engine cut out PLEASE HELP

[x-90240sx]

hey everyone im a constant viewer on this forum but dont post really at all......heres my problem

i performed a motor swap on a 89 240sx acctually just a replacement motor, 89 automatic 240sx was failing emissions so i swapped in a 1990 automatic with 96k miles on it now when i rev the motor it wont go above 2500 rpms its like its got another limiter at that rpm stage, its wierd but i dont een know where to start, also the engine wants to die when i come to a stop, i believe thats just some sort of vaccum leak and i can work that problem out but is there a way to check the codes or something, PLEASE HELP anyone who can point me in the rite direction,

thanks Jon

[navysnail]

checking codes is very easy on the obdI ecu. there is a how-to on 240sx.org, ill link to it when i find it.

[navysnail]

here it is, it is the same for 89 and 90

http://www.240sx.org/faq/articles/ecmcodes.htm

[DrIfT_FoReVeR]

dont mean to hijack, but whats the diff between obdI and obdII?

is obdI the SOHC and obdII the DOHC

[navysnail]

nope, obdII is the new engine management that also monitors things like proper operation of the cat and other things. obdI may say running rich, while obdII will say, misfire on number 3 cylinder. obdII requires a special scan tool, and obdI can often be read right on the side of the ecu (as well as read on a scaner)

edit: obdII is also required on all cars 96 and up as part of emmisions regulation

[DrIfT_FoReVeR]

k thanks, just wondering, i was always confused...thanks for clarifying

[NISTECH]

kid not true about obd II requiring a special scanner you can still pull codes the oldfashion way with the screw in the ecm,at least on nissans untill around 02 the screw is being omitted though from the ecms now.

[x-90240sx]

bump

[NISTECH]

did you check codes yet?

[Magnes]

From the FSM:

"When the MAF output voltage is outside spec, the TPS sensor is substituted to give the ECU an approximation of air flow volume.

It is possible to drive vehicle but engine speed will not rise above 2400 RPM in order to inform the driver of fail-safe operation while driving."

Make sure the MAF is getting clean airflow, and that the connector is solid. There are 3 pins in the MAF connector you can test.

The pin on the driver's side (pin A) should read between 1.0-3.0 V, engine running, depending on throttle opening.

The pin on the passenger side (pin C) should read battery voltage at the harness connector (disconnected, key ON).

The middle pin (pin B) should read 0 resistance between the MAF side connector and ground.

EDIT: If you get code 12 from your ECU that's the MAF error code

[S13ChucKAT]

yea.. your maf is shot/bad..

[x-90240sx]

thanks guys you all are such a huge help, you guys and club4ag are the friendliest and most informative forums i have visited recently....thanksJon