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ive tried everything! find out whats wrong with my car and ill give you ten bucks!
i have a 1993 sentra se-r ,123,000 miles. My problem is this, for about the past 4k miles i have been getting a violent hesitation when the car is cold,
it will start up fine and rev fine but the when you drive it it will hesitate and
surge violently. I believe that this is also why i had to change a motor mount!
any way i have tried a new fuel filter,cleaned throttle body,cleaned egr,new plugs,wires,distributor cap,rotor,i replaced every vaccuum line and also recently replaced my oxygen sensor. When i replaced the oxygen sensor the
hesitation went away and my acceleration went back to normal(8sec 0-60 instead of 13sec) i drove the car up to adirondacks and by the time i got back home it was started to hesitate again. the oxygen sensor made the car feel fine for about 800 miles and then it stopped making a difference.also when the oxygen sensor was working my gas mileage went up from 20 hwy to 35 hwy. My question is this. has a nyone ever heard of an oxygen sensor going bad so soon or do you think it went bad from some other underlying problem that is causing the car to run so bad?
i sort of have the same problem...when i start my car in the morning and and leave right away without warming up i get hesitation. i also changed and cleaned alot of stuff but it didnt really do anything, so i decided to sand down all of my engine grounds and now my car runs smooth, idles better and throttle response is crisp. try getting a grounding kit for your car
try doing a diagnostic test using your ecu. it tells you how to do it in the owners manuel and it is free. if your 02 sensor is bad the ecu code will tell u as well as some other sensors. when i had some problems less severe than you i did the diagnostic test and replaced an 02 sensor as well as a water temp sensor and it fixed my idle problem and made everything run smooth.
PROBLEM: Surge and hesitation between 1500 and 3000 rpm
Affects: All '91 - '93 SR20DE (Sentra SE-R, NX2000 and G20)
If the usual tune-up procedure doesn't take care of the problem, disconnect the EGR valve and plug the vacuum hose leading to it from the BPT valve. Take the car out for a ride, making sure to drive in the same manner that typically causes the car to surge and hesitate. If the problem is no longer present, chances are good that you're experiencing the infamous "EGR Problem".
Remove both vacuum hoses from BPT (right-most disk shaped object behind valve cover). Remove the two philips screws on its top. Push the BPT back toward the firewall. You should see a rubber hose running between the bottom of the BPT and a metal tube. Remove the BPT and rubber hose from the metal tube and set them aside.
This metal tube is connected to the EGR passage and, ultimately, to the exhaust manifold. Exhaust manifold pressure, via this metal tube, operates the BPT valve which regulates the vacuum to, and the opening of, the EGR valve. The less exhaust manifold pressure - the more the BPT valve opens - the more the EGR valve opens. The more exhaust manifold pressure - the less the BPT valve opens - the less the EGR valve opens. Carbon may block this metal tube which causes the BPT to not operate properly (if at all) which causes the EGR valve to operate uncontrollably.
Wait until the car is cold, then spray some carb and choke cleaner into the metal tube to soften up the blockage. Used a stiff piece of wire (a long chunk of 8 gauge wire left over from the big car stereo install will do) to ream out the tube. (*Note: DO THIS WHEN THE CAR IS COLD!! Carb cleaner and a hot exhaust don't mix well.*) Take note of how far you have pushed the wire into the tube before you pull it out. Lay the wire along side the BPT tube to gauge how far down the tube you have gone. When you've pushed the wire far enough down the tube to have reached the EGR tube it intersects, you've probably removed all of the blockage(s)
Wait about 10 minutes for the chemicals to evaporate. Start the car and hold your finger in front of the metal tube. You should feel a steady stream of exhaust coming from it. If not, try cleaning it again.
While you're waiting for the chemicals to evaporate, now would be a good time to remove your EGR valve and clean the carbon deposits from the plunger and seat. I find that the carbon build up eventually gets bad enough to hold the EGR valve slightly open. This changes your base idle speed (TPS disconnected) and can also cause a rough and wandering idle as well as possibly causing your car to stall when you push in the clutch.
Reassemble the system, hook your EGR valve back up and take your car out for a ride. You should find that the problem is gone and your local smog police will give you an award for being a law-abiding smog free citizen once more.
I make checking the metal tube and cleaning the EGR valve a part of every tune-up and/or oil change.
__________________ 91 SE-R w/DET
02 G20 Sport 5spd
94 Miata "homobile"
93 240SX Family Project
"Any man who is under 30, and is not a liberal, has no heart; and any man who is over 30, and is not a conservative, has no brains." Winston Churchill
If the problem goes away after your car warms up, don't suspect any emissions systems or 02 sensor. Check all the components that control your air intake while the engine is still cold. If it was 02 or spark plugs/wires it would be hesitating all the time.
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“Undermine their pompous authority, reject their moral standards, make anarchy and disorder your trademarks. Cause as much chaos and disruption as possible but don’t let them take you ALIVE.”
before closed loop your ecu uses the reference signal from your CTS check the cts if it's stuck reading a high coolant temperature it'll cause your car to go lean and run badly.
easy job and a cheap fix.
Also check for bad valve cover grommets allowing oil to get around the spark plugs causing a short and hesitation (similar to what you get after washing the engine w/o covering the spark plug holes).
After trying everything under the sun, this was the cause of an annoying hesitation in a 92 Classic.
i replaced my vc gasket after i got my vc powdercoated, i checked it any way and it looks good all the way around. i will pull the codes from my ecu tonite
naw man i know what the problem is try just running w/o your tps and try it mine has been unpluged for weeks and running great had the exaact same thing happen to me
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96 200sx Se-R "B14 Monster"
UK SR20DE red top, Hotshot CAI and Gen 5 header, Stillen strut bar, ACT Clutch, Optima Red Cap, B & M Short Shifter, Redline Fuilds, Kumho v712, K&N oil/air, Glow Gauges
93 Sentra Se-R "1SLO SER"
W11 DET, ACT Clutch, Strut Bar, GC Coilovers with AGX's, 3" DP and dynomax exhuast, Turbo XS RFL BOV, Optima Red Cap, Precision Front Mount
17" Rev Hard, auto meter ultra light (oil, boost, A/F)
before closed loop your ecu uses the reference signal from your CTS check the cts if it's stuck reading a high coolant temperature it'll cause your car to go lean and run badly.
easy job and a cheap fix.
have you checked this yet? also a bad o2 stuck lean will cause cold start problems
Jerry James Hays 9/1/1982-5/14/2006
