i have a hesitation problem with my 95 240sx. at first i thought it was because it needed a tune up so i changed wires, spark plugs, cap and rotor, changed oil cooland flush, changed tranny fluid and differential fluid.
Nothing changed. So i started to do my own research and it turns out hesitation is a common problems in 240sxs, after researching I:
cleaned mafs, Checked connectors
changed fuel pump
checked ground( added a gound kit)
checked oxygen sensor by pulling out my ecm.
changed fuel filter

The car idles fine so i discarded vacuum leaks, so the other possibility was that maybe my catalytic converter was clogged, so i pulled it out today only to find out that it is hollow. The problem is that when i accelerate the rpms rise fine untill they hit around the 3k mark and then the car will start to hesitate, the car can rev past 3k but acceleration is really poor so i dont even bother. the engine is a ka24de.. with pacceseter headers, apexi exhaust and injen intake... any help guys..please cuz driving my car is not enjoyable

oh btw i run the codes in my ecu even though i dont have the engine light on and i got a code 41...which is the air intake temperature sensor i believe and after doing my research some users have actually cut it and apperantly is not that important..? please help!

 

any help guys?

 

did the problem start just recently on it's own or was it the result of something you might have done to it? also are there any sounds, smells or anything out of the ordinary taking place as the car accelerates or even at idle?

 

well i used to own a manual civic..and i can tell the difference between the 2....when i bought the car the hesitation was already present but now its more noticeable....as for sound...when the car accelerates it sound as its suckin in air but the car does not pull...could a fan clutch affect acceleration...cuz i read somewhere that the fan should spin freely when the car is off bu mine barely moves...

 

Try running the codes. I bet it will be throwing a knock sensor code.

 

if you are saying its cutting out at 3k bro... thats the maf.. it has a factory set 3k safemode.

try another working maf.. they can look clean, read the right voltage and still be screwed up internally.

 

yea i think i am about to buy a used workin maf....the thing is that i read that when its a maf problem...u usually have bad idle and it wont let u rev past 3k...but i can and the car doesnt do that sputterin sound...is just that my acceleration is so poor after 3k...that i dont even bother pushin the throttle

but yea i ll try with a different maf....any other suggestions.....do u guys know a way to check for vacuum leaks?....besides lookin for cracked hoses?
help guys

 

The 95 Catylitic convertor is actually in the second half of your exhaust manifold... The one at the bottom is a dummy. This still sounds like a fuel issue with the car running fine until 3k, and then slowing down. Have you checked your fuel pressure yet? I forget the exact pressure, but it should be like 40psi or so. I know when my fuel pump was going bad the car would run fine partial throttle, and then die if I hit WOT.

 

i bought the car with headers(pacesster) and exhaust apexi n1...when i took out the thing that looks like a cat is hollow but b3fore dat is a small pipe with a o2 sensor conected and then comes the headers....as for fuel pressure...i changed my fuel pump...but how do i check for pressure..stick a pressure gauge between the fuel filter hoses?....could it be injectors??..clogged?...thanks guys i appreciate it

 

I guess I missed over the fact you have a header... in that case you dont have a cat. Well I've had it happen on 2 cars, and one was fuel filter, and the other was the pump. They sell inline gauges, or you can rig something to get an idea of where you are. I had an old compression tester that I just plugged the line going into the fuel rail. When you cut the ignition to the on position you should see ~40psi. If you dont the pump is your problem, and with that said I ended up just grabbing a walbro 255.

 

but i just changed my pump to a walbro 255

 

Well have you run the codes at all yet?

 

yea i did i got code 41 which i think its the air temperature sensor but i read that some users actually cut it and their cars perform well...umm i dunno wat to do...maybe i need a o2 sensor?

 

help guys...no change...could this be timming being off??...even though my idle is good..how about the tps?

 

Did you check the compression?