Running on 2 cylinders intermittently

[madmeg323]

Thursday ran alot around town...car runs fine. Got home left again car runs fine... go to leave again...car runs like its only on 2 cyclinders. Bad plug?? replaced a 4...same problem...bad wire, replaced all 4....same problem. Bad fuel filter!!! ok thats a streach but hey..replaced it, still same problem.

Cranked the mighty 2 cyclnder up and preformed injector test, diconnected each one and problem got worse..so injectors are good. Did the same with with the new wires and plugs..and after a good shock even the coil. Took time to think...drinks some beer....S E A R C H E D NICO.. drank some more beer. After about an hour I went to try it again and

wait for it..........Holy sh*t no problem at all.

So today going for lunch, 240sx monkey comes back to visit.. same problem.

Got pissed red lined it and it ran great after that all the way home ...not a problem one.

Now when I replaced the fuel filter there was no spraing of fuel like I thought there would be. Isnt the line supposed to have like 35psi??? Because If I have a fuel pump cutting out intermittingley it would cause the massive 2 cylcender to come back to life, Right!

Any help is greatly appercated....And I know I cannot spell.

Thanks
Modified by madmeg323 at 9:02 PM 6/24/2008

[dustbunny690]

Fuel pump strainer maybe? I don't know if 240's have them or not, but I've run into flow issues before that sound like what you're experiencing. If there's something (dirt, sediment, ping-pong ball) in the tank that gets sucked up into the strainer, it slows flow, bogs down the engine, falls back out, & repeats. I haven't taken my fuel pump out so I don't know how hard it is, but it may be worth checking.

[silvia_ks_69]

yeah man could be dirt and **** sucked up from being too low on the tank. have had that on my dd but never on the silvia (always keep it fullish) might need to get some injector or fuel system cleaner i dunno. hopefully it goes away

[mattblancarte]

I may be way off, but it sounds like an electrical gremlin. I had similar problems with my integra, and it ended up being the main relay.

[pntang]

run seafoam...through everything!!! then come back and maybe we'll start with the diagnostic

[VP4prez]

I may be way off, but it sounds like an electrical gremlin. I had similar problems with my integra, and it ended up being the main relay.

check all your connections involving drivetrain and engine management under the hood. make sure no wires have chaffed themselves to an intermitant ground. my supra had this same problem and not only did the cps main wire light off on the inner fender, the cps contact were also jacked. 2 birds with one stone. it dont really sound like a fuel delivery issue though bro. fuel pumps either work or they dont. on or off. and btw, if the car sits a while, the pressure will blead off teh fuel system. thats what charcoal canisters and evap systems and things like that are for.

[dustbunny690]

While the fuel pump may be fine, it could be a problem before the fuel pump, ie the strainer. Again, I don't know for sure if there is one on 240s. A slightly older Ford pump I worked on had a 3in hose between the pump & the hard line, inside the tank, that rotten through. I didn't find that until I pulled the pump. Just my 2 cents.

EDIT: did you check fuel pressure?

[madmeg323]

While the fuel pump may be fine, it could be a problem before the fuel pump, ie the strainer. Again, I don't know for sure if there is one on 240s. A slightly older Ford pump I worked on had a 3in hose between the pump & the hard line, inside the tank, that rotten through. I didn't find that until I pulled the pump. Just my 2 cents.

EDIT: did you check fuel pressure?

what is the proper fuel pressure?

[dustbunny690]

According to the FSM (EC-24) it primes at 43 psi, at idle it should be 34 psi. If its not acting up at the time, though, it might not do any good. Intermittent troubles suck. Are your battery terminal connections good?

[VP4prez]

According to the FSM (EC-24) it primes at 43 psi, at idle it should be 34 psi. If its not acting up at the time, though, it might not do any good. Intermittent troubles suck. Are your battery terminal connections good?

battery cable connections dont mean anything in the short term on obd1 cars. u cant still unplug them and the car will run fine. unless you do it for a long time, then the alt is gone.

[dustbunny690]

Sort of. I was thinking bad ground/intermittent spark maybe? Trying easy fixes first.

[VP4prez]

check all your connections involving drivetrain and engine management under the hood. make sure no wires have chaffed themselves to an intermitant ground. my supra had this same problem and not only did the cps main wire light off on the inner fender, the cps contact were also jacked. 2 birds with one stone. it dont really sound like a fuel delivery issue though bro. fuel pumps either work or they dont. on or off. and btw, if the car sits a while, the pressure will blead off teh fuel system. thats what charcoal canisters and evap systems and things like that are for.

just re itterating this point here. im almost positive youll finder ur problem this way

[markex33]

first of all i'm assuming your running KA,if its so,I had a problem like that not too long ago,found out the wiring harness was bad because the motor mounts were bad as well.You may think whats got to do with anything.the motor was rocking back and forth and it was pulling the wiring harness.to check that just wiggle the harness right betwen the engine and the firewall,see if it makes any diference

[statickx991]

i had a problem just like this with my s13 wit a sr in it, i had to take out pin by pin in the ecu plug and there is a little flap inside each pin that i pressed back down again cause they wernt getting a good connection, before u do that un mount the ecu and while its running move some wires around and see if it misses then runs good or anything