aschwerin

I bought Walker brand MAF sensor off rockauto for $36. MAF now reads 3.6 to 4.9 g/s at warm idle. Fuel trim movement looks normal. Car runs great. Thanks for the diagnosis. I've replaced 3 MAFs on Subarus but I don't think I've ever had to replace a different kind of sensor. I've always used the cleaner before replacing, and it has never helped. I guess these guys just have a short life span (10-20 years)

Cold start about 7.5 g/s, falling to around 3 g/s, then for a little bit sensors flatlined (around thermostat open) and it was up in the 4's. Functioning warm idle about 2.0 g/s. Revs around 700. Vacuum 22. STFT 30-32%.

I cleaned 7 grounds, no difference. 3 new codes, 302, 303, 304 - misfires on cylinders 2, 3, and 4. At this point I'm thinking the codes are indirect symptoms, not causes...?

I checked over the air box, and cleaned the filter, that looked to be a higher grade than cheap FRAM. I also was running the car and had left the airbox open, and was still getting the same running. I quadruple checked the vacuum lines. All the routing was correct per the emissions sticker. One line said "to canister", but I didn't follow it past where it turns into metal line going under the intake manifold. The vacuum lines looked like they were from 1999, so I sprayed starting fluid along all them and never got a correlating rise in RPM. So it was idling ok, STFT was still in the mid-20's, every 20 seconds or so the RPM would bump up a little then come back down. o2's were going up and down. And then at some point the idle got rough and the sensors had all flatlined again. ECU going bad? I've never had that happen before, but I've heard it does. Also, I think this is unrelated, but the speedo only works intermittently, from my research there is a bad ground on the circuit board in the dash, but I wouldn't think that circuit board would have anything to do with the main ECU? /A

I pulled the knock sensor off my parts car but it was cracked so I didn't bother using it. Then I thought, if the computer is in limp mode because of the knock sensor, it should be out of limp mode if I reset it. So I left the battery disconnected for half an hour. And I drove it, and I got readings. Front o2 sensor was going up and down as I understand it should. My STFT was mostly stuck up in the 20's. Sporadically, at the beginning of my drive, I would lose power with constant acceleration (uphill), just for a second - coinciding with a sharp drop in STFT. Other than that, mostly normal for awhile... when I went up a long hill, o2 was pegged at/near zero. Maybe normal? Then down the same long hill, also zero, but more oddly, the STFT wouldn't go lower than -3% (its a manual, in gear). Then, after a stop, in first gear it had very little power (around 1500 rpm) and o2 and fuel trim readings weren't moving. I pumped the gas and then it went back to being normal (or like 80% normal). After all the driving, there were no fault codes in the ECU. Cleaning ground connections still sounds like a good idea, other than that I'm not sure where to go. /Andrew

It was a warm engine, my wife had been driving it a bit in the morning - I took a short drive, and I did see at one point it was up to 188 deg. Can't confirm closed loop. Just to compare, I started a '96 Subaru, and while cold the o2's and the fuel trim had values, and the fuel trim would move significantly when I revved it. Unfortunately the '96 needs a full front end job so I'd prefer to get this '99 available. It very well could use a new knock sensor, but that wouldn't affect the other readings? Or would excessive knock cause the engine to go into limp mode and that might zero out values? I believe after I erased codes and drove it, when I checked again only the knock code was on again. If I remember right, that's an easily replaceable part that I could exchange tomorrow.

1999 Subaru Legacy 2.2L manual My wife was driving it for a few days with Check Engine light on. I pulled a P0170 (Bank 1 Fuel Trim Malfunction), P0325 (Knock Sensor), and an Evaporative Emissions code. I cleared codes. Car now has very little power. Using Torque, I looked at readings, O2 1 and O2 2 are both reading flat zero (or near zero, but flat). All the Fuel Trims are also pegged at zero. I am getting other readings, revs, and such, and MAF looks good, in the lower single digits, going up to lower teens with some acceleration. I checked engine (including o2 sensors) for bad wires and vacuum hoses, all looked ok.

24.1 mpg at the second fill-up. I think that's good considering how much I used 3/4 to full throttle. Overall, the rebuild seems to have worked fine, but it will take a long time to pay for itself. Assuming my build is representative, I would not choose to bother with a Frankenmotor unless it happens to be the only good parts sitting around. Might as well just buy a different car, or a turbo engine, etc. if one solely wants more power. But for a regular car, where engine work is not a hobby, at the end of the day its still a 2.5L engine.

I've driven it around 150 miles and did a compression check: #1 215 #2 221 #3 212 #4 210 So that looks pretty good. Here are the numbers from before the job: #1,2,3, have 228, 235, 242 psi not respectively. #4 cylinder has 68 psi (and when I checked this a year ago #4 had like 150 or so)

So its definitely improved. Smoother running sound, and smoother power. And I thought power was good, if not great. We have some good hills around here, so I a lot of good throttle uphill and engine braking downhill. Then I drove my 2.2L again, and it has slightly more power than the rebuilt 2.5L Frankenmotor.... Up a steep hill, I can easily accelerate (1/2 throttle) in 3rd gear at 40 mph with the 2.2L....the 2.5L barely accelerates at 3/4 throttle... I'll go another couple hundred miles to seat the rings and do another compression check... I was expecting some noticeable power from the rebuild...it'll also be good to see the mpg after a full tank of gas. And I'll check some more Torque measurements.

I got a CPS connector from nearby, worked like a charm, started on the first crank. Thanks everybody! I'm going to follow the manual's break-in instructions, so it'll be a little time until I take it for a real test drive.

Yes, it has the MAF. I sprayed near it with compressed air before re-installing. Had sprayed it with cleaner back before I tore engine apart. Funny, it wouldn't start at all until I saw the intake wasn't back on the throttle body...at least that was an easy problem to solve... I've checked over, big hose is on. I checked around, the IAC was buzzing/humming, but searches said this was normal for a time after car was turned off. I'll triple-check the air system. I think I can get the CPS wires and connector from a nearby junk car, tomorrow.

Pulled most evrything apart except splitting the case, I spent many hours just cleaning everything I took apart: -Side clearance of connecting rods checked from underneath, on the wider side of normal, but well within service limits. No movement felt on other axes. -Replaced pistons with '97 model Teikens and NPR rings. I know, I'll get piston slap, but that's the least of my worries right now. I may regret it down the road...or I'll just picture them belly slapping into a nice pool of oil with each stroke... - checked and lapped all valves...ground heads flat using the glass and wet/dry sandpaper method...replaced valve oil seals - rocker arm measurements all good...replaced all HLAs that showed any wear... - Cometic Frankenmotor headgaskets - cleaned oil pan (the inside), oil pump, etc. replaced gaskets/seals, kindofa waste really, shoulda just left the oil pump on - new clutch and pressure plate. Though they only had 30,000 miles on them, the clutch was unevenly worn and pressure plate had worn and bent fingers. I think the holder springs were missing off the release bearing? It would have been kinda loose in there...also put the new sleeve on, really needed it....and new rear main oil seal - new timing belt, oil seals, and pulleys/sprockets. Those parts also had 30,000 miles on them. A friend figures that since the timing belt covers weren't on, those things all wore a LOT faster. So I bought new timing belt covers. - replaced intake/exhaust gaskets...cleaned everything well...lots of miscellaneous... I figure about $600 in parts and $700 and rising in my labor (my labor is a much lower rate than shop labor...but I'm slower...and generally do a better job...can't say that yet about this job!)

I switched the CPS wires and now it kinda half starts up to 500 rpm, and as soon as I release the key from Start it dies. I tried disconnecting the CPS and it wouldn't start at all. The last two partial starts had a kinda knock before dying, so I'm just going to quit trying to start it before I ruin my rebuild. The manual clearly says it should start without much effort So I guess I'll try to redo the CPS wires? And if that doesn't work, I can't imagine much else but the timing...and I've done the timing belt a few times...it really should be good...lines, not arrows...

With much more effort, I managed to flash a check engine code...P0335 Crankshaft Position Sensor A Circuit So I'll see if I can switch those wires. I'll also check and make sure I pulled the wire I had holding the timing belt tensioner closed...