KA24E 4th and 5th limiting out??

[Menteith]

When the car get's up to about 4,100 RPM in 4th and about 3,500 RPM in 5th it's literally cutting the gas, or cutting the spark or both. The car just stops all throttle response. It just stops the engine from any further acceleration even if I try to stomp on it, nothing. It's not abrupt feeling or anything, it's just an instantaneous halt and the car slows down as though I had suddenly just taken my foot off the gas and let it coast.

If I change gears then everything goes back to normal...drives fine and everything...but as soon as it gets back up to either about 4,100 RPM in 4th or about 3,500 RPM in 5th, boom, stops and start to decelerate.

...any ideas?

No engine codes, car is an S12 with a SOHC KA24E in it.

1st, 2nd and 3rd are all perfectly fine. It's only 4th at about 4,100 RPM and 5th at about 3,500 RPM.

It feels exactly as if you were to suddenly from accelerating to take your foot right off the gas pedal all together and to let the car glide its way down.

...as soon as this happens the car does not respond to any throttle.

Any ideas? Any safety features on the KA24E that could be causing this?

[soreballz]

^Unplug the 4th and 5th gear sensors on the trans. Problem solved.

[charlie321]

i remember cutting one of the wires on the speed sensor and i couldn't go past 75 in 5th, check out those wires that soreballz mentioned.

[Menteith]

The 4th and 5th gear wires are not connected. The transmission is The S12 transmission. The bellhousing is the KA24E bellhousing.

[Menteith]

EDIT: It's not simply 4th and 5th...I just realized that it is also 3rd at about 5,200 RPM as well...

...so, all times the car is under it's heaviest load.

[soreballz]

MAF issue, perhaps? Those usually cut power around 3k rpms, though...

[Infamax]

Does your speedometer work?

I'm pretty sure you need the corresponding speed sensor that goes to your ecu. Since you're using the s12 tranny with the s13 bellhousing, you're still running the s12 speed sensor(i'm assuming). Swap the s12 speed sensor for an s13 sohc speed sensor.

[I LUV MY S13]

swap the ecu..worked for me

[speedfreak90]

im having the same problem. with mine to the T. i have a 90 that had a s14 tranny in it before i got it. but my friend who owned the car be fore me said he never had that problem.?? and if you swapped ecu's wich one did you swap it with???