landofopus Posted July 18, 2011 Share Posted July 18, 2011 Hey all, I have a 1997 Legacy Wagon, 2.2 Automatic. I've had a vibration in Drive at idle for a month or more now. There is a much lesser vibration in Park and Neutral, but it's still there. Anything above idle seems ok except for a slight hitch once in a while, like a slight misstep. So far I have tried: Checking for vacuum leaks Checking for broken or loose CV axles Cleaning the IAC valve Changing the spark plugs with NGK plugs Changing the spark plug wires with OEM Subaru wires Replacing all the vacuum lines Checking for a leak in the brake booster line, including using the E-brake to see if having your foot off the brake did anything Checked the engine mounts (as best I could). Transmission shop is checking them on Tuesday, along with the trans. Listened for fuel injectors Checked the TPS. One other thing, I had a P0420 code come on a couple weeks ago. I checked the O2 sensors using the bench test (with a torch and multimeter) and they both passed. I also tested the cats using the vacuum gauge test, and there was almost no PSI on either side of both cats, so they're not restricted. I think that's what that means, anyway. Right? I cleared the code after that and it hasn't come back since then. Ok, last thing. Checked the coil just now. The Haynes book says that for a Diamond it should be: Primary: 0.62 - 0.77 ohms Secondary: 17.9 - 24.5 I got 0.9 to 1.0 on one terminal and 0.8-0.9 on the other. They both fluctuate. Secondary was 14.3 for 1-2 and 14.8 for 3-4. At first I thought I had a Hitachi since those values are in spec for secondary and allllllmost in spec for primary. My question is, I definitely have a Diamond. Is my coil definitely bad? The book says if the numbers aren't in spec, replace it. If the answer is yes, is it ok to go to Autozone or O'Reilly's and get aftermarket? Autozone has Duralast, O'Reilly's had some other brand. I'd prefer to take care of this ASAP and not order something online. Thanks in advance! opus Link to comment Share on other sites More sharing options...
Fairtax4me Posted July 18, 2011 Share Posted July 18, 2011 Coil sounds fine. When a coil fails you typically get no spark on one half of the engine (front or rear). You covered all of the basics. Try the Seafoam treatment. Run some through the intake by way of the idle control valve. Pour the rest in the gas tank to help clean the fuel system. You have a vacuum gauge, did you hook it up to the intake to see engine vacuum at idle? Link to comment Share on other sites More sharing options...
landofopus Posted July 18, 2011 Author Share Posted July 18, 2011 Coil sounds fine. When a coil fails you typically get no spark on one half of the engine (front or rear). You covered all of the basics. Try the Seafoam treatment. Run some through the intake by way of the idle control valve. Pour the rest in the gas tank to help clean the fuel system. You have a vacuum gauge, did you hook it up to the intake to see engine vacuum at idle? Thanks for the reply. I ran Seafoam through the IAC first, when that didn't seem to make a difference I took the IAC off and used throttle body cleaner. I also cleaned the throttle plate at the same time. I've already run 10 Oz Seafoam through the gas tank. Vacuum gauge to the manifold shows 22 In-Hg (or whatever the unit is, can't remember at the moment. Revving to 2500 raises the value to 24-25, letting off the throttle drops it down to 20 or so, then it comes back to 22. You're not worried about the very off-spec coil values for a Diamond coil? Link to comment Share on other sites More sharing options...
landofopus Posted July 18, 2011 Author Share Posted July 18, 2011 One other thing, I didn't take the IAC valve off when the car was warm since I wasn't sure about the coolant spraying out. Do I need to do that for a true test? Book says it should be fully closed when warm. Link to comment Share on other sites More sharing options...
BigMattyD Posted July 18, 2011 Share Posted July 18, 2011 As far as the vibration is concerned, what about checking the engine and transmission mounts? Link to comment Share on other sites More sharing options...
landofopus Posted July 18, 2011 Author Share Posted July 18, 2011 As far as the vibration is concerned, what about checking the engine and transmission mounts? I put the car on jackstands then slightly lifted the engine up a little. I didn't see anything obviously wrong, no broken mounts or anything. I wasn't really sure what good mounts were supposed to be like, so they could possibly be bad. The dogbone off the firewall seems ok. We're taking the car in for a transmission inspection/drive test tomorrow afternoon and they are supposed to check the mounts. I'll know then. Link to comment Share on other sites More sharing options...
landofopus Posted July 18, 2011 Author Share Posted July 18, 2011 I'm still really curious about those coil values. Is it ok to be that far off, then? Link to comment Share on other sites More sharing options...
johnceggleston Posted July 18, 2011 Share Posted July 18, 2011 I'm still really curious about those coil values. Is it ok to be that far off, then? it is possible that the haynes manual has the values mis-labeled. get a copy of the FSM and find the values there. but i would look else where before i replaced the coil or wasted much time with it. http://www.main.experiencetherave.com/subaru_manual_scans/ Link to comment Share on other sites More sharing options...
landofopus Posted July 18, 2011 Author Share Posted July 18, 2011 it is possible that the haynes manual has the values mis-labeled. get a copy of the FSM and find the values there. but i would look else where before i replaced the coil or wasted much time with it. http://www.main.experiencetherave.com/subaru_manual_scans/ FSM shows max of .73 +- 10%, which means a max of 803. I have one terminal fluctuating between .9 and 1.0, the other is fluctuating between .8 and .9. Both are out of spec according to Haynes and the FSM. Seems like the few replies here have indicated it not being a major concern, though. Subaru OEM is $130, U-Pull-it has one for $59. Link to comment Share on other sites More sharing options...
johnceggleston Posted July 18, 2011 Share Posted July 18, 2011 it sounds like you have convinced your self that the coil is out of spec. if that is the case, i would suggest that you buy a used one and try it. you can test it as well. if it helps you are good, if it does not help you have only spent 60$. hopefully the coil is the solution. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted July 18, 2011 Share Posted July 18, 2011 (edited) Idle vibration in drive with the auto's is almost always the rear transmission mount. Very common. You can swap that coil out but it won't make any difference - those numbers are just fine and will fire the plugs all day long. General rule of thumb with coils is that the primary side is about 1 ohm and the secondary is about 10k to 15k ohms. You are easily within any reasonable spec - and the fact that it runs and your problem is at *idle* means it's not an ignition problem - if you were having weak spark you would experience a loss of ignition durring hard acceleration when cylinder pressure's are highest and would tend to prevent a weak spark from jumping the plug gap. P0420 code is from bad sensors, bad cat's, exhaust leaks, rotten/missing heat sheilds, or aftermarket headers without head sheilds. You have to keep the exhaust gasses AND the heat inside the system or the cats just won't work at full effeciency. GD Edited July 18, 2011 by GeneralDisorder Link to comment Share on other sites More sharing options...
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