Ok before i was wondering about the fuel cut off in 4th gear…and something weird happened. 2 weeks ago on the highway i hit the fuel cutoff in 4th gear…my car was done for a week because of repairs and now i dont hit the fuel cut off i go right up to 5600rpm before i switch…i know its good for me but any ideas as to how it just randomly started doing this?
I’ve never had a fuel cutoff in 4th gear…
this belongs in technical, and what kind of repairs were done?
oh it was just a gas tank replaced…sorry about not putting it in technical im a tard
Moved.
So we need more details about what was happening and what doesn’t happen now. I doubt changing the gas tank would have affected it though.
maybe your 4th gear sensor got damaged so now you don’t have fuel cut off in 4th.
I have it in my winter beater.
The Sock on the Pump is stupid durty and can’t supply the proper
amount of Fuel and Fuel Pressure that WOT in 4th Requires.
Maybe when you got the tank changed they put on a new Sock?
I have never heard of a 240 that has fuel cut off below 180km/h unless there is a peoblem with the fuel system (like Adam said). If it is cutting out at or around 6000rpm then it is the rev limiter which is cuting off your timeing and not the fuel.
maybe it was the sock i dont know…i dont think that the repair of the tank has much to do with it but maybe it does…but thanks for ur thoughts its much appreciated 
Well if you had the fuel cutout before you replaced the tank, then after you didn’t they must have done something.
Mechanically there is no fuel cutout in 4th gear as far as I know, as canadiandrifter240sx stated.
Anyways if it’s all good now, then I wouldn’t worry about it too much.
Yeah … definitely a fuel supply problem.
If your tank was rusty, odds are the connectors to the fuel pump were too.
or there was just a ton of rust chunks plugging the sock.
The pump was probably not operating 100% and was just not able to keep up the supply.
My 12 did this when the fuel pump started dying. It would just eventually run out of fuel, especially doing hard 1 through 4th runs. Once you shifted gears, it gave enough time for the weak pump to get the pressure back up.
But then it started doing it in all gears, anything WOT.
But yeah, it’s gone away now, so you’re probably in the clear.
Chris Nissans Utilize Fuel Cut when Hitting the Revlimiter not Spark Cut.
Ok, let’s get something straight here…
This “fuel cut”, what happens when it cuts?
If the motor seems to ‘quit’ for about 3 seconds, it is your speed limiter, which would not happen in 4th gear [unless you have messed with your drive ratios, your 4th will top out (hit the REV limiter) at about 170-173 km/h].
If the motor just seems to “bounce” at about 7250 rpm, that is your REV limiter, but you said it happens at 5600, so…?
BTW, this IS a 5 speed right?
ok its not at 5600 rpm it cuts its at 5000 rpm it would cut out…my brother was in the car numerous times with me when it would cut out, and same with my friend mark, it is a 5 speed, but i have read on club240.com that there is a 4th gear fuel cut off but it seams to differ from person to person…what i think is that before the fuel was all messed up and everything like mr200 said…also before i got the tank fixed, i was on the highway and the fuel would just randomly cut out…but i guess it doesnt have revelance now because i havent hit it in over a week and the cars 100% now…no need to ponder anymore unless it happens again…thanks for all the inquiry
I said 5600rpm rev limit thinking it was a SOHC and i was giving a little tolorance for fualty tach if he had 1.
Adam i find that hard to balieve…but i would be interested in reading some literature on it if you can tell me where i might find.
Hop in a 240sx with a stock ECU and rev it up to revlimit.
Listen to the sound…
It’s Fuel Cut, Spark Clut Sounds Totally Different.
To Check what Spark Cut Sounds like, Gap the Plugs to 2mm and revit to 6000rpm…
I think I have the same problem. It cuts off fuel on 4th around 5000 rpm and 3500 on 5th. When I rev up on 5th just reach 3500 and it cuts off the fuel, can’t do anything until it drops down to 3000, then I could rev it up again. I’m not sure this the fuel problem or somthing electrical. My speedo doesn’t work probably, it comes on and off all the time. I’m thinking might be the speed sensor causes that.
as decster620 said he is having the same problem…well mines back but now it seams to be worse…now in third at 5400 rpm my fuel cuts out untill about 3600rpm…my speedo doesnt work properly either sometimes it does work sometimes it doesnt…but even when its working the fuel still seams to cut out…it bothers me just in case i race some1 the fuel is going to cut out and im going to loose 
ok well i finally figured out about this whole stupid fuel cut off thingy…just like decster was having problems with his speedo i figured out that on my car when the speedo is acting up and isnt reading how fast i am going the fuel randomly cuts out in 5th at 5000rpm in fourth and at 5400 rpm in 3rd and 5700 in 2nd sometimes…therefor a broken speedo equals crappy performance because the ecu cant read it properly i am guessing so it cuts out to try to be a good thing
Damn, too late.
I just read a bit article on installing KAs in old Dattos.
And yeah, you guys figured it out. The Datsun guys refer to it as Nissan’s booby trap.
http://fiveoneoh.com/tech/ka24wiring.html
they also list some really good info on KAE to DE differences, as well as SR.
But yeah, this “fuel cut” issue, this is what they had to say
*** Speed Sensor issues… Nissan ECCS systems have a booby trap built into them. Basically if the ecu does not get a signal from the Vehicle Speed Sensor it can
cause some erratic behavior. Usually the symptom is the engine cutting out at 4500 or so RPM. And then not coming back on again until you get below 2000 or so rpm.
However this problem really only has been reported and persists with KA24e’s. KA24DE’s and SR20det’s seem to run okay without the VSS connected, although some minor strange mishaps have been reported. To fix the issue you can do two things. One is to connect the VSS. This requires wiring the VSS from the transmission to the matching S13 chassis speedometer, wiring in the speedometer so it works, and then wiring the speedometer to the ecu. The ecu VSS wire is the yellow green
wire on the dash connector. The ecu needs the speedometer in between it and the VSS for the circuit to work properly. The other fix is to have the ecu reprogrammed by
a company like Jim Wolf Technolgy. They can remove the speed sensor circuit completely.