1991 240sx: shuts off /no injector pulse

[onpoint357]

my 91 240sx will shut off with no warning. I replaced coil, ignition control module. I can not duplicate the problem it is very intermitant but it continues to happen. when you try to restart it shakes violently. if you wait long enough it will restart. I purchased a new fuel pump relay but I don't know were it goes. any Ideas on why it shuts off and were is the relay. P.S. it shut off at 85 mph and sitting in traffic.

[elwesso]

in the 240sx forum, there is a FSM that tells where allthe stuff goes...

Its possible this is related to the MAF... It kinda sounds like it to me..

[180fan]

Yep could definitely be a mafs or a TPS issue. I've seen issues with both do crazy stuff to peoples idles and running.

[onpoint357]

what can be done short of putting a new mass airflow sensor on the car. Is there anyway I can check this because as I said the problem is very intermitant. I have not been able to duplicate it. It may be heat related does this mean anything. does it still point at maf. I've never seen a car shut off so quick and without warning.

[elwesso]

Personally I would buy a new MAF.. you can usually get them cheap. try our nissan classifieds.....

You canmeasure the voltage at the ECU, and that might help confirm it, but lots of time VOM arent accurate enough or refresh fast enough to have any sort of realtime access to voltage, so it may look ok...

generaly speaking the only true way to diagnose a bad MAF is to swap in a new one. THats hwat I recommend to the Q guys and Q45 MAFs aremuch more expensive.

[onpoint357]

thank you. I will give it a try.

[onpoint357]

Well I've changed the maf and the throttle position sensor the coil the ignition module and the fuel pump relay. It still is shutting off. I don't know what else it could be. does anyone out there have any ideas. I also changed the fuel pump fuel filter and distributor cap and rotor. the car now will not start. I tested the fuel injectors and I am now not getting a pulse to the injectors. or i should say Im getting random pulse to the injectors. could this be the ecm? can it be tested and can it be repaired or do I need a new ecm?
Modified by onpoint357 at 7:17 PM 4/17/2006

[onpoint357]

on my 91 240sx im getting random pulse to my fuel injectors. It works when it wants to. Ive changed maf,throttle position sensor,fuel pump,coil,ignition control module,fuel pump relay. could it be the ecm can it be repaired?

[onpoint357]

My 91 240sx will not start it will crank but wont start. I have spark, I have fuel pressure, I get pulse at the injector sometimes. could this be the ecm?

[onpoint357]

need quick answere about no pulse at fuel injectors. and the injectors are good

[NISTECH]

How are you checking injector pulse? do you have spark at the plugs?

EDITI merged your 2 threads, no need to have 2 over the same issue.

[onpoint357]

Yes I have good spark good fuel preasure and now you can ad to the list a new ecm. Result, still shuts off. (I tested pulse using noid lights) Just to let you know Repaced parts include: Mafs, throttle position sensor, fuel pump, fuel pump relay, distributor cap and rotor, ecm, fuel filter coil ignition module. After changing the ecm I drove the car about tem min with no problem then it shut off. It started but shut off as soon as I touch the gas. I sat for about an hour and It started like nothing ever happend. I got it home shut it off and tried to start it again it started shook and shut off. I have no clue, and about to give up.

[NISTECH]

Take a look at your coolant temp sensor connector make sure the connections are clean and have good tight contact with the terminals in the sensor. Also check to make sure the Dist connector has good contact in its terminals. Sounds more to me you have a connection issue with something.

[onpoint357]

is it unrealistic to think about changing whole wire harnes?

[NISTECH]

yea that would be a bit extream

[onpoint357]

I will be checking all of the connections cleaning them and replacing as necessary. worst case cenario how difficult is it to change the harness and If it is to difficult to do shade tree mechanic still how much do you think It would cost to have it done proffessionally.

[rogoman]

If the fuel injectors are firing intermittently, the problem may be the crank position sensor which located on the bottom part of the distributor; check the harness connector.

[onpoint357]

well after all of the suggestions the car is still shutting off. The shop that i sent it to calibrated the throttle position sensor. they drove the car for two days it didnt shut off. I picked it up got about 3 miles and it shut off. needles to say the car is back int the shop. they have been driving it for about 4 days and it has not shut off. I know the problem is still there. do you have any suggestions?

[onpoint357]

car is still shutting off after changing ecm,mafs, coil, ignition module, distrib cap and rotor, fuel pump, fuel pump relay,throttle position sensor. had throttle position sensor calibrated and it still shutting off. nobody has any ideas?
Modified by onpoint357 at 7:38 PM 4/29/2006

[NISTECH]

I think the crank angle sensor was suggested. did you replace that? that is the whole distributor in your car.

[Zoom45]

I'm having the same problems as you and so far none of the items mentioned have fixed it. Did you ever get yours running right? Zoom45