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Impreza Code 301-2-3-4 Engine misfire


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Hi, Last week I started my car to go to work, the car has been running perfectly the day before, now it runs very rough.

 

Lack of power, almost stalling

Doesn't rev rpm easily even in neutral

Engine vibrates alot on idle

Blue Smoke coming out when accelerating

fuel coming from the exhaust pipe, exhaust pressure pulsating

CEL flashing then steady on when the engine gets warm

 

Went to the dealer to read the codes:

P301 P302 P303 P304

 

He says:

Must change the injectors, the plugs, the wires, the oil, gas filter and oil filter, then try the car again to see if it's fixed. He says that I have bas gas in the tank. I always fill it up at the local gas station and nobody else had a problem

He wants 1500$ Cnd for this

 

I took my car out of the dealer

 

The car:

2000 Impreza 2.2L man AWD wagon

130000km (about 80000milles)

50 month old

Maintenance as per the service manual

NGK iridium plugs last year

Original wiring, I was scedule to change this summer

Air filter 3 month old

Gas filter 1 year old

Castrol Syntek 10W30

Timing belt original, I was thinking about changing it next year, on my model, it is requires at 168000km 104000milles

 

This summer is very humid in my area, it has been raining at least 5 days/week so I was thinking about humidity getting in a sensor or the coils?

 

I have had many cars but a car 50 month old, well maintained that would cost me 1500$ in repairs after 4 years, I find it surprising

 

I am now located in a remote city the peoples seem to tell be that the Subaru dealership is run by a bad apple.

 

Tomorrow, I will do an oil change because my current oil is contasminated with fuel. Tried today but the oil filter and the oil plug are stuck!

 

Any suggestions, comments

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From your description it seems your engine has multipoint injection, is that correct? If you do have MPFI I can't see all four injectors leaking at once so I would have to check the fuel control system. I wouldn't bother changing the oil until you have the fuel problem fixed as you will just contaminate the oil again.

 

It sounds like the injector(s?) are being forced on more than they should be. I suppose they could be clogged with some debris that got through the fuel filter but that doesn't seem likely.

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You are roght, it is MPFI, I can clearly see four Denso injectors on two fuel rail

 

I changed the fuel filter but the old one (less than a year old) still looks good

 

I was thinking about a faulty sensor .

 

I will drive the car to try to get the check engine light to go on and I will try to read the code using the ECU diagnostic method.

 

Do you have any suggestion what to check on the fuel control system? The car did run well for 50 month with no CEL indication. About 6 month ago, I had a complete engine diagnostic performed and everything check ok

 

The only abuse that this car had was pulling a boat trailler and it was two month ago, and I would not call it abuse because the car seemed to love it.

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I just drove the car medium and full throttle for a while

 

The CEL flashed then went steady on.

 

After a while the CEL turned off for about 15s (hope!) then went back on :-(

 

Power of the engine is fairly good once the engine is over 2500rpm, it has to be running on all four cylinders

 

From a stand still, the car barely is able to get going, the engine misses alot, blue smoke is coming out of the exhaust but once it start reving, it runs well

 

My goal was to get the ECU diagnostic but once the engine is stopped, I check the ECU codes and the ECU reports steady 0.5 sec. flashes. According to the ECU diagnostic page, it means that every system is OK.

 

( text deleted)

 

I still agree that the injectors should not stop working all at one and I am still hoping that it is only one electronic module that failed since the faillure happened all at one.

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If you are saying in your last post that all those codes are showing a recorded fault then I would have to presume that there is something wrong with the ECU unit. If that is the case you may be able to fix things up by removing the battery ground connection for about ten minutes to reset the ECU. After you reconnect the battery lead there may be a proceedure you need to do after you start the car up. I think you are not supposed to touch the gas pedal for around 15 minutes as the car warms up and does some checks. Hopefully the owners manual will say something on that.

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My mistake, the ECU read code reported all systems OK!

 

The list was there bvecause since these systems reported OK, I can presume that they are working and I can look elsewere for a problem. I am sorry about the misinformation.

 

Status:

 

When reading the OBDII module by connecting the connector under the direction colomn, I get that all system are OK.

 

It doesn't seem to remember that there was a CEL on whan the engine was running

 

The diagnostic P301 P302 P303 P304 was performed at the dealership when the engine was running.

 

I will try to edit out the information from the last message

 

 

 

If you are saying in your last post that all those codes are showing a recorded fault then I would have to presume that there is something wrong with the ECU unit. If that is the case you may be able to fix things up by removing the battery ground connection for about ten minutes to reset the ECU. After you reconnect the battery lead there may be a proceedure you need to do after you start the car up. I think you are not supposed to touch the gas pedal for around 15 minutes as the car warms up and does some checks. Hopefully the owners manual will say something on that.
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OK on the codes. It seems though there should be some stored codes from when the CEL light came on. Though the condition may be clear now.

 

One place to start checking on this problem is to see if there is a problem with the fuel pressure regulator. Since you are getting excessive fuel to the engine, the regulator may have failed somehow and is letting too much pressure get to the injectors and thus flooding the engine. I'm sure the blue smoke you are seeing, and the black plugs are due to the fuel rich condition.

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All things Lead somewhere.....I've run into this very Issue several Times On Early gen Impreza's.....

 

Ok here is What I have found....A Failing Coil Pack will run poorly below 2000rpm, due to the Charging system running off the Battery.....At 2000 rpm things Start pulling more juice, and the Alternator kicks in throwing more juice into the system.....At low speed if your Coils are cross fireing , it gives your injectors false signals to pulse/give fuel.......causing you to get the Blue smoke, and Very raw fuel smell.....at 2000 or so rpm, things get more Juice/power, Coil Starts doing it's Job proper, and Car runs as it should......AS far as I know, The Dealer cannot Diagnose a bad coilpack....I have had 2 cars come to me from the dealer locally with this exact issue......

 

With the Coil acting up , you get All kinds of False Code reads, cause your system is doing things out of proper time sequence......My dealer sells the CoilPack for 90.00 My cost......When I did my first on I happened to have a Spare, and tryed the car out on it.....Before Buying a New one for the Lady who owned the Impreza......She's been running happy ever since......

 

My Money says CoilPack Bad.....Especially if it is Consistantly Running well above 2500rpm.......

 

Good Luck, Keep us Posted, John

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Hi Mudrat

 

I like it,

 

I tested the inginion coil and ingnitor assembly

 

Primary side

Between 1-2 I am getting infinity

Between 3-4 I am getting 1.96 Mega ohm

 

Specidied values in the Impreza 2002 is 0.73ohm

 

On the secondary dide, I am getting:

between A and B 12.46Kohm

between C and D 12.42Kohm

 

Spedicied value is 12.8Kohm +/- 15% I am within 2%

 

The only thing is that I am guessing that the ingnition coil had remained the same betrween 2000 impreza and 2002 impreza.

 

Another thing I checked the plugs myself:

Plug #1 had fuel on it, black deposit

Plug #3 Looked fairly dry, black deposit

Plug #2 Looked dry, black deposit

Plus #4 Looked dry, no deposit

 

Another thing, the plugs were sowing a very large gap, much more than 0.044", probably 0.060", I know that they had the proper gap when I recieved them last year. I will purchase a new set of plugs tomorrow

 

The only thing that bothers me is that the dealer told me that he tried another coil and it did not help. I am thinking that he is a crook but that would be a direct lie!

 

Anyways, this is the best lead that I have recieved so far, I will try to locate another ingnition coil.

 

 

All things Lead somewhere.....I've run into this very Issue several Times On Early gen Impreza's.....

 

Ok here is What I have found....A Failing Coil Pack will run poorly below 2000rpm, due to the Charging system running off the Battery.....At 2000 rpm things Start pulling more juice, and the Alternator kicks in throwing more juice into the system.....At low speed if your Coils are cross fireing , it gives your injectors false signals to pulse/give fuel.......causing you to get the Blue smoke, and Very raw fuel smell.....at 2000 or so rpm, things get more Juice/power, Coil Starts doing it's Job proper, and Car runs as it should......AS far as I know, The Dealer cannot Diagnose a bad coilpack....I have had 2 cars come to me from the dealer locally with this exact issue......

 

With the Coil acting up , you get All kinds of False Code reads, cause your system is doing things out of proper time sequence......My dealer sells the CoilPack for 90.00 My cost......When I did my first on I happened to have a Spare, and tryed the car out on it.....Before Buying a New one for the Lady who owned the Impreza......She's been running happy ever since......

 

My Money says CoilPack Bad.....Especially if it is Consistantly Running well above 2500rpm.......

 

Good Luck, Keep us Posted, John

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One thing about these new cars

 

Now I am walking from my computer and back with wiring diagrams, two multimeter and a set of tools and it's alot of fun.

 

According to the EGI troobleshooting diagram, I now have to check if I am getting 11 to 12 ohm between the injector terminal. It is already night here and I do not have a garage so I'll check tomorrow

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Have fun with the trouble shooting. I suspect the injectors will be ok since you are getting fuel. Just way too much of it. I would be sure to look at the fuel pressure after the regulator to see if that is abnormally high. Too much pressure would equal too much fuel delivered into the cylinders.

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Problem was solvet by paying 1400$ to the dealer.

 

He changed all four injectors

Chainge oil, filter, plugs

Put the car on the diagnostic computer, test drive, diagnostic again

 

The car runs good now... for how long? one can only hope...

 

I will revise my maintenance schedule and put fuel injector cleaner each three month, more often in the winter (each 6 weeks).

 

It would seem that regular unleaded fuel with 87 octane in the culprit. I have been noticing the arrival of winter gas for a few years since I moved in colder regions of Quebec.

 

Accordingly to my mechanic, Winter gas has more additives and might cause failure of the injectors. He also,points out that peoples driving with premium gas in the winter do not have this problem.

 

I am also thinking about moving to premium gas all around. It has a cost impact but with a little tinkering, I might be able to increase the output of my engine a bit.

 

I remember a article about builting a few pounds of torque by modification (resistor) of the signal of the O2 sensor, the intake temp, the knock sensor and putting premium plugs on the 2.5L enggine. Maybe a drop in performance filter and a cold air intake. If I choose to convert to premium, I will try to take advantage of it my "tuning" the car a bit more

 

Charles Leblanc

Out of warranty Impreza 2000

 

 

 

 

 

 

 

 

Have fun with the trouble shooting. I suspect the injectors will be ok since you are getting fuel. Just way too much of it. I would be sure to look at the fuel pressure after the regulator to see if that is abnormally high. Too much pressure would equal too much fuel delivered into the cylinders.
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Thanks for the update. It still seems strange to me that the engine runs fine the day before and then all four injectors go bad the next. I hope it was money well spent.

I agree completly, this problem was completly unexpected and the first contact with the service manager was less than professionnal. The second service manager was much better but I did not expect to put that king of money on a well maintained Subaru with only four years in it. The car runs MUCH better after the repair, a little less power but it runs fine now.

 

They gave me back the injectors and the plugs and I have 1 year warranty on the repair (I think it is required by law here to give a warranty on expensive repairs on recent cars)

 

Last winter was difficult and the injector froze once but I tought it was only a localized incident. In retrospect, it might bne that they were damaged at that time and that my ECU and Iridium plugs were able to compensate for the damage for a while.

 

I am still angry with the situation. The chances that I could end up with a Forester turbo are not so good now. Especially since the dealer took a direct aim at the upscale market:

 

"Subaru doesn't compete with Suzuki, it competes with Audi, BMW, Saab". Well, when I purchased my Impreza wagon back in 2000, it was competing with Mazda Protege, VW Golf, Honda Civic, Ford Focus, Hunday Elantra and even the Pt Cruiser. i gues I was wrong.

 

BTW here in Quebec, the Impreza wagon TS AMD 165hp 2.5l goes for 23000$can, the Suzuki Aerio wagon AWD 156hp 2.3l goes for 22000$can. About the same size overall, the Aerio is a bit more... ugly but roomier as well. We also have the Mazda5, the Vibe, the Matrix that are not in the same category.

 

Anyways, I was thinking about putting a few goodiers on it like a paint job same color but repairs on the scratches and dings, maybe new winter tires, rpm, replacing one wheel slightly out of balance and looking at the rear coil springs (the car sits lower at the back) Also maybe an anti-roll bar for the rear, these will have to wait.

 

Charles Leblanc

Impreza 2000

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