starting issues!!!

[oung]

alright guys i need ur help with my issue here....my brother just bought a 92 240sx FB, thing is this car has a real issue starting...it turns it just wont start....its fuel infected but if i pump the gas while trying to start it, it takes a little while and then it starts....but it also has a hard time staying on if i drive it a bit, the RPM needle will drop down to zero and sometimes it will come back up to idle position and at times it will kill the car......i've changed the fuel filter, fuel pump, spark plugs, spark plug wires, distributor cap and rotor, im running out of ideas here....last options are fuel injectors, but i unplugged each fuel injector and they each had an effect to where the car was sputtering so i was figuring the fuel injectors were still good....could i be wrong? and i havent swapped out the MAF sensor yet off the intake...i didnt think it would be the issue but i'll be trying that tomorrow....has anyone had this issue before?? please i need ur help!! also....my coolant temp is running on the Hot side.....i've filled it up with coolant full but it still runs up that way...i just changed the water pump on this car because it was bad....but still running to H side....any ideas?

[Z U L8R]

do a compression test A. so you know how strong the motor is, B. to know whether or not the headgasket blew when the water pump failed, thus causing your coolant consumption.

low compression will make the car not want to hold idle, and if it's a small headgasket sealing issue causing this low compression, then it will most likely get worse as the motor heats up and everything expands.

which will take you to your next step.

if the compression is bad, then game over, you know what it needs, repair it and be done

if the compression is good, then you know the compression is good and it's worth deducing then addressing each problem.

the next thing i would do if the compression is good would be to pressure test the cooling system and identify where the coolant is going, then fix that leak/problem.

next i would move on to the drivability idle problem by cleaning the throttle body and iac, smoke testing for any vacuum leaks, then probably replacing the coolant temperature sensor (the 2 wire one for the ecu, not the single wire sending unit the guage uses) and if that didn't remedy it, i'd do the oxygen sensor also.

at that point every sensor that could dictate fuel trim has been replaced aside from the maf which this doesn't sound like a maf problem.

anyways do the compression test and go from there.

Dave

[oung]

will any of these throw a check engine light code? my CEL doesnt come on for the IAC or anything....

[LONELY RIDER]

clean your maf with maf cleaner.
try replacing o2 sensor
jack up front of car and bleed the colant, my b thermostat isnt opening up all the way

maf and o2 might help with the idling ou
bleeding might help with running hot