.....sucks not having any time to get things done during the week!!

 

update us on what he finds because I'm having the same powerloss issues. I believe its fuel related. I'm too lazy and poor to buy a new sender from nissan for 650 a little steep.

 

Yeah this thread will stay updated as soon as I do something....its been a while..but I've either A. Been to drunk and stayed up late and got up late then got nothing done. or B. I have been working to much.....so time for C. Stop making excuses and at least do the DIY stuff....I"m going to pick up a propane torch tonight and at least do that test....I'm itching to get my full power potential...because the Max is still quick but....not near what it could be.....

 

Are your cats throwing a code? Seems like too much back pressure.

 

No CEL codes...but I don't have a muffler....I with straight through high flow resinator and no muffler....but if people unbolted their exhaust at the track, would that really cause this....?

 

No open exhaust or headers won't hurt you. The only thing I could recommend than would dyno the car open headers, just to make sure your exhaust is okay.

 

I'm not really understanding. What would be in between my headers and tailpipe that could be causing this? If I unbolt my headers and run again wouldnt it show the same...? If its possible that it wont, then explain if you would.

Thanks for everyones replies I'm taking care of this tomorrow and or Saturday.

 

Or, you look for symptoms of a clogged cat (I.E lower rpm readings than usual, poor acceleration, issues climbing hills, rotten egg smell from the exhaust, black smoke out the tailpipe). Using dyno time to troubleshoot a clogged CAT issue is stupid and waste of money. Looking into the symptoms won't cost you any money...and probably be fairly obvious.

S

 

well if he is running lean then you can expect that. you'll understand once you get on an old motorcycle with VM type carbs typically pre 1980 and you have to manually open the butter flys. when you do that you are making the perfect mix and it you dont have a good mix of fuel and air you get nothing.
for example I didnt understand the system at first and I was riding with the butterfly flaps closed and once I hit 4000k rpms when I was driving I would hit a wall. so I thought "oh I should add more air" so I reach down and turn the lever to open the flaps more and the thing just took off and flew.

I know with our modern cars we a lot of electronics so a lot diff than a 30 something year old bike but the mixture part is what im talking about.

Thank you
Jake

 

to much? more like to little if he wants a little more TQ he would want more back pressure from what is sounds like he has no back pressure almost.

Jake

 

Yeah thats the only thing I can think of that would be messing with me....I don't smell anything bad, haven't noticed black smoke, and no issues going up hills, its just a big power loss...

at this point its either too much are or not enough fuel for some reason

yeah i thought he said not enough for some reason lol...yay for minnnesota lol

anyway what would cause lack of back pressure?

 

yeah my example was backwards I for got to mention that. but my point was just focusing on the whole good mixture thing.

well from what I read you have a fairly open exhaust and you said "high flow resonator" and I think no muffler well a muffler gives a lot of back pressure so with no muffler you have very little back pressure. but essentially cutting back pressure will up your HP numbers in a 4th gear pull on the dyno because "essentially" it lets the engine breath better "essentially" but not nessisarially.

but any ways that is not gunna solve your problem, if the guy said lean try putting on your stock intake just for a try and maybe your injectors are dirty so try taking thos out and cleaning them.

I know these things sound so little and useless but they are basically free to try and being in college and rebuilding motorcycles I have found lots of ways to eleminate problems and narrow things down. but most deffinatly sounds like you need more fuel or less air.

So like guys are saying I would replace the fuel filter(very easy) and ask around on how to check other fuel related items(sorry I only know bikes well when it comes to fuel stuff) you may also want to get your car tuned if there is someone who can do that for you ar get a new ECU from jimwolf and tune that one then you should be in good shape unless your fuel pump is going under then get a 255LPH fuel pump and maybe that will help they are about $100 so not super bad.

Good luck

Jake

 

Update! So I did the carb cleaner test with a buddy of mine and we noticed no change in idle anywhere that we could find. Also here is a new noise we just came across..First engine is running, then turns off but hisses, then it makes the clicking noise sounds and feels like its from the VIAS area (mind you mine is deleted)

http://s64.photobucket.com/albums/h1...=VIDEO_015.flv

More thoughts please! lol

 

well im stumpped.

good luck with that one.

 

lol someone will figure it out

 

Or just put a vacuum gauge on the car and slowly rev the engine. If the vacuum starts to drop as the rpms slowly increase through the midrange, there is excessive back pressure.

 

Thanks for the info scottwax. I'm not sure where to hook up the gauge (obviously the vacuum lines) yet so I'll have to look into that....

Anyway another update...
I got my fuel injectors cleaned with some fuel cleaning pressure system thing (however did not take them out) and now it runs a bit smoother and better acceleration...however not 30-50hp better lol. I may be getting a dyno tomorrow so we will see then if it did help ANY or if its just my imagination.....

 

still no ideas on this noise? http://s64.photobucket.com/albums/h1...=VIDEO_015.flv

 

Lots of vacuum ports around the VIAS system.

 

going to pick up a vacuum gauge now!

 

stormzusmc did you ever try to fix the p1800 code. maybe it has something to do with it(just a thought). my bad vias caused me to fail emissions a few months back. my question that was never answered was this. when the block plate is installed what do we do about the solenoid itself besides plugging the vacuum line to the diaphragm.


when the vias solenoid goes bad, and we block off the valve, what about the solenoid itself. we bypass the valve, but the communication from the solenoid is still telling the ecm that the solenoid is not opening, even though its physically bypassed.

I've since purchased a functioning vias from a forum member, and passed emissions, and then installed the block plate. so if you have a defective vias solenoid, even bypassed, wont the ecm compensate for the air/fuel mixture leading to poor performance? its just a what if scenario, I'm not claiming to be any type of expert here.

before i purchased my block plate, i asked this question, but it as never fully answered.

 

Its not a CEL code...its pending/hidden...So Im not sure. Stormz just picked up the gauge and we are looking through the forums now to find where the best place to connect to. I see what you are asking, however I am not sure. He could try to replace it after we do this vacuum test....Did you have power loss or just your CEL was on?

 

After searching I still have not found where I should tap into to perform a vacuum test...What am I looking for exactly besides drop in vacuum when revving?

 

my car did suffer engine loss, plus my gas mileage was terrible, average between 14-17mpg. now that i have a functioning vias my code is no longer there, plus now bypassed the throttle response is strong . gas mileage is back to normal now.

i'm surprised that no one ever thought to address the bypass, if a vias is deemed non functioning. even though the code is pending, your engine still chokes if not bypassed. and then when you're bypassed with a defective solenoid the ecm is reading the vias as non functioning, remapping the air/fuel ratio. i don't know how we can look into this, but it does make some kind of sense.

 

MaxxxPower and I ran through some tests. I was showing P1800 code (VIAS system failure) or something like that. After buying a vacuum gauge I was trying to figure out where the hell the vacuum lines were (thanks for hinting to that scottwax). I was looking for a canister (as I know there HAS to be one) for the vacuum and could not find it. I then started to think about the VIAS plate (how its controlled by vacuum) and how the SAME shop that installed the spacers did the plate. We looked at my buddys Maxima and then the instructions, we determined that the shop TOOK OUT the canister, unhooked the electrical connection along with all the vacuum hoses. We then re-installed the components and after 30 minutes of the cars negative cable unplugged we ran again. I felt a huge throttle response difference and also better gain on top end (maybe not 30-50hp great but still good). So....I think the "performance shop" that I got this work done at is just a place that no one should go (saying professionally). I had a shop do it because I don't have the tools or time. I hope this helps someone and I'm going to get a dyno in the next month or so to confirm... I hate finding threads that don't have great updates OR solutions. I will do both.

Comments welcome.

 

Whose 'da man?

 

Hey man thats great news... Least you didnt have to pull the The upper and lower. I had a big feeling it was those guys who messed something up.......

It will help me in my quest when i hook up my 3.5(hopefully will do the timing this week) cause i dont know shet when it comes to the 3.5 vias.

 

glad you guys figured it out. sorry i couldnt be more helpful, in pointing you in the right direction.

 

Here are a few guides for interpreting vacuum gauge readings:

http://www.gregsengine.com/vacuum.htm

http://autorepair.about.com/cs/troub...a112401a_2.htm

Even though it appears you've found the problem, the links are good for future reference.

 

Well I'm still probably going to replace my injectors soon, I really have to get back on a dyno to see the difference.

No worries!

Thanks again. I will most likely do this anyway now that I found the vacuum lines, that WERE NOT on the car lol...
With that though I still need to get on a dyno to confirm....I'm getting a SAFC2 as well so this should help a ton. I'll be getting a dyno before and after I tune her.

 

So when they took out the canister and associated lines, did they plug up the other vacuum ports? I assume you're still using the NWP VIAS block plate and just simply reinstalled the canister and lines?

S

 

Yeah took out they following


Along with all lines associated. Then they capped off the UIM where the left hose is at....

This is a pick of a 6th gen with the plate installed. However yes we reinstalled my stuff and let the ECU reset itself (seems to have worked) I have to get the pending codes checked again to see if P1800 is still there. Then I have to check my timing to see if its retarded again. The engine sounds a lot better now, and better response. SO....dyno shortly

 

thats a rattling cat converter. my car does this as well. i however have no issues with power and such like you do.

 

It is actually the throttle body (i believe)...right behind the intake

 

Definitely the throttle body.

It closes all the way when you shut the car off and relearns its closed position.

Its completely normal.

 

Yeah its just louder then normal...my buddies maxima does it as well, just not as loud.....

 

Seems to me all you have to do is cap the vacuum line right by the block-off plate and leave the rest as is, correct?

Let me know if you get rid of the pending P1800 code. I can't have any codes, even pending ones to pass emissions here (they used an OBDII reader). I want to get the block-off plate but it would be kind of a pain to have to swap it out every year for emissions testing.

 

Negative, thats what I had thought at first, because thats what the "performance shop" did, and I had not read through the instructions. Once I had read through them and compared to another Maxima (that did not have the VIAS plate yet), it was discovered the the shop took this stuff out and capped the wrong area. If you look in the picture in post 114. Youll see the middle peice that is circled, then youll notice the little black cap is to the right of the hose that is there. That is where the VIAS electrical connection plugs into. After plugging that it, it got rid of my P1800 code......SO I should've listened to that more lol.....You will not throw any codes if you install this...youll be good.

Even if you did...its so easy to install and take out.