Okay i recently picked up a 91 240sx & im having a problem getting it running correctly.

Symptoms :
Gauge cluster either sits @ 0 mph or jumps around like a wild child.
Car runs fine till it reaches full operating temp then once it hits 1800-2300rpm's it starts to hesitate/jerks then will clear up.Also Cars CEL pops on when it starts to hesitate/fall on its face.
Car idles poorly.

What iv done:
Changed the plugs
Checked the timing
Gone over the few grounds that i see.
Fresh gas/seafoam


I found a bad engine ground that was nearly cut in half Replaced it the car ran fine for about 4 hours then started acting up again. Could there be another ground somewhere that is faulty or anyone have any other suggestions? Maybe a bad ground to the fuel pump?

Any response is highly appreciated
Thanks James

 

& is there really any way of checking if a ground is bad?

 

Is the cel light still poping up? What codes are showing?

 

it comes on & off. Only comes on in those rpm ranges.
When i checked the ecu for codes the other day it came back code 55 - Other Malfunction. CONSULT Terminal Required & i have no idea what that means.

 

Sounds like 1 of three things. Defective or incorrectly inserted PROM or a defective ECM.

I'm assuming this is a SOHC ???

 

Prom? is that like the lil chip they use when chipping the ecu? & ecm? Ecu? lol
Its a dual cam ka

 

Coolant temp sensor. Or knock sensor, but more likely the temp sensor. As far as your cluster, its gotta be some bad wiring. Check the harness under your pass side fender to see if it got chewed up.

 

thanks man, the car is bone stock but i think the previous owner had suspension on it so could be a possibility.
Like i said when i first fixed the ground the mph worked fine didnt seem very accurate but worked. & then a few hours later just went right back to 0

 

& i hope its not the knock sensor i dont wanna remove the intake mani & shit...looks impossible to get to without doing so.

 

Since you said its related to temp I'd definitely do the temp sensor first (the one for the ecu, red connector, next to your upper water neck). If it is the knock sensor, its not impossible to replace, but if you want you can delete it with a resistor (google it). G/L dude and PM me if you have any questions or anything