91 Nissan Sentra 1.6 4speed manual IAC question-
robbie
failing idle air control valve would have-
First- upon first cranking and until the engine reaches normal
operating temperature the idle is around 2500-3000 rpm
Then when at idle afterwards the idle oscillates from about 800-1300
rpm
When taking off from standing the car has symptoms like it is starved
for fuel - shudder, lack of power, etc. - if you let off the throttle
then apply more gently all the power is back and drives normally.
Things that have been checked:
fuel pressure- both at idle and at throttle- checked while driving- is
within specs (I forget the exact PSI)
when acting up the fuel pressure INCREASES slightly, like the
injectors are not opening?
EGR valve and EGR control have been checked and ruled out. The EGR I
know can cause similar symptoms but doesn't seem to be the culprit.
All vacuum/intake hoses/etc have been checked for vacuum leaks- all
small lines were replaced.
The MAF is working and the ground was checked to make sure it was
getting grounded properly
At highway cruising speeds (50-70mph) the car is smooth with good
power and acceleration.
At lower speeds when you press quickly on the throttle you will get
bucking and hesitation like you are in the wrong gear or are running
out of fuel. Also when running the AC all symptoms are magnified
somewhat- especially starting from standing- the car will almost
die...
I had an injector go out completely and I replaced it but can
injectors fail intermittently? that would explain my problem but it
doesn't seem really likely?
Thanks for any advice on what to check!
-rw
robbie
The EGR control solenoid- any way to check that? I think it may be bad.
Joe AutoDrill
distributor stalk (or whatever the real name is).
Did plugs. Did wires. Did cap and innards. All worked fine for a few
hundred miles then it started again until finally, I got stuck with no spark
on the side of the road.
Felt like a timing belt blew, but there was plenty of compression.
Regards,
Joe Agro, Jr.
(800) 871-5022
01.908.542.0244
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V8013-R
"robbie" <robbie....@gmail.com> wrote in message
news:119a50d1-cc73-4d99...@t35g2000yqj.googlegroups.com...
robbie
> I just had the exact same symptoms on a 1997 Sentra. turned out to be a bad
> distributor stalk (or whatever the real name is).
>
> Did plugs. Did wires. Did cap and innards. All worked fine for a few
> hundred miles then it started again until finally, I got stuck with no spark
> on the side of the road.
>
> Felt like a timing belt blew, but there was plenty of compression.
>
> Regards,
> Joe Agro, Jr.
> (800) 871-5022
> 01.908.542.0244
> Automatic / Pneumatic Drills:http://www.AutoDrill.com
> Multiple Spindle Drills:http://www.Multi-Drill.com
> Production Tapping:http://Production-Tapping-Equipment.com/
> Flagship Site:http://www.Drill-N-Tap.com
> VIDEOS:http://www.youtube.com/user/AutoDrill
> TWITTER:http://twitter.com/AutoDrill
> FACEBOOK:http://tinyurl.com/AutoDrill-Facebook
>
> V8013-R
>
I replaced the distributor already throwing parts at it and still have
the same symptoms. Also the car will not hesitate at all until it is
operating temperature. despite the erratic idle i have full power with
no issues until the engine warms up. i was still thinking the EGR
control assembly might be to blame but it acts the same whether the
EGR valve is hooked up or bypassed, and the EGR valve tests fine under
vacuum and is closed as it should be at idle. this is driving me
crazy!
Thanks for anyone out there with ANY ideas to try! without a check
engine light being set, is there any benefit of a computer analysis?
Does anyone even HAVE a machine to hook up to a 91 sentra? there is a
non-obd connector under the dash...
Joe AutoDrill
>the same symptoms. Also the car will not hesitate at all until it is
>operating temperature.
My problems only existed when the car was warm *until* it completely died...
Then even re-starting when cold wasnot possible,but it died under full load
driving (highway at 75 MPH both times) and when warmed both times.
Did you replace it all the way into the engine or just the top end? When I
say the "disributor stalk" I'm not sure what exactly is included, but I
envision them replacing mine all the way down to whatever gear inside the
engine spun the mechanism that is the dstributor and timing, etc. not just
the top end. Unfortunately, I had a mechanic do it so I don't know exactly
what parts are involved but I do know it was a multi-hour job, not just
spare parts.
For you, I hope it is just a small fix, but do not disregard the distributor
issue if you didn'tdo a 100% top to bottom pull and replace either. Which
for all I know, you actually did do.
robbie
what was malfunctioning. The car started fine but then when i tried to
give it throttle it bogged down as if it were losing power and then i
got it to run again (roll started it) for about 1/4 mile with very
light throttle. it was idling no problem.I parked, went into the
grocery store for less than 5 minutes, came back out, car refused to
start. it cranked over strong but i never heard it fire. about three
times i heard a muffled kind of detonation like it was thinking about
starting but it never did. so i'm thinking that the coil might be the
culprit. or the fuel pump died even though it always tested fine.
comments/suggestions? thanks! rw
Joe AutoDrill
I just had a complete failure and now I hope to be able to determine
what was malfunctioning. The car started fine but then when i tried to
give it throttle it bogged down as if it were losing power and then i
got it to run again (roll started it) for about 1/4 mile with very
light throttle. it was idling no problem.I parked, went into the
grocery store for less than 5 minutes, came back out, car refused to
start. it cranked over strong but i never heard it fire. about three
times i heard a muffled kind of detonation like it was thinking about
starting but it never did. so i'm thinking that the coil might be the
culprit. or the fuel pump died even though it always tested fine.
comments/suggestions? thanks! rw
...Exact same symptoms of my distributor "stalk" failure...
Had to pull and replace the entire thing from inside the engine to the
wires. All done from the outside, but a serious little effort anyhow.
I hope your fix is easier to implement.
--
robbie
> "robbie" <robbie.h.wil...@gmail.com> wrote in message
FINAL RESOLUTION- after the failure (and an illegal 1/4 mile rope tow
home later) I had a no start to diagnose. I was HOPING that when i
fixed it the hesitation would go away. IT WAS!
The old Sentra is running like a sewing machine again w/ 224k miles on
the clock. The problem- bad ignition coil. So if someone tells you the
ignition coil works or it doesn't that IS usually true, but NOT this
time- that damned coil had been going out for almost a year. I am SO
glad to have it running right again. On to the next issue....
INSTRUMENT LIGHTS!