alpop Posted February 1, 2015 Author Share Posted February 1, 2015 Actually that Beck Arnley looks like a three pin and my TPS is a 4-pin, It looks like my automatic takes the 4-pin TPS. Funny, my TPS has 4-pins but the connector only uses three of the spots with only 3 wires coming out of it? Anyways looks like I need the Standard Motor Products TH389 running more like $154.00 Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 1, 2015 Share Posted February 1, 2015 It may only go as high as 4.2ish. The more important thing is the starting voltage, which is higher than normal. You might just make sure the throttle valve is able to close all the way. Check inside the throttle body with the valve open and clean any carbon crud out of the bore and off of the valve with some throttle body cleaner and a rag. I've seen heavily carboned throttle bodies not allow the valve to fully close, and that will throw off the TPS reading at closed throttle. The blank in the middle is a problem, assuming you have a solid connection. Did you try wiggling the probe when it went blank to make sure it wasn't just loose? Honestly these TPS sensors don't fail often. A used one should be fine. Does the one on the car say Beck Arnley on the sensor? It should be either Nippon or Denso, IIRC. Possibly Hitachi. If it says B/A on the sensor that is a replacement, and that is probably why it's a problem. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 1, 2015 Author Share Posted February 1, 2015 One of the first things I did when I got the car was clean-up the throttle body, it wasn't very dirty. I have replicated the dead spot at least a dozen times going both up and down, sometimes it extends to 2.5-3.5 volts, always does it some with that weird buzzing (TPS I think). I could probably adjust the TPS and bring the starting voltage down, but this wouldn't fix the dead spot which is probably most of my problem. One (very) funny thing is sometimes I don't need to have the ignition on to get the voltage out of the TPS, I checked and none of the other ignition on things (radio, cabin fan etc.) work in this situation with the key out of the ignition. The TPS in there is identical to an Airtex with the writing A22-667-ROO on it, adjustable and 4-pins, $179 at Rock Auto. Saw a used one on e-bay for $50ish, but not sure I want to fool around with this again. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 2, 2015 Share Posted February 2, 2015 Sounds like you've ruled out a bad connection. No point adjusting it since it still won't act right. I wouldn't pay for a brand new one knowing that these are not a common failure item. But, to me, a TPS is such a simple change that its something I don't mind repeating. For others it may be worth the price of a new sensor for peace of mind. The computer will still power certain sensors even with the key out of the ignition. Sometimes for up to a hour. The ECU monitors coolant temperature, and if the temperature rises after turning off the engine (due to heat soak) it will turn the cooling fans on to help bring the temperature down. Most of the sensors use the same 5V reference supply circuits, so if one sensor is still powered, most if not all of the others will still have power going to them as well. The buzzing sound is probably coming from the idle air control valve. The valve changes position every time the throttle plate moves. The buzz is the small electric motor in the valve moving the valve back and forth. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 2, 2015 Author Share Posted February 2, 2015 Assuming that this indeed is the problem, I spent so much time figuring it out that I just want to make sure I'm done with it - so I ordered the new one from Amazon with free three day shipping (best price and best shipping). Hoping to use the car for a trip later this week. I would hate to get a used one, test it, and find a dead spot on it also! BTW the engine is supposed to have around 140k on it, the TPS in there sure looks original (grungy) and there is a paint slash across the unit and screw indicating where it is adjusted to. This is the case with many of the engine fittings that are adjustable (paint slashes) and I assume it came from the factory that way? Thanks for all that info on the ECU and IAC valve - explains a few things and good to know. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 5, 2015 Author Share Posted February 5, 2015 Got the new $154 (it said Standard on the internet but the box says Intermotor/SMP) TPS, anyways its weird. The old one had a gap or dead spot from about 3.0-3.4 volts, sometimes 2.8 - 3.4, this one has a tiny (very repeatable) dead spot from 3.21 - 3.27 volts going up and about 2.82-2.75 going down? Could the new one be defective? Guess I should throw things back together and see how it drives. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 5, 2015 Share Posted February 5, 2015 Intermotor Standard Motor Products. Intermotor is one of their electronic parts divisions. Dead spot in the new one sounds fishy to me. But its in roughly the same range as the old one. This one has 4 pins in the connector right? I wonder if it has two separate resistive slides in it and when the sweep slides across to the next one you're seeing the loss because the two are temporarily bridged. I'll have to do some digging on that one. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 5, 2015 Author Share Posted February 5, 2015 Tried another multimeter, no micro dead spot, although this one shows an instantaneous jump to 5 volts right at 4 volts - weirdness, nothing is as it seems. No, I'm not going to put the old TPS back in and test it with the 2nd multimeter and see if there is still a (much bigger) dead spot. I'll leave the new TPS in there and see how it drives. Ha, but I drained the battery with something I was doing, guess I left things hooked up for three days. Oh well, wait 'till the morning to jump it. Quote Link to comment Share on other sites More sharing options...
gdudik Posted February 5, 2015 Share Posted February 5, 2015 For the cooling fans cycling on and off and other problems, check to make sure that the green "test mode" connectors under the dash are unplugged. Should be under the dash on the driver's side. Car will do all kinds of bizarre things with them plugged in. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 8, 2015 Author Share Posted February 8, 2015 So I still have the intermittent acceleration problem even with the new TPS - foiled by a defective multi-meter (its in the garbage). Should have admitted this before, can't be an issue with the throttle position. I can start from a stop and keep the pedal/throttle in the same place - maybe halfway down, and it lags and lags and lags at lower rpms then finally hits 2500-3000 rpm and it takes off, then shifts gears and lags at the lower rpm again then takes off at higher again, etc. All the time not changing the pedal/throttle position. If you are impatient you can floor it at which point it shifts way down and takes off (at high RPMs obviously) So its really a lower engine RPM issue. I feel like I'm on a wild goose chase - and losing. What measures engine RPM? It looks to me like perhaps faulty crankshaft position sensor or camshaft position sensor could give these symptoms. No codes for these, guess I should check the wiring/plugs on these next. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 8, 2015 Share Posted February 8, 2015 Did you test both sensors with another meter? If the old TPS wasn't actually bad, put it back on and adjust it, send the new one back maybe If the code doesn't come back in a few weeks. It does suck to diagnose things that way, but it happens. The acceleration problem has the symptoms of a bad knock sensor. Search for my Knock sensor 101 thread for details on that. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 8, 2015 Author Share Posted February 8, 2015 I did not re-install the old TPS and voltage test it with the "good" multimeter, maybe I should. Yeah, for $140 maybe I should consider sending the new one back. Knock sensor was 2nd or 3rd replacement item. However maybe I should try the isolation test with it? Physically remove from engine, isolate in padding, leaving it plugged in. How about those crankshaft and camshaft sensors? What sensor inputs to the tachometer (crankshaft position?) If so its not that since it seems to be reading the RPMS rightI I guess a mal-functioning camshaft position sensor would throw off the timing and give the observed symptoms maaybe? I keep coming back to the ECU, one strange thing I have noticed is if I disconnect the battery for a little while then re-connect it, it drives beautifully for about 20-25 minutes before starting to act out again. I will try this a 3rd time and see. As mentioned earlier I read an account of someone having this exact problem with a 1999 with an automatic, solving it by installing an "older" ECU in the vehicle. There was a TSB for 1998 manual shift 2,2L for ECU responding to the knock sensor incorrectly. Subaru wouldn't send the TSB to me since my VIN# indicated a 1999 and automatic. Yeah, I'll try the disconnect battery test first, and then the knock sensor isolation test. If both tests correct the problem (temporarily and more permanently) it might be ECU response to knock sensor. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted February 8, 2015 Share Posted February 8, 2015 99 2.2 is the weird year where they have 2 airfilter boxes. Make sure the second one (attached to throttle body)the bottom tabs are seated securely and the clips are locked tight. Check for any other leaks in the Air intake. These will throw off the MAF. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 9, 2015 Author Share Posted February 9, 2015 Yes, the two airboxes are weird, had something to do with CA emissions.When I first got it I thought it didn't have an air filter, then I discovered the second box with the filter. The first box has just the rubber perimeter piece that seals the box but not the paper element part of it. I did an extensive search/test for air intake leaks including a fine mist of water all around any possible intake leak sites (don't like the idea of spraying a flammable liquid around a running engine), found nothing. There is a tiny spot of bare wire right where it goes into the MAF plug, insulation must have rubbed away. I sort of put a little electrical tape around it, but because of the location it was very hard to secure well. Have't had any MAF codes. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 9, 2015 Author Share Posted February 9, 2015 So I did put the old TPS back in and tested it with the good multimeter, it looks fine, no dead spots. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 13, 2015 Author Share Posted February 13, 2015 Car drives the same with old TPS or new TPS, still hesitation problem. So I'll leave the old one in there and try to get a refund for the new one. I did the battery disconnect test again (3rd time) and once again it drove great for 15-20 minutes but then started acting up. So the I think the ECU is definitely complicit, even if it may not be the origin of the problem. I am now focusing on the MAF sensor and the knock sensor again. The airbox closest to the throttle body actually had a few tablespoons of oil in it when I got the car, even though no oil in throttle body. I cleaned it out and it has not reappeared. I figure when the previous engine was burned up, oil must have come thru the old throttle body into the airbox. I guess its possible it continued to some extent all the way to the MAF sensor and gunked it up. I've read that you can just disconnect the MAF sensor and if the problem goes away then there's your problem? I also plan to take a look and clean the wires on the MAF sensor with the special spray cleaner. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 13, 2015 Share Posted February 13, 2015 (edited) Generally when you have a hesitation issue a computer reset will "cure" the problem for a little while because the computer runs on a default rich fuel setting until it learns a more efficient (lean) fuel setting. This generally takes 15-20 miles. Once it learns the more lean setting it switches to that and you get the hesitation problem back. Finding the offending sensor is tricky. If the O2 sensors are old you may consider changing those just for good measure. A skewed O2 sensor can cause the engine to run too lean, which can cause hesitation at lower RPM. MAF sensor also has a large input for fuel control. A good cleaning may work. You can try unplugging the MAF then start the engine and go for a drive. Do not plug in / unplug the MAF with the engine running. Edited February 13, 2015 by Fairtax4me Quote Link to comment Share on other sites More sharing options...
alpop Posted February 13, 2015 Author Share Posted February 13, 2015 Good information, thanks. So the ECU is doing what its supposed to do. From what you say it seems a sensor which gives input on appropriate fuel/air ratios is quite possibly the culprit. Unfortunately I think the only codes I have got are related to my fooling around with the ignition on. For example backprobing the TPS with the ignition on immediately threw a TPS code, and unplugging the IAC valve previously threw a code for it (though I thought the ignition was off, maybe there was still power to it) I will start with the MAF sensor, unplug with ignition off, good advice I was thinking of doing it with the engine running for some reason, probably something I saw on the internet. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 14, 2015 Author Share Posted February 14, 2015 So I cleaned the MAF sensor with the special cleaner, didn't look particularly dirty. No change in performance. Then I tried unplugging the MAF with the ignition off, this did not work. When started, it idled rough and when I tried to give it some gas it died, couldn't be driven. Also with MAF unplugged, check engine light came on as expected, but AT OIL light also came on flashing, after replugging in the MAF the AT OIL light stayed flashing for one or two starts then went away. Don't know if this means anything, manual says if it flashes the automatic transmission control system is malfunctioning take to dealer immediately ($$$ heh heh). Probably a result of no info from the MAF sensor? So I really don't have an answer as to whether its the MAF sensor, they are not that expensive so it might be worth just replacing ($50 or so). There was actually a recall on this year and model for the MAF sensor in 2002, when I checked with the dealer on this car they said they had records of it being replaced. Next on the list I'll try isolating the knock sensor. I read somewhere someone said when the motor mounts get old and thus the engine moves around more it can set off the knock sensor, his fix was to reattach the knock sensor to the threaded hole on the engine block (transmission?) up higher. I'm rapidly running out of possibilities- Quote Link to comment Share on other sites More sharing options...
Seth Daly Posted February 14, 2015 Share Posted February 14, 2015 (edited) Im having the exact same problem but with the manual transmission. Though mine is throwing the tps code but i tested mine and its good too. Im desperate for answers as well, ill post any findings as well. EDIT: I checked the codes again and now it is throwing the code for the knock sensor. Edited February 15, 2015 by Seth Daly Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted February 14, 2015 Share Posted February 14, 2015 Motor mounts have nothing to do with the knock sensor. That's Hogwarsh. Moving the sensor can "numb" the sensor, but if the sensor is reacting to a knock then it should not be moved because knock will eventually damage the engine. Most of the time the sensor element is damaged due to corrosion,(either the plastic housing splits, or the sensor is installed incorrectly and the housing stretches open at the bottom) or the sensor is not properly grounded to the block, again because of corrosion on the base of the sensor or on the mounting point on the block. Occasionally with a replacement sensor someone may overtighten the bolt that secures the sensor to the block and that can deform the sensor element. This can either alter the frequency that the sensor responds to (causing it to detect noises other than the ones it is designed to), or crush the element so it doesn't respond at all. Quote Link to comment Share on other sites More sharing options...
Legacy Posted February 15, 2015 Share Posted February 15, 2015 I'll chime in here pointing to the O2 sensor. In my case the vehicle in question is a 97 Civic (yes I know boo hiss). I used to have a 91 Legacy which sadly I sent to the wrecking yard... The problem first showed up in Sept 2014. For me the problem was intermittent, and basically it felt as though I had taken my foot off the accelerator, so the car would start coasting. Whenever it happened, I tried different things to see what would happen. I tried pushing the accelerator pedal more, no effect. I tried holding the accelerator steady, and the car would coast for a bit, engine RPM would would bleed off somewhat (don't know the numbers, no tach). Then suddenly it would roar back to life with a jolt. Then it would happen all over again but at this point the car is going a bit faster than before. This would happen 3 to 5 times in a row. I suspected the O2 sensor since it never happened in the first few minutes while the car is warming up. I disconnected the O2 sensor connector and although it was sluggish and idled rough, it didn't show the hesitation issue. I never got a check engline light or code, so it was frustrating, but I went ahead and replaced the primary O2 sensor and the hesitation issue has been gone since. I removed the old one to check the make and replaced with same which in my case was NTK. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 17, 2015 Author Share Posted February 17, 2015 Thanks for the input Legacy. Your symptoms were quite different than mine, of course it might still be the O2 sensor. I am getting a little frustrated chasing a problem for which the CEL and codes are not helpful, its hard to think about changing things that cost money and are a fair amount of trouble with no indication that they are really the problem. I did isolate the knock sensor (purely as a diagnostic method) by leaving it plugged in, unbolting from engine, grounding with a wire, wrapping in foam and duct taping to the (closest) air box. Left the battery connected. Mixed results - I guess its doing it less. Whereas before it would run great for 15-20 minutes after disconnecting the battery, (but did it 95% of the time otherwise), After the knock sensor isolation I started it and it did it for about 10 minutes than it drove perfectly for another 15 minutes 'till I parked it. I drove it later in the evening for ten minutes downtown and it ran perfectly, went to a movie, came out and drove home and it malfunctioned for the middle few minutes on the way home (at the worst possible spot, climbing a steep hill). Never any engine knock when it is driving well. Just to be clear I don't need a hill for the malfunction. Its funny, when it malfunctions (accelerates very sluggishly) there is a characteristic engine/exhaust noise, not a knock but maybe like the exhaust is getting louder and sounding different? The only good thing is the CEL came on right in the middle of the hill malfunction, need to go see what that was. When it malfunctions on a hill I can solve the problem by shifting into a gear where the engine stays above 3000 RPM and leaving it there until I get to the top of the hill. Otherwise it will lose power, shift down (automatic), have plenty of power and gain too much speed so I have to let off the gas, then as a result shift back up, lose power and then shift down again, well you get the idea - ad nauseum. I about used up a tank of gas test driving it during the last month or so, so I'm going to go fill it up and dump another bottle of fuel injector cleaner into it. Quote Link to comment Share on other sites More sharing options...
alpop Posted February 18, 2015 Author Share Posted February 18, 2015 Well CEL codes told me nothing; MAF which is probably due to my having disconnected it and then being unable to drive it, and knock sensor which means it doesn't like what I did with the knock sensor I guess. Drove it on an errand yesterday and it malfunctioned for the first few minutes then (I think) drove perfectly for the remaining 15-20 minutes - even did good on the hill it malfunctioned on the other day. There definitely does seem to be a change after what I did with the knock sensor, whether its causal - who knows? I also dumped in a can of Sea Foam and filled up the gas tank. Second tank of gas with a fuel injector cleaner in it. I may have to run an errand up to C'dA later this week which is 180 miles round trip. If its dirty fuel injectors maybe this will help. I have this problem where my daily driver is a bicycle, perhaps this is partly why I am moving so slow on this - I need an excuse to drive it. On a positive note I replaced the broken power antenna mast, reattached the ends of the front bumper cover so now flush with the fenders, repainted the front bumper cover (PO must not have liked the original shape/size of the car), gave it a quick wax and she is "looking" real sharp, now if I can only get it "running" right! Quote Link to comment Share on other sites More sharing options...
alpop Posted February 19, 2015 Author Share Posted February 19, 2015 Still have the knock sensor isolated, and took it out for a 30 minute drive this morning. Malfunctioned for about 10 minutes at first then after it was warmed up it drove fine the rest of the time including up hills. So it seems that with the knock sensor isolated, it malfunctions when engine is cold but is fine once its warmed up. Before isolating the knock sensor it malfunctioned most of the time cold or warm. I guess this is a clue, although I'm not sure exactly what it means. Since I replaced the old knock sensor with a new ($12) one a few weeks ago, probably not the knock sensor? Again, I never hear any spark knock. Used to have an old loyale that nobody could permanently fix the spark knock on, so I know what it sounds like. That really only leaves the ECU I guess. Quote Link to comment Share on other sites More sharing options...
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