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Mike V.
Mike V., Subaru Technician
Category: Subaru
Satisfied Customers: 23832
Experience:  Certified Subaru Technician, factory trained by Subaru.
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I have a 99 legacy l 2.2 that starts and then stalls after 3

Customer Question

I have a 99 legacy l 2.2 that starts and then stalls after 3 or 4 seconds.
Submitted: 12 months ago.
Category: Subaru
Expert:  Mastertech1 replied 12 months ago.

Does this vehicle have an alarm Factory or aftermarket? This sounds to be an alarm issue, It starts and runs for a couple seconds and then dies, Factory and many aftermarket alarm cancel out the electrial signal to the fuel injectors when it thinks it is started incorrectly, If you key is bad it will do this with a factory alarm, If factory alarm try a different key (key that came with vehicle, it is encoded) Also try opening and closing all doors, and then locking then from outside driver door wait 10 mins and the unlook outside drivers door and insert key into ignition and try starting, Tahnks, Please let me know if I can be of anyother assistance to you with this issue

Customer: replied 12 months ago.
The car is not equipped with a factory or aftermarket alarm. If the gas is pressed you can keep the car running. If it revs up to higher speeds you wouldn't know there was something wrong, however down at lower engine speeds it may buck or pop through the intake as you try to keep it alive. Still no codes even through minutes of this.
Expert:  Mastertech1 replied 12 months ago.

Have you checked to see if there is a vacuum leak from one of the vac. hoses (this will cause it to run rough at idle speeds and die out) many times it take a bit before any codes will log in the pcm on these years (like lean codes etc. )

Customer: replied 12 months ago.
The car has passed smoke leak test at 3psi, no vacuum leaks. The baro/vac sensor is new and operates normally. As does the pressure switching solenoid. This has been verified with a scope.
Customer: replied 11 months ago.
Any other input? I feel your advise so far is quite novice...
Expert:  Mike V. replied 11 months ago.

Hi there,

Do you have a scan tool that can see the live data inputs from the O2 sensors?
Was anything done to the car prior to this happening?

Customer: replied 11 months ago.
the history of the car is not known. Other than the obvious replaced parts. I can read data on the front and rear o2 sensors. Key on they read around 0.1 to 0.115 volts. After the car starts the scanner is very slow but shows them peak to around .35 volts. Unplugging the main o2 sensor cable makes no difference. New ect sensor also makes no difference. The car operates exactly the same with the entire intake removed from the Maf to the throttle body... Runs fast for 3-4 seconds, then sputters and dies...the moment it switches load determination seams to be the issue.
Expert:  Mike V. replied 11 months ago.

Ok

One the under side of the duct work from the air filter to the throttle is a 3/4 inch hose. Make sure this hose is connected. I am not sure if a smoke test would pick this hose out and since it's underneath it does get missed time to time. This actually is exactly how the car will run with it off.

I would like to know the fuel trims if possible, both long term and short term.

Is the car a manual or auto?

Customer: replied 11 months ago.
Is a federal 2.2, it does not have the larger hose to feed the idle air.
The car will not enter closed loop. The trims stay at zero.
Customer: replied 11 months ago.
The car is an auto. Unplugging the tcu also makes no difference.
Expert:  Mike V. replied 11 months ago.

Ok

Take the front O2 sensor right out of the exhaust pipe and see if it helps. You may be dealing with a plugged converter. Removing the sensor will give the exhaust a place to go.

Customer: replied 11 months ago.
I have already attempted that.
Expert:  Mike V. replied 11 months ago.

Are their any codes with this?

Customer: replied 11 months ago.
Only as I start unplugging things
Expert:  Mike V. replied 11 months ago.

Unplugging the maf makes no difference on this?

Customer: replied 11 months ago.
With a clean power up, as in, the battery has been disconnected for more than 5 minutes, if I take either one of the following wires at the ecu and unpin them, the car will run and idle. Pin c5, white, shielded Maf wire; or c8, pink, 'other' Maf wire. However, if the entire Maf is unplugged the car acts the same as if it were plugged in. In this case, if c8 is unplugged I get code p0103 Maf high, with p0325 knock sensor cuircuit. C5 unplugged only reviels code p0102 Maf low.
Expert:  Mike V. replied 11 months ago.

Ok, so the maf has influence here for sure then.

The shielded wire is the signal wire, I believe the other wire should be the power wire.

If you have a meter, check the voltage out at the sensor white wire, then back at the ecm and see if the reading is the same at both ends of the wire.

Also, check the ground wire on the maf for continuity to ground I have seen this fail on these.

I would say the maf is causing the issue or the wiring. I know you replaced the maf, but it seems to be a clue for us.

Customer: replied 11 months ago.
This Maf has no ground. It has 12v, 5v, the shield, and the 'other' wire at c8. I can only assume the ground is through this wire through the ecu. both it and the shield wire are perfectly sound. The 12v is right at battery voltage, the 5v reads 5.15 at the maf as well at the tps and baro.
Expert:  Mike V. replied 11 months ago.

Sorry for the delay,

I am showing 5 wires on the maf sensor not 3. Can you give me the wire colors on the maf?

What is the voltage on the shielded wire?

Expert:  Mike V. replied 11 months ago.

Sorry, I am showing this is a 4 wire sensor and one wire, yellow at position 2 on the connector should be the ground. It is grounded at the ecm, but it's also the ground for several other components.

Customer: replied 11 months ago.
Ummmm, no. Pin 2 is 12v shared from the main relay. Pin 3 goes to ecu C8, pin 4 goes to shared 5v + with baro and tps. Pin 5 is shield to ecu C5.
If you can't look and determine that wire was not a ground then I want my money back lol I feel like I'm teaching you.