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Hi,

 

I recently purchased a 92 Legacy, 2.2,  FWD automatic with 95K on the odometer. When I got it, I noticed it idled high (1200-1400 rpms) when cold and then once it warmed up it idled around 750-800 rpm's. I installed a new set of plugs and wires, cleaned the throttle body up with some carb cleaner, checked for vacuum leaks (didn't find any) and no change.

 

I also noticed the dreaded crankshaft pulley wobble... pulled the timing covers, replaced the woodruff key, center timing sprocket, front oil seal, timing belt, all the pulleys and put another crankshaft pulley on it...thankfully no damage to the crankshaft. While I was doing all this work I noticed the ignition igniter had a crack in it and replaced it as well. Work was completed last weekend and I still had the same idling issues until I went to start it up Weds. morning, it took me about 5 minutes to fire it up whereas on every previous occasion it would fire up immediately upon turning the key. Once I finally got it started, the check engine light was on....solid light, no flashing...no check engine light before Weds. morning. High idle issue has gone but now it idles rough and is hard to start when cold.

 

Any ideas?   

 

I don't want to start replacing sensors or other parts at random hoping to fix the problem. Any help that the forum could provide would be greatly appreciated!

 

Mike

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I'm guessing whatever the check engine light is for will be a great clue as to what the problem is.  You probably have something like the IACV unplugged. For what it's worth, a high idle when cold is 100% how it's supposed to work. It's done that every day since it was brand new.

 

It's a little 4 cylinder, it's going to idle a bit high when cold. As long as it comes down when it's warmed up, you have nothing to worry about.

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I noticed it idled high (1200-1400 rpms) when cold and then once it warmed up it idled around 750-800 rpm's.

 

This is perfectly normal behavior for these engines. They are supposed to idle higher when first started in colder weather - the colder it is, the longer it will maintain that higher idle.

 

you do need to find out what the code is for the CEL - that will point you in the right direction.

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Took the car to the dealer for a diagnostic, they pulled the following codes:

 

21- Coolant Temp Sensor

13- Cam Angle Sensor

31- Throttle Position Sensor

 

They recommended replacing the Coolant Sensor and then driving it for a few days to see if the issue was resolved, so I had them install one while I was there. I got about 3 miles down the road and the car lost power, pulled over and car started right back up. This happened about 5 times while on the way home, after the first instance I called the dealer and they said to replace the Cam Sensor.  

 

I know that the 90-94 Legacy's are compatible but are there any other years that will work? I know that the new sensors are a 2 piece unit; sensor and removable wiring harness vs the old one piece sensor wiring harness. I've heard that some of the Cam Sensors for some of the 95-99 cars will work but I haven't been able to confirm this, the difference in cost is about $100. Anybody have access to an interchange manual? 

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Well it really comes down to the fact that 90-94 uses a variable reluctor sensor, whereas the later models use a hall effect sensor. All EJ blocks and heads are designed to accept either kind of sensor, and cam/crank sensors are the same. Which is pretty damn amazing on Subaru's part, to be honest. Find me any other manufacture that thought that far ahead. Makes swapping things around a dream.

 

However, it puts the onus on the end user to buy the correct sensor for the application.

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All EJ blocks and heads are designed to accept either kind of sensor, and cam/crank sensors are the same. 

 

^ Are you saying the cam sensor is identical to the crank sensor?

 

 

 

@ilvbugs  To avoid potential money pit, you can get many sensors/parts at rockauto.com. You'll typically save a TON over dealer pricing, though the TPS and cam sensor for yours are stupid expensive. Also, these sensors are easy to replace, so unless you like throwing away $100 for hourly charge + whatever the sensor costs, you can typically buy it and install in 10 minutes with basic hand tool..

 

The cam sensor at RA is pricey, but I'm guessing it's way better than the dealer's price.  http://www.rockauto.com/catalog/x,carcode,1269558,parttype,7192

 

Other option is get one used.

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^ Are you saying the cam sensor is identical to the crank sensor?

 

Yep! Now I don't know about the 90-94 stuff, since the way a VR sensor works they might have used a different one for cam and crank.

But the receptacles in the block and head are physically the same.

 

And in the world of obd2 engines and hall effect sensors, cam and crank sensors are the same thing.

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987687- Thanks for providing some clarification on the different types of cam sensors used by Subaru.

 

I went to the junkyard this week and bought 2 cam sensors and 2 TPS Sensors (1/2 price sale, got all 4 sensors for under $30). I installed one of the cam sensors, no change, installed the other one, same result. I changed the fuel filter and replaced the cracked inlet hose to rule out a clogged fuel filter. 

 

Question 1: Do I need to reset the ECU after installing a sensor?

Question 2: Is there a test I can perform on the cam sensor before installing it to ensure that it's good?

 

I've found a test that can be done to check out the TPS, going to do that tomorrow. If that checks out, I'm going to pull the MAF off of my 93 Legacy and see if that does anything, if not I've got a spare fuel pump in the garage.

 

I really appreciate all the help that everyone has provided, this issue is frustrating the hell out of me. I've owned 3 other Legacy's all 200K + mile cars and they've never had an issue like this.

 

The irony is that I bought this car from a 93 yr old lady, who bought it new and had it serviced at the local dealership it's whole life. I was able to get a copy of all the service records when I was there on Monday having the CEL codes pulled and she took really good care of it. It's never had any major problems until now. 

 

Anyway, I'd appreciate any suggestions that will help get to the bottom of this.

 

Thanks!

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have you changed the coolant temp sensor yet?

 

If not - highly recommend you do so - before messing with the other sensors. Always start with the first code, address that issue, reset, and drive to see what comes back (if anything)

 

Disconnect the battery for 30 mins or so to reset the ECU.

 

you can read codes yourself - dont need to take to a dealer to get them.

 

If you need instructions to retrieve the codes, just ask.

Edited by heartless
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I a'm never changing sensers other than O2s subaru sensers fail very rarely but they have all sorts of wire harness problems but very few senser problems. 95 % of the time is a broken wire or power feed problem. Ex had a 01 outback Tps code over and over the customer had put 3 sensers in car still tps code changed engine wire harness problem gone and never came back was a broken wire somwere in engine harnes. It had passed all contanuity tests and muti meter tests anyway is good idea to check out wireing before blaming sensers

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have you changed the coolant temp sensor yet?

 

If not - highly recommend you do so - before messing with the other sensors. Always start with the first code, address that issue, reset, and drive to see what comes back (if anything)

 

 Coolant temp sensor was replaced at dealership when I had the codes checked. I'm assuming that the ECU was reset @ that time. I'll try to reset the ECU again since I've changed the cam sensor. 

 

The check engine light isn't flashing so I can't tell if there are any new codes, so I'm going by what the dealer told me at this point. I also understand how to read the codes if the CEL is flashing but it's not flashing and I've tried to find another shop that has an OBD1 reader for Subaru but no luck thus far.  

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Heartless,

 

Thanks for the link, I was under the impression that those wires were only used to clear the codes, I didn't realize they could be used to pull the codes. Will give it a shot tomorrow and see what it shows. 

 

 

you're welcome. and yes, they do both - reading and clearing, following the procedures outlined.

 

Let us know what you come up with.

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Disconnected the battery last night to reset the ECU. When I got home today I followed the procedure in the link provided by Heartless, with the black wires connected the CEL flashed code 31- Throttle Position Sensor...this was the only code that came up. I tried to do the other diagnostic with the green wires but my car stalled about a 1/2 block from home and I didn't get a chance to finish it. So it looks like I'll be switching out the TPS tomorrow.

 

I know that there is a calibration that has to be done, can someone provide me with the details? I'm not very good at using a multi-tester so if you could be very specific about what setting to select and what readings I should be receiving I'd appreciate it. Also, the terminology will mean nothing to me, so please keep it simple.

 

Thanks again!

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