look at your rotor (KIS) see if it is the cut out kind....i bet it is ! one dollar!

What do you mean by the "cut out kind?"

It is made to drop a couple of cylinders at 5500 RPM..look at it. You will see it is not a standard looking rotor

Same here
 

My '81 sc just started doing this as well. If I climb to 5500 RPM slowly, it does not "cut out". However, if I am hard on the throttle, that is when it "cuts out" around 5000-5500 rpm. It has only started doing this in the cold weather (10 degrees Celsius outside temperature). It almost feels like its not getting fuel or it's getting too much air. Anyone have any idea what's going on?

The rev limiter is part of the DME, it is not part of the rotor or the tach.

I'm pretty sure I have a good amount of gunk in my tank because when my fuel level gets low I hear the fuel pump working harder. Seeing the earlier posts in this thread mention an in tank filter make me wonder. How big of a deal is it to replace on a 72? Can the tank be flushed and/or cleaned out at the same time? What does the o ring replacement cover? Any other recommendations?

TIA!

Scott

My 3.2 used to pre detonate sometimes at higher rpms while accelerating hard.

I suspected it was my Autothority chip and it was.

I think with older motors with carbon deposits in the combustion chamber you can see this happen.

My '88 was having a similar problem.

Starting cutting out at 3k though. It was a worn resistor in the AFM. Replaced it with a rebuilt, and 1000 miles trouble free motoring.

I love these no return to say how it was fixed threads.....

I hate to bring it up but a number of years ago we had a 3.2 Carrera with a similar problem, breaking up/ loss of power over about 5,000. After chasing all the usual suspects.... the only thing left was the flywheel, so we removed the speed sensor, put some scotch brite on the end of a screw driver, had one mechanic crank the motor, while one mechanic cleaned the surface of the flywheel teeth. We then put the speed sensor back in and the symptoms change, it was at a higher rpm. Soo we pulled the engine, put a new flywheel in it and fixed the problem. Ended up finding a nick on one of the flywheel reference teeth. Just remember during diagnosis, cleaning the old flywheel, we saw a definite difference.

When you replaced the flywheel did you install a new sensor and/or set the gap?

The sensor counts the teeth by completing a magnetic circuit so unless the dirt on the flywheel was ferrous and it bridged the gap between teeth i would make no difference.

Old sensor, and check/reset the air gap. Always clean the shavings off the sensor while diagnosing, but it would have to look like a mushroom to be a problem.

On my 3rd 240sx that I bought we took it out drifting and noticed it would redline at 3k over and over. Knowing the engine was good, we went into the trunk and took the fuel pump out to see the filter where the fuel was picked up was copletely covered. We took the filter off, and cleaned it with brake cleaner. Dried it out and then put it back in. Drifted for a couple minutes until the problem happened again. Checked it out again and sure enough same thing. We had to change out the entire fuel tank.

You might get lucky and its just clogged and that is it. Just a thought, could be other issues.

Still not fixed...

Hi, I would bet on a clogged cat. At least if it just evens out over 5500 rpm, smoothly. I had that problem on another car, it ran perfectly under 4 k but it just lost power at higher rpm. Never got it higher than maybe 4200 rpm. It turned out the cat was ruined, and actually had burnt down to a golf ball sized piece, that in its turn got stuck further down in the exhaust blocking the flow.

Then I have had the clogged fuel tank screen on a 3.0 SC, but that had other symptoms. It would rev normal on low gears the first time I hammered the throttle, since it had fuel pressure. But on higher gears when it takes more time to spin up the revs, it lost power. Difference is that I actually would get to the redline, but it took more time.

Then I have had intermittent WOT switch failure on a 3.2, which I never diagnosed fully. Strange feeling when it sometimes lacked maybe 20 hp. But it wasnt too noticable, to be honest.


Regards,

Johan

I had what sounds similar to this when I first bought the car years ago, turned out to be the #3 cyl head temp. sensor