fuel cut/what feels to be a speed gov.?

[Vegascorbin]

Do you knoe the RPM you were at when it cut at 75MPH?

And when you put the car on jackstands and run it through the gears it DOES NOT cut out? Am I correct to say that the regular Rev Limitter DOES kick in at around 6500?

It has to do with the ECU determing that the car is under Load and having to make active corrections to the Fuel rather than looking at a predetermined fuel map.

The $64,000 question is what has changed from original as these cars were able to run with "active" fule when new.

[bikerskater]

alright so im pretty sure its a grounding problem but just some info i got a new hatch with a sohc and its weird it doesnt do the same thing its rev limiter is set at 5400 which really sucks while drifting.

i tried a new ecu still did the same thing :/

[Southerngentleman]

Do you knoe the RPM you were at when it cut at 75MPH?

approx.. 3400rpm in 5th, 4200 in 4th, 5k in 3rd

And when you put the car on jackstands and run it through the gears it DOES NOT cut out?

Correct, I can max out in all gears.

Am I correct to say that the regular Rev Limitter DOES kick in at around 6500?

Yes, which lets the car still be fun/safe in 1st and 2nd

It has to do with the ECU determing that the car is under Load and having to make active corrections to the Fuel rather than looking at a predetermined fuel map.

The $64,000 question is what has changed from original as these cars were able to run with "active" fule when new.

[Southerngentleman]

evey time I drive and it hits that "speed wall" I feel like the car is in "teenager mode" its kinda funny. just gotta find the adult/teen switch. lollike the new Suzuki Hayabusa, A,B,C,

[Southerngentleman]

so what is the fix???? someones gotta know...

[Vegascorbin]

I agree that someone, someplace knows what to do for a fix. Unfotunitly no one has posted it yet. My best guess is that it is an electrical problem of some type. I don't think it is a ground issue (even though that is extreamly important) I think it is more a sensor is not getting the proper voltage at the proper time. the why is the big question.

I have been busy working in the Tow vechicle (Dodge Ram 1500 quad cab Long bed)and not our race car (the 240) for the past couple weeks.

I will get back to work on the car this week and let you know what we find.

[ShaunakaRichard]

Just out of curiosity have you guys checked your fuel filters and etc? I ran into a clogged filter and it was acting like a limiter. Obviously the higher the RPM the more fuel your using and once I hit the point where it wasn't getting enough fuel to keep up it'd obviously back down. And it'd vary from gear to gear at which RPM it would happen. I know in the original post the guy was saying it'd mostly start happening when he would floor it, which is obviously going to be wanting a lot more fuel. Once I changed my filter, everything was golden. Just a thought.

[bikerskater]

update: i got the head gasket blew in my new car so i put in a new sohc kept the same ecu and everything and it now had no rev limiter and would rev to 7500 but would just die until 3k again and would kinda do the whole 3rd-5th limit thingy but now in 5th if i held the peddle down it would cut in and out then stay on until 6500.

so i tried the new ecu the guy gave me with the motor and now it had a rev limiter at 7500 but it would rev and limit not die and i also did 140 in the car and no speed limiter so iono.

the solution:

1. check your grounds and also if they are fine add a couple more never hurts 2.if you have a another ecu try it and if you can get an auto ecu get it

[MoldyOldy240]

I'm having the same problem, here is my thread:

zer...n-5th

[Vegascorbin]

No disrespect but your problem is differant. You are reporting a shake while the problem we are having is the engine totaly cutting out as if the key is turned off untill the rpms drop below 3000.

In your case it think the injector leak code is the key. The frustrating thing with our problem is that we have no codes.

[MoldyOldy240]

Vegascorbin - No problem (you'll have to forgive me, I read this thread during a 20 hour shift lol).

Good luck with that gang; I have no idea why that would be happening =(

[Southerngentleman]

SOLVED!!!!!!!! No more fuel cut!!!! replaced speedo cluster, found one right on this forum in the classifeds. plugged it in when for a test run OOOOOH YEAH !!! Thats more like what a 240SX should do. Hit 115mph in 4th!!!!! NO Prob. thanks guys

[bikerskater]

that sounds like it would work for some cars but not at all?

[Vegascorbin]

Solved 2In our case it was a combination of Bad wiring and ECU. End up it runs perfect wihout a speed cluster installed.

[nickshades]

my problem is similar in that if I hold down on the gas it will rev to about 6500 rpms and remain at that for a bit the cuts. It will cut back down to 0 (while my foot is still on the gas) and then shoot back up to 6500 again. Could this be the ECU that needs replacement. I know the egr valve is not connected since i'm using this car for autocross, but the leads have been hosed off. any help would be appreciated.

Thanks,

[tyrodtom]

Your problem sounds similiar to the problem I had a few months ago with my circle track 90 240SX. It would go about 1/2 way down the straightaway , cut out to nothing, then come back on fully on turn exit.This was in 3rd gear. When i'd put it in 4th the intervals were longer, but just as completely on or off. Like something in the ECU was heating up, but it'd only do this on full throttle. I cured it with a good ECU, the car has got every pole, and won 5 races since I replaced the ECU.

[bikerskater]

update: i think some of the problem comes from the trannys because me and my friend did a transmission swap and he swapped it with the transmission that was in my hatch which had the 5500 rev limiter and now his car does it also and he has a 95 s14

[project blackout]

if your speedo dies and then the problems pops up with the "fuel cut" then just replace the speedo. i had the same problem with mine. so im taken out the speedo from my first s13 and putting it in the new one. theres no reason why that wouldnt fix the cut out problem.

[bikerskater]

so get this i had a hatch that had this problem did a motor swap it stopped but i put in a new transmission with is and my friend used that transmission in his s14 but he doesnt have the fuel sort of thing he actually has a 5500rpm rev limiter in every gear so im thinking it may have been the trannys?

[project blackout]

ok so i had a 89 s13 that got ran over by a jacka$$ in a 4 door chevy pick up, so i took the speedo and the speed sensor out of that and put it in my new 89 s13 and it fixed my fuel cut, dash lights and heads up. the only thing i can think is that it has to show the speed along with a good working speed sensor for the ecu to get a good reading and work right. i hope this helps everyone else. it seems like no matter what everyone had a fuel cut and no speedo. i think i have a extra heads up if someone needs it, holla at me.

[bikerskater]

ok so i had a 89 s13 that got ran over by a jacka$$ in a 4 door chevy pick up, so i took the speedo and the speed sensor out of that and put it in my new 89 s13 and it fixed my fuel cut, dash lights and heads up. the only thing i can think is that it has to show the speed along with a good working speed sensor for the ecu to get a good reading and work right. i hope this helps everyone else. it seems like no matter what everyone had a fuel cut and no speedo. i think i have a extra heads up if someone needs it, holla at me.

my friend with the s14 is stupid even after i told him not to change the speed sensor from his s14 transmission cause it wont work he preceded to do it and in turn has no speedo also

[ray666]

hey guys i'm having the same problem with my car. i got an sr swapped in recently and just when i'm about to get to full boost it hits a "wall" at 4000rpms. it sputters which is weird. i know i'm getting enough fuel. i don't know where to start other than check my vac lines and intercooler piping for leaks

[bikerskater]

check for a boost leak and or you maybe boosting to high for your fuel to keep up did you put walboro in?

[StonedRhyder]

Did anyone find a solution for the cat randomly cutting out, besides totaling it? Have same issues with a dual cam ka. Just replaced fuel sending unit without luck