ROCKART

iTrader: (23)

This is a 97 GLE with 48k on the engine. Everything was working perfectly previous to this weekend.

so this past weekend the following was done:

1) Installed Budget Y-Pipe
2) Installed NWP Thermal Intake Spacers
3) Replaced valve cover gasket


THE SYMPTOMS:

A) after it was done I go to start my car and it has a REALLY hard start, almost seemed like it was about to stall. ill describe this by saying the actual ignition of the engine sounds dirty, not crisp like it was before the install - instead of the idle just jumping up into the 1200 range, it kind of stutters and hesitates before it gets up there.

its basically the same as if you flooded the engine with fuel by pressing the gas pedal BEFORE you ignite the car. thats the kind of choking im talking about here - too much fuel.....

the past few days the STARTING ISSUE HAS GOTTEN BETTER, but i still have the rough starting issue happen once a day.
no time has it been as clean and crisp as it was last week.



B) so im driving on the highway after i leave the shop and I notice my gas mileage is really bad. ive driven about half a tank and only have 130 miles on the odometer. i normally am just under 200 around the half tank mark.

im thinking to myself what could be wrong and the only really logical choices are bad 02 sensor or leak after putting the spacers in......

now we did run into a bit of the problem with the thermal spacers install - as you know, you have to re-drill the EGR and rear manifold brackets to adjust for the raised IM. well somehow the EGR gasket managed to slip out as we were trying to get the manifold back in, and when we tried to start the car initially, the idle was all over the place. however my friend managed to work that gasket back into place and everything "seemed" to be back to normal. my car was still choking a bit on startup, but the idle was smooth.

there were a couple of other small hiccups, but nothing serious.


C) the next day the hard starting issue seems to have gone away (its not perfect, but its better) and i am quite happy. i take my maxima out on the highway to see what she can do with the new bolt ons.

im in the middle lane of 95 and am coming up on a car quickly. i gun it past the car on the left (up to around the 4500-5k rpm range) and my CEL pops on immediately........

yesterday after work i took her over to AutoZone to get the codes read...

P0136 (a.k.a. 0707) which is rear bank 02 sensor (the rear-most of the three 02 sensors)

now as i understand it, this 02 sensor wouldnt affect gas mileage because it is past the cat. its just to measure the air/fuel mixture in the exhaust, correct?

could this bad 02 sensor be causing both the rough start and the poor gas mileage?


does it sound like it could be anything related to the spacers?



all help appreciated. and im sure ive forgotten to put in some parts of the story, so dont hesitate to ask questions.

MOHFpro90

iTrader: (11)

Its not the O2. Sounds like a vacuum leak. I would go back to the shop where you got the install done at and tell them to run a vacuum leak smoke check. GL frank.

ROCKART

iTrader: (23)

so do you think the rear bank 02 sensor is shot?

or it is just some bug that caused it to say it malfuntioned?


those headlights are looking sharp by the way

Snypa

iTrader: (35)

Question is though, would vacuum leak cause reduce in gas mileage.? Could it possibly be you were driving a little harder that day and sucked more gas Rocky.? For now i would reset the code and watch for it to come back on (sounds stupid) but its just to really see if the light will come back and if it will be the same sensor again.

BTW...i love the title of this thread.^_^

ROCKART

iTrader: (23)

yea im gettin like 260-270 miles from this tank. that is dispicable.

i normally get 325-375 from a tank in the city and 400+ on the highway.



i hope its as simple as in intake leak.

i forgot to mention as well that when we did the spacer kit we SKIPPED THE COOLANT BYPASS. i dunno if that makes a difference. ill call aaron tomorrow.

MOHFpro90

iTrader: (11)

Check with KRZZ350 about this, he knows exactly what this affects. It may be that. Also, do your brakes feel mushy/soft/weak? I was told this is a sign of a vacuum leak.




Thanks for the props on the lights BTW.

Coolsaber57

iTrader: (22)

A vacuum leak COULD be the problem, a few months back my CEL came on telling me that 2 O2 sensors were out...but it turned out that it was a vacuum leak. I got it fixed and was on my way.

Definitely check the intake again, there are a lot of random hoses, maybe you guys missed one putting it all back together?

MOHFpro90

iTrader: (11)

If he missed a hose, the car wouldnt run. Too much of a leak there. But do check them like he said they may be there, just loose/cracked etc...

hot_wax_tree

some times tanks get off have you filled up yet since then?

black_maxed95

iTrader: (41)

im willing to bet both are your problems...you have a bad o2 sensor which is why you have bad gas milage. and you also probably have a slight vacuum leak which is causing the weird idle. The vacuum leak is probably very slight tho because if it was a large leak your car would stall.

as far as the coolant by pass, it is not necassary to by pass the UIM but if you dont do it, it will make the spacers less effective. i already asked aaron about this, the reason the UIM is bypassed is because with the spacers, the coolant would actually be warming up the UIM.

I actually just installed my spacers today in conjunction with a mevi...i now have a large vacuum leak. my car starts and jumps to 4000rpms and then quickly dies. i ran out of daylight to fix it, will continue tomorrow. Also with regards to the EGR tube, I just blocked it off, it will cause a CEL but id rather have a CEL than dirty up my new intake manifold...

if you have any other questions rockart feel free to ask me.

edit: just realized 0707 is for the rear o2 sensor, not the rear bank o2 sensor (they are different). a bad rear sensor (0707) should not cause bad gas mileage...

kzoosho

iTrader: (16)

Yea i have a huge vacuum leak after my mevi install but my car idles at 2000rpm. If you have access to a smoke machine it saves plenty of time. I know i found where my leaks were in 5 mins. Also if you want to correct the a/f get a afc and a wideband.

MOHFpro90

iTrader: (11)

Just an FYI, and something that I am not sure how it spreads, You wont get a CEL for removing the EGR...Just leave the temp sensor plugged in...

ROCKART

iTrader: (23)

ok since ive been driving on this for the past 5 days ill give you guys a quick recap of whats going on. and thanks for everyones help here.


1) when the engine is cold (lets say after work, or after having sat overnight), and i put the key in to start it up, she starts up cleanly. the rpms jump to like 1500 initially, but then settle down to the 700 range once shes warm.
i.e. this is normal except for the 1500 rpm startup, it used to only go up to about 1200.

2) once the engine is warmed up and i shut the car off for a minute or two (run into the gas station, go get food, etc. etc.) and i try to start her up THEN i feel the hard/rough starting. it kind of sputters its way up the 1500 starting rpms, almost like its choking - but once its up there, its normal again and will settle back to the 700 range and idle ALMOST normally.

3) when im sitting at a long traffic light (with D engaged) and holding the brake, its idle is a steady 650. however after about 30 seconds of sitting there with my foot on the brake in DRIVE, it begins to move a little. i also can feel a rumbling through the brake pedal and the steering wheel and hear the engine change tones as the rpms drop.
it begins to fall down to the 500-550 range and then back up the 650 range and then goes back down. its not uniform or regular, but when it happens its hard to miss because the whole car is shaking.

4) my gas mileage is terrible



and yea blackmax, about the 0707 code, i was also told that it WOULD NOT affect gas mileage, because it sits behind the main cat and is just to measure air/fuel ratio.


also one more thing to mention:

the CEL has been on since the day i bought the car (code 0903 - evap cannister) so ive goten used to looking at it on my dash. ive gotten the codes "cleared" about 6 times over the past 6 months, and each time that same code comes back - sometimes in a day, sometimes in two weeks.

part of the work we did last saturday was to replace the evap cannister in hopes of getting rid of this code. so we did the valve cover gaskets, the NWP spacers (skipping the coolant bypass), the y pipe, new rotors, brake flush, tranny drain, AND replaced this cannister......then we cleared the codes and drove around a bit.

all of saturday, including the 100 mile drive home and driving around saturday night, the CEL remained off. it was not until SUNDAY during a trip on the highway, when i actually accelerated pretty hard to pass a car (going about 80mph), that the CEL for the 02 sensor came on.


if it was a faulty 02 sensor wouldnt it have triggered the CEL immediately after clearing the codes on saturday?
that leads me to believe that its not actually a bad 02 sensor, but some kind of communication/fuel mapping problem caused by the "leak" or just some other problem all together.

ROCKART

iTrader: (23)

spent 6 hours on saturday with kenny the nissan master mechanic and we discoverd a few things that i want your opinion on:


first off, there was an intake leak right in the front of the plenum gasket. so that was causing the irratic idle in D and the near-stalling at red lights longer than 30 seconds.
we lifted the intake and resealed the gasket.

problem solved.


my gas mileage issue seemed to have resolved itself even before the re-sealing of the gasket. i guess the ECM just had to adapt.



now to tackle the issue of the hard/choking startup that only occurs when the car is warm.....

we retightened the Y pipe mouting points and also cleared the 0707 code that was tripping the CEL.

after that was done he hooked my car up to the consult to check engine and emissions parameters - everything was working correctly, including the rear 02 sensor that the ECM had said was failing. wtf?

we drove around for 20 mins with the consult connected and came back and let the car sit for 5, then started her up.
once again, same problem, the choking start AND the consult was reading the 0707 code again....

he is totally stumped because everything seems to be running fine but the computer is throwing the code.


so its around 5pm and hes gettin ready to close up when he thinks of something:

as you know, last weekend we replaced the two lower valve body gaskets (?) AND the plenum gasket with the NWP spacers, which are made of plastic to allow heat to dissipate from the intake body (the whole point of them).
HOWEVER, the Nissan brand gaskets, that we would have used if not for the NWP kit, are metallic composite, which allow the intake and valve body to ground off each other upon startup. when the plastic .75 inch spacers are in there, they are totally seperated, restricting the size of the grounding area.

he also suspects this is what could be causing the ECM to trip the 02 sensor code when its actually functioning perfectly - because the ECM grounds are up on the front/top of the intake body.


does this sound like a legitimate cause of my starting issues? does the engine need to be completely connected to ground itself properly?

we did a little make-shift grounding kit that touches the ECM to the neg battery terminal, but it doesnt seem to have changed anything.


PLEASE HELP and thanks

pmohr

iTrader: (26)

Err...what about the valve body?

ROCKART

iTrader: (23)

in reference to what

black_maxed95

iTrader: (41)

you said something about the 2 valve body gaskets...i think you meant to reference the 2 gaskets under the LIM.

btw you said the whole point of the NWP spacers was to dissipate the heat...the whole point of the spacers is to do exactly the opposite of that...prevent heat from dissipating to the intake manifold.

If the nissan mechanic said it could be a grounding issue then you might want to try that out. I never had a grounding issue after installing my spacers but thats cause my car already has a grounding kit from hell. The LIM, UIM, and throttle body all have their separate grounding cables. You might want to check with aaron92se to see what he thinks about the grounding. a groudning kit can be bought off ebay for like $20 tho.

ROCKART

iTrader: (23)

yes thats correct, i didnt know what to call them.
thats why i put a (?) after caling them that.

yes i know what they do. they allow heat to dissipate (to dispurse) between the IM and valves and throttle body. instead of metal to metal, you have metal to plastic to metal.

yea immona call him tomorrow and see what he thinks. thanks.

S1cTech

Why in the world did u buy those thermal spacers for? That is what made u broke... The heat from the engine still makes the intake hot no matter what... Think about it, heat that the engine makes go up and into the hood and the hood is close to the intake. I think those spacers are a gimmick and really overpriced in my opinion for a minimal increase.

black_maxed95

iTrader: (41)

sorry dont mean to be a jerk but just to clarify:
they do not allow heat to dissipate or dispurse. the plastic is made out of a material that does not transfer heat, therefore preventing heat to reach the intake manifold. This is also the reason for the coolant bypass. (i remember before you said you skipped this part) With the spacers installed, the intake manifold should be cooler than the coolant, so running coolant through it would only heat it up which is what you dont want to do.

black_maxed95

iTrader: (41)

hey i have those spacers too...well you know what, i think your car is slow.

Aaron92se is a reputable org member. The spacers may be pricey but no one else makes them for the maxima. Also alot of design went into them to make them perfectly port matched for better air flow.
And yes they really do keep the IM cooler, take it from someone who has installed them. Think about it, metal on metal contact transfers heat alot easier than metal on air on metal. The spacers prevent the metal on metal contact.

sorry im OT, im just here to defend the spacers...

gtr_rider

iTrader: (50)

I installed a 30DE spacer kit recently and the only problem we ran into was th estrange loss in power for the day.. He reset the ECU, and shortly after the car started to pull real nice again. Working great so far from my understanding. Great product, really easy to install!

S1cTech

I Know this... The gaskets were made to prevent transfer, but I was just saying that the Intake will get hot no matter what. Thats all. The price of them just does not justify the price per performance imo...

black_maxed95

iTrader: (41)

post #20 was aimed at rockart, post #21 was aimed at you. I understand your $$/gain reasoning tho, they are pricey for what they do.

ROCKART

iTrader: (23)

alright guys this problem is still happening - after sitting for 5-9 hours my car stars fine, but if i drive for a bit then stop and turn it on again, it chokes and has trouble starting.

what could this be ??



if its a ground issue, why does it only happen when the car is warm?
when the car is cold it starts fine? wtF?

NmexMAX

iTrader: (22)

ECTS?

ROCKART

iTrader: (23)

what is ects?

pmohr

iTrader: (26)

Rather...


Engine Coolant Temp Sensor.

ROCKART

iTrader: (23)

i see you caught my ninja edit...

yea i was gonna make a joke, but decided i want to stay on topic here.



so thats your best suggestion? ECTS is malfuntioning?

would that trip the CEL?


how would the installation of those NWP spacers cause that?

ROCKART

iTrader: (23)

car sits for 8 hours: PERFECT START

car sits for 30 minutes: HORRIBLE WEAK START

car sits for 3 minutes: PERFECT START


wtf is this ?

NmexMAX

iTrader: (22)

ECTS

The problem probably existed prior to the spacers. It will eventually trip the CEL. It takes 5 mins and is 24$ to replace. Now stop acting like such a stop posting, order the thing from your local dealer or online.

ROCKART

iTrader: (23)

no. i absolutly guarantee it never happened previous to the spacer/valve cover gasket and y pipe install two weekends ago.

NmexMAX

iTrader: (22)

Well then you suck at the install.

Until then:

ROCKART

iTrader: (23)

as expected, the ECTS is fine and fully functional.

ALSO, my CEL has come back on (1 week after clearing it). I will go get the codes read again today, but i assume its still the P0136/0707 code for rear bank 02 sensor.


and the stupid warm starting issue is still there.....


im STUMPED

NmexMAX

iTrader: (22)

How do you know it';s fine and fully functional? Also, a rear O2 will not affect your situation, but we've been through that. Why not take 5 mins and get the code yourself?

ludanhismaxima

i found that my maxima was running a little rich also so i went to autozone and picked up some fuel injection cleaner i dunno i might sound like a noob but i was idling at 1500 rpms and after i finished my tank of gas after adding the cleaner im idleing at 700 again wont hurt to give it a shot

ROCKART

iTrader: (23)

alright i drove to autozone yesterday and had an interesting talk with one of the employees there....

basically i recreated the problem for him to experience when he turned the car on and he instantly said "thats an exhaust issue from your y pipe".
he said the spacers wouldnt have caused that issue, and if they were installed incorrectly, i would be seeing the issue all the time, instead of just when its warm.

he went on to explain that because i now have a high-flo Y pipe, but everything else stock, the "high flowness" of the y pipe is getting caught up/choked once it hits the rest of the smaller stock exhaust (right after at the cat). this is most likely the cause of the 02 code as well, because not all of that exhaust is getting purged, and some is coming back the wrong way.

like you have a bigger straw around a smaller straw, and some of the fluid is lost when going from the bigger to smaller diameter.


this makes perfect sense to me, and would definetly cause the starting-cold-fine/starting-warm-bad issue, because all the exhaust gases are still in there when the car is warm. but when its cold, theyve been given time to escape.


so he suggested i get an aftermarket "muffler" that is baffled, to supress noise, but still allows for a better flow of air through the system.


does this sound right?

what muffler or catback would you recommend to "balance" the exhaust while keeping it relatively quiet?

ROCKART

iTrader: (23)

on a side note, he also suggested i get some sort of aftermarket intake to further help with the "breathing"

f550maranello2

iTrader: (2)

dude... u went to autozone for advice.... give me a break.. how many people here have the y pipe on stock exhaust??

what i would do is remove the spacers and see if it happens again.. if it does they yea they aint the problem but if they dont.. problem solved...

ROCKART

iTrader: (23)

yea i know. but this kid has had all nissans.


and yea how many people on here have stock exhaust with their y pipe?

i frankly have no idea. and maybe those people dont have the Y plus the spacers, which adds even more volume to the IM.


the other side of that coin is, how many poeple on here have 4th gen thermal spacers from NWP with no problems?

the number i got from Aaron was 30.


plus, if it was the spacers, it still wouldnt explain why my issue is only noticeable when the car is warm