Fuel cut?!!!!

[dnbwithweed]

hey guys i just recently purchased a 89 240sx and it was runnin pretty bad when i got it. the car needed spark plugs and new wires. i gave it an oil change and it passed smog with no problem. but there is one issue with the car and that is when i give the car full throttle it instantly loses power. It mostly happens when im crusing in 4th and 5th gears. When i take it out of gear and put it back into gear i get throttle control back. my friend told me it might be a fuel cut of some sort...hes having the same trouble. does anyone know whatthis is or how to fix it. I did a search but it wont work...help?

['90RPS13]

DUDE, I JUST HAD THE SAME PROBLEM ON MY SOHC. PARK IT ASAP.

I replaced my Plugs and Wires, fresh rebuilt head, new oil and everything. All of sudden it ran fine and then like you said, I would be cruising around 4,500rpms in 4th and 5th and instant loss until I switched to a lower gear and then geared back up. Tonight I was driving mine, then all of a sudden it become apparent in every gear and then power loss was tremendous. Ended up getting to the point I would floor it and it went no higher then 2k rpms. Engine shook terribly and got out to find out I threw a rod. Checked my oil and still full. So I think its a clogged strainer or lack of oil making it inside the motor. I have to take it apart to find out more.

My advise would be park it until you find out whats up so you arent in the same boat as me. *a

[dnbwithweed]

ic....so it cuts out when it thinks there isnt enuff oil? damn..i need more info does anyone know more?this is my only car and daily driver i cant park it! HELP!

[Ruby240]

MAF.

If you throw a rod, you put a hole in your block and oil goes all over the road.

[Wykydtron]

Uh guys, please realize we are dealing with a SOHC... these things happen, this happened to me too!!!!!! PARK IT!

Maybe it's me, but lets say it happens now and then. Look for a DOHC engine... I sorry to rag on the KA24e faithfuls, but this is why I went dual cam.

:(

['90RPS13]

Same reason I am going DOHC again too. *a

P.S. Ruby240, I already tried the maf swap before it blew. No luck.

[tiresmokes13]

check your fuel pumps. Might be going out.

[Ruby240]

Uhm, I've been around cars a very long time, even blew up a DE in my 240. When a rod knocks, YOU HEAR IT. It sounds like a little man with a big hammer trying to get out of your engine.

'90 did you even tear down the engine that you "blew" to see what exactly happened? You are having a loss of power, when a rod knocks you don't really loose power, the noise just gets louder and then it stops and your engine stops.

It does sound like either a fuel issue with the pump, or a MAF (oh guess what you can get BAD ones, even brand new!).

Don't go apeshit and think your engine is blown before you check out the easier and more obvious possible problems. 3 main things cause loss of power:

1 MAF = bad
2 Fuel pump = dead
3 Clogged Catalyic Converter = stumbling and really really shitty power to none.

Then you have others:

Spark Plugs fouled out
Spark Plug wire fried
Coil Fried
Injector(s) clogged
Charge piping loose and not connected fully
Clogged Fuel line
Clogged Fuel Filter

These are all things I would definatly check way before I decided the engine was blown. Trust me, if you had a rod knocking or a bearing going out, you will know it by the noise. If you hear metal to metal grinding or knocking, then your engine has serious internal problems.

Oh and FWIW, if you don't have enough oil, your oil dummy light will come on (there is an oil level sensor at least there should be, in almost every car that has been produced since the 60's). And just because you don't have enough oil in the car, it will NOT cause your car to loose power, you just won't have any oil pressure.

[VRTMiKe]

it could be the harness. I've been having similar symptoms. my sohc was running really ruff, i pulled over and popped the hood. turned out to be the harness connecting to the maf and the injectors. i wiggled the wires and the car started to run better.

[Skullavera]

i wiggled the wires and the car started to run better.

Are you serious? :tweak: That should be a signal to you to fix your harness not a solution you give somebody else!

[VRTMiKe]

Are you serious? That should be a signal to you to fix your harness not a solution you give somebody else!

Yeah, no shite! i was just giving him another possibility for cause of his problem.
I already have a replacement harness to fix my problem. why are you even posting if you arn't even helping. I dont see you trying to help this guy figure out what his problem might be.

[zackt69]

Mine does the same thing... only in 4th and 5th over around 3500 rpms. Been happening for a few weeks now. Had it at drift buffet this past weekend and it was giving me no problems in 1st, or 2nd - ran like a champ all day and even on the drive home. I'll have to check all the things mentioned above, because when it cuts off on the freeway it's a bit scary!

[dnbwithweed]

ok well i know its not my maf harness...but my other buddy had that problem lol...i think its my speed sensor or something...cuz i know my cluster works except the speedo. so im guessing speed sensor? who knows...time for a dohc swap....