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Stumbling, bucking ... end of my rope


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28 replies to this topic

#1 salewit

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Posted 02 October 2008 - 12:16 AM

92 Legacy.

Symptoms: Bucking at light acceleration and coasting. Hot or cold. Ok only on heavy acceleration*. Has spasm attacks during idle. Can be idling smooth as silk and then all of the sudden starts trembling, then back to smooth. CEL light flashes on during moderate acceleration then shuts off. Codes are 12, 13, 14, 15, 16, 17 and 31. Cleared memory and same exact codes came back.


AFTER this started, replaced plugs, wires, coil, ignition control unit, MAF sensor, cam sensor, TPS, PVC, fuel filter, air filter, oxygen sensor (twice), temp sender (in rear).

Tested fuel pressure, fuel pressure regulator, compression, vacuum leaks, valve timing, ignition timing (but couldn't find mark on pulley).

I can't find anything else to change or check and I'm stumped. *This week I had a new symptom. During a heavy hill climb, it acted like it was running out of gas... or the engine shut down.... pumped the gas pedal and nothing. Minutes later it recovered and went back to stumbling and bucking but at least it had power again.

The only thing I haven't looked at was the ECU, but I can't find it. My book says it's behind the glove compartment or on the floor under the glove compartment. It's not there (hey maybe that's the problem!).

Any help would be really appreciated. I'm about ready to park it next to the junker I stripped the MAF out of.

#2 screwbaru2

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Posted 02 October 2008 - 12:37 AM

I know after replacing all that you'll say WTF to this but I noticed you omitted the pcv from your replacement list. If you haven't changed it you should a clogged valve will cause these symptoms though not a CEL. Also make sure the pcv hoses are clear.

#3 Gnuman

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Posted 02 October 2008 - 12:38 AM

Sent you a PM, call me. I'm near you. I make my living repairing Subarus. With just the list of CEL codes, it almost sounds like a bad connector in the wiring harness. . .
everything listed but the cam sensor goes through one connector by the battery.

#4 salewit

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Posted 02 October 2008 - 01:01 AM

I know after replacing all that you'll say WTF to this but I noticed you omitted the pcv from your replacement list. If you haven't changed it you should a clogged valve will cause these symptoms though not a CEL. Also make sure the pcv hoses are clear.


No it's on the list only I called it a PVC instead of a PCV. I've heard it referred both ways.

Gnuman: Interesting. The battery was loose on the deck and just floating around. I recently (months after the stumbling started) got a tie down kit. I'll look at that in the morning and give you a call.

#5 Manarius

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Posted 02 October 2008 - 08:10 AM

Are you sure that the MAF you pulled out of the junk car was good as well? I'd really want to test it against a known good MAF.

#6 bheinen74

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Posted 02 October 2008 - 08:38 AM

your timing belt is off a tooth or 2. please check that. mine was...how i got my 92ss so on the cheaps

#7 salewit

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Posted 02 October 2008 - 01:16 PM

your timing belt is off a tooth or 2. please check that. mine was...how i got my 92ss so on the cheaps


Yep... on the list. It's right on. In fact this is the first thing I did as I had a belt that jumped a couple of teeth when I put this engine in a year or so ago. It worked fine and smooth for more than a year after I fixed that problem.

No I'm not sure the replacement MAF is good. Where do I get a good one to check it against without buying one for $200+?

#8 Gnuman

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Posted 02 October 2008 - 04:19 PM

Yep... on the list. It's right on. In fact this is the first thing I did as I had a belt that jumped a couple of teeth when I put this engine in a year or so ago. It worked fine and smooth for more than a year after I fixed that problem.

No I'm not sure the replacement MAF is good. Where do I get a good one to check it against without buying one for $200+?

Easy, we take the one off my good running 92 Legacy, and see if that fixes things. . .

Stumbling and bucking could be caused by the MAF, but I'm also concerned about you getting all those codes, particularly all four of the injectors at once, as well as the TPS. that really sounds like a harness problem to me. . .

Oh, and the ECU on your model year is behind the drivers kick panel (behind the dash on the drivers side) If you have an automatic, it is the leftmost one. If you have a manual, it is the only one up there. . .

Edited by Gnuman, 02 October 2008 - 04:23 PM.


#9 crockettbrat

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Posted 02 October 2008 - 04:33 PM

I had a similar problem with my ej brat. The idle switch was set wrong. Its part of the tps. Very easy to adjust. Mine was just barely off and in stop and go traffic my check engine light would come on and then I'd get the bucking and jerking thing from right off idle and it would be fine once I was going more than about 15mph. Since I adjusted the idle switch I've had no problem. Hope this helps.

I'm in the east bay too if you need help.

Daniel

http://www.main.expe...PS_testing2.jpg This page has the procedure for checking the idle switch.

Edited by crockettbrat, 02 October 2008 - 04:41 PM.


#10 salewit

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Posted 02 October 2008 - 09:45 PM

Well Gnuman you nailed it! I popped the hood and wiggled the connectors behind the battery, then went under the dash and wiggled some connectors going into the ECU, and the problem is gone! I knew something was different the second I turned the key as the CEL came on and stayed on.

Tomorrow I'll clear the codes and see if the CEL stays off. I was also thinking of unplugging some of the connectors and carefully checking for bad pins and possibly spray them with an electrical cleaner before plugging back in.

But it's running just as smooth as silk and I can't thank you enough for the advice. I just wish I had tried this before spending close to $500 on all the above stuff I didn't need.

I've been driving my manual with my foot half-way down on the clutch the past 6 months to avoid this bucking. I'll have to learn how to drive again.

Thanks again!


Easy, we take the one off my good running 92 Legacy, and see if that fixes things. . .

Stumbling and bucking could be caused by the MAF, but I'm also concerned about you getting all those codes, particularly all four of the injectors at once, as well as the TPS. that really sounds like a harness problem to me. . .

Oh, and the ECU on your model year is behind the drivers kick panel (behind the dash on the drivers side) If you have an automatic, it is the leftmost one. If you have a manual, it is the only one up there. . .



#11 bmaness

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Posted 29 October 2016 - 11:34 AM

My 95 legacy started intermittent bucking today. All speeds in all auto transmission gears. Almost like bad gas but not quite. I limped home and am trying to dope out my best move. I disconnected the negative battery terminal and am waiting an hour to reset the ecu. I keep reading about MAF? Master something I suppose...There was no check engine light.

Most everything is original. Hose s look good but it might be pcv as I've read. Have not changed plugs or wires in at least 100k miles, but I've heretofore had no cause as the car runs well. I did replace the fuel filter awhile back.

I plan to drive it around the block in a while unless it would be considered a poor decision.

#12 bmaness

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Posted 29 October 2016 - 12:39 PM

And I meant to say above, it never died. I looked at the timing belt ( I'm running naked) and it looks good.

So I started it, idled for awhile, and took it on the road with no recurrence. The car runs like a dream when it runs. So now I think I know it's not plugs, wires, coil, timing belt, or gas. But, I know it will come back. At a I opportune time no doubt...

Ideas?

#13 Fairtax4me

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Posted 29 October 2016 - 03:49 PM

How old are the plugs and wires?

#14 bmaness

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Posted 29 October 2016 - 04:49 PM

100k at least on plugs and wires

#15 Caboobaroo

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Posted 29 October 2016 - 05:05 PM

Plugs needs to be replaced every 30k miles. Once they are worn, they can cause misfires under load, or "bucking" during acceleration.

#16 bmaness

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Posted 29 October 2016 - 05:20 PM

I checked r ockauto and plugs and wires are pretty inexpensive. Should I replace the coil as well?

#17 Fairtax4me

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Posted 29 October 2016 - 07:14 PM

No. Just plugs and wires. Use NGK or Denso. I've had good luck with both.

#18 bmaness

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Posted 29 October 2016 - 07:43 PM

So I drove it for 90k miles at least before it started bucking. A trip to oreillys magnolia in the morning for plugs and wires.

#19 bmaness

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Posted 30 October 2016 - 09:27 AM

I pulled the old plugs. NGK's. 3 were dry but the front left had oil film on it and in the hole it came from. The wet plug gapped .070 and the others weren't far behind.

I won't get the new parts until tomorrow. I think I saw .044 as the gap. Do they go in dry or can I use anti-seize? I also presume I need a 16mm spark plug socket to get them in more easily?

#20 1 Lucky Texan

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Posted 30 October 2016 - 11:39 AM

you may also need new valve cover gaskets. oil in a plug tube can cause misfires. NGK should be gapped properly outta the box but it doesn't hurt to carefully check. i THINK if the NGK part number ends in ' 11 ' that means gapped at 1.1mm or ~=0.044"



#21 bmaness

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Posted 31 October 2016 - 06:25 PM

They sold me NGKs and OmniSpark wires. They also sold me anti-seize and dielectric grease. I had to watch a web video to see how to properly apply the grease... All in all a pretty amateur job for $40 in parts and an hour or so of labor.

I gassed her up and rezeroed the trip meter. Before the bucking started I was getting 22 mpg. Surely i'll pick up one or two by making this repair.

#22 Fairtax4me

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Posted 31 October 2016 - 07:03 PM

95 ej22 plugs should have a .039-.043" gap. 44 is a little wide, but better than 70 for sure!

#23 1 Lucky Texan

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Posted 31 October 2016 - 11:00 PM

^^ good info

 

in 'the old days' if a range was listed, we'd set them tight figuring they'd wear larger.



#24 bmaness

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Posted 02 November 2016 - 10:10 AM

Wel, it drove great for 130 miles. Now bucking again.

What next?

#25 1 Lucky Texan

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Posted 02 November 2016 - 10:42 AM

none of us would have been likely to use Omnispark or most other aftermarket wires. perhaps we were just holding our breath hoping you'd report good performance? If you have the old wires, you could put them back on as a test but, seems like they are pretty old. OEM wires really do seem to be best. Perhaps 130 miles is what it took to oil-soak the new boot - maybe shorting high voltage again?

 

any codes stored?

 

um, any correlation with fuel level? maybe you have a fuel supply problem.


Edited by 1 Lucky Texan, 03 November 2016 - 11:13 AM.





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