Nissan 240SX needs your help

So, who can help diagnose my parents' 1991 Nissan 240SX? It occasionally hesitates. According to my dad, it feels like it's bogged down--like the accelerator has to be pushed through some kind of resistance. It seems to happen randomly. They have owned the car since new, and it's a five-speed model. When I was up there visiting, of course the car drove totally fine.

Things they have done to the car: replaced the injectors; cleaned the throttle body; changed plugs, distributor cap, rotor and plug wires; tried a new coil; changed the fuel filter.

It's been doing this for a few months now. I don't see a new air filter on my dad's list, but I'm pretty sure he mentioned that it's been changed.

Any help?

Change the motor. Clearly its bad. I suggest LS1.

Well, this is probably the last bone-stock S13, so I think they'd like to keep it that way.

that is kinda creepy

Sounds like the ECU is going out. I had that happen to my similar-vintage KA24 Nissan truck.

or the cat?

Also, I should add, the car has lived a mild existence. It's never been autocrossed, jumped or drifted. I have already put dibs on it.

I had one of my Corrados do that..turned out the fuel pump relay had vibrated almost all the way out of its mount.

Bad MAF.

David S. Wallens wrote: Well, this is probably the last bone-stock S13, so I think they'd like to keep it that way.

Unmolested s13? I don't believe it. And if it is, then yes, leave it alone. Probably be worth money some day after the drifters wear out all the other ones.

So you are accelerating through a gear and it hits a certain rpm then starts hesitating? I had a car that would sputter and stop accelerating when you hit about 4 pounds of boost. If you light footed the pedal you could get the rpm to keep going up but no boost. It turned out to be a bad fuel pump that couldn't keep up with the required higher fuel flow. I realize the 240 isn't boosted but it sounds like a similar problem.

No check engine light or stored codes? Air flow meter wouldn't surprise me either...

92CelicaHalfTrac wrote: Bad MAF.

+1 Not sure if thier car is the right vintage, but I know that there was a MAF harness update for the ground (adding additional) to solve some MAF problems.

My '97 240sx had a bad MAF at about 138k miles. Weird activity where it seemed like the accelerator pedal did not work. The car would surge and bog what seemed like on its own.

To be sure I should likely drive this one for a few months.

i would suggest a set of coilovers

If you love your Dad then you can't let him drive such a dangerous vehicle. I suggest you give it to me and show your Dad how much you care…….and what if your Mom is in the car when they get stuck on the side of the road.......really you have no other option.....

PM me for my address and tell your folks how much I care about them

David S. Wallens wrote: Also, I should add, the car has lived a mild existence. It's never been autocrossed, jumped or drifted. I have already put dibs on it.

damnit. was just going to say I'd take it off their hands.lol

It's a fuse! Fuses are the bane of automotive resistance! It amazes me how many people have electrical problems and say "i checked the fuses"

I third the bad MAF.

I bought a single owner, completely unmolested 93 240sx se from florida.

I put Q45 brakes on it and stainless brake lines.

I then sold it to someone for almost double what I paid for it.

Three days later it was wrapped around a tree.

arrrrrrrrrrrrrrrrrghhhhhhhhhhhhhhhhhhh!!!!!!!!!!!!!!!!!!!!!!!!!

coolant temperature sensor--if it has one. I have a miata that misbehaved similarly.

Sounds like the mix is wrong and it is especially showing up at one point. Too fat or too lean? Probably too lean. Either way, reason could be the MAF or whatever meters air on that (or the harness to it if that is a known failure point), temp sensor as suggested, or something like a bad fuel pump or pressure regulator, or the oxygen sensor. If you could monitor the oxygen sensor output, that may give you some clues. Tracking down things pre-ODBCII does get more challenging. Starting with whatever codes that ECU will store is a good idea.

Or put a SR20DET in it.

All the pertinent suggestions have been hit upon already:

• ECU is dying
• MAF is dying
• Fuel pump/Relay is dying
• Fuel press. reg. is dying
• Lack of SR20

In later SR20 equipped cars, a MAF Reground can do wonders to clear up hesitation and increase economy. You likely have a KA, but honestly, thats where I would start...

BoostedBrandon wrote: It's a fuse! Fuses are the bane of automotive resistance! It amazes me how many people have electrical problems and say "i checked the fuses" I third the bad MAF.

everyone knows that the solution to a 10a fuse blowing is to put a 30a fuse in place of it. duh!

You obviously want to pull the engine (leaving the lower harness) and give it to me. I'll see you soon.

4cylndrfury wrote: All the pertinent suggestions have been hit upon already: + ECU is dying + MAF is dying + Fuel pump/Relay is dying + Fuel press. reg. is dying + Lack of RB20 In later SR20 equipped cars, a MAF Reground can do wonders to clear up hesitation and increase economy. You likely have a KA, but honestly, thats where I would start...

FTFY