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MOONEYFLYER
Guest
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 Posted:
Sat Nov 05, 2005 5:00 am Post subject:
Nissan 240 SX fails to continue to run |
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1989 Nissan 240SX with the fuel pump, fuel filter, and fuel pressure
regulator replaced. Upon starting, the car will idle for about 1 minute
30 seconds and you can run the engine up to about 2000 RPM above this the
engine starts to die. Toward the end of this time the engine will speed
up slightly (similiar to running a little lean) and then it will die.
Subsequent restarts will have the car run for about 10 to 15 seconds then
die.
We do have a diagnostic code of 12 Airflow meter circuit.
Any ideas for trouble shooting the problem?
MOONEYFLYER
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Randy
Guest
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| Posted:
Sat Nov 05, 2005 9:15 am Post subject:
Re: Nissan 240 SX fails to continue to run |
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simple unplug the airflow and try it. As long as everything else is good
it should run. It will use preprogramed data against the tps and coolant
senser to determine air flow requirements.
MOONEYFLYER wrote:
| Quote: | 1989 Nissan 240SX with the fuel pump, fuel filter, and fuel pressure
regulator replaced. Upon starting, the car will idle for about 1 minute
30 seconds and you can run the engine up to about 2000 RPM above this the
engine starts to die. Toward the end of this time the engine will speed
up slightly (similiar to running a little lean) and then it will die.
Subsequent restarts will have the car run for about 10 to 15 seconds then
die.
We do have a diagnostic code of 12 Airflow meter circuit.
Any ideas for trouble shooting the problem?
MOONEYFLYER
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Peter Hill
Guest
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| Posted:
Sat Nov 05, 2005 9:15 am Post subject:
Re: Nissan 240 SX fails to continue to run |
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On Fri, 04 Nov 2005 18:00:03 -0500, "MOONEYFLYER"
<llamas@nospam.airris.com> wrote:
| Quote: | 1989 Nissan 240SX with the fuel pump, fuel filter, and fuel pressure
regulator replaced. Upon starting, the car will idle for about 1 minute
30 seconds and you can run the engine up to about 2000 RPM above this the
engine starts to die. Toward the end of this time the engine will speed
up slightly (similiar to running a little lean) and then it will die.
Subsequent restarts will have the car run for about 10 to 15 seconds then
die.
We do have a diagnostic code of 12 Airflow meter circuit.
Any ideas for trouble shooting the problem?
MOONEYFLYER
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With an AFM fault the ECU will limit the max rpm to 2000 or 2400 rpm
depending on model - limp home mode. An AFM fault is detected when no
signal is present or air flow reading is in excess of stored data for
max airflow at current rpm and throttle position.
1: no 12V feed to AFM.
2: broken wire or faulty connection.
3: short circuit - wire worn though somewhere in loom.
3: no output from AFM, should be 1.5v at idle and it should rise as
rpm is increased.
1: Check it has 12V supply at AFM connector when ignition is on.
Check fuses and ECCS relay.
2 & 3: Check connection to AFM. Wiggle connector while revving
engine. Disconnect ECU and AFM. Use ohm meter to test wiring between
ECU plug and AFM plug for continuity (will need test leads that reach
from ECU inside car to AFM in engine bay). Also test for shorts to
ground or each other.
3: with good 12V feed and good wiring lack of output signal means AFM
is dead.
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MOONEYFLYER
Guest
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| Posted:
Mon Nov 14, 2005 6:52 pm Post subject:
Re: Nissan 240 SX fails to continue to run |
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Randy & Peter Hill
Thank you for your suggestions. I want to report back to complete the
solution.
First, if I disconnected the MAF connector, the car would continue to run.
The max RPM was around 2400 and it was running poorly.
Secondly, I followed Peter's suggestions and all seem to be in order and I
planned on ordering a new MAF from a parts store (not the Nissan dealer)
There was a core charge and I decided to remove the MAF. After removing
the MAF, I removed the actual sensor (two screws). The way the air flows
past the sensor, it flows past the electrical sensor and continues through
a inner channel and re-enters the airflow stream at the end of the MAF.
I poured a little alcohol into the opening. At first it seeped. Applied
compressed air and it flowed a little better. Finally, I cleaned the
chamber with SimpleGreen followed by soap and water. A little more
alcohol and compressed air and the passage appeared clean. Reinstalled
the electronic sensor and then the MAF and the engine runs like a top.
Prior to scrapping the MAF, try cleaning the electronics airflow pathway.
Thank you. |
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