ECU says I need a camshaft sensor

[nipper]

the only other thing i can think of is a bad knock sensor or sticking valves.

 

Throw a vacume gauge on the car and let us know what it reads and what the needle is doing

 

 

nipper

[hankosolder2]

Ok.. changed the O2 sensor, went in for a smog again and she failed again.

 

Idle HC 233 (120 Max), CO 3.36 (1.0 Max)

2500 HC 66 (140 Max), CO 1.84 (1.0 Max)

 

I'm lost now. I don't know what to do or where to turn. I've replaced the PVC, Cam sensor, Coolant sensor, Oxygen sensor. The oil has been changed, there are no vacuum leaks. The car runs smooth as silk.

 

Any further suggestions? Tried the "magic potion" on this last round as well. I'm convinced it is something ON the engine (since my last engine always passed smog).

 

 

OK,

Here are some ideas. If the fuel pressure regulator is kaput or the hose going to it is not receiving proper engine vacuum, it'll run way too rich, especially @ idle. You did correctly reconnect the fuel supply and return lines to the tanks and the return is not obstructed, right? It wouldn't hurt to check fuel pressure.

How about a dud MAP/Barometric pressure sensor or solenoid? That could throw the mixture off. Dunno if the OBDIs had them though.

 

When you replaced the engine, did you swap over the manifold/injectors from the old engine, or just "Plug in" an engine assembly complete with intake, wiring harness, injectors, etc?

 

It's also quite possible you have damaged the catalytic converter(s) by driving the car with the various issues you described (cam sensor, valve timing off, possible bad coolant temp sensor.) I think the numbers you are citing are still a bit high even for a car without a properly functioning cat, though, and if your plugs are fouling, that's not due to the cat...

 

Good luck,

Nathan

[salewit]

Well the saga continues. After 3 years of high school automotive technical school, and 2 years of State University of NY for auto tech (in the 70's... fairly useless now), I bit the bullet and brought it into a local garage for diagnosis. My first time going to a garage in 30 years! I felt like I was going to a prostitute!

 

Anyway, they say the catalytic converter failed every test they gave it. When I asked how much, they told me they'd have to farm it out and get a price. I told them I'd *try* to do it myself. The question I have is this. When I go to Autozone or whatever, they list and front and rear cat. My repair book also shows a front and rear cat. When I called the garage back asking if they knew which it was, they thought there was only one in the front (where the maniforld Y's and the O2 sensor is). Do I have to replace them both? Is there any chance whatsoever I can do this myself? I do have a stick welder if welding is absolutely necessary. Is there anything wrong with using cats from a local parts store? They're both under $100, yet the OEM's are like $500.

 

Thanks for all the help here. I noticed someone in this thread mentioned the catalytic.

[porcupine73]

Typically the more expensive cats have more catalyst in them, platinum or palladium or whatever it is, hence the higher cost and hopefully longer life.

[Cougar]

OK,

Here are some ideas. If the fuel pressure regulator is kaput or the hose going to it is not receiving proper engine vacuum, it'll run way too rich, especially @ idle. You did correctly reconnect the fuel supply and return lines to the tanks and the return is not obstructed, right? It wouldn't hurt to check fuel pressure.

How about a dud MAP/Barometric pressure sensor or solenoid? That could throw the mixture off. Dunno if the OBDIs had them though.

 

When you replaced the engine, did you swap over the manifold/injectors from the old engine, or just "Plug in" an engine assembly complete with intake, wiring harness, injectors, etc?

 

It's also quite possible you have damaged the catalytic converter(s) by driving the car with the various issues you described (cam sensor, valve timing off, possible bad coolant temp sensor.) I think the numbers you are citing are still a bit high even for a car without a properly functioning cat, though, and if your plugs are fouling, that's not due to the cat...

 

Good luck,

Nathan

 

I think Nathan is on to something here about a bad pressure regulator. You may want to check the vacuum to it first and if that is ok then replace the regulator.

[salewit]

I think Nathan is on to something here about a bad pressure regulator. You may want to check the vacuum to it first and if that is ok then replace the regulator.

 

So are you saying I should change the regulator before the catalytic converter? If I don't change the regulator and it's bad, will that damage the new cat?

[OB99W]

[...]Anyway, they say the catalytic converter failed every test they gave it. [...]

You may well have a failed cat, but that doesn't necessarily mean that replacing it is the end to the problem. An overly-rich mixture can cause the HC and CO numbers you're reporting. If your engine is in otherwise good condition (and it certainly may be, based on the "needle is rock stead at about 22 inches" vacuum reading), the HC and CO shouldn't normally be that high once the engine has warmed up, even if there was no cat present.

 

If you'll indulge me, where does the needle of the temperature gauge point once the engine is warm?

[Cougar]

It does sound like you will need to replace the CAT(s) but before doing so you need to find out what damaged the orignials so the new ones don't get damaged also. I think the idea of too high of fuel pressure is a good one since other things haven't helped. It is interesting though that the numbers came way down when you replaced the PCV valve and fixed the timing and then they climbed up some on the third repair.

[salewit]

Ok well I'm a moron. All day long I was trying to remember to pick up a pressure gauge (my fuel pressure gauge only goes up to 12psi... it's really a vac gauge). Anyway, I didn't get the gauge, got home, jacked up the car and removed both cats. It was only after I broke a couple of bolts in the process did I remember I needed to check the fuel pressure FIRST. Duh!

 

Anyway, both cats are out, and they're both intact. Nothing broken inside them and no rattling. The honeycomb is black. Here's the best pic I can get (rear cat)

 

 

Here's wha the receipt from the car place says:

 

Do a 4 Gas Tailpipe printout at Idle and 2500 RPM...

Idle 243HC, 2.79 CO%, 13.6 CO2%, 0 02%

2500 84 HC, 1.21 CO%, 13.1 CO2%, 0 02%

 

"We did a cat efficiency test. The cat failed the test. The HC's when hot was at 755ppm, it should be below 500ppm. The CO2 was at 3.5%, it should be above 9%. The cat should be replaced.

 

Should I put the cats back in and test the pressure or just replace them both (at least $400) and test the pressure?

[OB99W]

Ok well I'm a moron.[...]

Don't beat yourself up; most of us will admit to having done things like that (and the rest are liars ).

 

 

Anyway, both cats are out, and they're both intact. Nothing broken inside them and no rattling. The honeycomb is black.[...]

 

Here's wha the receipt from the car place says:

 

Do a 4 Gas Tailpipe printout at Idle and 2500 RPM...

Idle 243HC, 2.79 CO%, 13.6 CO2%, 0 02%

2500 84 HC, 1.21 CO%, 13.1 CO2%, 0 02%

 

"We did a cat efficiency test. The cat failed the test. The HC's when hot was at 755ppm, it should be below 500ppm. The CO2 was at 3.5%, it should be above 9%. The cat should be replaced.

I've got a theory, but need a clarification and some additional info. First, it's unclear from your readings what the oxygen (O) levels are, since there's no decimal shown; is that 2%, 0.2%, or .02%. Secondly, you didn't respond to my question in #32, above. What is the temperature gauge reading with the engine fully warmed? For that matter, how long does it take from a cold engine to reach that reading?

[salewit]

First, it's unclear from your readings what the oxygen (O) levels are, since there's no decimal shown; is that 2%, 0.2%, or .02%. Secondly, you didn't respond to my question in #32, above. What is the temperature gauge reading with the engine fully warmed? For that matter, how long does it take from a cold engine to reach that reading?

This is the service stations report and he's (or she) has got just a zero (0) in the O2% columns.

 

The temperature gauge when fully warmed up, sits almost horizontal (3 o'clock or 9... I forget which way it goes). Maybe 15 minutes or so lower. And it takes a very short time to get there. Maybe a 1/4 mile. My smog place is 3 blocks away. I'd drive it around the block about 4 times and she's showing warmed up.

 

Not sure what you're getting at, but when I was getting ready to pull the engine a few months ago, and I pulled the top radiator hose, it was powdery white. I'm told this is from an air bubble up top. I know Subaru's are hard to get the air out of the cooling system. Since then I've refilled and massaged the heck out of the hoses to try and get the air out, and I'm pretty confident (but not positive) that the air is gone now.

 

Thanks everyone for sticking with me on this.... I'd be lost without you guys here.

[OB99W]

This is the service stations report and he's (or she) has got just a zero (0) in the O2% columns.

Sorry, but it's getting late here in the East and you had "02" (zero-2), not "O2" (Oh-2) in the original chart.

 

Anyway, it's "interesting". As I've said before, the high HCs and CO indicate an excessively rich mixture. The "car place" says the cat has failed. Someone may have forgotten how cats work. In order to get rid of excessive HC and CO, they're "burned" by the oxidation catalyst; that is, HC and CO are oxidized, a process which requires, not surprisingly, oxygen. Since the oxygen content of the exhaust is very low (it should be closer to 2%), one of two things is going on:

 

1) The mixture is very rich, the engine is using up all available oxygen trying to burn the mixture, and there is practically no oxygen left in the exhaust for the catalyst to use to oxidize the HC and CO (so the cat can't do its job, even if it's good).

--or--

2) The catalyst is functional and using all available oxygen in the exhaust to oxidize HC and CO, but can't do enough (which still points to an overly rich mixture).

 

Either way, as I see it, the cat condition (whatever it is) is secondary to an overly-rich mixture.

 

 

Should I put the cats back in and test the pressure or just replace them both (at least $400) and test the pressure?

If I were faced with this dilemma, I'd put the cats back. The blackened but seemingly intact honeycomb might be covered in soot. Pressure testing is something to do; even if the cat is fouled, the rich-running condition should be addressed first.

 

 

The temperature gauge when fully warmed up, sits almost horizontal (3 o'clock or 9... I forget which way it goes). Maybe 15 minutes or so lower. And it takes a very short time to get there. Maybe a 1/4 mile.

That seems normal; I asked because if the thermostat was stuck open, or you had the wrong 'stat, or someone removed it for whatever reason, the engine might not easily get warm enough to let the ECU go into closed loop; that would have the same effect as a bad temp sensor.

 

 

My smog place is 3 blocks away. I'd drive it around the block about 4 times and she's showing warmed up.

That may not get the cat hot enough, especially if the mixture's so rich that there's little oxygen in the exhaust. Initially, the exhaust is what warms the cat; but later on, once the cat is approaching normal running temperature, the catalytic oxidation reaction further warms the cat. Insufficient oxygen results in little or no reaction, as I explained above, and a too-cool cat doesn't work well.

 

 

[...]Thanks everyone for sticking with me on this.... I'd be lost without you guys here.

You're welcome; hopefully we'll help you get to the bottom of this.

[OB99W]

Since there haven't been new posts in this thread since my last one, I thought I'd give it a bump and propose another couple of possibilities.

 

First, was the 02 sensor replacement done with an OEM unit? Non-OEM might not be giving the ECU proper data.

 

Secondly, I'm wondering if the engine is just somewhat "tired", and burning a bit of oil. From http://www.ultimatesubaru.org/forum/showthread.php?t=74169 (when the timing belt was mispositioned on one bank), "Ran compression test today. All four plugs were sooty black. Compression rates all rose fairly quick and were 130, 125 on one side, and 105,105 on the other. When I squirted oil in the 105's they both went up to exactly 120.".

 

From the above, the "good" bank actually seems pretty low; more typical compression is about 170 lbs. It has to be done on a warmed engine, with the throttle plate held wide open. Crank with a remote starter switch; if you have to use the ignition switch, unplug the coil pack input connector and electrically disconnect the injectors. If the "dry" pressure doesn't come up to near 170 lbs on each cylinder, retest "wet" to get a better idea of what might be causing the low numbers.

 

I'm thinking about oil-burning because that could have fouled the cat as well as partially explain high exhaust HC numbers. In a three-way converter, NOx (nitrogen oxides) are reduced, which frees up some oxygen. If the NOx reduction isn't happening, there's less oxygen available for the oxidation portion of the cat to work with.

 

Anyway, there's another idea for someone to .

[salewit]

Well I'll be working on this thing today and I could do another compression test. That test was done before the valve timing was corrected. The O2 sensor is not an OEM. But this sensor was changed to the same non OEM (Bosch with the funky wire connector system) a few years ago, and it passed smog with no problem. By the way, when disconnecting the cats and the O2 sensor which is brand new... maybe 15 minutes of running time on it, it is sooty black already.

 

Let me ask this... there is no way of putting lets say a "Y" on the ECU to see what is feeding it the bad numbers to increase fuel?

 

The service place I picked to diagnose my problem is a Valuestar repair shop which means it's highly rated for satisfaction. They've also been in business for a long time. Not that any of this means a whole lot, it does lead me to believe that if customers are happy with their repair work, they're getting things done right the first time. Just my assumption.

 

 

But today I will put the cats back together, run the fuel compression test and then the engine compression test. I'll report back.

[salewit]

Okey doke... I reinstalled the cats, got a fuel gauge and hooked it up between the fuel filter and the fuel rail. Even 27psi at idle. Removed vacuum hose on the regulator and it jumped up to 36. Pinched return line for a second and it jumped up real high. Shut engine off and checked gauge after 5 minutes and it is dead on 30psi. According to my book, the "hold" after 5 minutes test can detect leaking fuel lines, bad regulator, leaking fuel injectors or a fuel pump. The specs in my book call for 26-32 normally, 32-38 with vac line disconnected from regulator, and 30 hold press. All 3 numbers I got are exactly where they should be, so I think it's safe to rule this one out.

 

 

I started the engine again and let it warm up for awhile. I then shut it down, propped open the throttle full, pulled the plugs, pulled the injector connectors, and pulled the harness on the coil. I cranked 7 turns on each one. All 4 cylinders jumped immediately on the gauge. #1 was 180, #2 was 185, #3 was 195 and #4 was 180.

 

Now I'm more depressed than ever. No matter what I check, everything is checking out. I took a picture of the plugs, and they are not as fouled as I remembered them. It's hard to see in the picture, but basically the plugs are sooty black except for the tip. Any possibility with all the things I've changed, I fixed the problem, but just never got it hot enough for smog check? Hmmm but then the repair shop also got high numbers too and you'd think they'd know enough to get things warmed up.

 

 

Oh and I re-read your previous post. We've been using this car for about a year until I was of course forced to get the smog test. In that year, we had to put in a quart of oil from time to time, but I certainly wouldn't classify it as an oil burner. An oil leaker maybe....

[OB99W]

Well I'll be working on this thing today and I could do another compression test. That test was done before the valve timing was corrected.

I realized that the timing was wrong on one bank, but thought it was correct on the other and therefore the compression readings might be trusted for those 2 cylinders.

 

 

The O2 sensor is not an OEM. But this sensor was changed to the same non OEM (Bosch with the funky wire connector system) a few years ago, and it passed smog with no problem.

Could still be enough "off" so that it's contributing to the problem. However...

 

 

By the way, when disconnecting the cats and the O2 sensor which is brand new... maybe 15 minutes of running time on it, it is sooty black already.

 

Let me ask this... there is no way of putting lets say a "Y" on the ECU to see what is feeding it the bad numbers to increase fuel?[...]

...one key to the problem is whether the ECU is going to closed-loop operation. If you have a way to look at the O2 sensor output in real time (have or can borrow an oscilloscope?), you could easily see if/when closed-loop is entered -- the voltage will rapidly switch low-to-high and back, several times per second. If it's not, then it would be good to look at what sensor input, etc., might be causing that.

 

 

Okey doke... I reinstalled the cats, got a fuel gauge and hooked it up between the fuel filter and the fuel rail. Even 27psi at idle.[...]

It does seem that the fuel pressure regulator is okay and injectors aren't leaking based on what you found.

 

 

I started the engine again and let it warm up for awhile. I then shut it down, propped open the throttle full, pulled the plugs, pulled the injector connectors, and pulled the harness on the coil. I cranked 7 turns on each one. All 4 cylinders jumped immediately on the gauge. #1 was 180, #2 was 185, #3 was 195 and #4 was 180.

Those look like good compression numbers -- high as would be expected in a healthy engine, and not too much variation from one cylinder to the next. If they all came up at about the same rate (number of cranks), even better.

 

 

Now I'm more depressed than ever. No matter what I check, everything is checking out.[...]

Finding things that are right isn't necessarily bad ! The current compression readings and steady/high vacuum you previously reported are encouraging in terms of the overall health of the engine.

 

 

Any possibility with all the things I've changed, I fixed the problem, but just never got it hot enough for smog check? Hmmm but then the repair shop also got high numbers too and you'd think they'd know enough to get things warmed up.

Have you been able to run the car enough to determine what gas mileage you're getting now? That can be a good indicator of just how rich the mixture is. I'm still concerned about the "zero" O2 reading, perhaps even more than the elevated HC and CO; as I mentioned before, the cat can't oxidize without oxygen.

 

 

Oh and I re-read your previous post. We've been using this car for about a year until I was of course forced to get the smog test. In that year, we had to put in a quart of oil from time to time, but I certainly wouldn't classify it as an oil burner. An oil leaker maybe....

I doesn't take much oil over a period of time, especially if the cat was also being attacked by unburned fuel due to the valve timing problem, to foul the catalyst. About how many miles passed between those added quarts? (I realize this may be a "red herring", but I'm trying to cover all bases.)

[salewit]

...one key to the problem is whether the ECU is going to closed-loop operation. If you have a way to look at the O2 sensor output in real time (have or can borrow an oscilloscope?), you could easily see if/when closed-loop is entered -- the voltage will rapidly switch low-to-high and back, several times per second. If it's not, then it would be good to look at what sensor input, etc., might be causing that.

 

I don't know anyone that would have a scope unfortunately. I'm guessing they don't rent those anywhere.

 

Have you been able to run the car enough to determine what gas mileage you're getting now? That can be a good indicator of just how rich the mixture is. I'm still concerned about the "zero" O2 reading, perhaps even more than the elevated HC and CO; as I mentioned before, the cat can't oxidize without oxygen.

 

Well the big problem is that I now have an expired tag on my plate. Leaving the car on the street I already got two tickets for an expired tag. I got an extension from DMV but that expired in June. Driving it around risks my getting pulled over and getting more tickets. So the vehicle is in our driveway and it's taking a chance to drive it around. I may check on getting another extension, but I was told that they give you one shot and that's it.

 

I wonder if the zero O2 reading was accurate from the garage? What I don't understand (and I don't really need to), is how they analyze the cat. Aren't they just picking up these readings from the tailpipe? If so, why couldn't the smog place flag this as a bad cat?

 

I doesn't take much oil over a period of time, especially if the cat was also being attacked by unburned fuel due to the valve timing problem, to foul the catalyst. About how many miles passed between those added quarts? (I realize this may be a "red herring", but I'm trying to cover all bases.)

 

It took about a quart every 3 months and the car was used by my wife who is a sales rep and used the car heavily at the time. She also thought it was due to leakage more than burning, but that's what it is.

 

Do you think I just need to take this out on a hot day and on a demanding road with the AC on and just try and blow out all this crap? Can it be that simple? I already did the Seafoam thing early on in the process.

[OB99W]

I don't know anyone that would have a scope unfortunately. I'm guessing they don't rent those anywhere.[...]

Test equipment rental is usually available, but may not be economical. Can you at least get a voltmeter reading of the O2 sensor output? Start with a cold engine, and note both the voltage (should be under one volt) and how steady it is. Take readings as the engine warms versus time and temp gauge indication. Of course, this won't be nearly as useful as with a scope, but maybe something will become obvious. By the way, I'm assuming you can get to the O2 sensor terminals reasonably easily; don't puncture any insulation to make connections. If you can do the above, would it be with a digital or analog meter?

 

Have you ever measured the CTS voltage? I know you've replaced it, but seeing a reasonable change as the engine warms would be reassuring.

 

 

I wonder if the zero O2 reading was accurate from the garage?

Hard to say, and knowing that is important.

 

 

What I don't understand (and I don't really need to), is how they analyze the cat. Aren't they just picking up these readings from the tailpipe? If so, why couldn't the smog place flag this as a bad cat?

I'll keep it simple . Cat efficiency can be determined in several ways. Removing the O2 sensor can provide for a place to sample the exhaust before the cat, and comparison can be made to what's at the tailpipe. Temperature rise from input to output of the cat can be measured. Propane can be injected and levels of HC and CO measured and compared to expected values. Etc.

 

Okay on the oil consumption; it may not be enough to contribute to the problem.

 

Do you think I just need to take this out on a hot day and on a demanding road with the AC on and just try and blow out all this crap? Can it be that simple? I already did the Seafoam thing early on in the process.

Possibly, if the cat just has surface contamination (which is why the O2 levels and determination of closed-loop operation are important to know). However, is it worth risking another ticket? Get enough of them, and the local mechanic may be cheaper .

[OB99W]

One more thought on this -- was the coolant temperature sensor replacement an OEM unit? This is one of those parts where using an aftermarket product may not be satisfactory.

[salewit]

Ok I spent the entire morning on this beast and checked a bunch of things with my digital voltmeter.

 

I checked the throttle position sensor. and had 0 ohms when closed, and it popped to 1 ohm just as soon as I opened it and it stayed at 1 until wide open.

 

Now on the variable rate, I got a little surprise, and I'm assuming my book (Haynes) is incorrect. It says "The voltage should vary from 0.5 to 1.0 volt at closed thorttle to 4.5-5.0 volts wide open". I got the complete opposite. I got 4.6 closed and smoothly went down to 1.0 at full open throttle.

 

The coolant sensor was behaving properly. I had 5v on the harness, and the ohms ranged from 2480 cold to 460 when the engine warmed up and I stopped. According to my book 2480 = 75F and 460 about 158F.

 

 

I checked for 5v on the harness for the MAF, but that was all I was able to check. My book says I'll need a scan tool to check it.

 

On the oxygen sensor, I got bad numbers. I had set a pin in the connector last night, checked continuity between the pin and the connector to make sure I had a connections. Then today with the engine cold, and my meter on the 2 volt scale, I checked voltage on the signal line of the sensor. This is the BLACK line, correct? Everything I'm reading is saying black is the signal line... connected to black on the replacement sensor, and the red and white are the heater lines. Anyway, I checked cold and got .001 volts. I started the engine and my voltmeter didn't budge. After about 5 minutes it sill hadn't budged. I stopped the car, disconnected the connector and checked continuitity with the pin, and there was none. So I set the pin, made SURE it was touching the connector, reconnected and ran the engine and I got .011 volts on the signal line. I checked the pin again and it was good. Plugged it back in and again .011 - .013 volts at operating temperature. I will check it again and even check the Bosch connectors when it cools down. But so far it looks like this sensor is not working.

 

If it IS the sensor, all I'm seeing are replacements. I haven't found any source that has OEM sensors. How important is this? I would like to find one with the connector already on it though. That funky Bosch system I don't like at all.

 

Sam

[Cougar]

Some TPS voltages are reversed so no problem there.

 

I would have thought the O2 sensor wire would be the white one. Did you have 12 volts on the red and white wires?

 

Edit:

After looking into this it looks like the black wire may be correct. The white should be the heater and the red should be ground.

[salewit]

Some TPS voltages are reversed so no problem there.

 

I would have thought the O2 sensor wire would be the white one. Did you have 12 volts on the red and white wires?

 

I didn't check. All I did was check between the BLACK and ground.

 

Check this out: http://www.sparkplugs.com/sparkplug411.asp?kw=Universal+O2+Sensor+Installation+Instructions&mfid=0 and click on the connection chart on the left side. I've got a Bosch.

 

And here: http://www.ultimatesubaru.org/forum/showthread.php?t=43580&highlight=oxygen+sensor+connections

 

The Bosch chart here: http://www.boschautoparts.com/NR/rdonlyres/3BB8A8FA-C707-4333-9098-727C01AF4B7D/0/OxygenSensorInstall.pdf is totally useless.

 

But here's the schematic from my book which confuses me more... it looks like the WHT is the signal... which would mean the O2 sensor has been hooked up wrong!

[OB99W]

Some TPS voltages are reversed so no problem there.[...]

That's right; see page 5 of: http://endwrench.com/images/pdfs/Fuel.pdf

[salewit]

Hmmmm you know I think I do have this O2 sensor installed wrong. I disconnected the connector, and measured 12V on the black and red with the engine cooled.

 

So the question is did I fry the sensor or should I try connecting it properly? How would I know if it's good? Also, could this have ruined my cats? If so, which one if not both?

[Cougar]

Well after looking at your provided print it looks like you need to tie the black wire of the sensor to the white wire coming from the ECU. You could see if the red heater wire on the sensor ties to the body of the sensor using your ohmmeter. Though if you had the heater wire backwards it should have blown the fusible link.