Jump to content
LegacyGT.com

Cylinder misfires or bad injectors, please post here.


what

Recommended Posts

  • Replies 660
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Code 31 is THROTTLE POSITION SENSOR.

DIAGNOSIS:

Input signal circuit of throttle position sensor is open or shorted.

TROUBLE SYMPTOM:

Shift point too high or too low; excessive shift shock; excessive tight corner “braking”.

Link to comment
Share on other sites

Code 31 is THROTTLE POSITION SENSOR.

DIAGNOSIS:

Input signal circuit of throttle position sensor is open or shorted.

TROUBLE SYMPTOM:

Shift point too high or too low; excessive shift shock; excessive tight corner “braking”.

 

great info!! So do you know if this can been 'pro-tuned' out or do I have to replace the TPS?

Link to comment
Share on other sites

I've got a cylinder 1 misfire code. Idle is a little rough but not too bad. Can anybody tell me how to figure out which is cylinder 1?

 

I was planning on changing the spark plugs soon so I might get that done first. I've got about 40K miles, AP stage 2, and a cobb catted dp.

Link to comment
Share on other sites

  • 3 weeks later...

I have followed the rough idle and misfire postings for a long time now since my '05 has been rough nearly all its 37K miles. Dealer has replaced MAF sensor, injector, O2 sensor, 2 computers, coil packs, and other items I don't even remember with only short term or limited success. My car has consistently had #3 misfire codes thrown, after warm-up at idle, and up to about 3000 rpm when under no load. I did a plug replacement on #3 with no success, and then swapped injectors hoping that the misfire would move.

Eureka! it didn't move, but the problem is fixed!

Here is my theory: (I do know my way around engines & have been building and tuning them for 25+ years & have had a car featured in Hot Rod mag.)

The Theory --- Fuel injectors don't all flow the same, particularly at low duty cycle (idle and light load) so in my case I had one cylinder (#3) that liked a little more fuel than some of the others (cam lobe variation, combustion chamber shape, port shape in intake, etc.) and unfortunately it was paired up with a fuel injector that had lower than average idle flow. When the motor is cold it runs extra fuel so all cylinders were happy, but once warm, it kicks into closed loop mode and the O2 sensor looks at OVERALL A/F ratio (not the ratio for #3 cylinder) and leans things out. #3 got too lean and could not fire consistently. When I moved the injector (which just happened to be a higher flowing one by chance) over to #3, the fuel demands of #3 cylinder were met, and the old #3 injector flowed enough to meet the demands of the other less demanding cylinder. When you have Exhaust Gas Temperature probes on an engine you can easily see how much cylinders vary from one another - and tune accordingly, but unfortunately we don't have that luxury with these factory engines.

Hope this makes some sence and can help some of you fellow rough idlers!

Link to comment
Share on other sites

My CEL P0302 storry is not over. Everything is replaced - coil's, plug's, injectors, wires. Before I used to have 301 and 302. Now it is only 302. But only if I'm using 87 (89) gas. If 91-94 - no CEL. Look like I have carbon on intake valve and this is the main reason of misfire.
Link to comment
Share on other sites

My CEL came on last week. I took it in to Subaru and they said it was a cylinder 4 misfire. They checked it out today, and said it is the injector. My warranty is going to cover it. Just thought I'd chime in...seems as though al ot of #4 injectors are craping out.
Link to comment
Share on other sites

  • 2 months later...
for the members with bad injectors, did you all have very rough idles when the injectors went bad? i ask this because my idle is terribly rough, and my cel is flashing, but if i reset the ecu (disconnect the battery, hit brake pedal) it all goes away for a while. last time this happened i replaced all 4 spark plugs, and swapped injector #3 with injector #1. it has been almost 5000 miles since that, and no problems until today :confused:
Link to comment
Share on other sites

i have a cylinder 2 misfire. i cleared the code. Will the code come up again if the cylinder misfires again or will it forever just stay off do to me clearing the code. i also just had my 30,000 mile check up done which included the injector cleaning. then like a day after i had that done it threw the injector code. wtf.
Link to comment
Share on other sites

Here's my problem. I've got a '97 Legacy GT Wagon with 136k miles that I bought used from my wife's friend. All scheduled maintenance had been done on schedule by one shop. I changed the spark plugs myself soon after I got it at 120k. Within a few months I started noticing a hesitation on acceleration. Taking it to a dealer near work they found two of the plugs arcing due to the inner boots missing on the plug wires. They replaced the wires and the two plugs along with brakes and a clutch.

 

That was this spring. Tooling along the highway my CEL comes on. Cylinder 1 and 2 misfire. I cleared them and they came back a bit later. Took it back to the shop and the tech replaced the coil pack and said I might start seeing cylinders 3 and 4 misfire. Within two weeks that's exactly what happened. I left it for a while and it started showing all cylinders misfiring. I took it back and the tech replaced the keyway and timing belt (had been done at 115k) and a crankshaft pulley. That cleared the code for a while and the car had no hesitation during acceleration. NICE!!!

 

Now, two weeks later it's back with cylinders 1 and 2. I'll be tooling down the road and the CEL will start flashing 10 - 20 times and then sometimes it will just come out without flashes. It's to the point now where it fires nearly every time I take it on the highway. It also seems like the engine is a bit sloppy just like before the crankshaft pulley. I'm wondering if that has someone loosened again. I did replace both the sensors ($47) as a last ditch idea.

 

The tech seems completely lost on this now and the stuff he's talking about would cost more than I paid for the car!

 

Never has the car ever lost power while driving and the CEL flashing. I can even accelerate without issue. It fires at fairly random times but mostly at 70 mph or faster. The idle is not rough but I've started to notice that it takes a little longer for the idle to return to around 700 from 1000 RPM.

 

HELP!!!

Edited by parshal
Link to comment
Share on other sites

hi,

I had the same hesitation and CEL issue. I got new #2 and #4 injectors and fuel rail installed. It still hesitated and the CEL still came on. I have a 2002 LGT with 132k miles. I took out the MAP sensor located on top of the motor and cleaned it with MAF cleaner. It was black with grime. After cleaning all the grime off it I reinstalled it and unplugged the negative battery terminal to reset the ECU. After 1/2 hour unplugged I attached the negative terminal back and went for a ride. The CEL went out on it's own and after over 800 miles the hesitation is gone and no more CEL. If your car has high miles cleaning the MAP or MAF sensor will definitely help. I see people changing all the parts but the sensor is what controls them and cleaning that is the best place to start. Good Luck.

regards,

Pete

Link to comment
Share on other sites

my cel went off again dismorning. same cel p0302 i believe. misfire in cylinder 2. so by the looks of it should i bring it to subaru and have them fix it, i'm not good with mechanics of a car but i dont really trust the subaru mechanics around me. all these sells start going off after i have them do my 30,000 inspection, which involved cleaning the injectors!!! so what should i do ahhhhhh!
Link to comment
Share on other sites

I had a misfire @ about 50k miles and swapped the front 2 injectors and the misfire followed so I replaced the injector and no problem since.
Braille B2015, RBS grill, Borla CBE, Zero/Sports rad shroud, Hayden TC, Group A crank & alt pulley - Mike
Link to comment
Share on other sites

so my code is back on again and the car is idling rough and i have a lot of hesitation throughout the rpm range, i will accelerate under normal conditions and the car will buck forward then kinda die then go again, also once in awhile at any given speed it will just feels like i let off the gas but the gas peddle is still pushed in. do you think this is a injector problem? i dont even have 30,000 miles on the car
Link to comment
Share on other sites

  • 2 weeks later...
I've got a 2006 legacy gt. Had a P0304 (misfire in Cylinder 4). I replaced the plugs, which did not resolve the issue. Took it to the dealer, they say injectors are good and the next step is to see if the valves need adjustment. If that doesn't fix it they said they need to remove the heads to see what the problem is. I've got 54000 miles, I'm hoping the powertrain warranty will cover it if they need to start pulling apart the engine.
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...

Important Information

Terms of Use