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Discussion Starter · #1 ·
Ok, so i have this 96 200sx SE-R. And it feels like when i accelerate/drive at low rpms (Around 2000-2500) it feels like it's misfiring, and it doesn't accelerate smoothly. Now this is just a faint little thing, i don't hear anything and i can barly tell if it's actually the car or road bumps, but the tach doesn't move slowly upwards. Once at higher rpm's though it gets smoother though and i don't even notice. The other odd thing is that if i'm parked and i just slowly rev it up, it doesn't do this, so i was thinking that my clutch might be warped, because it's felt weird from Day 1, weirder the the 31 year old clutch on my beetle. Any help would be really appriciated cause it's kinda annoying.
 

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Discussion Starter · #2 ·
Is blignorence iss on this one? Have i stumped the forizzle? My friends father says he think's it's just the pre-programming on the knock sensor holding the engine back at risky rev levels. But i'd really like to know if that's true, because i have alot of other work to do and i want ot make sure i don't need to worry.
 

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i have this exact same problem, could the knock sensor have somthing to do with it. i just bought the car and it had codes 0304(knock sensor) and 0706(fuel injection system). i erased them and only the knock sensor came back... is the ECU limiting revs?
 

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iacv could definently be it, that requires a bit of work to get at if you do it yourself.

I know where you could get a good deal on one if you need a new one ^^;
 

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I have the exact same problem.. but first, does it happen with the car cold? Mine doesnt. Which leads me to believe it has to do with the EGR

If it is the same problem... lets see what Ive gone over.
Cleaned the IACV
Cleaned EGR
Full Tuneup (when I bought the car, dont know if it did beforehand)
Replaced Knock Sensor (Had the code when I bought it, replaced right away)

I also have a missfire for cylinder 1 that seems to always come back, again only when warm. Reading for a fix for this someone mentioned cleaning his EGR and replacing his BPT. The only thing I havent done is replace the BPT.

The EGR isnt too hard to clean either.

Cant find a dirrect link.. so...


Fix for the engine running rough or stumbling when warm under light throttle below 3000rpm.
Dan Thompson ([email protected])

If your EGR valve (left-most disk shaped object behind valve cover) is disconnected, hook it back up. Reach up under the EGR valve and touch the diaphragm while the engine is fully warmed and running. Lightly rev the engine between 2000 and 3000 rpm. If the EGR diaphragm flutters or moves erratically instead of opening and closing smoothly then I've got your solution.

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, operat es 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.

I waited until the car was cold, then I sprayed about a half can of carb and choke cleaner into the metal tube to soften up the blockage. I used a stiff piece of wire (a long chunk of 8 or 10 gauge wire left over from the big car stereo install will do) to ream out the tube. Please note: DO THIS WHEN THE CAR IS COLD!! Carb cleaner and a hot exhaust don't mix well.

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. And GUESS WHAT!!?? If the build-up gets bad enough it can cause your SR20DE equipped ride to stall when you push in the clutch!!

Reassemble the system, hook your EGR valve back up and take your SR20DE 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.
 

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Just felt I needed to update this. I pulled the tube out of the top of the EGR today and capped it off with a screw. NO MORE HESITATION! Even with a EGR cleaning it happen, which means now its the BPT not funtioning properly. My advice, run the same test and see if it happens. If it goes away clean your EGR. If its still there after cleaning buy a new BPT. Its an easy thing to test because its just blocking off one vacume tube, you dont need to spend any money to do it. If its still there then you can easily check elsewhere. If its not then its also pretty easy to clean out your EGR, still no money spent.

Edit: Sorry, I couldnt find this link before now. But there is a small test to do in it to see if its the problem
http://www.se-r.net/car_info/problems/index.html#Surge and hesitation
 
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