91 nissan sentra 1.6 liter 4spd problem with stumbling/etc
Robbie Wilson
when car is cold (not up to operating temp) it performs as it has the last 6
years - perfectly.
when the engine is warm, pressing the accelerator about a third down (where
you normally would want to accelerate when starting out in first) there is
stumbling and hesitation that is like there is lack of fuel. if you back off
slightly then reapply the accelerator, all is good and the acceleration is
normal.there is no check engine light, and there are no vacuum leaks that i
have discovered- i checked all the vacuum hoses, etc. Fuel pressure is fine
as well. I have not looked at the computer readout (where you turn the screw
all the way in to display codes on the computer under the dash) - but i was
hoping to hear from the pros! Thanks. - robbie
ps - i want to say its a throttle position sensor, but that is supposed to
trigger the CEL according to the manual.
Thanks!
willshak
You might check for a clogged catalytic converter. I had a similar
problem with my 87 Pulsar and that was my problem.
--
Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @
al
wrote:
That phenomenon can be indicative of an oxygen sensor getting lazy.
If you have a scan tool you can watch the oxygen sensor switching at
idle and determine if it is switching too slowly. I assume the
distributor cap, rotor and spark plugs are known to be good. Without
diagnosis with a scan tool you're shooting in the dark. Good luck. Al
NissanTech
Lots of possibilities there, and with it not throwing a CEL, you'll
want to go through the FSM diagnostic tree. Grab your FSM here
( http://www.nicoclub.com/FSM/Sentra/1994_Sentra/ )...
EDIT: Just realized you have a 91, not 94. Procedure should be the
same. As Al said, I'd be checking O2 sensor, but ALSO the temp sensor
(believe it or not).
Louis
Welcome back NissTech...you have been sorely missed
NissTech
Just have not been replying too much,the group has been kinda dead.
"Louis" <Lger...@cox.net> wrote in message
news:Ue%Cm.44267$Ku5....@newsfe04.iad...
robbie
> I've been here all along.
>
> Just have not been replying too much,the group has been kinda dead.
>
> >> same. As Al said, I'd be checking O2 sensor, but ALSO the temp sensor
> >> (believe it or not).
>
> > Welcome back NissTech...you have been sorely missed
Second the post that NissTech is a username I love to see- always the
intelligent, easy for a layman to follow response!
NOW- the (un-obvious) solution to my sentra problem- i experienced a
no-start condition on the sentra and immediately started
troubleshooting the ignition system. i remembered that at some point
the switch was giving intermittent trouble but it went away. I took
the (pressed-together) electric portion of the keyswitch apart and
cleaned the contacts and reinstalled. THEN the switch blew the 30a
fuse - which let me no there was a short in the switch. So I ordered
the replacement switch for 33.00 and waited. When I got it and
reinstalled and put in new fuses I was rewarded with an engine that
would crank and run. What I did not realize was that the engine has
also been cured of the stumbling! A eureka! moment of course but it
makes good sense- the CEL is not going to be triggered by someone
turning the switch on and off more rapidly than you can blink, but it
WILL cause the car to lose power for small amounts of time. I plan on
an extended drive to confirm the fix, but I'm thinking the problem is
solved (til next time!) :) Thanks to all posters, and particularly
NissTech - you rock!