Author Topic: Power loss while driving (Read 6420 times)

96GT-B · « **on:** January 15, 2013, 10:27:57 pm »

extremely hard to explain what was happening on my drive home from timmies this evening, but I had extreme power loss/sparatic revs to the point of doing 30km/h on 16th ave at WOT, had to pull over twice and shut the car off/restart just to be able to drive

here's a video i took after I got home, the first part is at WOT till it revs right up
then around 20sec it's at ~50% throttle until it revs over 4k at which point it starts revving normally (you can see when it revs smoothly up to 3.5-4k its running as per usual) any time its fluctuating, the throttle is steady.

Sonny · « **Reply #1 on:** January 15, 2013, 10:36:21 pm »

mass air flow if i had to guess. could be ignition problems too. check for corrosion or loose wires on maf, see that all the time on these cars

NiceEqualLengths · « **Reply #2 on:** January 15, 2013, 10:46:30 pm »

If you want you can try using my maf if theres a problem. At least to try and diagnose. And if you need to replace it,the SR20DET Mafs work on subies. (Atleast the WRX/STi)

NiceEqualLengths · « **Reply #3 on:** January 15, 2013, 10:54:12 pm »

Also could be the tps. Shot in the dark

purdy · « **Reply #4 on:** January 15, 2013, 11:41:51 pm »

Could be MAF, try cleaning it. Did it shut off while driving at all?

96GT-B · « **Reply #5 on:** January 16, 2013, 12:50:36 am »

Nope no stalling, or shutting down whilst driving, checked the MAF last week when I changed the spark plugs/air filter and seemed to be clean and in good condition, though possible flat out failure? I'll take a look at the connections tomorrow to make double sure that nothing is corroded or loose.

purdy · « **Reply #6 on:** January 16, 2013, 01:03:19 am »

I've had a maf flat out fail before. Erratic idle, power loss on acceleration, and shutting off while driving lol. Do the legacy's have the black test connectors under the dash like gc's? If so, pull codes...maf code should be 23

Cbxj · « **Reply #7 on:** January 16, 2013, 07:17:50 am »

Could it be a plugged fuel filter?... might be a cheap thing to try as well.
Leggy wagons are taking over WSC !, TWO of us at timmies last night. Hope you get this sorted out, I dont want our "attendance" numbers to fall by 50%.

Cbxj · « **Reply #8 on:** January 16, 2013, 07:30:11 am »

Actually, Im quite sure it's your headlights, they really want to be in my car... yep thats it.. headlghts...

96GT-B · « **Reply #9 on:** January 16, 2013, 07:59:50 am »

Hahaha

I was told the fuel filter was changed right before I bought the car (October), however what's it, like $15 for a fuel filter?
I'll check my connections and inspect the MAF/TPS today, and if that doesnt help I'll pick up another filter... so annyoing

On the drive to work this morning, ~30km all highway, i was able to keep speed but was having noticable power cuts again nearly the whole way.. almost seemed to be 'pulsing' .. hmmm

blessthekellen · « **Reply #10 on:** January 16, 2013, 01:26:36 pm »

Bad tank of gas?

GC8REX · « **Reply #11 on:** January 16, 2013, 01:30:24 pm »

Check the pins of the maf. Often the solder will wear out. If so you can open the top of the maf, heat up the old solder and fix the connections.

96GT-B · « **Reply #12 on:** January 16, 2013, 04:52:45 pm »

I took gas into consideration, as i was just under 1/4 last night, so filled this morning, with no change afterwards.
Inspected the MAF, still seemed okay, but cleaned with sensor cleaner anyways. checked TPS as well, also unpluged both seperately with thecar running and there was a noticeable difference in idle on both and threw CEL instantly. the connections seem to be okay too.

Havent driven home yet, so we'll see if the MAF cleaner made a difference.
Anyone have a fuel pressure tester/would lend a hand to test ? Leaning kind of towards a failing fuel pump possibly... thoughts? May go pick up a fuel filter tonight if nothing has changed on the drive home.. I'm guessing that the 02 wrx filter would be the one tobuy?

Cbxj · « **Reply #13 on:** January 16, 2013, 06:17:23 pm »

Just has a quick look at the pic I snapped of under you hood yesterday. Looks like a canadian 97 leggy filter is 'zakly the same.

NiceEqualLengths · « **Reply #14 on:** January 16, 2013, 10:14:32 pm »

I'd go with the leggy fuel filter. same setup and everything. I've got a fuel pressure gauge that you could use. a in line one.

96GT-B · « **Reply #15 on:** January 16, 2013, 11:44:01 pm »

10-4 on the legacy filter. The drive home from work was as if the car never had this problem at all.. So maybe it was a dirty MAF..
Though I'm not holding by breath, and am expecting SOMETHING to happen again in the next couple days..

I'll still probably pick up a new fuel filter just for peace of mind..
I'll keep y'all posted!

gc8guy · « **Reply #16 on:** January 21, 2013, 12:53:02 pm »

have you checked for stored codes?

96GT-B · « **Reply #17 on:** January 22, 2013, 08:28:14 am »

No I haven't, as I don't have anything to do so with...
Anyone have a code reader?

GC8REX · « **Reply #18 on:** January 22, 2013, 08:41:36 am »

Quote from: 96GT-B on January 22, 2013, 08:28:14 am

No I haven't, as I don't have anything to do so with...
Anyone have a code reader?

if its like the gc's (not sure if it is), there should be a pair of black connectors and green connectors under the dash looking up from the pedals. Turn the key off, plug in the black ones, turn the key to on (don't start), read the pulses of the cel. Long flashes are tens, short are ones.

purdy · « **Reply #19 on:** January 22, 2013, 08:47:41 am »

Quote from: purdy on January 16, 2013, 01:03:19 am

I've had a maf flat out fail before. Erratic idle, power loss on acceleration, and shutting off while driving lol. Do the legacy's have the black test connectors under the dash like gc's? If so, pull codes...maf code should be 23

I already mentioned that!

96GT-B · « **Reply #20 on:** January 22, 2013, 12:55:23 pm »

Ahhhh... I didn't know you could just connect plugs under the dash! Haha

I was assuming that you would need an obd reader or something along those lines.
I will take a look today and see what I can gather.

purdy · « **Reply #21 on:** January 22, 2013, 01:15:35 pm »

http://www.perth-wrx.com/vb/stock-ecu-discussion/30024-how-read-subaru-cel-gc8-stock-engine-control-unit-only.html#post406615

The legacy's should have the connectors too....this link is super helpful with the code reading and resetting the ECU

96GT-B · « **Reply #22 on:** January 26, 2013, 09:05:20 am »

Thanks for the link, proved to be rather helpful!

From what I gathered, I had codes
23 Mass air flow sensor
24 Idle air control solenoid

so I reset the ecu as well, who knows how old those codes are... checked again, and all clear. I'll check again in a week or so to see if anything has re-appeared and go from there!

GC8REX · « **Reply #23 on:** January 26, 2013, 10:37:11 am »

I would put my money on the maf needing to be resoldered as mentioned. Makes sense with your symptoms and is a somewhat regular issue on the jdms.

Grasp · « **Reply #24 on:** January 26, 2013, 03:49:51 pm »

A resolder will not always fix the problem either. I had this on my gt-b. Resolder got things running again from 2000rpm up, but she was still sluggish before 2k. A new maf fixed er right up, and it ran mint after that. Be certain to get the right maf though!