Flat spot on B13

[Blood]

Has anyone got a flat spot on the acceleration ?
approx 2500 - 2850 RPM
only while accelerating a bit..
if u floor it .. it is there, but not very noticeable

how can i fix it ?

[NXR]

theres a big thread on this somewhere, cant seem to find it though??

[bogan]

its called a search button :)

http://forum.nissanexa.com/showthread.php?t=14068&highlight=nx+flat+spot

this is from the pulsar site - http://forum.pulsar.org.au/showthread.php?t=13005&page=1&pp=20


the pulsar site tells u how to fix it

[Herbs]

I have a b13 and have the same problem mate...
tried everything under the sun but nothing fixes it for good.... read all the posts and forums....
The only help was blocking the egr valve pipe... Cleaning my throttle body (taking it off and cleaning it properly) and if you have a pod filter make sure the bracket isnt intruding on the airflow to your sensor...
Whats actually happening is the car is leaning out hard (so my air/fuel gauge me) and gets starved for fuel, and should only really do this when the car is cold.
Other then that just keep trying, you'll find you might be able to get rid of it temporarily but for me it always came back. If you fix it for good pm me with your secret.....

[NXT51]

correction: the pulsar site has a thread that's been running for 2years trying to fix the problem - still not solved. From the thread bogan has linked to, this was my summary of the reasons for the flat spot:

"All the things mentioned - reasons or things that may need a clean or change or whatever: Leaning out when cold (checked with gas analyser in exhaust on dyno), Mass Air Flow Sensor (MAF), Throttle position sensor (TPS), timing to 17 (may help), O2 sensor, positive crankcase ventilation valve (PSV), air to fuel ratio (AFR), spark plug leads, fuel injector clean, high-octane to lower-octane fuel, ECU problem (closed loop), piggyback chip to change way ECU is reading fuel mix/accelorator push/air ratios etc. (not sure), incorrect oil (being too viscous)...."

Blood, this is a very common problem in the SR20 - I believe it's an innate computer fault that of course Nissan does not want to know about. Yes the car leans out, only happens in my car when it's cold. I think most people just learn to accept it.

Good luck - if you solve the mystery let me know.

[fahootie]

I don't have the SR20 flat spot!!!!! :redfinger

I did on my N14 Q, but so far so good.

[mio]

what do flat spots feel like ? a dip in power and nose dive as your car accelerates? noob here.

[jazza]

Sort of stuttering... my mates sr20 SSS Pulsar has one!! It annoyed the SHIT outta me hahaha

Good to hear its a common problem.. well in a way its good n in another its bad for sr20de owners :( lol

[bogan]

would a re-chipped ECU help ?

[Herbs]

that is possible, i found that when i got my apexi safc (air flow converter) tuned in the flatspot seemed to nearly disapear, still not completely gone though... Have u tried the good ol "italian tune" :kewl:

[sicknx]

a safc or any piggyback computer will not fix the problem 100% because its acting like a band-aid when the actual ecu itself is rooted... i know its alot of money and probably not worth it on a DE but a standalone ecu like a microtech would fix the problem as they could tune it until its perfect

[Blood]

what about getting it re-chipped ?

same ecu, just geting the maps re done ?...

like the "sports chip" / "power chip" as some ppl call them

[nx2die4]

alright guys i wanna re open this old thread cause i know everyone has this problem well most of us do ..... whats the verdict do u get a new ecu? im thinking on doig wat blood has done and get a safc in my car .... wat do we do.....

i know that i changed my ecu when i converted my car and my car was runnin still the same then i cleaned my egr valve and piping and everything started to clear up but it is still there..... i also need to change the egr valve cause it is hammered ....

i know if u discount the battery for 24 hours it resets the ecu .... but some how i dont think that will work only because it will then relearn wats going on ....

so is it new ecu or safc or piggy back chip

if it is one of them which one will it be


EDIT: i just read all 22 pages of that thread that pulsar org members have..... basically wat i gathered was it is either the oil being to thick or the oxy sensor blocking the egr knock sensor or the ecu needs to be upgrafed or have a chip installed in the daughter board .......

[dsp26]

dont bother trying to fix it, its not that bad a problem..... you can try all the fixes for it as some have had success, im personally replacing my entire intake manifold with a U13 DET one so no EGR stuff =))

oh and as for the bogging... it was built into the design of the engine... here have a look in pg6:
http://www.nissansportscarclub.org/bbs/files/sr_desin_sae.pdf

at the end of the day, many of the SR20s sensors contribute to this and its just a matter of finding which one is rooted. you need to have a Haynes manual handy to get all the correct voltage ranges for the sensors... specifically 02,coolant temp,afm...

also if you want to attempt an EGR clean, full instructions and diagrams:
http://members.optushome.com.au/xlnsss/

[dsp26]

nx2die4: if your just looking to corerct your mixtures, you may want to consider the Jaycar DFA for only $150 with hand controller.

it has 128 load points with 100rpm increments. this is ok even though it doesn't have interpolation + its 2D which pretty much only works at WOT.

[nx2die4]

already cleaned the egr valve and turned my idle to 1000 revs when ac is on it drops to 800 ...(which is normal)


would a u13 det mainifold fit right onto our sr20 ..... if so im gonna get one ....

then i would need to get rid of the pipe that goes to the exhaust .... ohw ait i got extractors in the garage with no extractors inlet :) sweet

[dsp26]

already cleaned the egr valve and turned my idle to 1000 revs when ac is on it drops to 800 ...(which is normal)


would a u13 det mainifold fit right onto our sr20 ..... if so im gonna get one ....

then i would need to get rid of the pipe that goes to the exhaust .... ohw ait i got extractors in the garage with no extractors inlet :) sweet

the U12/13 Inlet manifold has no egr stuff whatsoever so the pipe won't even be there.

It will bolt on directly as it is the only High-Port DET. all Low-Port DETs are S13/14/15.

For those who do not know, all Aus delivered SR20s are High Port = Injectors above throttle. Low Ports have the intake plenum above the injectors.

[nx2die4]

i might get one as well then dsp when u go to get one see if they got another one maybe they will make a special for two and ill help u put it in

[dsp26]

i might get one as well then dsp when u go to get one see if they got another one maybe they will make a special for two and ill help u put it in

sorry bro, mate in NZ is shipping one over to me:hehehe:

trademe.co.nz is my new bestfriend... ebays been a bitch lately....

you find that their fairly willing to ship to Aus considering the slight currency difference evnt hough the item is still a bargain to you

[NX1992]

had the flat spot pretty bad so just changed the 02 sensor located on the

manifold at the front cos it was running the ecu rich.

the flatspot is 85-90% better. my car used to almost stop from the flatspot esp

when cold... now it is smooth as to drive.
get the 3pin plug it plugs straight in no mofofication required.

costs $147 from repco give it a go. gives better economy aswell.

nissan recommends to replace the 02 sensor every 80000 kms my car did 178000 before i did

mine. i am on 199000kms now still no flat spot.

[Impacter]

Christ this is an oldy

I have a flat spot when it's cold around what was originally said but pretty much allways warm 'er up so neva really get it

i've just hit over 200K

[Nvious]

It's the EGR..
Happens to all sr20de's..

[Impacter]

Try driving a carby without warming it up you'll have the same probs i rekon, sluggy ol' lumpy goats

[Pretty White]

http://www.se-r.net/car_info/problems/index.html#Surge%20and%20hesitation

[nx2die4]

dsp u cant swap the intake mainifolds because the ecu will be looking for the egr valve o cold starts and will fuck up the idle

[dsp26]

the fast idle control will compensate for it