labman Posted May 3, 2005 Share Posted May 3, 2005 Hi All! I have an '85 GL turbo that I just got running after a loooong (14yr) rest . . . Runs great, passed emissions just fine, but it has a stubborn miss at idle. I have replaced _all_ of the fuel hardware; gas tank, fuel pump, injectors, injector rail (whatever ya call it), pressure regulator, filter, etc. (Had to; worst case of "varnish" I've ever seen . . .) Also replaced the plugs, plug wires, cap, and rotor. As such, I have had the engine down to basically a long block and back; The intake plumbing is intact and tightened, and all of the vacuum lines are good, and presumably in the correct locations. But the roughness at idle remains. The emissions tech (surprised that it passed) said that he thought it was a "lean mis-fire", caused by the ECU trying to minimize CO (O2) readings at the oxygen sensor. While I've never heard of this before, it seems at least possible; certainly it gets _worse_ as the engine warms, which would seem consistent with his diagnosis. BTW, this car has an automatic tranny. I have another EA81T car (MT) that doesn't have the rough idle issue, and am planning on swapping parts in an effort to isolate the problem. Before I do, tho, I thought I'd ask to see if anyone in the group has experienced this sort of problem, and if there is an easy fix. Any thoughts on this greatly appreciated. TIA! PS: The AT car only has 67,000 miles on it. 4sale if anyones interested; $1000, $1200 after I (hopefully) fix the idle and replace the windshield. Very clean little car; the missus sez it has to go :-( ByeBye! S. Quote Link to comment Share on other sites More sharing options...
labman Posted May 3, 2005 Author Share Posted May 3, 2005 Hi again! Caught an "oops" _after_ hitting the send button . . . Hi All! I have an '85 GL turbo that I just got running after a loooong (14yr) rest . . . Runs great, passed emissions just fine, but it has a stubborn miss at idle. I have replaced _all_ of the fuel hardware; gas tank, fuel pump, injectors, injector rail (whatever ya call it), pressure regulator, filter, etc. (Had to; worst case of "varnish" I've ever seen . . .) Also replaced the plugs, plug wires, cap, and rotor. As such, I have had the engine down to basically a long block and back; The intake plumbing is intact and tightened, and all of the vacuum lines are good, and presumably in the correct locations. But the roughness at idle remains. The emissions tech (surprised that it passed) said that he thought it was a "lean mis-fire", caused by the ECU trying to minimize CO (O2) readings at the oxygen sensor. While I've never heard of this before, it seems at least possible; certainly it gets _worse_ as the engine warms, which would seem consistent with his diagnosis. BTW, this car has an automatic tranny. I have another EA81T Mmmmm, another EA82T that is car (MT) that doesn't have the rough idle issue, and am planning on swapping parts in an effort to isolate the problem. Before I do, tho, I thought I'd ask to see if anyone in the group has experienced this sort of problem, and if there is an easy fix. Any thoughts on this greatly appreciated. TIA! PS: The AT car only has 67,000 miles on it. 4sale if anyones interested; $1000, $1200 after I (hopefully) fix the idle and replace the windshield. Very clean little car; the missus sez it has to go :-( ByeBye! S. Bye Again! S. Quote Link to comment Share on other sites More sharing options...
EA82Turbo Posted May 4, 2005 Share Posted May 4, 2005 I would try the air flow sensor (air mass or what it has). swap from other leone. Hope this helps Hayden Quote Link to comment Share on other sites More sharing options...
Ross Posted May 4, 2005 Share Posted May 4, 2005 Does the misfire/roughness occur when the engine is first started cold? If not, it may be an oxygen sensor prob. Quote Link to comment Share on other sites More sharing options...
Steveman09 Posted May 4, 2005 Share Posted May 4, 2005 I bet its the TPS/IDLE Control Unit. Older Subaru's are notorious for TPS/IDLE Unit problems. Quote Link to comment Share on other sites More sharing options...
labman Posted May 4, 2005 Author Share Posted May 4, 2005 Hi Ross, All! Ross asks: Does the misfire/roughness occur when the engine is first started cold? If not, it may be an oxygen sensor prob. Nope. Drove it into work this morning. It idles nice -n- smooth from cold start (started at first bump of the starter, air temp. this morning ~30'F) til it's pretty much at operating temperature. Runs great goin' down the highway. The problem is most evident while sitting at a traffic light with the tranny in "drive"; if you slip it into neutral, it smoothes out quite a bit. One of my students is interested in it. Sure would be nice to get that damned idle fixed first, but I guess for a 20yo car, it's really not all that bad . . . And thanx for the suggestions guys; pretty much the order I had planned to start swapping parts (mostly based on ease of implementation): air-flow meter, O2 sensor (whole down-pipe assy, actually), throttle body/TPS. Anyone know if the ECU will swap AT vs MT (same year car, '85)? What about that anti-knock thingie? Any easy way to tell if it's working correctly? Can I just pull the plug to disable it? Timing at idle set per specification (20' BTDC IIRC), + a couple degrees to compensate for my 7200ft elevation. See any problems with that? Thanx again. ByeBye! S. Quote Link to comment Share on other sites More sharing options...
labman Posted May 4, 2005 Author Share Posted May 4, 2005 Me again! I notice my sig. isn't getting posted. Pretty sure I selected the "show signature" box; it is there in the "preview post" window, but doesn't seem to make it onto the board. ByeBye! S. - Steve Jernigan Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101 (entered manually; watch, it'll work as advertized this time. Darned computers, anyway ;-) Quote Link to comment Share on other sites More sharing options...
Steveman09 Posted May 5, 2005 Share Posted May 5, 2005 Hi Ross, All! Ross asks: Nope. Drove it into work this morning. It idles nice -n- smooth from cold start (started at first bump of the starter, air temp. this morning ~30'F) til it's pretty much at operating temperature. Runs great goin' down the highway. The problem is most evident while sitting at a traffic light with the tranny in "drive"; if you slip it into neutral, it smoothes out quite a bit. One of my students is interested in it. Sure would be nice to get that damned idle fixed first, but I guess for a 20yo car, it's really not all that bad . . . And thanx for the suggestions guys; pretty much the order I had planned to start swapping parts (mostly based on ease of implementation): air-flow meter, O2 sensor (whole down-pipe assy, actually), throttle body/TPS. Anyone know if the ECU will swap AT vs MT (same year car, '85)? What about that anti-knock thingie? Any easy way to tell if it's working correctly? Can I just pull the plug to disable it? Timing at idle set per specification (20' BTDC IIRC), + a couple degrees to compensate for my 7200ft elevation. See any problems with that? Thanx again. ByeBye! S. You did make sure to adjust your timing with the green test connector connected right? You have to do this to get the correct initial ignition timing. BTW: I doubt its the knock sensor, I ran mine without one for a week without issue, just the light was on. Quote Link to comment Share on other sites More sharing options...
Ross Posted May 5, 2005 Share Posted May 5, 2005 You may want to try runngin without the knock sensor if everything else fails. If there is an intermitant fault in the knock control system, it may be fluctuating the timing as it idles. So, yes, you could unplug the knock sensor and reset your timing. I wouldn't suggest running it permenently like this though. Quote Link to comment Share on other sites More sharing options...
Buddy Posted May 5, 2005 Share Posted May 5, 2005 PS: The AT car only has 67,000 miles on it. 4sale if anyones interested; $1000, $1200 after I (hopefully) fix the idle and replace the windshield. Very clean little car; the missus sez it has to go :-( ByeBye! S. why would you want to sell such a good car? if you fix it you could drive it for another 200,000 miles. dude, is your wife crazy or what? i would,t sell that car for nothing if i where you! Quote Link to comment Share on other sites More sharing options...
labman Posted May 5, 2005 Author Share Posted May 5, 2005 Hi Buddy, All! Buddy asks: why would you want to sell such a good car? if you fix it you could drive it for another 200,000 miles. dude, is your wife crazy or what? i would,t sell that car for nothing if i where you! Well! The original plan was to use the ultra-clean chassis as a starting point to build a rallycross car; I have an '85 GL-RX with a hot motor that is a killer-diller on dirt roads and such. Alas, the RX has been thru a severe hail storm, and kinda resembles a golf ball. This project was side-lined when I had a chance to get a screamin' deal on a lo-miles '96 Legacy; the Ms. informed me that if I brought another car home, she was gonna stick it up . . . well, never mind, but it _would_ have solved the problem of where to park it ;-) Some fire in alla the smoke. We have way too many vehicles sitting around the homestead; 2 '84 GL wagons (offroad car + parts car), the two '85 GL sedans, an '02 Forester (the spousal carrage), 2 '85 MR2s (one a dedicated CSP autocross car, one the teenaged girl-child drives), an '89 MR2 (My daily driver unless the weather's bad), a beat-up old Ford truck, and an antique Bobcat. Enter the Legacy . . . something had to go; the obvious choice was the clean GL, as I don't particularly care for the 3spd automatic in it. If it had come with a 5spd manual box, I would have fought a bit harder to keep it in the stable. <http://www.ultimatesubaru.org/forum/showthread.php?t=12938> We do what we can . . . ByeBye! S. -- Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101 Quote Link to comment Share on other sites More sharing options...
Cougar Posted May 5, 2005 Share Posted May 5, 2005 Have you checked for an intake manifold leak after it has warmed up? Quote Link to comment Share on other sites More sharing options...
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