WELL NOT REV OVER 5000RPM? HELP KA24E

[casper82]

i just got two 90 240's to replace my s13.5 i crashed. the ka in one will not go over 5000 rpm, i have put new intake,plugs,mass air flow,fuel filter and wires with no change. if i hold down the throttle it will riff up to 5000 then choke to 3000 then back to 5000 over and over. any ideas, i was thinking maybe a clogged exhaust but i dont know. thank you

[casper82]

i still don't know. here's what i have been told to check,

1. ecu(done new one),no change

2. sensor on trans( ? ..not sure on this,because it does this in all gears and in neutral)

3. heads up display( ? .. i don't think this is it,because the car has no power,takes long time to get from gear to gear not like my other 240's

4 exhaust ( maybe blocked)

5 old injectors. ( i guess it could be injectors)

i think its some kind of rev limiter, but in all gears and in neutral....WHY? NONE OF MY OLD 240S HAD THIS

[480sx]

Cam timing?

[casper82]

not sure, i not to sabbie on this, the last two i had niver had anything wrong.

[Firewind]

This is a hard one to test. with out seeing or hearing the problem. However, you may want to see if your cat has become blocked. I busted mine out, but I don't have emissions. Have we verified the timing? May want to barrow some one's timing light. Could be injectors, try to see if there is a place near you that does injector cleaning for can cost about 100 dollars. Another thought would be to check your fuel pressure. Maybe it's starving out because of a bad FPR, or fuel pump that isn't going to last much longer.

[casper82]

i have all the parts off my old 240 ( that ran like a bat outta hell) so ill try to swap injecters and bust out the cat. i have a timing light so ill check that too and see where were at. and swap the fuel pump too.. thanks alot

[casper82]

well its not the exhaust, just took it off .....same thing damn

[casper82]

the distributer is upside down, no.1 is no.4 .....180 out but it still runs,,could this be it

[Vegascorbin]

assumeing this is a Manual trans.

Fix the distributor and if it still does it unplug the 5th gear sensor on the transmission.

There is an addtional rev limiter that is only for when you are in 5th gear. It limits you to about 5k rpm. If your 5th gear sensor is faulty (shorted) your ECU will think it is allways in 5th no matter what gear you are really in.

Check your FSM for which sensor is the correct one. You can run with all sensors unpluged if you wish. Thats how we run our race car all the time.

Try that and let us know.

[casper82]

ok things i have done with no effect

1.new intake and mass air flow

2 new plugs, wires ,coil

3. took off exhaust

4. new fuel filter and fuel lines

5. check the timing.. 20 over tdc

6. unplugged trans sensers..no change still well not go over 5000 rpm

[adrianfromthecastle]

possibly bad mafs, whether it be the pigtail or the sensor itself

[elithe240guy]

coolant temp sensor or o2 or maf.. thats all I got good luck!

[Vegascorbin]

although it could be MAF, generaly if you have a bad MAF you can't rev over 3000.

If my discription of your problem is correct then it is either a bad cluster or ECU.

[casper82]

i have put a new and good( tested ) ecu and mafs in the car already without change..i just dont know anymore

[Vegascorbin]

Have you tried changing the speedo cluster?

[casper82]

not yet, could that really be it...ill try it

[miggs11]

i had this problem and what i found out was that the speed sensor had shorted out and and the pulses were incorrect make\ing the car go into speed cut.

[casper82]

its not the speedo cluster. just put a new one in. same thing

[casper82]

i also unpluged the speed sensor and all other trans sensors

[kennymillsjr]

man i had the exact same prob..does ur tach in ur cluster work??if not CHECK THE WIRES COMIN FROM THE CLUSTER TO THE COMPUTER...its a yellow wire with a red stripe..mine was cut..i hooked it back up and bam it was PERFECT!!

[240dx]

I know you checked the ecu but I had the same problem with my s14. it wouldnt rev past 5500.after lots of testing and some logical thinking It almost has to be the ECU.I bought another stock ecu and it still didnt work.I the borrowed a third ecu from a working s14 friend and it worked.

Try an automatic ECU. they dont have a rev limiter