engine cuts off after 2-3 minutes of idleing

[dkdeleon68]

I can not figure out what the hell is wrong with my friends 1991 240sx.It starts and idles great but after 2-3 minutes of idleing it shuts off without any hesitation or sputtering. (By the way its a KA24DE). I checked for vacuum leaks, injectors are working fine, I checked fuel pump and fuel filter. I am thinking that it might be electrical. If anyone has had the same problem and fixed it please help a bro out. Thanks for any help in advance.

[shista240sx]

lemme know also if you figure it out.......

[dkdeleon68]

I'm thinking maybe the ignition switch or related electrical problem.

[dkdeleon68]

anyone?

[dkdeleon68]

"Tap" "Tap" Is this thing on?

[dkdeleon68]

I checked the coolent temp sensor with it out of the engine and the ohms reading is 1.791 k ohms and the with the element under hot water (running hot water from the sink) and it reads .853 k ohms.

[ZiG]

Those numbers look a little off:

-4 F 5190 ohm86 F 480 ohm210 F 207 ohm

that's mine anyway.

did you check to make sure the iacv is working? The thermal fast idle valve might be the only thing letting air into the engine, so when it heats up and closes after a couple minutes, then it would die. will it start again right away? What if you hold the throttle open a little?

[dkdeleon68]

Yes it starts back up right away.

[dkdeleon68]

I just started back on my friends car again and still I am stumped. It is acting like when it reaches a certain temp something shuts off or opens up and it dies like some one turned the key off. It starts right back up but it doesn't take 4 or 5 minutes to shut off like when i first start it, after I restart it, it takes 1 or 2 minutes. any ideas would be much helpful.

[dkdeleon68]

any one?

[s13fOr_me]

hmmmm does it cut off only at idle or does it cut off when your driving too?

[rogoman]

When the motor is fully warmed up, check your idle speed; it should be at 700 rpm. If it's not, here's a procedure:

To adjust the idle speed, warm up the engine first. Shut off the engine and disconnect the throttle sensor harness connector. It's located on the passenger's side of the engine at the top in front of the intake manifold; easy to see. Start the engine and let it idle in neutral. The idle speed should be 650 RPM. If not adjust the idle speed screw located on the IAA unit. The IAA is next to the air regulator. You'll need a flash light to find it because it's not easy to see. After you've set the idle speed to 650, shut off the engine and reconnect the throttle sensor harness connector. Start the engine and now the idle speed should be around 700 RPM in neutral.

[dkdeleon68]

it cuts off when I'm driving too. 5 minutes after I start it it dies like the key was turned off, at idle or driving.

[dkdeleon68]

any one?

[Lost_In_Translation]

Sounds like a fuel pump wiring problem.. Also check the grounds.

[dkdeleon68]

fuel pump works perfectly

[jinjinweiwei]

very possible it is ur MAF mass air flow sensor or air flow meter. mine did the same thing after i changed MAF the problem went away.

[dkdeleon68]

Im not getting any codes from the ecu for the maf, so thats not it.

[ZiG]

eh, make sure the iacv is getting air through it. I suppose it's possible that that whole system could be doing funny things..

might not hurt to try the maf anyways. apparently they dont always give codes when they get screwed up. for example i unplugged mine and still didnt get a code........

[dkdeleon68]

how do you check to see if it is getting air through it?

[dkdeleon68]

anyone?

[s13sr240]

Im not getting any codes from the ecu for the maf, so thats not it.

you wont always get a code for the maf, i also had the same problem.

when you go to rev it up will it stop at around 2200 or 2500 rpm. if so then maf might be worth looking into, if not them im stumped too.

[dkdeleon68]

no, it revs fine.

[s13sr240]

humm..... then im stumped

[rogoman]

The fuel pressure regulator may be failing. Tee-in a tempoarary fuel pressure gauge at the output side of the fuel filter. The readings at idle should be as follows:- with vacuum hose connected to the fuel pressure regulator: 33 psi- with vacuum hose disconnected from the fuel pressure regulator: 43 psi

[dkdeleon68]

could it be my remote start on my alarm? It hasn't worked for a while and it shuts off like it would if you remote started it and didn't get in and put the key in before the five minutes are up and it shuts off.

[dkdeleon68]

Could it be the crank angle sensor in the distributor? how do you check this sensor?

[Rucca]

I'd heavily suspect any aftermarket remote start/alarm systems. Crank angle sensor would set a code so check for codes. The other way to test it is to probe it with multimeter on AC and spin the distributor by hand. It should make a nice sine wave of -0.5v to +0.5v. Doesn't really sound like a CAS problem.

[GeneStarWindGSW]

Double check your EGR unit itself and vacuum lines. this was happening to my friends 240 and it would turn on for a little bit and it would all of the sudden it'd die. Once we got the issue worked out and figured out it was the EGR it would stay on but the Idle was about at 1,100rpms.

Hope this helps

[dkdeleon68]

i checked for vacuum leaks and i checked the egr and no leaks and egr is fine.