mtsmiths Posted August 12, 2005 Share Posted August 12, 2005 Guess it wasn't fuel filter after all. Oh well, that was due for a change anyhow. Ran fine for two days ... then. No engine or outside air temp/humidity, driving time, rpm, grade, or any other parameters seem to control the cutting out. When it occurs it acts like fuel shut-off, hard acceleration usually clears it, usually idles fine, occassionally cuts out completely from a dead stop. When it isn't acting up it runs perfectly. I dunno, fuel pump, coil, (plugs and wires are 'bout 20,000 miles old). Any notions? Quote Link to comment Share on other sites More sharing options...
subeman90 Posted August 12, 2005 Share Posted August 12, 2005 let me guess..... no CEL right? I'm thinking for some strange reason...MAF? Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 12, 2005 Author Share Posted August 12, 2005 Well, coming from a member who has a demonstrated track record. sounds plausable. Please elucidate. And correct, no CEL. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 12, 2005 Share Posted August 12, 2005 What about road surface? Is it more likely to happen over certain types of rough pavement or after a dip or chuck hole? You might try pulling, pushing and wiggling cable harnesses while it's idling to see if you can create a cut-out condition. Do you have much corrosion on the battery cables? Sometimes they can wick acid inside and coorode quite a bit internally. Are there any stored codes in the ECU? Autozone or a friendly mech will read it for free. Carl Quote Link to comment Share on other sites More sharing options...
friendly_jacek Posted August 12, 2005 Share Posted August 12, 2005 00 has MAP and not MAF. More reliable albeit less precise. What do you mean by cutting out? Like car jerking back and forth? Any unusual tranny shifting, like hard shfts and high RPM shift points? AT temp blinking, etc? I had the above with defective TPS/defective connection. It could also be problems with any of the tranny sensors. Measure the fuel pressure before deciding to replace a fuel pump! Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 12, 2005 Author Share Posted August 12, 2005 Road surface is a non-issue, smooth or potholes. Cables (and primary ground) are clean, that was the 1st thing I did. Cutting out, basically perfect smooth running, stumble, maybe quit, perfectly sommoth running again. Might be seconds or days apart. Quote Link to comment Share on other sites More sharing options...
ferret Posted August 12, 2005 Share Posted August 12, 2005 Had this on my 02 Forester...and a neighbors 01 Legacy. Both turned out to be the Front O2 sensor. After warmup, it would send a signal as if the engine were running too rich and cut off the injectors. Both Bucked like crazy. Only happened after warmup. If these are your symptoms, try the following (but be aware, this WILL set a code, You can erase by removing the battery cable). The way I proved it was when it was acting up (on an interstate for me), I pulled off and 'unplugged' the front O2 sensor. Engine goes into 'open loop' mode. (no sensor feedback). Engine IMMEDIATLY ran better. Plugged sensor back in, Buck-Buck-Buck.....took a little persuading of the dealer to change it under warrenty (I was well under 36K), but without a code, he didn't believe me. He finally did after the 3rd visit. Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 12, 2005 Author Share Posted August 12, 2005 Had this on my 02 Forester...and a neighbors 01 Legacy. Both turned out to be the Front O2 sensor. After warmup, it would send a signal as if the engine were running too rich and cut off the injectors. Both Bucked like crazy. Only happened after warmup. Hmmm, altho' it sometimes does it after less than a minute of driving. It DID all start a couple of weeks after my wife and I were under there fixing the cat shield rattle. I was careful and pretty sure I didn't hit the O2 sensor or wires, but maybe? That would be typical, three years of off & on bogus O2 codes, the real thing would happen with NO code, and after three months (the longest ever) without a false CEL? Quote Link to comment Share on other sites More sharing options...
ferret Posted August 12, 2005 Share Posted August 12, 2005 I've owned 7 Subaru's to date, all 5 speeds...currently an 04 Forester XS. The WORST was an 02 Forester.....7 Oxygen sensors in 2 yrs.....lived with a Ck Eng light at least once a week....(many many other things also caused this light) Bad Bad case of Piston Slap (as the Avitar was created for)...Clutch replaced Twice (for the shutter problem)....Many Many letters to Subaru did nothing.......but with the good service I had from the 5 previous ones, I was willing to give them another try. The 04 IS the car I thought I purchased in 02 and restored my confidence in them. My wife even said the 02 must have been built on a Friday, by other than Subaru employees.....Heck our 94 Caravan outlived and was far more reliable than that 02 Forester.....(02 Forester 58K when traded, 94 Caravan 4 cyl/ 5 speed stick...yes a 5 speed.....179K) Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 12, 2005 Author Share Posted August 12, 2005 OK, I traded cars with The Pretty One so I could see for myself what hers was doing since I replaced the fuel filter (it was perfect when I test drove it, and yesterday). Today after driving into work she said she thought she wasn't going to make it. It ran like cr@p from start-up through town traffic for the first ten minutes or so. As I got through the last of town, several light changes, it was fine in traffic, then all the way up the grade fron Kalispell to Whitefish (12 miles) it ran fine, both on throttle and cruise - 70+ and all speeds up to. In town again in Whitefish it was fine in stop and go. SO! It seems to be running badly when cold, and fine when warmed up. Still no CEL. Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 13, 2005 Share Posted August 13, 2005 OK, I traded cars with The Pretty One so I could see for myself what hers was doing since I replaced the fuel filter (it was perfect when I test drove it, and yesterday). Today after driving into work she said she thought she wasn't going to make it. It ran like cr@p from start-up through town traffic for the first ten minutes or so. As I got through the last of town, several light changes, it was fine in traffic, then all the way up the grade fron Kalispell to Whitefish (12 miles) it ran fine, both on throttle and cruise - 70+ and all speeds up to. In town again in Whitefish it was fine in stop and go. SO! It seems to be running badly when cold, and fine when warmed up. Still no CEL. I vote engine temp sensor or O2 sensor. Also, have you cleared the ECU since any major changes or sensor replacements? I doubt the 'learned' map could be that far off fromt the default map - but it is something that should be done after working on the car's mechanicals. Carl Quote Link to comment Share on other sites More sharing options...
subeman90 Posted August 13, 2005 Share Posted August 13, 2005 is the fuel mileage good or is it in the tank? I have had O2 sensors go before and never leave a CEL but my mileage usually suffered.... i replaced the one in my old 95 impreza once and went up 2 mpg on the spot. As for the map/maf or whatever...if there is a disruption of signal it will shut you down quick. I have had issues with the plug getting corroded etc. this may sound stupid but....do you have the a/c on when this happens? Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 13, 2005 Author Share Posted August 13, 2005 Tex, I haven't done any work on this car, the last bogus CEL was read and cleared, and I did a battery dance anyhow after. The O2 sensor (second warranty replacement by SOA) has about 20,000 on it. Subieman, A/C on or off makes NO change in the behaviour (I did try it to check). Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 14, 2005 Author Share Posted August 14, 2005 OK, all I can do this afternoon is check condition and connections. The O2 sensor I know the location, where's the MAP and what am I looking at/for? Quote Link to comment Share on other sites More sharing options...
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