Subaru Leone EA82T running lean

[funktio02]

Here's something to know about the car in question. I bought my first Subaru few months ago. It's 1987 Subaru Leone GL with EA82T engine. It's done now about 228 000km(~ 141670 miles). Overall it's in fairly good condition. Engine isn't all original, previous owner has done some chainges to increase the performance. It now has: TD04 HL 13 turbo, intercooler, Green filter - cone air filter, lighter flywheel, bigger downpipe, stainless steel exhaust manifolds, a bigger stanless steel exhaust pipe, Wilkerson(not sure if I'm using the right name for this part cause english isn't my home language) relief valve, more powerful fuelpump and some Fse fuel pressure regulator. It also has Autometer fuel mixture meter just like this http://shop.advanceautoparts.com/1/1/581583-electric-air-fuel-ratio-gauge-by-autometer-part-3375.html

Nowadays car runs on 0,5bar pressure(which is about 7psi if I'm correct) but previous owner ran it with bigger pressure and had it tuned to run a bit rich just incase.

 

Couple of days ago i was driving home and suddenly the mixture meter was saying the engine was running really lean. The light on the meter was right at the left end of the scale. As I writed earlier the previous owner had the car tuned to run a little rich so normally the light in the meter is somewhere in the Rich area of the scale. I've heard that this kind of mixture meter isn't the most accurate one but I think it's readings shouldn't be ignored. So I drove home and the meter said I was running really lean rest of the way(lucky there was only few hundred meter to go) and according to it the mixture didn't come richer even if I accelerated. The next day I discovered that meter shows the engine is running rich atleast when the choke is when cold starting the car but mixture goes leaner and leaner as the engine warms up and start to idle normaly. I did a little test run around the block and mixture got richer for a moment when I started accelerating from 1000-1200rpm but then it goes lean again. When idling you can here some puff-sounds in exhaust like there was some misfires sometimes and normally when cold starting it starts right up but now I have to try couple of times before it starts to run nice so I would say it really is running lean. Oh, and sometimes the idle also drops to 400-500rpm which it has never done before as long as I've owned the car. It was summer when I bought the car and it hasn't had any major problems until now and it's been cold couple of moths now already so I'm not sure if the weather is the one that has done the damage.

 

I don't have own garage and it's winter now and really cold(minus 15-20 celsius) here in Finland so it's not really nice to do any repairs outside but I can occasionally use my friends garage. I don't have previous mechanical experience on cars with turbos and fuel injections but I'm willing to learn and do as much repairs as I can on my own. I haven't been using the car to avoid doing any damage to engine. I'll be going to my friends garage soon so people could you give me some hints where to start looking for faults. I already found a crack on one of hoses coming from fuel pressure regulator, it looked like a vacuum hose but changing it to a new one didn't help. Sparkplugs(iridium) and wires and stuff are a bit old and should be changed soon and they will be and I will check those but other than those what would be the places to look for faults and I would appreciate detailed instruction of how-to test the parts in question to see if they work.

Edited December 21, 2010 by funktio02

[naru]

It may be a problem with the coolant temperature sensor.

You can check it with an ohmmeter.

At -15C the resistance should be more than 7000 ohms.

 

There is a factory shop manual for the north american version of your car here:http://www.finleyweb.net/JonsStuff/SubaruDocumentation.aspx

[Turbone]

A tune-up would help rule out some of your problems. I would also change the fuel filter, this should be done at least once a year.

The condition of the sparkplugs will show if you are running lean also.

If the electrodes look like they are cooked, its been running lean.

http://www.sparkplugs.com/sparkplug411.asp?kw=Detonation&mfid=0

 

Make sure you time it when the tune-up is done.

[naru]

Given the suddeness of the problem,I would also look for cracked or disconnected vacuum lines.

 

A fuel pressure test may be helpful.

[NorthWet]

I would be cautious in putting too much faith in a simplistic F/A mixture gauge. I assume that this is taking its input from the stock EGO (O2) sensor? If it is, the EGO sensor might be failing, a connection might have issues... all sorts of stuff caused by relying on indirect information. Especially one that does not give linear results.

 

I'm with Turbone on checking the sparkplugs.

[naru]

I would be cautious in putting too much faith in a simplistic F/A mixture gauge. I assume that this is taking its input from the stock EGO (O2) sensor? If it is, the EGO sensor might be failing, a connection might have issues... all sorts of stuff caused by relying on indirect information. Especially one that does not give linear results.

 

I'm with Turbone on checking the sparkplugs.

 

I`d agree w/the faulty meter theory except for the coincident onset of difficult starting.

[NorthWet]

How about a misinterpretation of what is happening?

 

What the meter is probably displaying is a representation of the voltage from the EGO sensor. The EGO sensor does NOT indicate air/fuel mixture. What it does give is an indication of how much free oxygen is in the exhaust.

 

Free oxygen MIGHT mean a lean mixture, but it can also mean an exhaust leak that allows O2 to get sucked into the system. It can also mean misfire and other incomplete combustion. The exhaust can be lousy with unburned hydrocarbons and still appear "lean".

 

Look at the sparkplugs. I would suggest that you replace plugs, wires, cap, rotor.

[Myxalplyx]

I suggest a full tune up!

 

When you start the car, it is normal for your air/fuel ratio to read rich. As soon as the car is 'warm', if your air/fuel ratio does not constantly run back and forth, I say you have a bad O2 sensor (or EGO sensor unless this is something different).

 

Anytime I had an air/fuel ratio meter that did not constantly cycle back and forth, from rich to lean to rich again, once it warms up, it was a bad oxygen sensor.

 

Again, never hurts to do a full tune-up and replace all vacuum hoses needlessly. Yep, I said needlessly. If they are cheap to get, just replace the hard ones with fresh, flexible soft ones so you KNOW you aren't going to have a problem with that one for a long, long time. :-p There's no better time I'd like to have peace of mind than in cold weather. Welcome to the site!

[naru]

Check compression when you change spark plugs.

[NorthWet]

I suggest a full tune up!

 

When you start the car, it is normal for your air/fuel ratio to read rich. As soon as the car is 'warm', if your air/fuel ratio does not constantly run back and forth, I say you have a bad O2 sensor (or EGO sensor unless this is something different).

 

Anytime I had an air/fuel ratio meter that did not constantly cycle back and forth, from rich to lean to rich again, once it warms up, it was a bad oxygen sensor...

Sorry for any confusion due to the EGO reference. Partly my age (I could have called it a Lambda sensor and really confused people!), but mostly to shake the complacency of those thinking that they "know" that an O2 sensor measures air/fuel mixture.

 

Regarding readings of the "A/F Meter" fluctuating, without knowing the specs of the meter nothing can be concluded. The hysteresis of the meter combined with its time gate might make it so that it wouldn't show the normal fluctuations of a properly functioning O2 sensor's output.

 

Look for better indicators of what is going on: check the sparkplugs.

[funktio02]

Hi again. Although I haven't been posting there has been some progress. Leone now has new sparkplugs (Brisk Racing Iridium DOR12, previous owner had also used those), new sparkplug and coil cables, new distributor rotor and cap and fuel filter. While changing the plugs I checked cylinder compression: both cylinders near the firewall had about 9bar(130.5psi), the other passanger side cylinder had 10bar(145psi) and the other driver side cylinder had 9,5bar(137.8psi) so nothing too catastrophic going on there, keeping in mind the engine has done some miles.

 

After measuring o2 sensor with my supercheap-pieceofcrap(as I now call it) digital electric meter, which can also measure volts, I was a bit confused about the number it gave me and wheter the oxygen sensor was broken or not. I just wanted to be sure and decided to buy a new o2 sensor which cost 40€(something like 50 usd) so nothing too expensive. Turned out that my cheap electric meter had some connection issues and the original o2 sensor was actually ok. I bought new digital electric meter and not a cheap one just to make sure this kind of stuff wouldn't happen again.

After all those parts were installed the car runs overall slightly smoother but idle is still rough and air/fuel mixture gauge showes mainly lean and every now and the and at certain rpm which is around 1000rpm and 2000rpm when accelerating it shows rich or stoich for a sec and after idling about 15min it shows rich.

 

Now then about the condition and colour of those old sparkplugs, some of them were a bit dry white..-ish in the middle and black around the edges one some brounish with a hint of white around the middle and black around edges. Those plugs had done probaply something like 40 000-50 000km(25 000-30 000miles) and those Brisk iridium racing plugs should be replaced every 40000km(25 000miles). Things got very interesting when I was changing the o2 sensor, the sensor umm sensing part was white and I took my flashlight and checked the inside of the downpipe through the hole where o2 sensor should be and the inside was all white as snow. I'm no expert but in my eyes that's pretty strong indicator saying car runs lean or something is not right at all, I mean exhaust pipe is usually black inside and there aren't many cases when finding a white matter inside of and engine would be a good thing.

 

Here's pics of the old plugs. - http://i53.tinypic.com/1678a3n.jpg

 

Here's a pic of the old o2 sensor - http://i53.tinypic.com/9s5r4k.jpg

 

I haven't changed any vacuum or other hoses since I inspected them and all seemed to be ok expect the the cracked one that I mentioned earlier, the one that goes to fuel pressure regulator. I was thinking, what next? I downloaded a repair manual and read through it few times. Althought there isn't any fault codes other than the one saying that EGR valve is constantly on/off(which it should be I quess since it's been blocked) I thought would be necessary to check the mass air flow sensor, which I had never heard before until now, and take some electric measurments from it. I did not remove and clean the maf before measuring any volts or ohms and that was dumb. Voltage between sensor signal terminal and the one of the two ground wires pointed in repair manual should be 1-2 volts but I got 3,9v so that would indicate it's faulty. If i remember right the previous owner had changed the maf atleast once but can't remember if he replaced the old one with a new or used one. At the moment I've removed the maf from the car and I sprayid some CRC maf cleaner, made just for that purpose, in it cause it looked a bit oily inside. The oil is propably from the Green filter my car has and which previous owner has been oiling. He's used a Green filters own filter oil.

 

More about the maf, what does it actually mean if the voltage is so high where I measured it, can it be understood so that the maf may be unrepairable or could the cleaning actually help? The hotwires looked clean and shiny but since the its surroundings were covered in a thin layer of brownish oily stuff I thought it could be covered as well, I mean your eyes can't see everything and the hotwire element is pretty damn fragile the way I've understood it. I spoke with local Subaru parts dealer and the man said new one would be almost 700€ which is over 900 usd and that's a hell of a lot money. Of course there are always used ones at the scrap yards and those cost just a fraction of the price of a new part.

 

Anyway I have cleaned the maf with the proper CRC stuff but hadn't put it back to the car and test it yet. Let's pray it works and if not... does any of you by change have a one that hasn't done million miles and 100% works and you would be willing to sell it to me for a appropriate amount of money?

Edited February 16, 2011 by funktio02
typos

[Ricearu]

try it, honestly the plugs look pretty normal to me. not horrible by any means. I personally would check the resistance of the coolant temp sensor. They are NOTORIOUS for failing (usually because of corrosion IN the wires) and causing all kinds of problems. Start there. There is a Factory serivce manual here http://www.ch601.org/engines.htm

[NorthWet]

It seems generally considered to be a BAD idea to use an oiled air-filter on a hotwire MAF system. Stock pleated-paper filters provide sufficient air flow and superior filtering to stock-replacement oiled elements, and superior airflow to cone filters.

 

The oil will cause MAF sensor issues.

 

As mentioned, the CTS tends to be flakey, mostly due to connector corrosion. Before I did the connector "fix" that had been suggested by grossgary, my EA82T would have all sorts of iisues while running, including throwing check engine codes, and sudden power losses.

 

White tip on the O2 sensor is normal. you might gets some opinions that certain shades of offwhite are better than others. Things get hot ans stay hot around the O2 bung, and any extra hydrocarbons will tend to cook off unless they are in really excessive amounts.

 

The O2 sensor is in the engine management system to provide feedback, to help correct for any minor inaccuracies in fuel amount computation based on the other sensors. If the MAF readings are off a little, the O2-sensor signal should compensate. If the CTS is off a little, the O2-sensor should help there, too. If the computation is way off, the O2 signal would probably peg either "full rich" or "full lean".

[funktio02]

Yes I was thinking about getting either stock air filtering equipment, box etc. or some other aftermarket filter that doesn't require oiling. Previous owner has constructed a nice little stanless steel umm.. box or pit inside the engine compartment where the cone filter sits isolated and not able to suck in hot air from around the engine, it's located right behind passanger front light. Would be a shame to waste it but what's best for the engine comes first.

 

I'll be checkin the CTS right after reinstalling the cleaned maf sensor. I was going to do it right after changing plugs etc. but honestly forgot.

 

I'll measure the maf's volts and resistance detailed in repair manual when I get it installed. When measuring the resistance between body and ground terminals of the maf is there a any specific spot on body where I should ground the electrit meter, of course to some clean metal but some specific ground spot etc.?

[Ricearu]

firewall, intake manifold, fender. try multiple places, if there is a difference in readings, you may need to beef up your grounds for good measure

[funktio02]

Haven't been working on the car yet but I was thinking here(which I do a lot, maybe sometimes even too much) and some questions emerged concerning the EGR solenoid valve and the EGR system.

There are two almost identical valves on top of the engine passanger side next to the throttle body and both of them have couple of wires going in and some pipes(obviously vacuum ones) aswell and if I'm right the one more near the throttle body is EGR solenoid valve, am I correct? Previous owner said that the exhaust recirculation sytem has been cut off. Is there any change there could become a vacuum leak hidden somewhere in there if the blocking of the hoses and pipes has been done half fast? Could someone explain what parts in the engine bay are related to EGR system and what hoses should go where and so on? What I know at the moment is that the UFO-like thing near the intake manifold on driver side is the EGR valve itself and then some tube should go to intake manifold and some pipes to exhaust am I right so far? Where the EGR solenoid thingy fit in?

Even if there weren't a fault in there I'm still curious to know what parts in there are part of the EGR system and what is missing(if there is something missing). Couple of things I noticed, there was a clamped hose coming from EGR valve and there was a big bolt screwed into the firewall side of the intake manifold.

 

The only fault code that the computer gives and that's on D-mode is 34 - EGR solenoid valve (Solenoid switch continuously in ON or OFF position)

 

How sensitive is the computer system to deciding to give fault codes? I mean how broken or bad some part or problem must be before it gives you a signal there is a problem somewhere?

 

I can post pics if needed. I really would like to learn a lot about this car since at the moment it's my everyday car and I really like to do maintenance and repairs myself and in the future(not too near thought) after I buy a new car this one may stay with me as a how do you say.. umm hobby car or whatever which I could drive around during the summer and maybe have some fun on the ice tracks in winter too. Not the best everyday car in 2011 but I really love it.. duhh, that's why I bought it.

Edited February 19, 2011 by funktio02

[funktio02]

Once again hello.

I installed the cleaned MAF and run the engine, sounded pretty good, took a test drive, took some measurements, oh and the air/fuel gauge is working fine, showing green when supposed to just like few moths ago. Everything looked normal at first but half way during test drive at crossroad engine stalled. Stalling happened few times and starting after stalling was a bit tricky, eventually I got it going again and got back home. I let it idle some time and it was wierd, most of the time idle was normal but every now and the rpm drop few hundred rounds and almost stalled but just almost.

 

I did the MAF measuring stuff shortly after test drive. The signal-to-ground(Black Red) terminal voltage which I mentioned earlier was now within the 1-2volt as it should be. The BlackRed ground wire had resistance(measured from the MAF connector to body,) way below the limit which was said in the repair manual to be max. 10ohm. but the other ground wire coming from MAF, the Black one had resistance of 55 to 60ohm depending on grounding point on body(found few good places to ground the meter).

It said in the repair manual and I'm quoting: "If resistance is greater than 10ohm, check the harness and internal circuits of the control unit for discontinuity and the ground terminal on the intake manifold for poor contact."Any ground terminals on intake manifold didn't caught my I so here I am asking questions again: where does that Black wire go from the MAF and where should I find this intake manifold ground point that this repair manual is referring to? Only ground point that I saw on the engine was just above driver side valve cover and it didnt' look original but pretty decent, pretty clean. There were two wires connected to it: a thick one and it's other end was connected near the driver side front light and front corner of driver side quarterpanel and the other one was some Black wire coming near the firewall. There was other Black wire coming from inside of the driver side fender and it was connected to the ground point which the thick cables other end was connected, near the driver side front light.

Edited February 19, 2011 by funktio02
There were some typos and I did some underlining for lazy people.

[funktio02]

Well, it took me a while to notice that I have complete wiring diagrams(or whatever they are in english) in the repair manual I downloaded. It looks like the Black ground wire goes from MAF straight to the MPFI control unit. So that's one mystery solved. Now I just have to locate the problem itself and fix it.

[funktio02]

Here again. A bit unclear to me if the MAF connector needs to be connected or not while measuring the resistance of those MAF ground wires. If the connector is connected to MAF the resistance between body and the previously mentioned black ground wire when measured from the MAF connector is ~60ohm and if the MAF's not connected it's about 1ohm. I measured that black wires resistance from ECU connector too and if MAF wasn't connected the resistance were almost 70ohm and if not connected it was 2-3ohm. Could the fault be in ECU? Every little hint helps, please.

Edited February 26, 2011 by funktio02

[naru]

MAF should be unplugged.

 

Things need to be very bad before a code is set.

 

ECU is probably not the problem.

 

Maybe the previous owner moved the ground wire from the intake.

 

I would measure from battery negative instead of the body regardless of what the manual says.

 

Did the air fuel gauge read OK after it started running bad again?

If you clean the MAF again,do things improve again?

[funktio02]

I just checked the fault code history and there were two codes: 22 - Knock sensor (open or shortet circuit) and 23 - Air flow meter (open or shorter circuit). I have been checking the history like once a week or so now that there have been this running problems and I have been driving the car occationally around the town. It's been about a week since I last checked the fault code history. Check engine light haven't been on even a single time.

 

I forgot to mention that I found the ground wire on intake manifold, it was on passanger side of the engine and was under one of the bolts that holds intake manifold. Didn't look too suspicious but I cleaned it anyway. I got a tip of it's location from finnish Subaru club's forum. I've been posting these same questions there but there aren't either that many active users there or that many people who know much about Leone model. I measured it's resistance to body too but only when it was bolted on to the intake manifold and it seemed ok but then it propably would. What is the exact purpose of that ground wire going to intake manifold, does it ground other devices to through engine to body(since I saw a additional ground wires go from engine to body, didn't look original) or does it ground engine to body and that way ground the devices grounded to engine to body. Where does the other end of that ground wire go/come from?

 

I measured the MAFs black wires resistance between MAF connector(which was at that time unplugged) and batterys negative thingy and resistance was about 58ohm. The MAFs blackred wire had resitance of 0,9ohm.

 

I have cleaned the MAF two or three times. The fuel mixture gauge have been reading fine after cleaning the MAF. When idle is normal it shows rich and everytime the rpm drop it goes to lean for a sec but then comes back to rich and stays there until rpm drop again.

Edited February 27, 2011 by funktio02
typos & adding text

[naru]

 

I measured the MAFs black wires resistance between MAF connector(which was at that time unplugged) and batterys negative thingy and resistance was about 58ohm.

 

That doesn`t sound good.

Did you say you measured between the ECU connector and the MAF plug as well? I`m not clear if it was 70 ohms with the MAF unplugged.If so,trouble is in the harness.

 

I would measure resistance of the ECU grounds(ECU plug to battery negative)

 

I still don`t think ECU is the problem.

[funktio02]

That doesn`t sound good.

Did you say you measured between the ECU connector and the MAF plug as well? I`m not clear if it was 70 ohms with the MAF unplugged.If so,trouble is in the harness.

 

I would measure resistance of the ECU grounds(ECU plug to battery negative)

 

I still don`t think ECU is the problem.

 

I didn't measure between ECU connector and MAF plug or neither have I measured ECU ground wires resistance between battery neg./body, didn't come to my mind at the time but those are something to check. I measured resistance between body and the black wire coming from MAF from the ECU connector while that connector was connected to ECU while MAF plug unconnected(then it was 68ohm) and connected(result was 2-3ohm). Not sure if that's supposed to solve anything just some wild though that came to my mind.

 

EDIT: just measured the resistance of the black wire from ECU-connector to MAF-connector and it was 1ohm so that seems to be ok.

Edited February 27, 2011 by funktio02
EDIT

[funktio02]

Well, after careful inspection of wiring diagrams I found out what wires coming or should I say are going in ECU, are the ground wires. I measured the resistance between each single ground wire and battery negative and the BlackYellow wire which goes to pin 28 in ECU had resitance of ... well I guess infinity since my multimeter shows 1.(one and a dot) when not connected to anything and the value didn't change when I connected the meter but all the other wires I tested showed ~1ohm. The ECU connectors were disconnected from ECU while taking these measurements and key was in ignition but OFF position.

 

Here's a copy of the wiring diagram in which I have marked the ground wires in red.

http://i53.tinypic.com/2wcit8m.jpg

You need to zoom a bit to see anything and even then it looks like crap. In repair manual it looks much better.

 

One of the marked ones isn't ground, my bad, it's the one going to pin 8 in ECU. The blue wire is the ground wire going from MAF to ECU. Those wires that go zikzak like they were wrapped around some other wire(-s), how are they placed in the car and the wiring loom?

 

Tomorrow I'll be checking again some connectors in engine bay especially the one where that BlackYellow wire goes.