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View Full Version : Sr20d flat spot cure ?? resolved ??



Blood
18th January 2005, 06:53 PM
Maybe this could help fix the know flat spots on the b13 NX ?
Taken from hte PDF file(s) of the service manual.

* PLEASE READ THIS FIRST *
The following general procedures are to be used if
driveability problems are encountered after power loss or battery has
been disconnected. These procedures may provide an aid in eliminating
these problems.
To reduce the possibility of complaints, after any service
which requires battery power to be disconnected, vehicle should be
road tested.
COMPUTER RELEARN PROCEDURES
Vehicles equipped with engine or transmission computers may
require a relearn procedure after vehicle battery is disconnected.
Many vehicle computers memorize and store vehicle operation patterns
for optimum driveability and performance. When vehicle battery is
disconnected, this memory is lost. The computer will use default data
until new data from each key start is stored. As computer memorizes
vehicle operation for each new key start, driveability is restored.
Vehicle computers may memorize vehicles operation patterns for 40 of
more key starts.
Customers often complain of driveability problems during
relearn stage because vehicle acts differently then before being
serviced. Depending on type and make of vehicle and how it is
equipped, the following complaints (driveability problems) may exist:

* Harsh Or Poor Shift Quality
* Rough Or Unstable Idle
* Hesitation Or Stumble
* Rich Or Lean Running
* Poor Fuel Mileage

These symptoms and complaints should disappear after a number
of drive cycles have been memorized. To reduce the possibility of
complaints, after any service which requires battery power to be
disconnected, vehicle should be road tested. If a specific relearn
procedure is not available, the following procedure may be used:
Manual Transmission

* Place transmission in Neutral position.
* Ensure emergency brake has been set and all accessories are turned off.
* Start engine and bring to normal operating temperature.
* Allow vehicle to idle in Neutral for one minute.
* Initial relearn is complete: process will be completed during
normal driving.
Some manufacturers identify a specific relearn procedure
which will help establish suitable driveability during relearn stage.
These procedures are especially important if vehicle is equipped with
and electronically controlled automatic transmission or transaxle.
Always complete procedure before returning vehicle to customer.


I suggest using this is at your own risk, thought it may help some of u.:D

ZeffriN
19th January 2005, 06:42 PM
well, I gave this a try today and believe it or not but it might actually be the cure?!

I disconnected the battery for a few minutes, put it back on, started the car and let it idle 10 mins or so (well after it had reached operating temp) and took it out for a nice steady drive.

While warm the flat spot is gone, well, it may still have an ever so slight twitch in power its only noticeable because im looking for it, its also a little earlier in the rev range than before.

I've let it cool and taken it out twice cold now and the flat spot is still there while cold but quickly vanishes... it may also need to do additional learning.

I'll give it a week or so and post again my findings, but great find Blood, thanks heaps!

Blood
19th January 2005, 07:00 PM
will try it myself on weekend...
glad to be of service :)

dipe
19th January 2005, 08:58 PM
the way its worded it sounds like a general nissan thing? or is it just for the nx?

MaxNx
21st January 2005, 09:06 AM
The disconnect battery trick has been tried before by a bunch of the PGA guys complaining of flat spots. For some it has been successfull, for some not so. I definatley wouldn't call it a definate flat spot remover but it is another technique in our ever growing aresenal against the 'flat spot' :thumbsup:

ZeffriN
21st January 2005, 10:24 AM
flat spot is getting more pronounced in certain conditions, kind of interesting.

I think there may be something otherwise off with my car, but so far it's running much nicer than when I first got it

Pretty White
24th January 2005, 05:26 PM
Just clean your throttle body.
This is ridiculous.
Flatspot is a tune up issue. It is another way of saying poor throttle response.
Clean your contacts on the dizzy and cap.

If you have a flatspot before the ECU is reset it will still be there once it is relearning the engines parameters.

jazza
24th January 2005, 05:32 PM
err no its not poor throttle responce..
Its when u hit certain rpm (around 2.5k i believe) you get a small jitter in the engine where its not smooth!

Pretty White
24th January 2005, 05:33 PM
err no its not poor throttle responce..
Its when u hit certain rpm (around 2.5k i believe) you get a small jitter in the engine where its not smooth!

Thats not a flatspot then. Thats a bad EGR valve. Disconnect it and I bet the "stutter" goes away. There is a procedure to clean it out if you want.

jazza
24th January 2005, 05:34 PM
interestin..

Pretty White
24th January 2005, 05:34 PM
http://www.se-r.net/car_info/problems/index.html#Surge%20and%20hesitation

Fellas, these SR20's are not as technical and difficult as you are making it out to be.

jazza
24th January 2005, 05:41 PM
fuk off.. how cool is that site :P

Pretty White
24th January 2005, 05:45 PM
fuk off.. how cool is that site :P
And that is the old stuff. We have not updated that site in years. But still interesting reference.
Also the www.sr20forum.com is your SR20 friend! :)
www.pulsar.org.au is also your friend in Australia. :playboyre