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Kevin C.
Kevin C., Subaru Master Tech.
Category: Subaru
Satisfied Customers: 1727
Experience:  34 years of Subaru service experience, ASE Master Technician.
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My 2004 subaru impreza ts wagon has some issues. When egine

Customer Question

Hi my 2004 subaru impreza ts wagon has some issues. When egine gets warm, it stalls when i shift from P too D, or from D to P. When it stalls, i have to wait a couple of minutes before i can start it as there are no lights on the dash when i turn to "ignition".
After a few minutes lights on dash go on but I have to start the car in N (i use the bypass buttton on the shifter), so that when i shift to D the engine does not stall. The car runs normally thereafter as long as i do not shift to P or R. Doing so when engine is warm kills the motor, but when its cold it does not happen.
It used to have stalling issues but i have cleaned the throttle body and idle air control valve and now it runs better and doesnt stall anymore, but now the above problem arose. Hope you can help.
Submitted: 11 months ago.
Category: Subaru
Expert:  Chad Farhat replied 11 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 11 months ago.

is there check engine light on at this time ?

have you scanned for fault codes & do you have them ?

have you checked for vacuum leaks ,especially air hose from air box to throttle body ?

what is the mileage on it ?

what has been done to it other than idle air valve cleaning & throttle?Please let me know

Thank You

Chad Farhat

ASE Certified Technician

Customer: replied 11 months ago.
Hi ChadThere is no CEL and i have also used a scan tool and there are no codes. I did a supposed hard reset of the ECU by disconnecting the battery for some time. The car only has 60,000 miles or 92k kms on it. The problem only occurs when the engine goes up to operating temperature. When it is cold theres no problem. The only thing done before this occured on friday evening was changing the oil n the morning using mobil 1 full synthetic 5w 30. Not seeing that as a cause of the problem though.
Customer: replied 11 months ago.
like i said, its only when i shift from P to D or when i pass R. I have to wait like 5 minutes before the ignition lights come on. Before that there is no power even in ACC.
Expert:  Chad Farhat replied 11 months ago.

i will opt out your question and let another expert help you on this one .,not sure on it what would be the problem

Expert:  david craig replied 11 months ago.

Hi Im David, you have no fault codes? Somewhere along the lines when the ECM switches its fuel map after it warms up, you are losing the mix. It is either the fuel you use, a vacuum leak you haven't found, a bad ground or battery (or both), loose connection at a sensor or fuel pump.
Vacuum leaks should have been taken care of when the engine was overhauled.
Fuel is a tricky thing. If you buy cheap, you get cheap. If you buy a major brand gas, or a station that has a major brand label/sign, and the station doesn't see a lot of fuel traffic, water can be an issue, or the settlement of alcohol on the base of the tank is finding its way in to your tank.
Bad grounding and/or conductivity. Electricity is the heart of everything electronic on the car. Sensors, actuators and the computers. If the systems do not have enough electrical flow for use, you get a dumbed down car. Think in relationship to a laptop or cell phone with a low battery, it slows down. Same with the ECM. And if the electrical flow is low,solenoids and switches will either work poorly or not at all. Start with the battery and check ampere output and work outward from it.
Corrosion is resistance. loose pins at the plugs mean sporadic outputs or operation. Check them.
Fuel pump could be running great and supplying sufficient fuel a for cold running engine and then as it heats up, with the engine, expansion of the metals in the pump or module reduces the pump output. Check the fuel pressure cold, then after the engine warms up and acts up.

Expert:  david craig replied 11 months ago.

you can also have a hairline crack in the igintion coil that will expand as it gets warm. i would check it very closely.

Expert:  david craig replied 11 months ago.

checking in to see how its going?

Customer: replied 11 months ago.
Hi DavidSorry for the late reply I was on holiday with family and just got back. So today I worked on the car as it is still stalling. I believe the battery and grounding are good - car cranks fine and strong and always one click start. The car really idles fine and throttle response is good, but the engine just dies randomly - there's no pattern whether hot or cold. Sometimes it idles and revs fine with A/C for 8 to 10 minutes, sometimes it just dies after a few minutes - and no sputtering. According to a manual I read, the "dead ignition" after a stall is actually a safety feature of the fuel pump relay. It will re-engage after a few minutes so I can start the car with just one click.I suspected that the problem would be with the crank position sensor. An interesting thing I noticed was when I tapped on the sensor with a wrench (engine and Ignition off), I could hear a buzzing sound on the ignition coil. I started the car, then the CEL lit up and threw a code P0335 (crankshaft position sensor "a" circuit). Car was running rich you could smell it. I checked the wiring for ohms from the connector to the coupling, and the coupling to the ECM and all were within specs. I checked and cleaned all connectors and grounding and all ok. The sensor's ohms were also ok. I cleared the code and also bought a new crank sensor (for good measure) but still no luck - still stalls.I also suspected fuel starvation so I removed the fuel filter and it wasn't clogged and dirt was minimal. I could freely blow on the inlet pipe and there were no restrictions. The manual said that to relieve pressure in the fuel system, disconnect fuel pump relay then start and let car idle until it stalls, then crank a few more times. My car does not start at all when I disconnect the fuel pump relay, it just cranks - could this be a sign of not enough fuel pressure in the system? Not sure if this is the problem as there is no rough idle and throttle response is good so I am still thinking it's a electrical issue.Appreciate all the help!
Expert:  david craig replied 11 months ago.

if you pull the fuel pump relay and there is no pressure left at the rail then it wont start, but, if the car was running , you shut it down then immediately pull the relay it should still start until the residual fuel is used up left in the fuel rail. if that isnt happening then yes, pressure is a problem. probably the fpr, which is supposed to hold pressure at the rail. tapping on the crank position sensor and getting that code is leaving me thinking the reluctor wheel that the crank positon sensor generators it signal from may be bent or full of oil or grime, causing intermittent issues.

Customer: replied 11 months ago.
was thinking of the reluctor wheel on the crank gear too. It is interesting as i iust read on the service manual that the crank sensor sends the signal to the ecm which in turn signals the fpr to operate. Will check both and let you know. Still a bit wary of fuel starvation since what i see online is that rough, low idling and poor throttle response is a symptom.
Expert:  david craig replied 11 months ago.

absolutely, thats why a fuel pressure test needs to be done.

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