BigDogJonx

iTrader: (7)

Dont know why this is happening but it seems to be ****ing me more and more off everyday.

Let me try to explain this as best as I can.

Basically lets say you are in 5th gear on the hwy and going about 80mph and you decide to slow down a bit, so you take your foot off the accelerator and let the car slow down while in 5th gear. Well while this is happening, the engine is sputtering as it slows down. Let me see if I can explain. Basically you know how you have the nice and smooth engine Vroooom noise as it slows down right? Well mine would be more like Vroooooo-putt putt---ooooom-put----ooooom kinda thing. At that same time the exhaust is popping. Now this happening in any gear, whether it be slowing down in 1st, 2nd, 3rd, 4th, or 5th. Also while this happens the car jerks a bit, not crazy jerk like if you mis shift, this is the type of jerk you can feel through your seat.

Now here is the wierd part which I cant figure out. When this jerking/sputtering is happening, if I put the throttle to say just 1% (looking from my SAFCII) it doesnt do it anymore. This crap only seems to happen when the TPS is at 0%. I mean the sec this sputtering happens, if I put the slightest pressure on the throttle like anything above 1%, it sounds fine and slows down like a normal sounding engine while engine braking.

What can be my problem? I dont think its MAF cause I just recently dynoed and put down good #s. Plus when Im driving and rowing through the gears the car pulls rediculously hard. I mea 1st and 2nd gear is worthless if I floor it at anytime. Also my car idles fine, idles around 700-800rpm. The idle is almost steady, but it bounces around id say about +/- 25rpm.

This gets really annoying cause when you on the hwy and using cruise, when the computer tells the cruise to let off cause its going to fast, the car starts making popping noises and the car jerks making me think something is wrong.

Any help on where to start with this would be appreciated. BTW, Ive re-learned the idle air volume to see if that would help, no change there.

Dixit

Igor911

iTrader: (10)

My car makes that same noice and the exhaust does the same exact thing. Sorta is like backfire?

My mechanic said that it is because i changed to 2.5" pipe and took off the resonator. He said that if i put it back on, it will stop.

DA-MAX

iTrader: (10)

I'd also like to know why the shaking happens...my Integra does the same. the "popping" is probably just unburnt fuel igniting in the exhaust after you let off the gas, I think

BigDogJonx

iTrader: (7)

Damn so you are seeing the same problem Addae. Its wierd how once i give it 1% Throttle its fine. Makes me think its fuel/air related in that its not getting enough air. So can be airfilter or something else.

Im going to disconnect the turbo piping, put on a short pipe with a MAF and run it like that (with a filter of course) and see how that runs.

Dixit

DA-MAX

iTrader: (10)

yup same here...coasting in gear, let off...putt, putt, putt, jerk, jerk....tap the gas for a second(ie- 1% throttle) and its back to normal. I'm with you on it being air/fuel related for sure!

and I was on some site, and someone explained this I'll try and dig it up...seems common on a lot of modded manual tranny cars!

MrGone

iTrader: (30)

engine vacuum


eh?

BigDogJonx

iTrader: (7)

Shawn cant be vacuum cause I show almost 20-22Hg when this is happening.

Addae, I was thinking about ghetto doing it by moving the throttle plate open like a hair using the set screw which will in a sense make my throttle pecentage 1%, but i got a feeling the idle will be like 2500 then.

Dixit

JeEvE

iTrader: (10)

I seem to have a similar type problem. When in first and sometimes second, I let off the gas and the car jerks and when I give it throttle it stops. I used some BG 44k and today I poured some sea foam in the manifold and it seems like it went away. I not really sure if the fuel cleaner or the sea foam really did it.

MrGone

iTrader: (30)

hmmm

question though, if your SAFC-II fixes the problem by adjusting the TPS to say 1%, then I think its a computer thing and mechanically adjusting that screw isnt going to do anything

BigDogJonx

iTrader: (7)

Well whats wierd is I suspected that as well, so I seafoam'ed the engine and started it 15mins later (gobs of smoke coming out) and also put the 2nd bottle in the gas tank. Also hand cleaned the throttle body with cleaner and a rag, same crap.

Even replaced the plugs. Same crap.

Dixit

BigDogJonx

iTrader: (7)

Cant use the SAFCII to adjust the TPS. TPS is basically Throttle Position Sensor. It just reads how much the plate as opened. Thats basically mechanical, no way to electronically control that on the 2k-2k1. The set screw hold it from going back too far.

Dixit

MrGone

iTrader: (30)

now I'm confused lol

BigDogJonx

iTrader: (7)

What Im saying there is when I PUSH the accelerator and then look up at my SAFCII display it shows me how much Ive pressed the throttle, I can see that Im at 1%+ and the sputtering is gone. Thats where the SAFC came into play, it just PROVES that im pushing the throttle and its actually opening and just me pressing the initial spring back part of the accelerator.

Dixit

MrGone

iTrader: (30)

ohhhhhhh ok gotcha. I thought you could have the SAFC trick the ECU into thinking the throttle is open 1%



break out the wrenches and flat head screwdriver (if its like the VE throttle body... sorry, dont spend too much time on the 5th gen )

ukeyman

iTrader: (1)

What you're experiencing is normal on all manual transmission cars. It's much more noticable and prevalent when you have any type of exhaust mod. Depending on how much you are modded it can get as loud as a backfire. What it sounds like you're hearing is a gurgling or burbling (not even a word, i know) that is a result of backpressue and engine vacuum. A larger, freer flowing exhaust will cause this sound to become more noticable. Although this is not a mechanical problem the only sure fire way to fix it is to take it out of gear when you are coasting, yes, a pain in the a$$. If you watch any type of sport touring racing you will sometimes hear this, it's easy to mistake for backfires, but it just means you have a relatively badass car w/ a nice exhaust. Enjoy the sound, I think it sounds mean. Whew, sorry for the long response.

maxspeed96CT

iTrader: (9)

yup this is normal . Mines does the same thing. It started being very noticable when i got my y-pipe. Andthat 1% thing is tru because sometimes when i roll by cops i barely touch the throtle and my exhaust noise goes away completly.

JeEvE

iTrader: (10)

I didnt know it was a normal thing, I have been driving manual for a little over a month so im still learning.

DA-MAX

iTrader: (10)

yeah thats what I read a while back...so I guess thats right. I knew it was common in modded 5spds, but never knew exactly why...still have a strange feeling its somewhat dependent on the A/F as well though and unbrunt fuel puddling and heating up inside the down/Y-pipe during deacceleration

|Bijan|

iTrader: (12)

Could it be a fuel related problem? Like...a hose or line is getting kinked after letting off the accelerator?

Are you running rich or lean or neither? Or...do you think that has nothing to do w/ it?

BigDogJonx

iTrader: (7)

DAMN!. I wish this wasnt the case. Cause more and more mods it gets worse, so that means with me its even more noticeable.

And this did actually happen with the Auto except being the design of an auto, the torque convertor absorbs most of that stuff.

Dixit

HitManSE

iTrader: (1)

Weird, my car (auto) actually kinda exibited the same characteristics. Not to the same exact point as yours but only at certain points back when I had the magnaflow on. It only happened in 4th, say I accelerate very lightly from 35-40 and let off, you could actually hear the exhaust poping as it decelerated. Hell I even had a resonator on It never really did it in any other situations due to the fact its an auto but I wouldnt be surprised if every1 has this problem who has a maunal & an exhaust. If you have a y-pipe or atleast a resonator removed, its going to pop. I dont know how loud yours is though.

|Bijan|

iTrader: (12)

What about exhasut leak?

HitManSE

iTrader: (1)

Would that not be kinda obvious?

Broaner

iTrader: (10)

I always thought this was normal. All cars do this, except it is more difficult to hear with a stock exhaust. Stock performance cars like STI do this. I kinda like the sound. Immiating race cars is always fun.

ryand.white

Like was stated before it has to do with backpressure and vaccuum. there is nothing wrong with the car.

Xugg

My Automatic does this everytime I let off the gas, not that noticible with the radio on but since I got my y-pipe its got a kinda raspy tone to the gurgling now...but I have no complants, I like it

HitManSE

iTrader: (1)

Hell I actually liked that too, it wasnt loud or anything. You had to listen for it, so I shouldnt exactly call it a problem. Now its quiet as hell though

Hotnicks

Just to make things more confusing...
Working down in Florida for 3 months back in '01, I had a rental Maxima. It was a '00 GXE auto. That particular car had this exact same problem. It would happen at all speeds. It is an annoying studder that only happens when releasing the gas pedal. As you mention BigDog, the slightest application of the gas pedal would make this behavior go away.

That was a bone stock Maxima, so my thinking is that it is not related to any of the performance upgrades you have.

I had that car for about 3 days. It got so annoying, that I called Budget up and requested a replacement. I had a total of 4 rental Maximas in the 3 months and only that one exhibited this behavior.

BigDogJonx

iTrader: (7)

Damn, cause this is getting worse for me. In the sense when it is really cold out in the morning and I pull the car out the garage and say its 30 out, the car studders very baddly if Im coasting in any gear. And the jerking is very bad, the whole car jerks.

I really feel that it almost looks like when I take the foot off the gas, the car WANTS to turn off but it cant cause the 5spd is in gear and keep the crank moving. I tested this a few time when the jerking would start, i pressed on the clutch and the car flat out dropped in RPMs and turned off. So it seems that it wants to turn off and thats what might be causing this.

I know everyone here says this is normal, but I really need to get this fixed it at least lowered in the intensity it happens. Unfortunately I dont know where to start. I cant raise the idle with the screw on the TB cause if you do the ECU goes out of wack and keeps reving the car up and down. I know you are not supposed to touch that screw for any reason. But you know me, I still messed with it and no change.

There has to be a reason this is happening.

Dixit