DaveT

In my experiences with a number of EA82 wagons - If you run low on coolant, and over normal operating temp, the head gasket/s get damaged. How fast they fail to the point of unusable varies widely. From immediately, to a few months. From the first time, every low coolant over normal event accelerates the failure. Check for air in the upper hose and level in the tank before every drive until you know the system is staying 100% coolant, no air gurgling. Do not open the cap to check the coolant in the radiator, squeeze the upper hose, and listen for air gurgling, and the jiggle pin in the thermostat.

I had one with that configuration. Made the slot longer, got the next shorter belt.

There are at least a few connectors in the path.. the pins can get loose or loos their springy ness and make poor contact. If you find a melted connector, both ends likely need replaceing.

I figure a +/- 30 year old CTS doesn't owe anyone much.... It's an electronic sensor that gets a thermal cycle every time you run the car. The one I had fail since 1988 made for random crummy running & drive ability. It wasn't out of the range limits so I had no ECU code.

Is there a particular type of silicone hose to look for - I was looking for some a while back, and was having a hard time finding any that stated that it could handle stuff that can be found in vacuum lines - oil vapor, fuel vapor, etc... Or am I just being too picky? I know, fuel isn't typically in there.

The engine harness combines all the wiring on the engine, goes through 2 connectors to the harness on the body. That goes into the passenger compartment. .. kind of behind the fuse box. Iirc, when I found the broken wite, I was using an ohm meter on the wire - one lead on the ECU connector, one on the sensor connector. Wiggling the engine harness turned up the area if the break. I got lucky.

Definitely check the wire and connectors. I've seen wire break inside it's insulation inside the harness.

To read the codes that are currently flagged - just leave them unconnected. If the CEL is on, the codes are being flashed on the LED on the ECU, which is bolted to the bottom of the steering column. You have to remove the plastic kick panel to see the hole where the LED is hidden. Long flashes are the tens place, short are the 1s. If there are more than one code, they are flashed sequentially, and repeated.

There is a related thread on tuning EA82 engines on this forum. There are links to many threads about the attempts and failures to get any kind of power increase with this engine. The ECU is the first gen OBD system, so very simple. Reading the blinks from the LED on the ECU is about it for diagnostics. It will set the CEL for blatant failure of a sensor or solenoid, but will not catch a sensor that is wrong but inside the normal range of data.

Back when EA82Ts were fairly common, I read lots of threads where people were trying to tweak them. They would spend lots of time and or $ to get maybe small gains while trading off reliability, which there wasn't a lot of to spare. Long ago, I decided reliability is more important. And if I ever were to spend the time to try to get more power, it would be through an EJ22 swap, because for the amount of time and $, you get far more HP gain AND reliability than any of the other tried and failed to varying degrees other options.

Look for used parts. Lots of parts for these models are NLA, so, keeping an eye out for parts cars, extras from when someone decides to move to something newer, etc. The nut should be around 150ft lbs torque, and then cotter pin. It's also good to go somewhere, then re check after 10 miles or so, just in case. The differential is just a plain open diff, so if one side has no load, it spins, and the other side gets no power.

The 2WD vs 4WD power routing is done in the transmission, after the clutch. The most common won't move in 2WD problem is a stripped hub - due to the axle nut not tight enough. Theoretically, a failed CV / axle shaft, or a differential problem could also cause similar results, but I don't remember seeing a thread about that.

I have not had to troubleshoot one, but yeah, check those connections. Measure the voltage from each to the body, and across the 2. The car will have to be on to get meaningful readings.

There are wiring differences between 1990 and 1987.. when you go back further, the differences get more significant the further back you go.

I haven't had enough different CTS failures to have a solid answer for that. I did have another problem once that seems similar - the car wouldn't idle. Had to hold the throttle to keep it idling. It was also intermittent. Turned out to be the wire in the engine harness that goes to the Idle Air Control Valve. If that coil doesn't get drive, or it's dead, no [or not enough] idle air.

The CTS testing ok only at cold temp doesn't mean it is good.

In general, for EA82s, you want to start collecting spare parts whenever you find them. Many are NLA from Subaru or the aftermarket.

I just took a look at my 2. And remembered that the TPS I took apart was on an intake that was off the engine. I would unbolt the A/C compressor, and swing it out of the way if I had to get one off an assembled engine. The hoses are long enough.

One way the CTS can fail is to read incorrectly when hot. If the engine temp is not reported correctly to the ECU, it will not trigger the injector to supply the correct amount of fuel. The result is running poorly. A cold engine needs a lot more fuel to run well. A hot engine will not run well with that higher amount of fuel. I had a CTS fail so it randomly varied making all sorts of drivability problems. But it never went out if range to trip a code.

Here is my compilation of CTS data - Subaru CTS temps.rtf

I check the CTS with an ohmmeter. Run the engine till normal operating temp. Shut off. Log the temp immediately, and several time on the way back down. If you don't have one of those IR thermometers, a meat thermometer works, just have to mechanically connect its sensor to the block. Fill one of the unused holes with grease, stick it in kind of thing. I have a few threads with temps vs ohms I made from values I collected of the years. That other small sensor looks like the one on my CA car - it just verifies that the EGR is actually opening by measuring the heat in the passage.

A bad CTS can cause major drivability problems. And also, not nesisarily trigger a fault code. Fuel pressure is critical also, T a gauge into the line after the filter under the hood. Iirc, it has to be 21 psi minimum.

Check the coolant temperature sensor also. I have not had a problem with a TPS. I took one apart recently, they are incredibly well made. Been running and maintaining EA82 powered wagons since 1988.

+1 regarding the green connector and test mode.

Check all the fuses? Or at least that the ECU and coil gets power.