91 240sx fastback_A/T: Hard starts 400RPM,Bogs & dies,Dies quicker w/gas depress

[240sd]

I have a 1991 240sx fastback, Automatic Transmission w/ 250k miles. She is currently not starting, but she turns over fine. I pulle the ecu code: 34 also='s KNOCK sensor. I reset ecu, and pull the code again. Now its suppose to be cleared as It read code: 55. After it reads 55, I took the key out of the ign....then try to start....Nothing. Same results, she just turns over and no fire. This is the 4th time it has been not starting. 1st, a month ago when the rain first came in. Along with driving with a low gas tank. One morning, I pulled her up to the driveway to load a PC.monitor in the trunk. After quick loading, I went to start her up...CRANK.CRANK.CRANK......-----After many cranks and 1gallon of gasoline added just to elimate the empty tank. Still just only cranks...I kept at it for a half-hour or so....I notice the fuel pump was not priming with the key in the ON position. So I kept turning key on and off. Now with the gas pedal depress a little there seem to be a buzzing sound from engine bay or underneath the vehicle(transmission)??? Soon after the buzzing noise I started cranking with the foot on gas technic *5-10mins**she responded, but it was really hard to start. I had to rev her up while cranking. She basically wanted to die.....

The next evening, same rainy weather. Same result, after a 40min drive. Lounged for 2hrs and when I left my friends house. She just would not start. This time I had at least 1/4 tank of gas. So I end up killing the battery Cranking (long cranks) At this point I added 1gallon of gas, but it was no use even with jump starting with my friends car....((((I have an A/T)) I abandon her for a week, and did some online searching..........1.5hrs , after checking for sparks, -orange/yellow sparks....Plugs seem to be fine. I though I figured her out after unplugging the Battery and stepping on the brakes for 5mins then reconnected the neg-battery connector....FLAMES!!!!!!!she fired right up on the first crank. WOW!!

After that she ran for a 5weeks/ 1300miles. Then last week, again with the low fuel tank when I got home. The next morning, She only cranks..... This time the battery / dis-reconnect did not work...so I pulled out the ECU and tried reseting it that way......Code read #34....I reset it and same results....after #34 and reset then #55..reset. Key out of ignition...Went to start her up====No Cigar...........I gave up....and went to dinner......and 2hrs later....before I went upstairs I jump in her and I notice the fuel pump...Then I knew she was going to Fire.......she bogg and fired up just like the original time it happened.....Rev her up for a 20min drive....parked the next day....I went to return my pops pickup and on the way home I picked up some grocery....30mins later....I came out and start her up. She fired and RPM@ 400max.....Bogging and trying to start.....As soon as I tapped the gas and try to rev her up. She dies automatically.....Doing this for 5mins and then she only cranks now like before......Now when she turns over, it seem the car shakes more roughly........That is where she sits.

Thank you for looking. Someone please help.

My thoughts were that code:#34 knock sensor, = FAIL SAFE MODE?Causing the fuel pump cut out and not allow the engine to fire. Grounding issue?? Distributor/ crk sensor???
Modified by 240sd at 10:30 PM 4/18/2006

[180fan]

The fuel pump not turning on at the "On" position would lead me to believe it's got something to do with the fuel pump. At 250k might just be a good idea to replace it anyway. The knock sensor could also be bad, but I don't believe it'd keep your car from starting up. I'm drawing a blank on the test for the knock sensor as it's been a while for me and it's an expensive sensor. Have you d/led the fsm for it by any chance?

Next thing to do is try to find out where the buzzing is coming from. I'd find that a bit unnerving to say the least.

[sleepyRPS13]

how is the battery?

[240sd]

The battery is brand new.....but I notice the ground to chasis is a bit coroded and could be the cause but I'm clueless....someone help.

On another post, I read that the knock sensor could have lost ground contact. Witch leads me to believe its not the fuel pump and its in fail safe mode, and causing the fuel pump not to function. The sparks are orange/ yellow which could be weak. and the knock senor code retarding the timing could be causing it not to start. Where does the grounding usually get mess up?

I was thinking upon it to start like it has in the pass. Do I have to crank the starter over 50 times in order to dump the error code #34 and then she will fire up? Thanks in advance.......

[NISTECH]

Knock sensor wont cause this.

[240sd]

ecu reads 34, reset and read again=55 equals okay

key out and back in to start the car....crank but no fire....check ecu and it reads 34.....same story over and over...

any help will be greatly appreciated....thanks

[NISTECH]

The code keeps poping up because it is an open circuit. I have covered this extensively more recently in this forum. It will not affect the car starting. 180fan has already stated your likely proplem. Bad fuel pump or poor connection to it.

[240sd]

are you sure it's the fuel pump? I've check the connection in the rear right and seem okay...is there a switch on the rear left hand side....to turn the pump off and on....?

thanks again