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FIXED!! 90 Lego loosing power/misfire under fully warmed up conditions?


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the car: 1990 Legacy LS wagon, AWD, Auto, 194,000 miles

 

the problem - this past Saturday, while on a longish trip (approx 3 hours one way) about 1/2 way the car began to lose power, chug, sputter, miss, then surge & run ok for a few minutes, then repeat. Also saw an intermittant CEL - would come on for a few seconds, then go out - happened 2-3 times. (BTW - weather was cool - upper 40's to low 50's - had some rain on the trip down, dry on the way back)

 

pulled off the hiway, shut off the car & popped the hood & checked things over - no obvoius problems. Started the car, idling rough - check wires again while it is running - found one bad plug wire (it was arcing out the side of the boot!) wrapped it with electrical tape to get where we were going (it ran ok with only occasional mild sputters) & got a new set of wires thinking that would cure the issue...

 

return trip - car ran great for about 45 mins or so and began to act up as before - WTF?? stopped, checked things over again, could find no obvious problems - wires all seemed to be fine & were tight...we were stopped for maybe 10-15 mins w/car turned off.

 

get back in the car, start up, no problem, took off and it ran fine the rest of the way home - no sputtering, missing or any other sign of the problem.

Made plans to get new plugs, air & fuel filters installed on Tuesday after it got done getting exhuast leak repaired.

 

FF to today (tuesday) Took car in for exhuast repair - ran fine on the 30 min trip to town. Went & got my tune-up stuff while it was being worked on - new air & fuel filters, new set of correct NGK plugs, properly gapped. Get the car back from the muffler shop, (sounds good) & get the items installed - time for a test run...

 

Got up on the big hiway and got up to speed (70+) doing fine for about 20 mins, then it started again - loosing power, sputtering, etc...again with a brief CEL (only on for about 30 seconds or so). Pulled off the hiway, and pointed it home, had no power trying to take off from a dead stop unless i really got into the throttle, ran like crap then would surge up and run smooth for a few minutes, then back to running like crap all the way home...FWIW - weather today - cool and rainy :mad:

 

This problem only seems to rear it's ugly head when the car is fully warmed up and running at hiway speed (70+) - if it gets shut down and allowed to cool, then kept under 65 mph it seems to run fine...at a loss here???

 

MAF??? O2 sensor??? Plugged cat??? :confused: I do have some spare parts available from parts cars, but condition of said parts is unknown...

 

it is raining out right now, but i do plan on getting the stored code out of it as soon as it dries up (or i take it back into town) - in the mean time, would appreciate any thoughts, suggestions, comments on what to check/look at...

 

Will post back later with the code(s) retireved

Edited by heartless
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ok, update with codes...

 

initial read (black conectors)

 

code 24 - Air Control Valve

Code 32 - O2 Sensor

 

D check (green connectors) gave no additional info

 

Checked the Air Control Valve per FSM

 

Voltage check - FSM minimum 10 v - my reading - 12+v

 

Ohm Check:

FSM Spec My Readings

pin 1 to pin 2 - 9 ohms 10.7 ohms

pin 2 to pin 3 - 9 ohms 10.8 ohms

 

A mechanic friend (over the phone) said the higher readings might be caused by the engine still being warm, but he didnt seem to think they were too far out of whack - thoughts anyone???

 

anyway, went ahead and cleared codes and took it for another drive - it did start acting up again. Checked for codes again when i got home - only one this time....drum roll please...Code 32 - O2 sensor!

 

So, I am going to try putting in a used O2 sensor and give it a spin, see if it clears things up or not - or would I be wasting my time?

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Did you check the Ignition Coil? I have seen lazy o2 / AF sensors cause some odd problems so if the ECU is saying that personally that is prob where I would begin also...the o2 sensor would make some sense to me also fore it reads the exhaust gas when in closed loop ( up at operating temp )...

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Coil packs seemed to be fine - could see a very strong spark in broad daylight no problem when pulling the wires to check them.

 

like i said, the car seems to be perfectly fine as long as it is kept under 65 mph - drove it roughly 75-80 miles home saturday night, then 30 miles into town sunday eve, then 30 miles home. then 30 miles back to town this morning with no problems what-so-ever. but shortly after getting it on the freeway and getting over 65 mph is when it starts acting up.

 

For now, i guess i am going to go with the O2 sensor getting lazy - will see about getting it changed out and hopefully it will cure the problem - got lots of longer trips coming up and really need it to be running right!

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if you didn't use Subaru wires, EJ engines are not the most forgiving. i've seen brand new auto parts store wires cause basically undrivable conditions, massive bucking, hesitating, etc. i would expect a cylinder misfire code though so my first thought is yours - try and check that O2 sensor. i've seen O2 sensors cause drivability issues when the wire sheathing wears off exposing the wire to exhaust parts or the cross member.

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Thanks for the reply, Gary - yeah, they are auto parts store wires, but only because i am broke, dont have a dealer anywhere near me (nearest is several hours away) & had to have them NOW! (no waiting for an online purchase) LOL Will be looking into ordering some proper wires later when the cash flow is better. (would appreciate suggestions for where to order from online...price, shipping, cust. service...)

 

Going to try that used O2 sensor we have on hand and see if that improves anything or not. It looks ok, but looks can be decieving... May have to try to order one of those, too.

 

Which begs the question - is there a difference between auto and manual O2 sensors?? I didnt see anything listed specifically for one or the other when looking at them online...

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Someone has to have a set of used wires around they could send you to test if that's the problem or not?

 

Without a CEL I doubt it's your issue anyway though. But I have see non-CEL faults before.

 

I just order them from the online dealers, $36 last set of wires I bought from Subaru.

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the set of wires i got were $22 & change - i know, you get what you pay for... lol $36 isnt bad tho for the dealer wires. :) for right now they are ok, but have had burn thru problems before with the cheap wires...

 

any specific online dealer that I should look at?? havent ordered stuff from any before - always made do with either used or local store parts... :rolleyes:

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i forgot, for one part shipping will kill the deal probably. best bet is to have a local dealer match the online pricing. it's roughly 20% difference so the $36 wires online would run $42 at the dealer. they've always given that to me when I ask. it's easy for them since they have a price point for local mechanics and shops so they're already doing it every day.

 

one of the online vendors has a $12.95 minimum shipping charge, so it's not economical for one inexpensive part. a few of the more popular Subaru online:

 

1stsubaruparts

subarugenuineparts

liberty subaru

and Jason at Auburn Subaru is a USMB favorite

 

info on all of those places is on USMB.

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Thanks for the info guys! it really is appreciated! :)

 

Hoping to have everything sorted out tonight - keep your fingers crossed for me that the O2 sensor does the trick!

(btw - if the used one does correct the issue, i will be springing for a new one for the old girl, just for the longevity factor - no telling how long the used one would last)

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Well - looks like I will be springing for a new O2 sensor anyway...

 

swapped out the used one we had and it made the situation worse - it now acts up at lower speeds (50-60 mph) and it did throw the code 32 yet again...

 

no one near me has one in stock (not even the small dealer I found an hour away! :mad: ) so i am gonna have to order one and wait for it to get here. :-\ totally bummed right now.

 

anyway - thanks for the parts leads guys - gotta go make some calls & see how bad this is gonna hurt the wallet.

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Well, after making several phone calls, I ordered my O2 sensor from the local parts house - before I go getting flamed about it - it was the absolute fastest option for me - next day instead of late next week from a dealer, and i NEED the car!

 

anyway, got that installed, cleared the last code and went for a test run. About 35 miles +/- out at about 75 mph, turn around and the same back and she ran flawlessly!! :banana::banana: no hiccups, no power loss, no problems what-so-ever! the real test will be Saturday when we head to Madison again (3+ hours one way, about half 2 lane/half freeway)

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that's what i would have done. i've never had a problem with afermarket sensors but i haven't used many in EJ's. thing is, those early gen legacy's like yours seem much more forgiving mechanically/electrically anyway so i'd think about it even less in those. rock on.

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Yes, it is a good feeling to have it running right again. :)

 

the new sensor is a direct fit Bosch (the old one was a Bosch as well) so i feel pretty good about using it, and it does have a little heavier wires, so maybe it will last longer (altho 194,000+ is a pretty long time! LOL and this poor car had a rough life)

 

Next big project will be a reseal to fix all the oil leaks - gonna be yanking the engine for that! :eek: for now, i just make sure i carry extra oil with me!

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Well, car is definitly fixed! :banana:

 

Took her to Madison Saturday - ran beautifully both ways - and an added bonus - my fuel mileage has increased!!! went from an average of 28mpg, to just over 30mpg!! Yeah! In the 2 yrs I have had this car I could never quite break that 30 mpg mark (highest previously was 29.9) - now it has done it not just once, but twice!! :grin: 30.1 and 30.3! yippee!!

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