new idea about problem

[ShifDown96240SE]

most of you all know about the stupid problem i have with my engine not running. It was a 92/93 KA with the head ported out all the way to match the big porting job done to the intake manifold(which do match perfectly) and it has a 3 angle valve job.

Now Im thinking that when i switch the 96 manifold over to the 93 block and head, so that the sensors will be read correctly by the OBD2 computer that i have in my 96, that the stock intake manifold ports arent matching(which they dont, the intake manifold holes are really small compared to the heads').\

would this cause the engine to run all weird??

and im looking into the 5th gear sensor/switch to see if the car thinks it is in 5th all the time cause the car freakin cuts out dead at 5000 rpms, and its slow and kinda pinging/raspy all the way to that new redline it has created. between 4-5K it starts to pull.

But im thinking that if i put the old manifold on(OBD1) and switch to a obd1 ECU that it will read the cams the sensors, everything like stock, then i just have to fine tune it. The heads are both really different than each other, even the valve covers arent the same, but the cams will swap back and fourth easily enough.ORION...anythjing you can think of????

[Structure240sx]

the port sizes wont make a difference in how it runs. thats just the air getting in and out smoother, maybe.

are you turbo?

i belive the only reason for a 5th gear sensor is for a speed cut at 115mph ish. no reason why it would cut at 5k rpms. if your turbo maybe your spark is blowing out. and if its not pulling til 4-5k there could be a bad exhuast leak which would also cause the rasyness.

i could help more if i knew more about your car/setup

[:: orion ::]

ShiftDown -

I said this in the other post about this problem...the ECU could care less what cams are in the motor.

And OBD doesn't matter...I have run a '95, 96, and '98 ECU in my '96 car...with S13 cams, S14 cams, and JWT cams. They all made the car start and go fast, some better than other...but never the problems you're having.

And other than the valve cover and cams, the heads are basically IDENTICAL.

I'd wager that your timing (either cam timing or ignition timing) is way off, and the 5th gear switch is messing things up.

You can unplug the 5th gear switch, with no ill effects other than a CEL and the cruise control will be disabled.

Then check ignition timing, and maybe a compression test. If the cams are way off, you'll have bad compression...

Good luck.

- - - - -

Structure - The backup speed limiter on an S14 is a 5000rpm rev limit in 5th gear only...

- Brian

[ShifDown96240SE]

thanks alot, i know i have to do something about the 5th gear switch, so i'll try that and screw with the overall timing on everything. BTW: what color cam is which?? I have green and brown(from the 93), and i am probably going to just rebuild the engine again with a forged bottom end, etc in about a week or so. thanks alot again, ill do what i can and post the results later.....