thekage

I bought a new 240sx las week. 121k on the KA. It idles really rough at around 500rpm.. kinda low. And every once in a while I have to pump the gas when cranking to get it to start. Planned for this weekend is an oil change and new spark plugs. Anything else off the bat I should think about with this engine? Clean this? Change that? kind of things?

Also when Accelerating.. it is really sluggish until I hit 1,000 rpms then it sreams. Any ideas?

Adixion

Well if the spark plugs havent been changed ever than yes do it by all means and the oil change it will be good for the car but it isnt goin to make a difference. Ur 240 idleing at 500rpm is fine although mine idles at 600rpm but it shouldnt matter..... Just in case you could check the timing in case it had been tampered with before you got the car. But if the timing is fine who knows the engine could be beatin from past drivers but doubtfull because KA's can take a beating. Try checking the injecters they could be corroded or clogged. If you run the cheapest gas you can find that could be part of the problem because it could be alcohol based gas which isnt worth it. I stick to Cheveron and Shell two good gas stations not alcohol based. But yeah try running better gas and try some fuel injecter cleaner and just for safes check your timing. Just hope its not a blown head gasket because all cars run sluggish and ****ty with a blown head gasket although it is doubtfull that that is the problem because you would know it would run REEEEAAALLLLYYY ****ty.

re037

fsm says idle should be aroun 750rpm +/- 50 rpm
but yeah check timing and adjust idle control screw. make sure to disconnetc tps before changing timing or idle. factory setting should be 15 btdc. clean the maf with alcohol, see if that helps (be carefulw ith the filament). also check injectors like what he said. if it aint clicking you have a dud also if you unplug one and see no change in idle roughness you found your dud. thats all i can think of for now. good luck.

if youre lazy/dont have time take it in, save yourself some headaches and get a diagnostic only (if you have a friend thats a mechanic, even better ). see what the guy says about it then go for the diy work.

BigVinnie

iTrader: (2)

New spark plug wire's, new plugs, new distributor cap, 91 octane,
I would also get some fuel injector cleaner. Low idle and sluggishness can happened from clogged injectors.
Other than that run a ecu diagnostic and see if any codes pop up.
That idle could be happening for several reasons.

tryiian

another thing, all engines accelerate poorly below 1000 rpm unless they`re in first gear, and unless you`re in first gear you`re probably doing damage to your car by trying to accelerate from that low, downshift!

When I started driving I thought that I could save gas by shifting up as early as possible and that pressing the pedal in farther in a higher gear would give me better mileage. I ignored the fact that the car felt horrible as it was accelerating.

The truth is, the two things that affect your mileage that you can control at pretty much all times are 1. how far in the pedal is, this controls how much fuel is being given to the engine so think about it. and 2. how many RPMs the engine is turning, thus using more gas per second versus a lower RPM.

You might think that running the lowest rpm possible will always save you gas ( like I did once) but if you have to press the pedal down farther than you would in a lower gear to accelerate, you should probably downshift to get to where you want to be. If you`re going to be doing any accelerating or hill climbing and the car doesn`t start changing speed as soon as you push your foot down, you should change gears until that does happen. In short, don`t run your car in too high a gear, if the rpms get below 1500, downshift!

thekage

its an auto tryiian

miked808

First off check Compression because if thats bad no use spending money on maintainence issues. If Compression is in tolerences pull your entire Intake track off and clean all Intake Pipes and Throttle Body with Intake Cleaner. Then get a 300zx Fuel Filter, 121k is a lot of miles. If the Intake Filter is acceptable check inside the Intake Resonator Box because Iv'e seen some wierd stuff in there Blocking Airflow. Pull the PCV Valve and clean. Finally clean the Vacumn and Fuel Injection system with Seafoam and BG 44K.