Time to play "Which sensor's broken?"!!!

[SVX10]

Originally Posted by TomsSVX

Low mileage does not always mean better IMHO

It is pretty simple to check the timing marks, just remove the two end covers (4 bolt each) and get the marks on the gears to match the ones on the cover. Don't worry about the marks on the belt or on the crank yet.

If they line up, its time to pull all the belts and center pulley to check the timing between the crank and the cams. If this is good, it is time to pull the timing belt and cam gears to make sure they are not worn out.

Tom

Pardon my repetitiveness, but wouldn't worn cam gears prevent a perfectly smooth idle when cold? This is pretty invasive stuff you're recommending and doesn't seem to be a possible cause given the symptoms. Am I mistaken in my assumption that incorrect timing would cause crappy idle warm or cold?

Did you have a chance to ship the sensors yet? I really appreciate you letting me test with those.

[SoCal LS-L]

If your is like mine, the pass. side timing cover is a PITA to remove since the power steering return hose and charcoal canister are in the way.

Someone mentioned a wrong CTS, but you already stated it stalls even when the CTS is disconnected.

Hopefully one of the sensors Tom sent was the CPS so we can rule that out.

[TomsSVX]

Yes/No its a funny thing that I had a lot of trouble explaining as well. Sometime the car would run fine... others, it would run like ****. The only thing that could make the RH bank of the engine miss is this problem. The Cam angle sensor would scatter the cylinders to both banks based on the firing order and how the Cam angle sensor operates. The crank angle sensor would drop all cylinders' spark and fuel.

So if the issue is secluded to the RH side of the engine you either have an intermittent power issue to the RH coils OR an issue with the cam timing.

Tom

[SVX10]

Well, re-checking the timing will be high on the list then since the timing belt was recently changed. I checked it 3 times to ensure that everything lined up before I re-installed the covers and crank pulley, but who knows.

I'm really hoping the OBD1 reader gave the answer of crank position sensor. Did you have a chance to mail those yet, Tom?

[SVX10]

Originally Posted by SoCal LS-L

Another thing could be the Auxilary Air Control valve sticking, I believe this valve provides the extra air to increase your cold idle speed. If this valve does not shut when the engine warms up, it will make the engine run too lean causing idling and stalling issues. The bypass air control valve (aka IAC valve) could also be a problem, if its clogged, once the auxillary air control valve closes when the engine reaches normal temp theres nothing else to supply air to the engine without the throttle being pressed, which of course will stall it.

Where is the AAC and how do I check it? My memory tells me that it's connected to one of the tubes connected to the air intake, and I check it by blowing air through said tube to see if it flows freely or not.

I already cleand the IAC valve in the throttle body.

[TomsSVX]

When you did the timing belt did you change the cam seals?

Tom

[oab_au]

Originally Posted by SVX10

Where is the AAC and how do I check it? My memory tells me that it's connected to one of the tubes connected to the air intake, and I check it by blowing air through said tube to see if it flows freely or not.

I already cleand the IAC valve in the throttle body.

The AAC is under the inlet manifold, above No.6 cylinder, has the larger pipe to it.
Should be open when cold, if you turn the Ignition on for a few minutes it should close.
It provides the fast idle for a cold start.

Harvey.

[SVX10]

OK....got some good time with the car tonight with various symptoms to report, all in line with what has been happening.

Started the car. For the first second or 2 it was mis-firing on a few cylinders, but it corrected itself too quickly to ID which ones were mis-firing. I let it warm up for about 2 minutes then unplugged the Coolant Temp Sensor. The idle dropped at that point, but not a bad drop...just settling into a lower idle. I was then able to drive it home (10mi) in this condition, with the sensor unplugged, with no issues. Seemed down on power, and not totally smooth like I'd expect of an H6, but no stalling issues. When I got home, I got under the hood and plugged the CTS back in, and immediately the idle got lower and lower, and right before it was about to die I unplugged the CTS and it recovered. It was a repeatable thing. CTS plugged in = stall. CTS unplugged = run.

So, all the sensors and timing are good enough that it runs on the open loop map. But once it gets plugged in, some signal somewhere is not what the engine wants to see as it tries to enter closed loop operation.

Tom, I did change the cam seals when I did the timing belt. Good question. I'd like to again look at the things that were most recently done on the engine:

1) new plugs
2) new valve cover gaskets
3) new cam seals
4) new rear seal
5) new timing belt

in fact, here's a thread documenting that process and the problems I had back then...
http://www.subaru-svx.net/forum/show...ht=timing+belt
Man...this is bad...it appears that I have no idea what I'm doing here! Some of y'all were helping me way back then, so I appreciate the continued support.

I know we've already been here, but in light of the CTS finding and the knowledge of the 5 things that changed most recently, what are y'all's thoughts? Is there any next steps we can all agree on?

[SoCal LS-L]

I have the low idle problem with very occasional stalling, and my CTS tested with too low resistance for the temperature, AT the CTS itself. You circuit may have even more resistance from age or corrosion, causing the ECU to map for a higher temp reading, which I think is whats going on with mine as well, to a lesser extent.

Can you resistance check your CTS and post the readings here? Its helpful to have an infrared thermometer to correspond to the reading but you can do it in the morning and use the ambient air temp as a rough indicator also. Id like to see what its telling your ECU.

[TomsSVX]

Originally Posted by SVX10

OK....got some good time with the car tonight with various symptoms to report, all in line with what has been happening.

Started the car. For the first second or 2 it was mis-firing on a few cylinders, but it corrected itself too quickly to ID which ones were mis-firing. I let it warm up for about 2 minutes then unplugged the Coolant Temp Sensor. The idle dropped at that point, but not a bad drop...just settling into a lower idle. I was then able to drive it home (10mi) in this condition, with the sensor unplugged, with no issues. Seemed down on power, and not totally smooth like I'd expect of an H6, but no stalling issues. When I got home, I got under the hood and plugged the CTS back in, and immediately the idle got lower and lower, and right before it was about to die I unplugged the CTS and it recovered. It was a repeatable thing. CTS plugged in = stall. CTS unplugged = run.

So, all the sensors and timing are good enough that it runs on the open loop map. But once it gets plugged in, some signal somewhere is not what the engine wants to see as it tries to enter closed loop operation.

Tom, I did change the cam seals when I did the timing belt. Good question. I'd like to again look at the things that were most recently done on the engine:

1) new plugs
2) new valve cover gaskets
3) new cam seals
4) new rear seal
5) new timing belt

in fact, here's a thread documenting that process and the problems I had back then...
http://www.subaru-svx.net/forum/show...ht=timing+belt
Man...this is bad...it appears that I have no idea what I'm doing here! Some of y'all were helping me way back then, so I appreciate the continued support.

I know we've already been here, but in light of the CTS finding and the knowledge of the 5 things that changed most recently, what are y'all's thoughts? Is there any next steps we can all agree on?

There is a possibility the cam bolts have backed out..> Take a look at this http://www.subaru-svx.net/forum/showthread.php?t=45408


Tom

[SVX10]

I don't really follow what's going on in those pics. Please explain

I also seem to remember that even though I got NGK plugs, they were cheap. I don't recall spending $10 each...seems to me they were more like $2 each @ Checker. After reading about our engine's sensitivity to plugs, I'll start there as a next step.

So, my approach from this point is
1) clear stored codes and re-check and hope my car will simply tell me what's wrong.
2) check timing belt - make sure it's all aligned properly
3) check CTS resistance @ ambient and @ operating temp
4) replace Cam/Crank sensors with test sensors provided by Tom
5) replace spark plugs

If all of that comes up empty, then I'll pull the crank pulley and start to look in more detail at the cams

[SoCal LS-L]

Save yourself some time and dont worry about the plugs.... I got the correct type NGK plugs and they were only about $2-3 a piece.

Based on your original post, I wouldnt do anything at all until you have a chance to swap out the sensors that Tom's sending.

If this all started after 6-10 months of sitting, is there a possibility that a rat or desert gerbil or something got into your air intake, or gnawed on some wiring ? I had this problem in my truck whilst living in the Mojave desert near Lake Mead. Little bleepers love the cozy recesses and tasty wiring of our cars

[SVX10]

it's possible it's a chew issue, but there's no visual evidence of it. I've gone over the wiring visually.

Could it be a vacuum hose causing this? Haven't gone over all the vacuum lines.

I already ordered the plugs...I'll pull the current ones and make sure they're the right model. If so, I won't bother changing and I'll just sell the new ones to somebody here.

Definitely looking forward to seeing how the sensors from Tom change stuff...

[SVX10]

checked the timing, and it looks to be properly aligned to the timing cover. The only question is whether or not the crank pulley is aligned. I'm assuming it is because the text is centered vertically.

Driver's side


Passenger's side


Crank pulley

[SoCal LS-L]

Err maybe...... there could be a mark on the interior recess of the pulley so you'll need a mechanics mirror to check. I really think the timings ok since your problem only manifests itself in closed loop. As previously mentioned, I think its possible the Curie effect is mokkbarring your crank or cam sensor as soon as they warm up.... guess we will have to see when they arrive.