98 Legacy Outback- hard start and rough idle

[DrRockNC]

Hi all, here are the facts:

 

1998 Legacy Outback, 187,000 miles total; 60K on a CCR engine.

 

Car has been throwing P0303, P0304 codes for years. I gave up trying to fix this problem, never seemed to be a real problem anyway. (Cylinder 3 and 4 misfire)

 

For the past 6 months I've been getting a P0440 code (evap system). Need to fix, just haven't gotten around to it.

 

The problem I am having now started about 3 months ago. On occasion, usually when the car is cold, but not always, it won't start on first key turn. Sounds like it's about to catch but doesn't. Then I turn key again, and it cranks and cranks but won't start unless I press accelerator to the floor. It eventually starts then.

 

Also on occasion, right after starting, the idle can be very irregular. Races up to 3,000, dives down to 700, goes back up to 2,000, etc. After the car gets warmed up (a few minutes) idle settles down to 800 or so and stays there.

 

Could the evap system problem be causing the starting and idling problems? If not, any ideas on what might be the source or how I might track down the culprit?

 

Many thanks!

[Fairtax4me]

Sounds like it might be the engine coolant temp sensor. You can check the resistance of the sensor at different temperatures to see if it's within the proper range. Some searching here should dig up the numbers you need to look for. Or if you have a spare sensor, or a junkyard close by, you can swap in a different sensor and see if it changes anything.

These are also known for the Idle air control motor getting gummed up and causing idle trouble. But I think I'd try the ECT first.

[DrRockNC]

Thanks for the info! Part arrived yesterday, but now the hard part: where IS this coolant sensor? From the schematics I've seen, which are hard to read, it appears to be under the intake manifold. Is this correct? Do I really need to remove the manifold to access the sensor? From what I can tell, that operation is non-trivial. I hope I am making this harder than necessary. Many thanks!

[Olnick]

but now the hard part: where IS this coolant sensor?

 

Not hard at all, it's all here on the USMB. You just have to search a little bit.

 

Here's a thread that may help you (took about 10 seconds to find it):

 

http://www.ultimatesubaru.org/forum/showthread.php?t=109755&highlight=ects+coolant+temp+sensor

 

Good luck.

[Fairtax4me]

You just have to push a bunch of hoses and wires out of the way to get at it.

[bstone]

Clean the throttle plate. Get some carb cleaner and a few rags and clean it for about 10 minutes.

 

Have you ever talked to CCR about the misfires? I wouldn't be happy with that.

[DrRockNC]

Thanks for all the tips. To be honest, I can't remember if I mentioned this to CCR. If I did, I think I was told to change the coil pack or something like that (which I did). The cylinder 3 and 4 misfire seems to be a gremlin that several of us have had a very hard time eradicating (e.g. http://www.ultimatesubaru.org/forum/showthread.php?t=90806&highlight=p0303)

Edited July 25, 2010 by DrRockNC

[bstone]

Did you change the plugs and wires for 3 and 4, using subaru parts?

[DrRockNC]

Did you change the plugs and wires for 3 and 4, using subaru parts?

 

At least twice, maybe three times :-)

[bstone]

At least twice, maybe three times :-)

 

My next guess (if you have already replaced the coil and the ECU) would be a stuck lifter. It's a rebuild, so it's entirely possible.

[DrRockNC]

Thanks for the info. I'm a novice DIY mechanic; how does one go about diagnosing/repairing a stuck lifter. Thanks again!

[SuBrat84]

Knock Sensor! Make sure it's not touching anywhere other than where it's supposed to. (The plastic can touch other parts of the engine and mess things up.) Make sure the mounting surfaces are clean. Also, If you don't have one, find someone with a torque wrench.. DO NOT go past 17 Ft. Lbs. (I Set mine for 15 Ft. Lbs.) So far the problem has not re-occurred since I adjusted the knock sensor!

[DrRockNC]

Knock Sensor! Make sure it's not touching anywhere other than where it's supposed to. (The plastic can touch other parts of the engine and mess things up.) Make sure the mounting surfaces are clean. Also, If you don't have one, find someone with a torque wrench.. DO NOT go past 17 Ft. Lbs. (I Set mine for 15 Ft. Lbs.) So far the problem has not re-occurred since I adjusted the knock sensor!

 

 

Interesting. I actually got a knock sensor code a few months back and replaced the sensor. I was careful about the torque, etc. and the code hasn't come back. Now, if I could only remember if my rough start/idle issues began before or after that. I think before... Or were you talking about this as a cure for the misfire issue?

 

Thanks!

[SuBrat84]

I was referring mostly to misfires.. I was having the same problem but mine was 1&3. Adjusting the knock sensor seems to have fixed it. As far as the erratic idle I would work on tracking down the P0440 code... Evap Emissions could be a lot of things.. vacuum leak.. clogged pcv system.. dirty sensor in the intake.. Check real close from as many angles as you can all the hoses attached to the air box.. (Below and behind especially!) Do a search on here about Seafoam.. cleaning up your intake might help. I'm not sure if these cars have a "fast-idle-air-control valve/sensor" like my honda (that had that same problem) does.

Worst case scenario you can always pay a Subaru dealer $95 to tell you what the specific problem is. (Make sure you get them to agree BEFORE-HAND you want the problem diagnosed, and not just the code read!)