Misfiring/Fuel cut? after 5500 rpms.....

[Lopin18]

Ok im cruising, WOT!, revving good but once i hit 5300-5500 rpms it starts misfiring, or fuel cutting dont know, it keeps revving up but misfiring...

i had a fuel pump electrical gremlin, fuel pump wasnt working, so i got my harness checked and fixed and now its all good, but now i have this sputtering misfire thing, someone was running a green cable to my fuel pump... and the electrician removed it when redoing the harness, could it be that my fuel pump is getting less volts or something now?

The car cruises just fine but after 5500 its a mess, how can i track down the problem? the pump was working fine until the gremlin thing... so what now...?

Help Thanks!

[imjoe]

Im havin the same problem and I've heard this before. It always seems to be different things...

[Lopin18]

Well just this morning i turn the car on.... really bad idle, i see to my trunk and i see light smoke.... i notice misfiring and sputtering on idle... so i go check and the Fuel feed hose on the pump is leaking.... yesterday it wasnt leaking so thats my idle problem...

im still yet to find out why im getting fuel cut on high rpms, ill just swap the fuel pump and get a new hose if not, fuel filter.. i hope that solves it.

[Lopin18]

HEEELPPP!!!!

Changed Fuel pump, fuel filter, Fuel lines, no leaks, and still misfiring around 5000 rpms....

Things i noticed:-Fuel pump 15Amp fuse is melting slowly-Key assembly is hot, cables also (I rewired the ignition Red/Black cable that goes to ignition coil, fuel pump fuse, ecu, etc... rewired where it was melting in hope to fix my problem but its still getting hot but not melting like before)-After like 2 hours of cruising the car started shutting down every 15 mins, had to let it cool like 30 secs before he would start again.....

Soooo plz.... any tips?? tomorrow im changing spark plugs, but that fuel pump melting and hot key assembly+cable is still a mistery to me.....

Tips, Help, Guides, plz im really desperate ive tryed a lot of things already :S

[ShaunakaRichard]

Okay for one thing if your fuse is slowly melting, thats not good. I wouldn't continue driving it in that condition. If everything is getting hot then that means that your drawing more amperage than your suppose to. If its getting that hot i'm surprised your fuse hasn't blown, or its melted inside and officially is no longer acting like a fuse. I would normally say that something is shorted out somewhere , but since you did change the fuel pump its doubtful that thats it. It sounds like you've had a lot of people messing around with your wiring which is never good, not knowing what the others have done exactly. Plain and simply if your getting hot something is drawing too much on the system, or your used the wrong gauge wiring. Start by getting yourself an amp meter and see what your fuel pump is drawing and what your ignition is drawing. All your ignition does is activate relays, nothing is directly running off those wires. Did you accidental wire around the relays? Or its possible that you have some shorted out relays somewhere. Without looking at it personally there could be a number of different things wrong.

[Lopin18]

Hmm these things seem complicated... well tomorrow im gonna check all wiring to see if theres something extra connected to any cable, check if some cable is melted etc check everything for splices and extra connections.

I know the alarm is feeding from the key assembly (has for over 1 year doubt its that since... i mean all is going haywire now.....)

Anyways ill get a wiring guy that makes SR20 wirings for 240sx, ill have him check and rewire everything to spec....

changing sparks will prolly be the fix for the misfires... but what intriges me is WHY my car shuted down 3 times after 2 hours of cruising....

Ill check all the damn wiring for damage / splicing.

Thx for the tips man