Engine sounds like its comming apart....

[soobcollektor]

Well as the saga continues on my newly aquired 99 Impreza L with the 2.2, The check engine light has been on since I bought it so I decided to head up to Autozone and have it checked out today. Well the Autozone here in town is located on a very long rather steep 2 lane hill, heading up the hill, I gave it some gas to get up the hill and it downshifted I was going about 50-55 mph, it started pinging REALLY badly and the check engine light started flashing. It flashed for maybe 20 seconds and then stopped flashing but remained on, I pulled into Autozone and had them read the code and it was PO170 Fuel Trim Malfunction on Bank 1. What in the heck does that mean? And why did the CEL start flashing?

 

After having him read the code I convinced him to clear it (even though they're not allowed to he said) and I started the car and left. The light stayed out for a majority of the rest of the day. Then tonight I was driving real easy in traffic and it came back on again. What gives? The engine is still pinging, not as bad but its an occasional thing, sometimes when you gas it you get none and sometimes when you run it hard it pings so bad it seriously sounds like the engine is going to come apart. Other than that the car is running fine and i'm getting excellent gas mileage.

 

What should I do to get rid of this CEL scary sounding pinging?

 

Thanks

[nipper]

Physically inspect the knock sensor. i bet it is broken, and i would just replace it anyway as its not that expensive. i dont condone repalcing parts for the sake of replacing parts, but thats what i suspect. The knock sensor's job is to keep that from happening.

 

 

 

nipper

[soobcollektor]

Would that be causing my check engine light with the P0170 code? I'l check out that knock sensor today and post back what I fnd. thanks

[Setright]

If the connector on the knock sensor is grey, you must replace it with a new one. This will have a white connector.

 

It's still possible for the new type to have a cracked housing, so get under the bonnet and have look below the throttle body. Black ring, with a 10mm hex bolt through it.

 

It's the best place to start, as nipper suggests.

 

 

Next up would be spark plugs, plug cables, fuel filter, fuel pressure regulator, fuel pump...

[sea#3]

Get your serial # off your car and phone your local dealer and see if the Air flow meter recall has been done on your car . There is a recall on the air flow meter and it will prioduce that code . It maybe going so lean that it is pinging and the knock control can not compensate for it

There ia a blue painted dot ussally on the top edge of the air flow meter by the screw if it has been done

 

Hope that helps

 

SEA#3

[1 Lucky Texan]

Just a reminder to 'reset' the ECU after a sensor change or other major work. Disconnect neg batt cable, tap the brakes, re-connect after 15-30 minutes or so.

[soobcollektor]

Update:

 

I just checked the Knock Sensor, it has a white connector where it plugs into the other wire, The housing around it looks fine with no cracks. I got a price and the dealer wants 70+ dollars for a new one so i'd like to be sure its bad before I replace it.

 

The Mass Air Flow recall has been performed on my car and it currently has no open recalls according to Subaru, I called SOA to verify.

 

I picked up a set of plugs and a new fuel filter at the dealer today, also got a can of Seafoam to run through it to see if that helps. Checked the code today to verify when the light came back on last night that it was still the same code PO170 Fuel Trim On bank 1......

What else should I do/check/replace to get this light turned off, that thing is annoying and at night its bright as hell.

 

Thanks

[soobcollektor]

Just got done cleaning the throttle body with the Subaru Spray in stuff, it was pretty dirty, changed the fuel filter and ran some SeaFoam through the PCV valve (man what a smoke screen) i've never used that stuff before but what a difference it makes. Started car let it idle for a while runs awesome but now its pinging worse than ever, moderate pining on light acceleration and HEAVY pinging on WOT.

 

I currently have the Negative battery terminal disconnected and am waiting to see if the light comes back on, i'm going to put new plugs in it tomorrow but if that doesnt fix it i'm out of ideas :-(

 

I'm desperately trying to get this CEL turned out because I really don't want to pay the dealer to diagnose it and repair it. I talked to the mechanic that I used to work with today at the dealer and he said it could be anything with that code....some help he was, but they were busy so I did'nt take the time to go in depth with him on it.

[1 Lucky Texan]

Did this begin after the MAF or other work? Sounds like your car MIGHT be running in 'open loop' (due to a bad connection to a sensor) with low octane gas or something. Or possibly it has 'jumped' time?

 

I dunno

[soobcollektor]

As far as when it began, I could'nt tell you, I bought it just about a week ago and the light has been on since, It is always just the one code PO170 and thats it. The previous owner didnt know what was causing it either, but never told me how long the light had been on

 

Anywas, after posting, I went back down and re-attached the battery cable and started it up, No check engine light, So I went to drive it and it is powerless. If you accelerate gently your fine, but if you get on it, over 1/2 throttle, it surges and has no power.

 

After that drive I took it back home and replaced the spark plugs then drove it again and still powerless. The light has remained off which leaves me even more perplexed because when the light was on the car ran awesome except for the extremely severe pinging, now that the light is off it runs like crap.

 

What gives? Anybody got any ideas. I was so happy to see that the light had turned off only to be dissapointed 2 minutes later on the test run.

[dmanaenk]

I did not get, did you check knock sensor other than by looking at is? You should check for continuity between sensor's electric terminal and ground. If its there - sensor's dead. That's what I had recently, but the CEL code was consistent with knock sensor problem.

[1 Lucky Texan]

If you don't have and can't get any history on the car, I think you should start with basic, easy stuff. If for no other reason than you'll have good info to proceed with.

 

Get the tank of gas that came in it out. Try throwing some gas dryer, injector cleaner or something and burn it out. Then put in the proper octane clean gas. Change the fuel filter. maybe do a compression test. Try to determine if the car runs better/worse/the same after it warms up. IF it idles rough, pull one plug wire ata time to spot a dead cylinder. Inspect the plugs for 1 or 2 with a radically different appearance. Check ALL ground connections and wiring harnesses to sensors. I feel you may have a sensor that is bad/disconnected but, could be one of several. A radical change after clearing the ECU points to an attempt by the car's computer to radically alter things just to keep running. You likely have a dead sensor or other 'serious' issue confusing the ECU.

 

I dunno

[soobcollektor]

The tank of gas that came with the car is long burnt out of it, Ive gotten gas probably 4 times in the past week, so I dont think its the issue, I have also sweitched gas stations thinking that may be the problem. I am currently running an entire bottel of Redline Fuel System Cleaner. I was told that this was the best you can buy for fuel injection cleaner ands it was like 7 bucks for the bottle.

 

The fuel filter has been changed, as well as the plugs, the old ones looked fine when I pilled them but I still replaced just to be aon the safe side, I used OEM plugs.

 

It doesnt seem to matter whether the car is warm or cold it still seems to run the same, its fine on moderate acceleration, but when you get into the throttle it just surges and bogs down.

 

I'll check all the connectors today after work for bad connections, The CEL still remains off after the ECU reset but its running like crap.

[1 Lucky Texan]

I think it may be time to investigate some of Setright's suggestions about the fuel system. Including the injectors.

 

How many miles on this car? Wonder if the O2 sensor's been changed or the cat converter tested?

 

Your car only has a 'bank one' (even though its a flat four - OBDII considers it a single bank 4 cyl) and there is evidently some weird air/fuel issue. It may be worthwhile also removing the covers to confirm a camshaft hasn't jumped a tooth on the timing belt. While it's idling, hold a strip of paper to the tailpipe, if it sucks the paper back in, you may have slipped time or have a broken valve.

 

good luck

 

Carl

[soobcollektor]

The car has 146,000 miles on it, I looked under the car and the O2 sensor appears to be the original (doesnt look new or anything) its kinda rusty colored so I assume its the original.

 

Anyways, the surging and no power issue seemd to fix itself this morning but about after an hours worth of driving later the CEL was back on again. It seesm to come back on after driving on the highway. I don't know why but thats when it came back on after the AutoZone guy shut it off and after I reset the ECU yesterday.

 

I'll check the timing, and try the tailpipe trick....I'll post back

Thanks

[1 Lucky Texan]

The car has 146,000 miles on it, I looked under the car and the O2 sensor appears to be the original (doesnt look new or anything) its kinda rusty colored so I assume its the original.

 

Anyways, the surging and no power issue seemd to fix itself this morning but about after an hours worth of driving later the CEL was back on again. It seesm to come back on after driving on the highway. I don't know why but thats when it came back on after the AutoZone guy shut it off and after I reset the ECU yesterday.

 

I'll check the timing, and try the tailpipe trick....I'll post back

Thanks

 

There's a front sensor too. Though the CEL you're getting might not indictae them. There is a scope or other test a tech can do. An hours worth of driving might be enough time for an excessively lean OR rich condition to make the cat conv block exhaust flow - maybe. (anyone else have more on this?)

 

good luck

[sea#3]

There's a front sensor too. Though the CEL you're getting might not indictae them. There is a scope or other test a tech can do. An hours worth of driving might be enough time for an excessively lean OR rich condition to make the cat conv block exhaust flow - maybe. (anyone else have more on this?)

 

good luck

 

 

The front A/F sensor (o2 sensor ) can go bad and "lie" to the ECM and set that code as well . usually more on the 2.5s but basically the same sensor

You could disconnect it and see if it changes anything , it will set a code

Easier to tell if you have a scan tool and you can check the data between the front and rear sensor to see if it is reacting properly

 

 

Hope this helps

 

SEA#3

[tkt117]

I would definately call your Subaru Dealer with your vin number. My car (1999 Subaru Legacy Wagon) had a recall in November, and it didn't cost me a dime to have it replaced. If your car is affected by the recall, there is no cost to you...

 

It is worth a try. My MAF sensor was replaced in December, but now my car is giving me a Knock Sensor error. LOL Why can't these cars just run forever...

 

 

Good Luck

[Chef]

He mentioned he car has already had the recall performed on it. I dunno, sounds like a failing knock sensor or bad timing for sure. Either that or some sensor ECU malfunction. The intermittent nature of course makes it even more of a PITA to fix.

 

 

 

I would definately call your Subaru Dealer with your vin number. My car (1999 Subaru Legacy Wagon) had a recall in November, and it didn't cost me a dime to have it replaced. If your car is affected by the recall, there is no cost to you...

 

It is worth a try. My MAF sensor was replaced in December, but now my car is giving me a Knock Sensor error. LOL Why can't these cars just run forever...

 

 

Good Luck

[Lawsonmh15]

Ive gotten gas probably 4 times in the past week, so I dont think its the issue, I have also sweitched gas stations thinking that may be the problem

 

 

Wow!!! Either you're getting 2 gallons per mile , or are driving an insane amount. With winter gas, I stick at 24MPG. Summer, Hwy, ~28mpg. I'd say you have problems. Just a shot in the dark, but you may want to take a look under your drivers' side dash and see if there is a green two-prong connector connected to it's mate. If there is... That's your problem. If not... I don't know. I know first hand how it runs when connected (HORRIBLE), then again, I shut it off as soon as I heard it run. If this is not the case, I would suggest you get ahold of a Subie Specialist with a used knock sensor. In Colorado, we have two such shops. Silverstar (303) 690-1225, and Super Rupair. I wouldn't expect to pay more than $70-$90. May not be what you wanted to hear, but if you continue driving with a bad knock sensor, you WILL (from what I've read) tear your engine apart. I'll bet $70; well at that point $300 doesn't seem bad after considering the pitfall. Good Luck.

 

Re-Read orig post, Now I'm wondering if a connector to one of your injectors is disconnected or in VERY bad shape. Just a thought.

[soobcollektor]

haha yeah I drive ALOT. I work with special education/mentally handicapped teens and adults (quite a change in nature of jobs from working at the Subie dealer to this) but yes we do a ton of driving around from various activities to shopping etc etc. Always good to see them excited when I roll in to pick them up in the SVX or Xt-6.

 

I didn't get a chance to check the timing today but I will definetly check that and the other stuff tomorrow. I did however listen to the exhaust when it was idleing, didnt hold the paper up to it though, and it sounds very steady and even, so hopefuly it hasnt jumped time. I am going to unplug the front O2 sensor also and see what that does. I hope thats what it is and that it isnt a computer problem, that would definetly suck. The previous owner said it always ran great (miles are mostly highway miles) and it has run great for me today just that dang light is still on.

 

Thanks for all the advise here, it truly has been a tremendous help. I would have gotten so mad and given up if it wasnt for this board. Im used to OBD1 Soobs so im learning. At the dealer believe it or not we never really got to many CEL services for Soobs, seems people dont want to pay and would rather go to Autozone and get it doene for free.

 

I'll post back the results of all the tests tomorrow.

 

Thanks again,

Tim

[1 Lucky Texan]

haha yeah I drive ALOT. I work with special education/mentally handicapped teens and adults (quite a change in nature of jobs from working at the Subie dealer to this) but yes we do a ton of driving around from various activities to shopping etc etc. Always good to see them excited when I roll in to pick them up in the SVX or Xt-6.

 

I didn't get a chance to check the timing today but I will definetly check that and the other stuff tomorrow. I did however listen to the exhaust when it was idleing, didnt hold the paper up to it though, and it sounds very steady and even, so hopefuly it hasnt jumped time. I am going to unplug the front O2 sensor also and see what that does. I hope thats what it is and that it isnt a computer problem, that would definetly suck. The previous owner said it always ran great (miles are mostly highway miles) and it has run great for me today just that dang light is still on.

 

Thanks for all the advise here, it truly has been a tremendous help. I would have gotten so mad and given up if it wasnt for this board. Im used to OBD1 Soobs so im learning. At the dealer believe it or not we never really got to many CEL services for Soobs, seems people dont want to pay and would rather go to Autozone and get it doene for free.

 

I'll post back the results of all the tests tomorrow.

 

Thanks again,

Tim

 

I was just looking at the soob Usenet posts and saw someone post about a vacuum leak. Miight be worth double checking all the vacuum hoses - maybe put on a vacuum gauge - might point to a bad valve or something.

 

good luck

[friendly_jacek]

Vaccum leak would be likely with these problems. He is clearly running lean and the fuel system cannot compensate any longer.

But, it could be easly be O2 sensor, MAF sensor, fuel filter, fuel pump, or even ECU problem. The original poster needs either learn how to troubleshoot the problem correctly or pay someone to do it (I would not recommend a dealer though).

[soobcollektor]

Update.....I unplugged the O2 sensor and drove it and really noticed no difference. It might have had a tiny bit less power but it was so small I couldnt realy even notice it. It was still pinging but seemed to run the same.

 

Could it really be that simple just an O2 sensor? Im going to go check the exhaust with the paper and check fro vacuum leaks that was mentioned and report back.

 

Thanks

[tunered]

whats the chance of a wrong crank sensor? would a completly plugged cat cause this?